CN116897508A - Noise reduction circuit, method, device, equipment and optical receiver - Google Patents

Abstract

The embodiment of the application discloses a noise reduction circuit, which comprises: the first signal detection module, the first earthing circuit, the first transimpedance amplifier, the second operational amplifier and the reference voltage generator; the first signal detection module is used for outputting a direct current signal and an alternating current signal; the first grounding circuit is coupled between the grounding end and the output end of the first signal detection module; the first transimpedance amplifier is coupled to the output end of the first signal detection module, and the signal output by the output end of the first operational amplifier included in the first transimpedance amplifier is opposite to the signal received by the input end; the negative input end of the second operational amplifier is coupled with the output end of the first operational amplifier; the positive input end of the second operational amplifier is coupled with the reference voltage generator and is used for receiving the adjustable reference voltage output by the reference voltage generator. The application also provides a method, a device, equipment, an optical receiver and a medium, and the noise value generated by grounding the direct current signal can be adjusted by adjusting the voltage input by the reference voltage generator.

Description

Noise reduction circuit, method, device, equipment and optical receiver Technical field

The present application relates to the field of circuits, and in particular, to a noise reduction circuit, method, device, equipment and optical receiver.

Background technique

In broadband communications, the coherent communication method of heterodyne detection in radio digital communication systems is usually applied to broadband communications. Using heterodyne or homodyne detection methods in bandwidth communication systems significantly improves receiving sensitivity and selectivity. Bandwidth communication makes full use of the mixing gain, excellent channel selectivity and adjustability of coherent communication.

However, current broadband communications usually have large input noise, which affects reception performance.

Contents of the invention

Embodiments of the present application provide a noise reduction circuit, method, device, equipment and optical receiver for improving the noise performance of the input receiver.

In view of this, the first aspect of the embodiment of the present application provides a noise reduction circuit, including: a first signal detection module, a first ground circuit, a first transimpedance amplifier, a second operational amplifier and a reference voltage generator; the first The signal detection module is used to output a first DC signal and a first AC signal; the first ground circuit is coupled between the ground terminal and the output terminal of the first signal detection module; the first transimpedance amplifier is coupled to the first The output terminal of the signal detection module. The first transimpedance amplifier includes a first operational amplifier and a first resistor. The first resistor is coupled between the input terminal and the output terminal of the first operational amplifier. The output of the first operational amplifier The signal output by the terminal is opposite to the signal received by the input terminal of the first operational amplifier; the second operational amplifier includes a positive input terminal, a negative input terminal and an output terminal, and the negative input terminal of the second operational amplifier is connected to the first operational amplifier. The output terminal of the amplifier is coupled; the positive input terminal of the second operational amplifier is coupled with the reference voltage generator for receiving the adjustable reference voltage output by the reference voltage generator; the output terminal of the second operational amplifier is coupled with the first The ground circuit coupling is used to adjust the signal coupled from the first ground circuit to the ground.

In this embodiment, since the signal output by the output terminal of the first operational amplifier is opposite to the signal received by the input terminal of the first operational amplifier, and the signal received by the input terminal of the first operational amplifier is the reference voltage generator through the second operation amplifier input, so the reference voltage generator remains equal to the potential of the first transimpedance amplifier. Since the reference voltage output by the reference voltage generator is an adjustable reference voltage, the potential of the reference voltage generator changes with the size of the output adjustable reference voltage. When the potential of the reference voltage generator changes, the first span The potential of the resistance amplifier also changes accordingly, and then the proportion of the first DC signal flowing into the first operational amplifier will change accordingly, resulting in a reduction in the proportion of the first DC signal flowing into the first ground circuit, thereby reducing the DC The noise generated by the signal in the ground circuit improves the overall noise reduction performance.

Optionally, the reference voltage generator includes a third operational amplifier, a first input current source is coupled between an input terminal of the third operational amplifier and a power terminal, and the current size of the first input current source is adjustable.

In this embodiment, since the input current of the first input current source is adjustable, the reference voltage output by the reference voltage generator will change correspondingly with the input current of the first input current source, so that the potential of the reference voltage generator Highs and lows change. Therefore, by adjusting the size of the input current, the proportion of the DC signal flowing into the first transimpedance amplifier can be adjusted.

Optionally, the reference voltage generator includes a third operational amplifier, an output current source is coupled to the output terminal of the third operational amplifier and the ground terminal, and the current size of the output current source is adjustable.

In this embodiment, since the output current of the output current source is adjustable, the reference voltage output by the reference voltage generator will change correspondingly with the output current of the output current source, so that the potential of the reference voltage generator changes. Therefore, by adjusting the size of the output current, the proportion of the DC current flowing into the first transimpedance amplifier can be adjusted.

Optionally, the output end of the first operational amplifier is coupled with an output current source, and the output current source is grounded.

In this embodiment, an output current source is coupled to the output end of the first operational amplifier, and the output current source is grounded. Therefore, the output current source can derive the DC signal flowing into the first operational amplifier.

Optionally, the third operational amplifier is in a proportional relationship with the first operational amplifier circuit.

In this embodiment, the third operational amplifier has a proportional relationship with the first operational amplifier circuit, so that changes in potential on the third operational amplifier will cause corresponding changes in the potential of the first operational amplifier.

Optionally, the first signal detection module includes a first diode PD, and the first PD is coupled to an optical mixer. The Mixer is used to mix the first signal and the second signal and send them to the first PD, optionally, the first signal may be signal light (Signal), and the second signal may be local oscillator light (Local Oscillator). The first PD is used to output the first DC signal and the first AC signal. .

In this embodiment, the Mixer mixes the first signal and the second signal and sends them to the first PD, so that the first PD detects the signal, and then the first PD outputs the first DC according to the mixed signal. signal and the first AC signal, thus realizing the signal input to the sensory noise reduction circuit.

Optionally, the noise reduction circuit is coupled to a variable gain stage, the variable gain stage is coupled to an output driver stage, the variable gain stage is used to amplify the first AC signal, and the output driver stage is used to amplify the amplified The first AC signal is sent to the analog-to-digital sampler ADC.

In this embodiment, the noise reduction circuit, the variable gain stage and the output driver stage filter, amplify and output the signal respectively, thereby realizing the reception and amplification of the signal by the optical receiver.

Optionally, the first ground circuit includes an N-type metal oxide semiconductor field effect transistor NMOS transistor. The gate terminal of the NMOS transistor is coupled between the first signal detection module and the first transimpedance amplifier. The source of the NMOS transistor is The stage terminal is coupled to this ground terminal.

In this embodiment, the DC signal is grounded through the NMOS tube, thereby realizing the grounding derivation of the DC signal. Since the DC signal is adjusted by the reference voltage generator, part of it flows into the first transimpedance amplifier, thereby reducing the flow into the NMOS tube. signal, reducing the noise generated by the passage of DC signals in the NMOS tube.

Optionally, the noise reduction circuit also includes a second signal detection module, a second ground circuit, a second transimpedance amplifier and a fifth operational amplifier; the second signal detection module is used to output a second DC signal and a second AC signal. ; The first ground circuit is coupled between the ground terminal and the positive output terminal of the first signal detection module, the second ground circuit is coupled between the ground terminal and the negative output terminal of the second signal detection module, the ground The terminal and the ground terminal are different ground terminals; the first transimpedance amplifier is coupled to the positive output terminal of the first signal detection module, the second transimpedance amplifier is coupled to the negative output terminal of the second signal detection module, and the The second transimpedance amplifier includes a fourth operational amplifier and a second resistor. The second resistor is coupled between the input terminal and the output terminal of the fourth operational amplifier. The signal output by the output terminal of the fourth operational amplifier is consistent with the fourth operational amplifier. The signal received by the input terminal of the operational amplifier is reversed; the fifth operational amplifier includes a positive input terminal, a negative input terminal and an output terminal, and the negative input terminal of the fifth operational amplifier is coupled with the output terminal of the fourth operational amplifier; the fifth operational amplifier includes a positive input terminal, a negative input terminal and an output terminal. The positive input terminal of the fifth operational amplifier is coupled to the reference voltage generator and is used to receive the adjustable reference voltage output by the reference voltage generator; the output terminal of the fifth operational amplifier is coupled to the second ground circuit and is used to adjust the A second ground circuit couples the signal to ground.

In this embodiment, the first ground circuit, the first transimpedance amplifier and the second operational amplifier constitute the first sub-noise reduction circuit; the above-mentioned second ground circuit, the second transimpedance amplifier and the fifth operational amplifier constitute the second sub-noise reduction circuit. Noise reduction circuit. The first sub-noise reduction circuit and the second sub-noise reduction circuit are connected to the same reference voltage generator through the positive input terminals of the second operational amplifier and the fifth operational amplifier respectively. The reference voltage generator simultaneously supplies signals to the first sub-noise reduction circuit and the third sub-noise reduction circuit. The second sub-noise reduction circuit inputs the reference voltage, so that the adjustment of the reference voltage generator has a mirror effect between the first sub-noise reduction circuit and the second sub-noise reduction circuit. The ratio of the DC signal flowing into the first transimpedance amplifier is the same as that of the second sub-noise reduction circuit. The ratio of DC signals flowing into the two transimpedance amplifiers remains synchronized.

A second aspect of the embodiment of the present application provides an optical receiver, including: a signal light input optical path, a local oscillator optical input optical path, a first optical mixer Mixer, a second Mixer, a first diode PD, and a second PD, The third PD, the fourth PD, the fifth PD, the sixth PD, the seventh PD, the eighth PD, the first transimpedance amplifier stage TIA, the second TIA, the third TIA, the fourth TIA, the first analog-to-digital converter ADC, second ADC, third ADC, fourth ADC and digital signal processor DSP;

The signal light input optical path is used to input two channels of signal light into the first Mixer and the second Mixer respectively;

The local oscillator light input optical path is used to input two channels of local oscillator light into the first Mixer and the second Mixer respectively;

The first Mixer and the second Mixer are respectively used to mix the received signal light and the local oscillator light to obtain a first signal and a second signal;

The first Mixer sends the first signal to the first PD, the second PD, the third PD and the fourth PD;

The second Mixer sends the second signal to the fifth PD, the sixth PD, the seventh PD and the eighth PD;

The first TIA, the second TIA, the third TIA and the fourth TIA respectively include a positive input terminal, a negative input terminal and an output terminal, wherein the first PD is coupled to the positive input terminal of the first TIA, the The second PD is coupled to the negative input terminal of the first TIA, the third PD is coupled to the positive input terminal of the second TIA, the fourth PD is coupled to the negative input terminal of the second TIA, and the fifth PD is coupled to the negative input terminal of the second TIA. The positive input terminal of the third TIA is coupled, the sixth PD is coupled with the negative input terminal of the third TIA, the seventh PD is coupled with the positive input terminal of the fourth TIA, and the eighth PD is coupled with the negative input terminal of the fourth TIA. The input terminal is coupled, the output terminal of the first TIA is coupled with the first ADC, the output terminal of the second TIA is coupled with the second ADC, the output terminal of the third TIA is coupled with the third ADC, and the fourth TIA The output terminal is coupled with the fourth ADC;

The first PD and the second PD are used to output a first AC signal and a first DC signal according to the first signal, and send the first AC signal and the first DC signal to the first TIA;

The third PD and the fourth PD are used to output a second AC signal and a second DC signal according to the first signal, and send the second AC signal and the second DC signal to the second TIA;

The fifth PD and the sixth PD are used to output a third AC signal and a third DC signal according to the second signal, and send the third AC signal and the third DC signal to the third TIA;

The seventh PD and the eighth PD are used to output a fourth AC signal and a fourth DC signal according to the second signal, and send the fourth AC signal and the fourth DC signal to the fourth TIA;

The first TIA, the second TIA, the third TIA and the fourth TIA are respectively used to filter the first DC signal, the second DC signal, the third DC signal and the fourth DC signal. amplifying the first AC signal, the second AC signal, the third AC signal and the fourth AC signal;

The first TIA, the second TIA, the third TIA and the fourth TIA are respectively provided with a noise reduction device, the noise reduction device is used to reduce the first DC signal, the second DC signal, the third DC signal The noise generated by the signal and the fourth DC signal when passing through the first TIA, the second TIA, the third TIA and the fourth TIA;

The first TIA, the second TIA, the third TIA and the fourth TIA are respectively used to transmit the amplified first AC signal, the second AC signal, the third AC signal and the fourth AC signal. to the first ADC, the second ADC, the third ADC and the fourth ADC;

The first ADC, the second ADC, the third ADC and the fourth ADC are used to respectively collect the first AC signal, the second AC signal, the third AC signal and the fourth AC signal and then send them to the DSP;

The DSP is used to process the first AC signal, the second AC signal, the third AC signal and the fourth AC signal.

In this embodiment, through the circuit structure of the above-mentioned optical receiver, the reception, collection, amplification, noise reduction and processing of optical signals are realized, thereby realizing a complete optical receiver receiving process. Among them, due to the TIA-level noise reduction The device can reduce noise in the process of filtering DC signals, thereby improving the overall performance of the entire optical receiver.

Optionally, the noise reduction device includes a noise reduction circuit, which includes: a first ground circuit, a first transimpedance amplifier, a second operational amplifier and a reference voltage generator;

The first ground circuit is coupled between the ground terminal and the first PD, the second PD, the third PD, the fourth PD, the fifth PD, the sixth PD, the seventh PD or the eighth PD. between the output terminals for coupling the signal output by the first PD, the second PD, the third PD, the fourth PD, the fifth PD, the sixth PD, the seventh PD or the eighth PD to land;

the first transimpedance amplifier is coupled to the output end of the first PD, the second PD, the third PD, the fourth PD, the fifth PD, the sixth PD, the seventh PD or the eighth PD, The first transimpedance amplifier includes a first operational amplifier and a first resistor. The first resistor is coupled between an input terminal and an output terminal of the first operational amplifier. A signal output by the output terminal of the first operational amplifier is related to the first resistor. The signal received by the input terminal of an operational amplifier is reversed;

The second operational amplifier includes a positive input terminal, a negative input terminal and an output terminal, and the negative input terminal of the second operational amplifier is coupled with the output terminal of the first operational amplifier;

The positive input terminal of the second operational amplifier is coupled to the reference voltage generator and is used for receiving the adjustable reference voltage output by the reference voltage generator;

The output end of the second operational amplifier is coupled to the first ground circuit and used to adjust the signal coupled to the ground by the first ground circuit.

In this embodiment, since the signal output by the output terminal of the first operational amplifier in the noise reduction circuit is opposite to the signal received by the input terminal of the first operational amplifier, and the signal received by the input terminal of the first operational amplifier is the reference voltage generator is input through the second operational amplifier, so the reference voltage generator remains equal to the potential of the first transimpedance amplifier. Since the reference voltage output by the reference voltage generator is an adjustable reference voltage, the potential of the reference voltage generator changes with the size of the output adjustable reference voltage. When the potential of the reference voltage generator changes, the first span The potential of the resistance amplifier also changes accordingly, and then the proportion of the first DC signal flowing into the first operational amplifier will change accordingly, resulting in a reduction in the proportion of the first DC signal flowing into the first ground circuit, thereby reducing the DC The noise generated by the signal in the ground circuit improves the overall noise reduction performance of the optical receiver.

Optionally, the reference voltage generator in the noise reduction circuit of the TIA includes a third operational amplifier, a first input current source is coupled between the input terminal of the third operational amplifier and the power supply terminal, and the first input current source The current size is adjustable.

In this embodiment, since the input current of the first input current source is adjustable, the reference voltage output by the reference voltage generator will change correspondingly with the input current of the first input current source, so that the potential of the reference voltage generator Highs and lows change. Therefore, by adjusting the size of the input current, the proportion of the DC signal flowing into the first transimpedance amplifier can be adjusted.

Optionally, the reference voltage generator in the noise reduction circuit of the TIA includes a third operational amplifier, an output current source is coupled to the output terminal of the third operational amplifier and the ground terminal, and the current size of the output current source is adjustable.

In this embodiment, since the output current of the output current source is adjustable, the reference voltage output by the reference voltage generator will change correspondingly with the output current of the output current source, so that the potential of the reference voltage generator changes. Therefore, by adjusting the size of the output current, the proportion of the DC current flowing into the first transimpedance amplifier can be adjusted.

Optionally, the output end of the first operational amplifier in the noise reduction circuit of the TIA is coupled with an output current source, and the output current source is grounded.

In this embodiment, an output current source is coupled to the output end of the first operational amplifier, and the output current source is grounded. Therefore, the output current source can derive the DC signal flowing into the first operational amplifier.

Optionally, the first signal detection module in the noise reduction circuit of the TIA includes a first diode PD, the first PD is coupled to an optical mixer Mixer, the Mixer is used to mix the first signal with the second signal. After frequency, it is sent to the first PD. Optionally, the first signal can be signal light (Signal), and the second signal can be local oscillator light (Local Oscillator). The first PD is used to output the first DC signal and the first AC signal.

In this embodiment, the Mixer mixes the first signal and the second signal and sends them to the first PD, so that the first PD detects the signal, and then the first PD outputs the first DC according to the mixed signal. signal and the first AC signal, thus realizing the signal input to the sensory noise reduction circuit.

Optionally, the first ground circuit in the noise reduction circuit of the TIA includes an N-type metal oxide semi-field effect transistor NMOS transistor, the gate terminal of the NMOS transistor is coupled between the first signal detection module and the first transimpedance amplifier. During the period, the source terminal of the NMOS tube is coupled with the ground terminal.

In this embodiment, the DC signal is grounded through the NMOS tube, thereby realizing the grounding derivation of the DC signal. Since the DC signal is adjusted by the reference voltage generator, part of it flows into the first transimpedance amplifier, thereby reducing the flow into the NMOS tube. signal, reducing the noise generated by the passage of DC signals in the NMOS tube.

Optionally, the noise reduction circuit in the TIA noise reduction circuit also includes a second signal detection module, a second ground circuit, a second transimpedance amplifier and a fifth operational amplifier; the second signal detection module is used to output a second DC signal and second AC signal; the first ground circuit is coupled between the ground terminal and the positive output terminal of the first signal detection module, and the second ground circuit is coupled between the ground terminal and the negative terminal of the second signal detection module Between the output terminals, the ground terminal and the ground terminal are different ground terminals; the first transimpedance amplifier is coupled to the positive output terminal of the first signal detection module, and the second transimpedance amplifier is coupled to the second signal detection module. The negative output terminal of the module, the second transimpedance amplifier includes a fourth operational amplifier and a second resistor, the second resistor is coupled between the input terminal and the output terminal of the fourth operational amplifier, the output terminal of the fourth operational amplifier The output signal is opposite to the signal received by the input terminal of the fourth operational amplifier; the fifth operational amplifier includes a positive input terminal, a negative input terminal and an output terminal, and the negative input terminal of the fifth operational amplifier is connected to the fourth operational amplifier The output terminal is coupled; the positive input terminal of the fifth operational amplifier is coupled with the reference voltage generator for receiving the adjustable reference voltage output by the reference voltage generator; the output terminal of the fifth operational amplifier is coupled with the second ground Circuit coupling is used to adjust the signal coupled to the ground from the second ground circuit.

In this embodiment, the first ground circuit, the first transimpedance amplifier and the second operational amplifier constitute the first sub-noise reduction circuit; the above-mentioned second ground circuit, the second transimpedance amplifier and the fifth operational amplifier constitute the second sub-noise reduction circuit. Noise reduction circuit. The first sub-noise reduction circuit and the second sub-noise reduction circuit are connected to the same reference voltage generator through the positive input terminals of the second operational amplifier and the fifth operational amplifier respectively. The reference voltage generator simultaneously supplies signals to the first sub-noise reduction circuit and the third sub-noise reduction circuit. The second sub-noise reduction circuit inputs the reference voltage, so that the adjustment of the reference voltage generator has a mirror effect between the first sub-noise reduction circuit and the second sub-noise reduction circuit. The ratio of the DC signal flowing into the first transimpedance amplifier is the same as that of the second sub-noise reduction circuit. The ratio of DC signals flowing into the two transimpedance amplifiers remains synchronized.

The third aspect of the embodiment of the present application provides a circuit noise reduction method. The method is applied to a noise reduction circuit. The noise reduction circuit includes: a first signal detection module, a first ground circuit, a first transimpedance amplifier, and a second operational amplifier. and a reference voltage generator; the first signal detection module is used to output a first DC signal and a first AC signal; the first ground circuit is coupled between the ground terminal and the output terminal of the first signal detection module; A transimpedance amplifier is coupled to the output end of the first signal detection module. The first transimpedance amplifier includes a first operational amplifier and a first resistor. The first resistor is coupled between the input end and the output end of the first operational amplifier. time, the signal output by the output terminal of the first operational amplifier is opposite to the signal received by the input terminal of the first operational amplifier; the second operational amplifier includes a positive input terminal, a negative input terminal and an output terminal. The second operational amplifier The negative input terminal is coupled to the output terminal of the first operational amplifier; the positive input terminal of the second operational amplifier is coupled to the reference voltage generator for receiving the adjustable reference voltage output by the reference voltage generator; the second The output end of the operational amplifier is coupled to the first ground circuit for adjusting the signal coupled to the ground by the first ground circuit; the method includes: obtaining the first DC signal and the first AC signal output by the first signal detection module ; Adjust the proportion of the first DC signal input to the first operational amplifier by adjusting the adjustable reference voltage output by the reference voltage generator.

In this embodiment, since the signal output by the output terminal of the first operational amplifier is opposite to the signal received by the input terminal of the first operational amplifier, and the signal received by the input terminal of the first operational amplifier is the reference voltage generator through the second operation amplifier input, so the reference voltage generator remains equal to the potential of the first transimpedance amplifier. Since the reference voltage output by the reference voltage generator is an adjustable reference voltage, the potential of the reference voltage generator changes with the size of the output adjustable reference voltage. When the potential of the reference voltage generator changes, the first span The potential of the resistance amplifier also changes accordingly, and then the proportion of the first DC signal flowing into the first operational amplifier will change accordingly, resulting in a reduction in the proportion of the first DC signal flowing into the first ground circuit, thereby reducing the DC The noise generated by the signal in the ground circuit improves the overall noise reduction performance.

Optionally, the reference voltage generator includes a third operational amplifier, a first input current source is coupled between the input terminal of the third operational amplifier and the power terminal, and the current size of the first input current source is adjustable; Adjusting the adjustable reference voltage output by the reference voltage generator to adjust the ratio of the first DC signal input to the first operational amplifier includes: adjusting the first DC signal input by adjusting the input current size of the first input current source. The ratio of the first operational amplifier, wherein the greater the current input by the first input current source to the third operational amplifier, the higher the ratio of the first DC signal input to the first operational amplifier.

In this embodiment, since the input current of the first input current source is adjustable, the reference voltage output by the reference voltage generator will change correspondingly with the input current of the first input current source, so that the potential of the reference voltage generator Highs and lows change. Therefore, by adjusting the size of the input current, the proportion of the DC signal flowing into the first transimpedance amplifier can be adjusted.

Optionally, the reference voltage generator includes a third operational amplifier, an output current source is coupled to the output terminal of the third operational amplifier and the ground terminal, and the current size of the output current source is adjustable; by adjusting the reference voltage generator The output adjustable reference voltage adjusts the ratio of the first DC signal input to the first operational amplifier, including:

The proportion of the first DC signal input to the first operational amplifier is adjusted by adjusting the size of the current flowing out of the output current source. The greater the current value flowing out of the output current source, the greater the input of the first DC signal into the first operational amplifier. The ratio of op amps is lower.

In this embodiment, since the output current of the output current source is adjustable, the reference voltage output by the reference voltage generator will change correspondingly with the output current of the output current source, so that the potential of the reference voltage generator changes. Therefore, by adjusting the size of the output current, the proportion of the DC current flowing into the first transimpedance amplifier can be adjusted.

Optionally, the noise reduction circuit also includes a second signal detection module, a second ground circuit, a second transimpedance amplifier and a fifth operational amplifier; the second signal detection module is used to output a second DC signal and a second AC signal. ; The first ground circuit is coupled between the ground terminal and the positive output terminal of the first signal detection module, the second ground circuit is coupled between the ground terminal and the negative output terminal of the second signal detection module, the ground The terminal and the ground terminal are different ground terminals; the first transimpedance amplifier is coupled to the positive output terminal of the first signal detection module, the second transimpedance amplifier is coupled to the negative output terminal of the second signal detection module, and the The second transimpedance amplifier includes a fourth operational amplifier and a second resistor. The second resistor is coupled between the input terminal and the output terminal of the fourth operational amplifier. The signal output by the output terminal of the fourth operational amplifier is consistent with the fourth operational amplifier. The signal received by the input terminal of the operational amplifier is reversed; the fifth operational amplifier includes a positive input terminal, a negative input terminal and an output terminal, and the negative input terminal of the fifth operational amplifier is coupled with the output terminal of the fourth operational amplifier; the fifth operational amplifier includes a positive input terminal, a negative input terminal and an output terminal. The positive input terminal of the fifth operational amplifier is coupled to the reference voltage generator and is used to receive the adjustable reference voltage output by the reference voltage generator; the output terminal of the fifth operational amplifier is coupled to the second ground circuit and is used to adjust the The second ground circuit couples the signal to the ground; the method further includes: adjusting the ratio of the second DC signal input to the fourth operational amplifier by adjusting the ratio of the first DC signal input to the first operational amplifier, wherein the third The ratio of the two DC signals input to the fourth operational amplifier is synchronized with the ratio of the first DC signal input to the first operational amplifier.

In this embodiment, the first ground circuit, the first transimpedance amplifier and the second operational amplifier constitute the first sub-noise reduction circuit; the above-mentioned second ground circuit, the second transimpedance amplifier and the fifth operational amplifier constitute the second sub-noise reduction circuit. Noise reduction circuit. The first sub-noise reduction circuit and the second sub-noise reduction circuit are connected to the same reference voltage generator through the positive input terminals of the second operational amplifier and the fifth operational amplifier respectively. The reference voltage generator simultaneously supplies signals to the first sub-noise reduction circuit and the third sub-noise reduction circuit. The second sub-noise reduction circuit inputs the reference voltage, so that the adjustment of the reference voltage generator has a mirror effect between the first sub-noise reduction circuit and the second sub-noise reduction circuit. The ratio of the DC signal flowing into the first transimpedance amplifier is the same as that of the second sub-noise reduction circuit. The ratio of DC signals flowing into the two transimpedance amplifiers remains synchronized.

The fourth aspect of the embodiment of the present application provides a broadband receiving device, which is applied to a noise reduction circuit. The noise reduction circuit includes: a first signal detection module, a first ground circuit, a first transimpedance amplifier, a second operational amplifier and A reference voltage generator; the first signal detection module is used to output a first DC signal and a first AC signal; the first ground circuit is coupled between the ground terminal and the output terminal of the first signal detection module; the first The transimpedance amplifier is coupled to the output end of the first signal detection module. The first transimpedance amplifier includes a first operational amplifier and a first resistor. The first resistor is coupled between the input end and the output end of the first operational amplifier. , the signal output by the output terminal of the first operational amplifier is opposite to the signal received by the input terminal of the first operational amplifier; the second operational amplifier includes a positive input terminal, a negative input terminal and an output terminal, and the second operational amplifier The negative input terminal is coupled to the output terminal of the first operational amplifier; the positive input terminal of the second operational amplifier is coupled to the reference voltage generator for receiving the adjustable reference voltage output by the reference voltage generator; the second operational amplifier The output end of the amplifier is coupled to the first ground circuit for adjusting the signal coupled to the ground from the first ground circuit; the device includes:

An acquisition unit, configured to acquire the first DC signal and the first AC signal output by the first signal detection module;

The adjustment unit is configured to adjust the proportion of the first DC signal acquired by the acquisition unit being input into the first operational amplifier by adjusting the adjustable reference voltage output by the reference voltage generator.

Optionally, the reference voltage generator includes a third operational amplifier, a first input current source is coupled between the input terminal of the third operational amplifier and the power terminal, and the current size of the first input current source is adjustable; the adjustment Unit, also used for:

The proportion of the first DC signal input to the first operational amplifier is adjusted by adjusting the input current size of the first input current source. The greater the current input by the first input current source to the third operational amplifier, the greater the input current of the first input current source to the third operational amplifier. The higher the proportion of DC signal input to the first operational amplifier.

Optionally, the reference voltage generator includes a third operational amplifier, an output current source is coupled to the output terminal of the third operational amplifier and the ground terminal, and the current size of the output current source is adjustable; the adjustment unit is also used for:

The proportion of the first DC signal input to the first operational amplifier is adjusted by adjusting the size of the current flowing out of the output current source. The greater the current value flowing out of the output current source, the greater the input of the first DC signal into the first operational amplifier. The ratio of op amps is lower.

Optionally, the noise reduction circuit also includes a second signal detection module, a second ground circuit, a second transimpedance amplifier and a fifth operational amplifier; the second signal detection module is used to output a second DC signal and a second AC signal. ; The first ground circuit is coupled between the ground terminal and the positive output terminal of the first signal detection module, the second ground circuit is coupled between the ground terminal and the negative output terminal of the second signal detection module, the ground The terminal and the ground terminal are different ground terminals; the first transimpedance amplifier is coupled to the positive output terminal of the first signal detection module, the second transimpedance amplifier is coupled to the negative output terminal of the second signal detection module, and the The second transimpedance amplifier includes a fourth operational amplifier and a second resistor. The second resistor is coupled between the input terminal and the output terminal of the fourth operational amplifier. The signal output by the output terminal of the fourth operational amplifier is consistent with the fourth operational amplifier. The signal received by the input terminal of the operational amplifier is reversed; the fifth operational amplifier includes a positive input terminal, a negative input terminal and an output terminal, and the negative input terminal of the fifth operational amplifier is coupled with the output terminal of the fourth operational amplifier; the fifth operational amplifier includes a positive input terminal, a negative input terminal and an output terminal. The positive input terminal of the fifth operational amplifier is coupled to the reference voltage generator and is used to receive the adjustable reference voltage output by the reference voltage generator; the output terminal of the fifth operational amplifier is coupled to the second ground circuit and is used to adjust the The second ground circuit couples the signal to the ground; the adjustment unit is also used for:

The ratio of the second DC signal input to the fourth operational amplifier is adjusted by adjusting the ratio of the first DC signal input to the first operational amplifier, wherein the ratio of the second DC signal input to the fourth operational amplifier is the same as the ratio of the second DC signal input to the fourth operational amplifier. The ratio of the DC signal input to the first operational amplifier remains synchronized.

A fifth aspect of the embodiment of the present application provides an electronic device, including a memory, a processor, and a computer program stored on the memory. When the processor executes the computer program, the above third aspect or the third aspect is implemented. The steps of the method described in any alternative implementation.

Description of the drawings

Figure 1 is an architectural diagram of an optical receiver in an embodiment of the present application;

Figure 2 is a schematic diagram of the signal processing by the diode PD in the embodiment of the present application;

Figure 3 is a schematic diagram of the noise reduction circuit in the optical receiver architecture according to the embodiment of the present application;

Figure 4 is a schematic diagram of the transimpedance amplification stage TIA deriving the DC signal in the embodiment of the present application;

Figure 5 is a circuit diagram of the noise reduction circuit in the optical receiver according to the embodiment of the present application;

Figure 6 is a circuit diagram of an implementation of the noise reduction circuit provided by the embodiment of the present application;

Figure 7 is a circuit diagram of another implementation of the noise reduction circuit provided by the embodiment of the present application;

Figure 8 is a circuit diagram of another implementation of the noise reduction circuit provided by the embodiment of the present application;

Figure 9a is a schematic diagram of an optical receiver provided by an embodiment of the present application;

Figure 9b is a schematic diagram of the circuit noise reduction method provided by the embodiment of the present application;

Figure 10 is a schematic diagram of an electronic device provided by an embodiment of the present application;

Figure 11 is a schematic diagram of a broadband receiving device provided by an embodiment of the present application.

Detailed ways

Embodiments of the present invention provide a noise reduction circuit, method, device, equipment, optical receiver, and medium to solve the problem of large input noise of the optical receiver.

In order to enable those in the technical field to better understand the solutions of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only These are part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative efforts should fall within the scope of protection of this application.

The terms "first", "second", "third", "fourth", etc. (if present) in the description and claims of this application and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used for Describe a specific order or sequence. It is to be understood that the data so used are interchangeable under appropriate circumstances so that the embodiments described herein can be practiced in sequences other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, e.g., a process, method, system, product, or apparatus that encompasses a series of steps or units and need not be limited to those explicitly listed. Those steps or elements may instead include other steps or elements not expressly listed or inherent to the process, method, product or apparatus.

In broadband communications, the coherent communication method of heterodyne detection in radio digital communication systems is usually applied to broadband communications. The coherent receiver in coherent optical communication is an important implementation method, and its schematic block diagram is shown in Figure 1. The signal light Signal101 is coupled with the local oscillator light Local Oscillator102 and then passes through the optical mixer Mixer103, and then the optical signal is converted into an electrical signal by the diode (photo diode, PD) 104, and is amplified by the transimpedance amplifier (TIA) 105 Afterwards, the sample is sampled by an analog to digital converter (ADC) 106, and then sent to a digital signal processor (DSP) 107 for data processing.

Based on the architecture shown in Figure 1, the conversion principle of the signal after Mixer optical mixing through PD is shown in Figure 2. After the signal light Es201 and the local oscillator light Elo202 enter the optical mixer Mixer203 and PD204 respectively, an AC signal is obtained There are two outputs, Q (205) and DC signal I (206), where the I signal 206 includes P1 and P2, and the Q signal 205 includes P3 and P4. Therefore, it can be seen that the current output by the PD includes a large DC signal and a pair of differential AC signals.

For PD output AC signals and DC signals, they need to be amplified by the transimpedance amplification stage TIA and then used by the ADC. The principle is shown in Figure 3. Figure 3 shows the working principle diagram of TIA, in which PD31 includes a diode 301 , the diode 301 sends the DC signal and the AC signal to the transimpedance amplification stage TIA32. The TIA32 includes a noise reduction circuit 302, a variable gain stage 303 and an output driver stage 304. The noise reduction circuit 302 is used to filter the DC input of the PD31. signal, the variable gain stage 303 is used to amplify the AC signal input by the PD31, and the output driver stage 304 is used to send the amplified AC signal to the ADC33. The ADC33 includes an analog-to-digital sampler 305.

During the working process as shown in Figure 3, since the variable gain stage in the TIA only amplifies the AC current, the noise reduction circuit in the TIA needs to bypass the DC current to ground. The implementation method is shown in Figure 4. Figure 4 is a schematic diagram of the current TIA principle that needs to bypass the DC current to the ground. As shown in Figure 4, the output end of PD401 is coupled to the input end of the transimpedance amplifier 402. PD401 will The DC signal Idc and the AC signal Iac are input into the transimpedance amplifier 402, and the N-type MOSFET NMOS transistor 403 is coupled between the ground terminal and the output terminal of the PD401. Therefore, the DC signal Idc can be bypassed to the ground through the NMOS transistor 403.

The specific implementation of the schematic diagram shown in Figure 4 can be found in Figure 5. Figure 5 is a specific implementation of the current noise reduction circuit. As shown in FIG. 5 , the circuit includes a first transimpedance amplifier 501 , a second transimpedance amplifier 502 , a second operational amplifier 503 , a diode PD504 and an N-type metal oxide semiconductor field effect transistor NMOS transistor 505 . Among them, PD504 is used to output DC signals and AC signals; NMOS tube 505 is coupled between the ground terminal and the output terminal of PD504; the first transimpedance amplifier 501 is coupled to the output terminal of PD504, and the first transimpedance amplifier 501 includes a first operation Amplifier 5011 and first resistor 5012. The first resistor 5012 is coupled between the input terminal 5011 and the output terminal of the first operational amplifier 5011. The signal output by the output terminal of the first operational amplifier 5011 is the same as the signal received by the input terminal of the first operational amplifier 5011. The signal is reversed; the second operational amplifier 503 includes a positive input terminal, a negative input terminal and an output terminal. The negative input terminal of the second operational amplifier 503 is coupled with the output terminal of the first operational amplifier 5011; the positive input terminal of the second operational amplifier 503 Coupled with the second transimpedance amplifier 502; the output end of the second operational amplifier 503 is coupled with the NMOS transistor 505 for adjusting the signal coupled to the ground from the first ground circuit.

In Figure 5, the two operational amplifiers coupled to the output end of the reference voltage generator 502 have the same structure. The difference is that one structure is used to receive the positive electrode of the PD output, and the other structure is used to receive the negative electrode of the PD output. Therefore, only one of them is used. A structure serves as an illustration.

In the structure shown in Figure 5, since the signal output by the output terminal of the first operational amplifier 5011 is opposite to the signal received by the input terminal of the first operational amplifier 5011, and the signal received by the input terminal of the first operational amplifier 5011 is the third The input of the two transimpedance amplifiers 502 is through the second operational amplifier 503, so the potentials of the first transimpedance amplifier 501 and the second transimpedance amplifier 502 remain equal.

When the PD 504 inputs the DC signal Idc and the AC signal Iac to the first transimpedance amplifier 501, since the potential of the AC signal Iac fluctuates up and down around the 0 point, the potential of the AC signal Iac is zero as a whole and does not cause the first transimpedance amplifier 501. The potential of the first transimpedance amplifier 501 increases, so the AC signal Iac can be input into the first transimpedance amplifier 501 through the input terminal, and the DC signal Idc will cause the potential of the first transimpedance amplifier 501 to rise. Therefore, the DC signal Idc passes through the NMOS Pipe 505 flows out. Thus, the DC current is bypassed to ground.

During the specific working process, due to the large DC signal current of the coherent receiver, large input noise will be generated when the DC current flows through the NMOS tube, affecting the performance of the receiver.

Therefore, in order to solve the above problem, embodiments of the present application provide a noise reduction circuit that can reduce the noise amplitude generated by the DC signal, thereby improving the overall performance of the receiver. For ease of understanding, the solutions of the embodiments of the present application are described in detail below with reference to the accompanying drawings.

Please refer to Figure 6. As shown in Figure 6, the noise reduction circuit provided by the embodiment of the present application includes.

The first signal detection module 604, the first ground circuit 605, the first transimpedance amplifier 602, the second operational amplifier 603 and the reference voltage generator 601; wherein,

The first signal detection module 604 is used to output the first DC signal Idc and the first AC signal Iac; optionally, the first signal detection module 604 includes a first diode PD, and the first PD is coupled to the optical mixer Mixer , the Mixer is used to mix the first signal and the second signal and send them to the first PD, and the first PD is used to output the above-mentioned first DC signal Idc and the above-mentioned first AC signal Iac.

The first ground circuit 605 is coupled between the ground terminal and the output terminal of the first signal detection module 604; optionally, the first ground circuit includes an N-type metal oxide semiconductor field effect transistor NMOS transistor, and the gate terminal of the NMOS transistor is coupled to the first Between a signal detection module 604 and the first transimpedance amplifier 602, the source terminal and the ground terminal of the NMOS tube are coupled.

The first transimpedance amplifier 602 is coupled to the output end of the first signal detection module 604. The first transimpedance amplifier 602 includes a first operational amplifier 6021 and a first resistor 6022. The first resistor 6022 is coupled to the input end of the first operational amplifier 6021. and the output terminal, the signal output by the output terminal of the first operational amplifier 6021 is opposite to the signal received by the input terminal of the first operational amplifier 6021;

The second operational amplifier 603 includes a positive input terminal, a negative input terminal and an output terminal, and the negative input terminal of the second operational amplifier 603 is coupled with the output terminal of the first operational amplifier 6021;

The positive input terminal of the second operational amplifier 603 is coupled to the reference voltage generator 601 and is used for receiving the adjustable reference voltage output by the reference voltage generator 601;

The output end of the second operational amplifier 603 is coupled to the first ground circuit 605 for adjusting the signal coupled to the ground by the first ground circuit 605.

In the structure shown in Figure 6, since the signal output by the output terminal of the first operational amplifier 6021 is opposite to the signal received by the input terminal of the first operational amplifier 6021, and the signal received by the input terminal of the first operational amplifier 6021 is a reference The voltage generator 601 is input through the second operational amplifier 603, so the potentials of the reference voltage generator 601 and the first transimpedance amplifier 602 remain equal.

Since the reference voltage output by the reference voltage generator 601 is an adjustable reference voltage, the potential of the reference voltage generator 601 changes with the size of the output adjustable reference voltage. When the potential of the reference voltage generator 601 changes, The potential of the first transimpedance amplifier 602 also changes accordingly. At this time, the proportion (nIdc) of the first DC signal flowing into the first operational amplifier 6021 will change accordingly, causing the first DC signal to flow into the first ground circuit. The ratio (1-n) Idc of 605 (can be an NMOS tube) decreases, and the above n is a positive integer greater than or equal to zero.

In this embodiment, in the structure shown in Figure 6, the first operational amplifier 6021 can absorb the first AC signal and the first DC signal (either fully or partially). When the first operational amplifier 6021 When part of the first DC signal is absorbed, the remaining DC signal is bypassed to the ground through the first ground circuit 605, so that the DC current flowing in the first ground circuit 605 (NMOS tube) is reduced, and the DC current generated in the NMOS tube is reduced. The noise will be greatly reduced, thereby greatly improving the performance of the coherent receiver.

Optionally, an output current source (not shown in the figure) may be coupled to the output terminal of the first operational amplifier, and the output current source may be grounded. Therefore, the output current source can derive the DC signal flowing into the first operational amplifier.

Optionally, embodiments of the present application provide two methods for adjusting the reference voltage output by the reference voltage generator, which are: 1. Adjusting the input current at the input end of the reference voltage generator. 2. Adjust the output current at the output end of the reference voltage generator. For ease of understanding, these two methods are described in detail below with reference to the accompanying drawings.

1. Adjust the input current at the input end of the reference voltage generator.

Please refer to Figure 7. As shown in Figure 7, the reference voltage generator 701 includes a third operational amplifier 7011. Optionally, the reference voltage generator 701 also includes a third resistor 7012. The third resistor 7012 is coupled to the third operational amplifier. between the input and output of amplifier 7011. A first input current source 702 is coupled between the input terminal of the third operational amplifier 7011 and the power terminal, and the current size of the first input current source 702 is adjustable.

In this embodiment, since the input current of the first input current source 702 is adjustable, the reference voltage output by the reference voltage generator 701 will change accordingly with the input current of the first input current source 702, so that the reference voltage is generated. The potential level of device 701 changes. Therefore, by adjusting the size of the input current, the proportion of the DC signal flowing into the first transimpedance amplifier 703 can be adjusted.

2. Adjust the output current at the output end of the reference voltage generator.

Please refer to Figure 8. As shown in Figure 8, the reference voltage generator 801 includes a third operational amplifier 8011. Optionally, the reference voltage generator 801 also includes a third resistor 8012. The third resistor 8012 is coupled to the third operational amplifier. between the input and output of amplifier 8011. An output current source 802 is coupled between the output terminal of the third operational amplifier 8011 and the ground terminal, and the current size of the output current source 802 is adjustable.

In this embodiment, since the output current of the output current source 802 is adjustable, the reference voltage output by the reference voltage generator 801 will change correspondingly with the output current of the output current source 802, so that the potential of the reference voltage generator 801 Highs and lows change. Therefore, by adjusting the size of the output current, the proportion of the DC current flowing into the first transimpedance amplifier 803 can be adjusted.

It should be noted that the above-mentioned third operational amplifier is in a proportional relationship with the above-mentioned first operational amplifier circuit. Optionally, the third operational amplifier and the first operational amplifier have the same circuit structure, and the parameters of the circuit components may be different between them.

It should be noted that the above provides two ways of adjusting the reference voltage output by the reference voltage generator. Those skilled in the art can also use other ways to change the reference voltage output by the reference voltage generator. These methods all belong to the embodiments of the present application. scope of protection.

Further, as shown in Figure 6, the noise reduction circuit provided by the embodiment of the present application also includes a second signal detection module 606, a second ground circuit 607, a second transimpedance amplifier 608 and a fifth operational amplifier 609; wherein,

The second signal detection module 606 is used to output a second DC signal and a second AC signal;

The first ground circuit is coupled between the ground terminal and the positive output terminal of the first signal detection module. The second ground circuit 607 is coupled between the ground terminal and the negative output terminal of the second signal detection module 606. The ground terminal and the ground terminal are different ground terminals;

The first transimpedance amplifier is coupled to the positive output terminal of the first signal detection module, and the second transimpedance amplifier 608 is coupled to the negative output terminal of the second signal detection module 606. The second transimpedance amplifier 608 includes a fourth operational amplifier 6081 and a third operational amplifier 6081. Two resistors 6082. The second resistor 6082 is coupled between the input terminal and the output terminal of the fourth operational amplifier 6081. The signal output by the output terminal 6081 of the fourth operational amplifier 6081 is opposite to the signal received by the input terminal of the fourth operational amplifier 6081;

The fifth operational amplifier 609 includes a positive input terminal, a negative input terminal and an output terminal, and the negative input terminal of the fifth operational amplifier 609 is coupled with the output terminal of the fourth operational amplifier 6081;

The positive input terminal of the fifth operational amplifier 609 is coupled with the reference voltage generator and is used for receiving the adjustable reference voltage output by the reference voltage generator 601;

The output end of the fifth operational amplifier 609 is coupled to the second ground circuit 607 for adjusting the signal coupled to the ground by the second ground circuit 607.

In this embodiment, the first signal detection module corresponds to PD1 (1041) in Figure 1, and the second detection module corresponds to PD2 (1042) in Figure 1. As shown in Figure 1, PD1 (1041) and the transimpedance amplification stage TIA105 The positive input terminal is coupled, PD2 (1042) is coupled with the negative input terminal of the transimpedance amplifier TIA105, where the positive input terminal of TIA105 is coupled with the first transimpedance amplifier, and the negative input terminal of TIA105 is coupled with the second transimpedance amplifier. The first transimpedance amplifier and the second transimpedance amplifier of TIA105 are respectively connected to the same ADC106, so that TIA105 sends the amplified signal to ADC106.

Further, the specific working principles of the second signal detection module 606, the second ground circuit, the second transimpedance amplifier and the fifth operational amplifier in Figure 6 are the same as the aforementioned first signal detection module, the first ground circuit, the first transresistance amplifier and the second operational amplifier work in the same way, so please refer to the previous record and will not repeat them here.

It should be noted that the above-mentioned first grounding circuit, the first transimpedance amplifier and the second operational amplifier constitute the first sub-noise reduction circuit; the above-mentioned second grounding circuit, the second transimpedance amplifier and the fifth operational amplifier constitute the second sub-noise reduction circuit. Sub-noise reduction circuit. The first sub-noise reduction circuit and the second sub-noise reduction circuit are connected to the same reference voltage generator through the positive input terminals of the second operational amplifier and the fifth operational amplifier respectively. The reference voltage generator simultaneously supplies signals to the first sub-noise reduction circuit and the third sub-noise reduction circuit. The second sub-noise reduction circuit inputs the reference voltage, so that the adjustment of the reference voltage generator has a mirror effect between the first sub-noise reduction circuit and the second sub-noise reduction circuit. The ratio of the DC signal flowing into the first transimpedance amplifier is the same as that of the second sub-noise reduction circuit. The ratio of DC signals flowing into the two transimpedance amplifiers remains synchronized.

Further, based on the noise reduction circuit provided by the embodiment of the present application, the embodiment of the present application further provides an optical receiver. Please refer to Figure 9a. The structure of the optical receiver provided by the embodiment of the present application is shown in Figure 9a, including : Signal light input optical path 91, local oscillator optical input optical path 92, first optical mixer Mixer93a, second Mixer93b, first diode PD94a, second PD94b, third PD94c, fourth PD94d, fifth PD94e, Sixth PD94f, seventh PD94g, eighth PD94h, first transimpedance amplifier stage TIA95a, second TIA95b, third TIA95c, fourth TIA95d, first analog-to-digital converter ADC96a, second ADC96b, third ADC96c, fourth ADC96d and digital signal processor DSP97;

The signal light input optical path 91 is used to input two channels of signal light into the first Mixer 93a and the second Mixer 93b respectively;

The local oscillator light input optical path 92 is used to input the two local oscillator lights into the first Mixer 93a and the second Mixer 93b respectively;

The first Mixer93a and the second Mixer93b are respectively used to mix the received signal light and the local oscillator light to obtain the first signal and the second signal;

The first Mixer93a sends the first signal to the first PD94a, the second PD94b, the third PD94c and the fourth PD94d;

The second Mixer93b sends the second signal to the fifth PD94e, the sixth PD94f, the seventh PD94g and the eighth PD94h;

The first TIA95a, the second TIA95b, the third TIA95c and the fourth TIA95d respectively include a positive input terminal, a negative input terminal and an output terminal, wherein the first PD94a is coupled with the positive input terminal of the first TIA95a, and the second PD94b is coupled with the first TIA95a The negative input terminal of the third PD94c is coupled with the positive input terminal of the second TIA95b, the fourth PD94d is coupled with the negative input terminal of the second TIA95b, the fifth PD94e is coupled with the positive input terminal of the third TIA95c, and the sixth PD94f is coupled with the positive input terminal of the second TIA95b. The negative input terminal of the third TIA95c is coupled, the seventh PD94g is coupled with the positive input terminal of the fourth TIA95d, the eighth PD94h is coupled with the negative input terminal of the fourth TIA95d, the output terminal of the first TIA95a is coupled with the first ADC96a, and the second IA The output terminal is coupled with the second ADC96b, the output terminal of the third TIA95c is coupled with the third ADC96c, and the output terminal of the fourth TIA95d is coupled with the fourth ADC96d;

The first PD94a and the second PD94b are used to output the first AC signal and the first DC signal according to the first signal, and send the first AC signal and the first DC signal to the first TIA95a;

The third PD94c and the fourth PD94d are used to output the second AC signal and the second DC signal according to the first signal, and send the second AC signal and the second DC signal to the second TIA95b;

The fifth PD94e and the sixth PD94f are used to output a third AC signal and a third DC signal according to the second signal, and send the third AC signal and the third DC signal to the third TIA95c;

The seventh PD94g and the eighth PD94h are used to output the fourth AC signal and the fourth DC signal according to the second signal, and send the fourth AC signal and the fourth DC signal to the fourth TIA95d;

The first TIA95a, the second TIA95b, the third TIA95c and the fourth TIA95d are respectively used to filter the first DC signal, the second DC signal, the third DC signal and the fourth DC signal, and amplify the first AC signal and the second AC signal. signals, third AC signal and fourth AC signal;

The first TIA95a, the second TIA95b, the third TIA95c and the fourth TIA95d are respectively provided with noise reduction devices. The noise reduction devices are used to reduce the first DC signal, the second DC signal, the third DC signal and the fourth DC signal. The noise generated when passing through the first TIA95a, the second TIA95b, the third TIA95c and the fourth TIA95d;

Optionally, the noise reduction device includes a noise reduction circuit. The noise reduction circuit includes: a first ground circuit, a first transimpedance amplifier, a second operational amplifier and a reference voltage generator; the first ground circuit is coupled between the ground terminal and the first PD. , between the output terminals of the second PD, the third PD, the fourth PD, the fifth PD, the sixth PD, the seventh PD or the eighth PD, for coupling the first PD, the second PD, the third PD, the The signals output by the fourth PD, the fifth PD, the sixth PD, the seventh PD or the eighth PD go to ground; the first transimpedance amplifier is coupled to the first PD, the second PD, the third PD, the fourth PD and the fifth PD. , the output terminal of the sixth PD, the seventh PD or the eighth PD, the first transimpedance amplifier includes a first operational amplifier and a first resistor, the first resistor is coupled between the input terminal and the output terminal of the first operational amplifier, the first transimpedance amplifier The signal output by the output terminal of an operational amplifier is opposite to the signal received by the input terminal of the first operational amplifier; the second operational amplifier includes a positive input terminal, a negative input terminal and an output terminal, and the negative input terminal of the second operational amplifier is connected to the first operational amplifier. The output terminal of the operational amplifier is coupled; the positive input terminal of the second operational amplifier is coupled with the reference voltage generator, and is used for receiving the adjustable reference voltage output by the reference voltage generator; the output terminal of the second operational amplifier is coupled with the first ground circuit, Used to adjust the signal coupled to the ground from the first ground circuit.

Further, the reference voltage generator includes a third operational amplifier, the input terminal of the third operational amplifier is coupled with a first input current source, and the current size of the first input current source is adjustable. Alternatively, an output current source is coupled between the output terminal of the third operational amplifier and the ground terminal, and the current size of the output current source is adjustable.

The first TIA95a, the second TIA95b, the third TIA95c and the fourth TIA95d are respectively used to send the amplified first AC signal, the second AC signal, the third AC signal and the fourth AC signal to the first ADC96a and the second ADC96b , the third ADC96c and the fourth ADC96d;

The first ADC96a, the second ADC96b, the third ADC96c and the fourth ADC96d are used to collect the first AC signal, the second AC signal, the third AC signal and the fourth AC signal respectively and send them to the DSP97;

DSP97 is used to process the first AC signal, the second AC signal, the third AC signal and the fourth AC signal.

In the optical receiver provided by the embodiment of the present application, the noise reduction circuit in the TIA provided is the noise reduction circuit provided by the embodiment of the present application. Through the above introduction, the optical receiver provided in the embodiment of the present application adopts the above-mentioned noise reduction circuit, which can greatly reduce the noise generated by the DC signal in the TIA, thereby improving the performance of the optical receiver.

Further, in order to ensure that the above-mentioned noise reduction circuit and optical receiver provided by the embodiment of the present application can work smoothly, based on the above structure, the embodiment of the present application also provides a circuit noise reduction method. For ease of understanding, the following is combined with the accompanying drawings, The methods provided by the embodiments of this application will be described in detail.

Please refer to Figure 9b. As shown in Figure 9b, the circuit noise reduction method provided by the embodiment of the present application includes the following steps.

901. Obtain the first DC signal and the first AC signal output by the first signal detection module.

In this embodiment, the optical mixer sends the optical signal coupled with the local oscillator light to the first signal detection module. The first signal detection module can be a PD. The PD converts the optical signal into an electrical signal and sends it to the host. TIA, wherein the electrical signal includes a first AC signal Iac and a first DC signal Idc.

902. Adjust the ratio of the first DC signal input to the first operational amplifier by adjusting the adjustable reference voltage output by the reference voltage generator.

In this embodiment, the adjustable reference voltage output by the reference voltage generator is over-adjusted to adjust the proportion of the DC signal nIdc input to the first operational amplifier. The DC signal (1-n)Idc not input to the first operational amplifier is grounded through the NMOS tube. Export. Thus, the proportion of the DC current input to the first operational amplifier is distributed. Specifically, the proportion, that is, the value of n, can be realized by adjusting the adjustable reference voltage output by the reference voltage generator.

Embodiments of the present application provide two methods for adjusting the reference voltage output by the reference voltage generator, which are: 1. Adjusting the input current at the input end of the reference voltage generator. 2. Adjust the output current at the output end of the reference voltage generator. For ease of understanding, these two methods are described in detail below with reference to the accompanying drawings.

1. Adjust the input current at the input end of the reference voltage generator.

As shown in FIG. 7 , the reference voltage generator includes a third operational amplifier. A first input current source is coupled between the input terminal of the third operational amplifier and the power terminal. The current size of the first input current source is adjustable.

The specific method of adjustment is: adjusting the input current of the first input current source to adjust the proportion of the first DC signal input to the first operational amplifier. The greater the current input to the third operational amplifier by the first input current source, the greater the input current of the first DC signal to the third operational amplifier. The higher the proportion of DC signal input to the first operational amplifier. The magnitude of the input current of the output current source is inversely proportional to the potential of the first operational amplifier.

2. Adjust the output current at the output end of the reference voltage generator.

As shown in FIG. 8 , the reference voltage generator includes a third operational amplifier. An output current source is coupled to the output terminal of the third operational amplifier and the ground terminal. The current size of the output current source is adjustable.

The specific method of adjustment is: adjusting the proportion of the first DC signal input to the first operational amplifier by adjusting the size of the current flowing out of the output current source, wherein the greater the value of the current flowing out of the output current source. , the lower the proportion of the first DC signal input to the first operational amplifier. The value of the current flowing out of the output current source is proportional to the potential of the first operational amplifier.

Optionally, the above two methods can also be combined to simultaneously adjust the input current of the first input current source and the output current of the output current source to realize adjustment of the potential of the first operational amplifier. This will not be described again in the embodiments of the present application.

Optionally, those skilled in the art can also adopt other methods of changing the reference voltage output by the reference voltage generator according to other structures according to actual needs, which all fall within the protection scope of the method provided by the embodiments of the present application.

Further, as mentioned above, since the second sub-noise reduction circuit and the first sub-noise reduction circuit are respectively connected to the same reference voltage generator, the reference voltage generator maintains Mirror synchronization, so that the ratio of the second DC signal input to the fourth operational amplifier can be adjusted by adjusting the ratio of the first DC signal input to the first operational amplifier, wherein the ratio of the second DC signal input to the fourth operational amplifier is the same as the ratio of the first DC signal input to the fourth operational amplifier. The ratio of the signal input to the first operational amplifier remains synchronized.

The circuit noise reduction method provided by the embodiment of the present application includes: obtaining the first DC signal and the first AC signal output by the first signal detection module; adjusting the first DC signal by adjusting the adjustable reference voltage output by the reference voltage generator The signal input to the first op amp is proportional. Therefore, by adjusting the adjustable reference voltage output by the reference voltage generator, the proportion of the DC signal input to the first operational amplifier in the noise reduction circuit is changed, thereby reducing the proportion of DC current passing through the NMOS tube and reducing the voltage of the NMOS tube. The DC noise generated improves the overall performance of the optical receiver.

The embodiments of the present application are introduced above from the perspective of methods and physical equipment. Next, from the perspective of functional modules, the database processing device provided by the embodiment of the present application is introduced.

From the perspective of functional modules, this application can divide the device of the database processing method into functional modules according to the above method embodiments. For example, each functional module can be divided corresponding to each function, or two or more functions can be integrated. in a function module. The above integrated functional modules can be implemented in the form of hardware or software functional units.

An embodiment of the present application provides an electronic device. The electronic device includes a circuit board. The circuit board includes the noise reduction circuit or optical receiver provided by the embodiment of the present application. Optionally, Figure 10 shows an embodiment of the present application. An implementation of an electronic device is provided. As shown in Figure 10, the device includes at least one processor 1001, a communication line 1002, a memory 1003 and at least one communication interface 1004.

The processor 1001 may be a general central processing unit (CPU), a microprocessor, an application-specific integrated circuit (ASIC), or one or more processors used to control the execution of the program of the present application. integrated circuit.

Communication line 1002 may include a path for communicating information between the above-mentioned components.

The communication interface 1004 uses any device such as a transceiver to communicate with other devices or communication networks, such as Ethernet, wireless access network (radio access network, RAN), wireless local area network (WLAN), etc. .

Memory 1003 may be a read-only memory (ROM) or other type of static storage device that can store non-volatile information and instructions, a random access memory (random access memory (RAM)) or a device that can store information and instructions. Other types of dynamic storage devices can also be electrically erasable programmable read-only memory (EEPROM), compact disc read-only memory (CD-ROM) or other optical disk storage , optical disc storage (including compressed optical disc, laser disc, optical disc, digital versatile disc, Blu-ray disc, etc.), magnetic disk storage media or other magnetic storage devices, or can be used to carry or store the desired program code in the form of instructions or data structures and Any other media capable of being accessed by a computer, without limitation. The memory may exist independently and be connected to the processor through the communication line 1002 . Memory can also be integrated with the processor.

Among them, the memory 1003 is used to store computer execution instructions for executing the solution of the present application, and is controlled by the processor 1001 for execution. The processor 1001 is configured to execute computer execution instructions stored in the memory 1003, thereby implementing the billing management method provided in the following application of this application.

Optionally, the computer execution instructions in this application can also be called application codes, which are not specifically limited in this application.

In specific implementation, as an embodiment, the processor 1001 may include one or more CPUs, such as CPU0 and CPU1 in FIG. 10 .

In specific implementation, as an embodiment, the electronic device may include multiple processors, such as the processor 1001 and the processor 1007 in FIG. 10 . Each of these processors can be a single-core processor or a multi-core processor. A processor here may refer to one or more devices, circuits, and/or processing cores for processing data (eg, computer program instructions).

In specific implementation, as an embodiment, the electronic device may also include an output device 1005 and an input device 1006. The output device 1005 communicates with the processor 1001 and can display information in a variety of ways. For example, the output device 1005 may be a liquid crystal display (LCD), a light emitting diode (LED) display device, a cathode ray tube (CRT) display device, or a projector. wait. Input device 1006 communicates with processor 1001 and can receive user input in a variety of ways. For example, the input device 1006 may be a mouse, a keyboard, a touch screen device, a sensing device, or the like.

The above-mentioned electronic device may be a general device or a special device. In a specific implementation, the electronic device may be the device used to run the circuit noise reduction method in the embodiment of the present application. This application does not limit the type of electronic equipment.

Embodiments of the present application can divide the electronic device into functional units according to the above method examples. For example, each functional unit can be divided corresponding to each function, or two or more functions can be integrated into one processing unit. The above integrated units can be implemented in the form of hardware or software functional units. It should be noted that the division of units in the embodiment of the present application is schematic and is only a logical function division. In actual implementation, there may be other division methods.

For example, when each functional unit is divided in an integrated manner, FIG. 11 shows a schematic structural diagram of a broadband receiving device provided by an embodiment of the present application.

As shown in Figure 11, the broadband receiving device provided by the embodiment of the present application includes.

The device is applied to a noise reduction circuit. The noise reduction circuit includes: a first signal detection module, a first ground circuit, a first transimpedance amplifier, a second operational amplifier and a reference voltage generator; the first signal detection module is used to output The first DC signal and the first AC signal; the first ground circuit is coupled between the ground terminal and the output terminal of the first signal detection module; the first transimpedance amplifier is coupled to the output terminal of the first signal detection module , the first transimpedance amplifier includes a first operational amplifier and a first resistor, the first resistor is coupled between the input terminal and the output terminal of the first operational amplifier, and the signal output by the output terminal of the first operational amplifier is related to the The signal received by the input terminal of the first operational amplifier is reversed; the second operational amplifier includes a positive input terminal, a negative input terminal and an output terminal, and the negative input terminal of the second operational amplifier is coupled with the output terminal of the first operational amplifier; The positive input terminal of the second operational amplifier is coupled to the reference voltage generator for receiving the adjustable reference voltage output by the reference voltage generator; the output terminal of the second operational amplifier is coupled to the first ground circuit for receiving Adjust the signal coupled to the ground by the first ground circuit; the device includes:

The acquisition unit 1101 is used to acquire the first DC signal and the first AC signal output by the first signal detection module;

The adjustment unit 1102 is configured to adjust the proportion of the first DC signal acquired by the acquisition unit 1101 being input into the first operational amplifier by adjusting the adjustable reference voltage output by the reference voltage generator.

Optionally, the reference voltage generator includes a third operational amplifier, a first input current source is coupled between the input terminal of the third operational amplifier and the power terminal, and the current size of the first input current source is adjustable; the adjustment Unit 1102, also used for:

The proportion of the first DC signal input to the first operational amplifier is adjusted by adjusting the input current size of the first input current source. The greater the current input by the first input current source to the third operational amplifier, the greater the input current of the first input current source to the third operational amplifier. The higher the proportion of DC signal input to the first operational amplifier.

Optionally, the reference voltage generator includes a third operational amplifier, and an output current source is coupled to the output terminal of the third operational amplifier and the ground terminal. The current size of the output current source is adjustable; the adjustment unit 1102 is also used to :

The proportion of the first DC signal input to the first operational amplifier is adjusted by adjusting the size of the current flowing out of the output current source. The greater the current value flowing out of the output current source, the greater the input of the first DC signal into the first operational amplifier. The ratio of op amps is lower.

Optionally, the noise reduction circuit also includes a second signal detection module, a second ground circuit, a second transimpedance amplifier and a fifth operational amplifier; the second signal detection module is used to output a second DC signal and a second AC signal. ; The first ground circuit is coupled between the ground terminal and the positive output terminal of the first signal detection module, the second ground circuit is coupled between the ground terminal and the negative output terminal of the second signal detection module, the ground The terminal and the ground terminal are different ground terminals; the first transimpedance amplifier is coupled to the positive output terminal of the first signal detection module, the second transimpedance amplifier is coupled to the negative output terminal of the second signal detection module, and the The second transimpedance amplifier includes a fourth operational amplifier and a second resistor. The second resistor is coupled between the input terminal and the output terminal of the fourth operational amplifier. The signal output by the output terminal of the fourth operational amplifier is consistent with the fourth operational amplifier. The signal received by the input terminal of the operational amplifier is reversed; the fifth operational amplifier includes a positive input terminal, a negative input terminal and an output terminal, and the negative input terminal of the fifth operational amplifier is coupled with the output terminal of the fourth operational amplifier; the fifth operational amplifier includes a positive input terminal, a negative input terminal and an output terminal. The positive input terminal of the fifth operational amplifier is coupled to the reference voltage generator and is used to receive the adjustable reference voltage output by the reference voltage generator; the output terminal of the fifth operational amplifier is coupled to the second ground circuit and is used to adjust the The second ground circuit couples the signal to the ground; the adjustment unit 1102 is also used for:

The ratio of the second DC signal input to the fourth operational amplifier is adjusted by adjusting the ratio of the first DC signal input to the first operational amplifier, wherein the ratio of the second DC signal input to the fourth operational amplifier is the same as the ratio of the second DC signal input to the fourth operational amplifier. The ratio of the DC signal input to the first operational amplifier remains synchronized.

The above embodiments may be implemented in whole or in part by software, hardware, firmware, or any combination thereof. When implemented using software, they may be implemented in whole or in part in the form of a computer program product.

The computer program product includes one or more computer instructions. When the computer execution instructions are loaded and executed on the computer, the processes or functions described in the embodiments of the present application are generated in whole or in part. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions may be stored in or transmitted from one computer-readable storage medium to another computer-readable storage medium, for example, the computer instructions may be transferred from a website, computer, server, or data center Transmission to another website, computer, server or data center by wired (such as coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (such as infrared, wireless, microwave, etc.) means. The computer-readable storage medium may be any available medium that a computer can store, or a data storage device such as a server or data center integrated with one or more available media. The available media may be magnetic media (eg, floppy disk, hard disk, magnetic tape), optical media (eg, DVD), or semiconductor media (eg, Solid State Disk (SSD)), etc.

The terms "first", "second", etc. in the description and claims of this application and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that the terms so used are interchangeable under appropriate circumstances, and are merely a way of distinguishing objects with the same attributes in describing the embodiments of the present application. Furthermore, the terms "include" and "having" and any variations thereof, are intended to cover non-exclusive inclusions, such that a process, method, system, product or apparatus comprising a series of elements need not be limited to those elements, but may include not explicitly other elements specifically listed or inherent to such processes, methods, products or equipment. In the embodiment of this application, "multiple" refers to two or more than two.

In the embodiments of this application, words such as "exemplary" or "for example" are used to represent examples, illustrations or explanations. Any embodiment or design described as "exemplary" or "such as" in the embodiments of the present application is not to be construed as preferred or advantageous over other embodiments or designs. Rather, use of the words "exemplary" or "such as" is intended to present the concept in a concrete manner.

In each embodiment of the present application, various examples are given for better understanding. However, these examples are only examples and do not mean that they are the best ways to implement the present application.

The technical solutions provided by this application are introduced in detail above. Specific examples are used in this application to illustrate the principles and implementation methods of this application. The description of the above embodiments is only used to help understand the method and its core idea of this application. ; At the same time, for those of ordinary skill in the art, there will be changes in the specific implementation and application scope based on the ideas of this application. In summary, the content of this description should not be understood as a limitation of this application.

Claims (16)

1. A noise reduction circuit, comprising: the first signal detection module, the first earthing circuit, the first transimpedance amplifier, the second operational amplifier and the reference voltage generator;

   the first signal detection module is used for outputting a first direct current signal and a first alternating current signal;

   the first grounding circuit is coupled between a grounding end and an output end of the first signal detection module and is used for coupling signals output by the first signal detection module to ground;

   The first transimpedance amplifier is coupled to the output end of the first signal detection module, and comprises a first operational amplifier and a first resistor, wherein the first resistor is coupled between the input end and the output end of the first operational amplifier, and a signal output by the output end of the first operational amplifier is opposite to a signal received by the input end of the first operational amplifier;

   the second operational amplifier comprises a positive input end, a negative input end and an output end, and the negative input end of the second operational amplifier is coupled with the output end of the first operational amplifier;

   the positive input end of the second operational amplifier is coupled with the reference voltage generator and is used for receiving the adjustable reference voltage output by the reference voltage generator;

   the output of the second operational amplifier is coupled to the first ground circuit for conditioning signals of the first ground circuit coupled to ground.
2. The noise reduction circuit of claim 1, wherein the reference voltage generator comprises a third operational amplifier having a first input current source coupled to an input thereof, the first input current source having an adjustable current magnitude.
3. The noise reduction circuit according to claim 1, wherein the reference voltage generator comprises a third operational amplifier, an output current source is coupled between an output terminal of the third operational amplifier and the ground terminal, and a current magnitude of the output current source is adjustable.
4. A noise reduction circuit according to any one of claims 1 to 3, wherein an output of the first operational amplifier is coupled to an output current source, the output current source being coupled to ground.
5. A noise reduction circuit according to claim 3, wherein the third operational amplifier is in proportional relationship to the first operational amplifier circuit.
6. The noise reduction circuit of any of claims 1-5, wherein the first signal detection module comprises a first diode PD coupled to an optical Mixer for mixing a first signal with a second signal and then transmitting the mixed signal to the first PD, and wherein the first PD is configured to output the first dc signal and the first ac signal.
7. The noise reduction circuit of claim 6, wherein the noise reduction circuit is coupled to a variable gain stage coupled to an output driver stage, the variable gain stage for amplifying the first ac signal, the output driver stage for transmitting the amplified first ac signal to an analog-to-digital sampler ADC.
8. The noise reduction circuit according to any one of claims 1 to 7, wherein the first grounding circuit comprises an NMOS transistor having a gate terminal coupled to the output terminal of the second operational amplifier, and a source terminal coupled to the ground terminal.
9. The noise reduction circuit according to any one of claims 1 to 8, further comprising a second signal detection module, a second ground circuit, a second transimpedance amplifier, and a fifth operational amplifier;

   the second signal detection module is used for outputting a second direct current signal and a second alternating current signal;

   the second grounding circuit is coupled between the grounding end and the output end of the second signal detection module;

   the second transimpedance amplifier is coupled to the output end of the second signal detection module, and comprises a fourth operational amplifier and a second resistor, wherein the second resistor is coupled between the input end and the output end of the fourth operational amplifier, and the signal output by the output end of the fourth operational amplifier is opposite to the signal received by the input end of the fourth operational amplifier;

   the fifth operational amplifier comprises a positive input end, a negative input end and an output end, wherein the negative input end of the fifth operational amplifier is coupled with the output end of the fourth operational amplifier;

   The positive input end of the fifth operational amplifier is coupled with the reference voltage generator and is used for receiving the adjustable reference voltage;

   an output of the fifth operational amplifier is coupled to the second ground circuit for conditioning signals of the second ground circuit coupled to ground.
10. An optical receiver, comprising: the optical signal processing circuit comprises a signal light input optical path, a local oscillator light input optical path, a first optical Mixer, a second Mixer, a first diode PD, a second PD, a third PD, a fourth PD, a fifth PD, a sixth PD, a seventh PD, an eighth PD, a first transimpedance amplifier stage TIA, a second TIA, a third TIA, a fourth TIA, a first analog-to-digital converter ADC, a second ADC, a third ADC, a fourth ADC and a digital signal processor DSP;

    the signal light input optical path is used for inputting two paths of signal light into the first Mixer and the second Mixer respectively;

    the local oscillation light input optical path is used for inputting two paths of local oscillation light into the first Mixer and the second Mixer respectively;

    the first Mixer and the second Mixer are respectively used for mixing the received signal light and the local oscillator light to obtain a first signal and a second signal;

    the first Mixer sends the first signal to the first PD, the second PD, the third PD and the fourth PD;

    The second Mixer sends the second signal to the fifth PD, the sixth PD, the seventh PD and the eighth PD;

    the first TIA, the second TIA, the third TIA and the fourth TIA respectively comprise a positive input end, a negative input end and an output end, wherein the first PD is coupled with the positive input end of the first TIA, the second PD is coupled with the negative input end of the first TIA, the third PD is coupled with the positive input end of the second TIA, the fourth PD is coupled with the negative input end of the second TIA, the fifth PD is coupled with the positive input end of the third TIA, the sixth PD is coupled with the negative input end of the third TIA, the seventh PD is coupled with the positive input end of the fourth TIA, the eighth PD is coupled with the negative input end of the fourth TIA, the output end of the first TIA is coupled with the first ADC, the output end of the second IA is coupled with the second ADC, the output end of the third TIA is coupled with the third ADC, and the fourth ADC are coupled with the fourth ADC;

    the first PD and the second PD are used for outputting a first alternating current signal and a first direct current signal according to the first signal and sending the first alternating current signal and the first direct current signal to the first TIA;

    The third PD and the fourth PD are configured to output a second ac signal and a second dc signal according to the first signal, and send the second ac signal and the second dc signal to the second TIA;

    the fifth PD and the sixth PD are configured to output a third ac signal and a third dc signal according to the second signal, and send the third ac signal and the third dc signal to the third TIA;

    the seventh PD and the eighth PD are configured to output a fourth ac signal and a fourth dc signal according to the second signal, and send the fourth ac signal and the fourth dc signal to the fourth TIA;

    the first TIA, the second TIA, the third TIA and the fourth TIA are respectively configured to filter the first direct current signal, the second direct current signal, the third direct current signal and the fourth direct current signal, and amplify the first alternating current signal, the second alternating current signal, the third alternating current signal and the fourth alternating current signal;

    the first TIA, the second TIA, the third TIA and the fourth TIA are respectively provided with a noise reduction device, the noise reduction devices are used for reducing noise generated when the first direct current signal, the second direct current signal, the third direct current signal and the fourth direct current signal pass through the first TIA, the second TIA, the third TIA and the fourth TIA;

    The first TIA, the second TIA, the third TIA and the fourth TIA are configured to send the amplified first ac signal, the second ac signal, the third ac signal and the fourth ac signal to the first ADC, the second ADC, the third ADC and the fourth ADC, respectively;

    the first ADC, the second ADC, the third ADC and the fourth ADC are used for respectively collecting the first alternating current signal, the second alternating current signal and the third alternating current signal and the fourth alternating current signal and then sending the signals to the DSP;

    the DSP is used for processing the first alternating current signal, the second alternating current signal, the third alternating current signal and the fourth alternating current signal.
11. The optical receiver of claim 10, wherein the noise reduction device comprises a noise reduction circuit comprising: a first ground circuit, a first transimpedance amplifier, a second operational amplifier and a reference voltage generator;

    the first grounding circuit is coupled between the grounding end and the output end of the first PD, the second PD, the third PD, the fourth PD, the fifth PD, the sixth PD, the seventh PD or the eighth PD, and is used for coupling signals output by the first PD, the second PD, the third PD, the fourth PD, the fifth PD, the sixth PD, the seventh PD or the eighth PD to the ground;

    The first transimpedance amplifier is coupled to a first PD, the second PD, the third PD, the fourth PD, the fifth PD, the sixth PD, the seventh PD or the output end of the eighth PD, and comprises a first operational amplifier and a first resistor, wherein the first resistor is coupled between the input end and the output end of the first operational amplifier, and the signal output by the output end of the first operational amplifier is opposite to the signal received by the input end of the first operational amplifier;

    the second operational amplifier comprises a positive input end, a negative input end and an output end, and the negative input end of the second operational amplifier is coupled with the output end of the first operational amplifier;

    the positive input end of the second operational amplifier is coupled with the reference voltage generator and is used for receiving the adjustable reference voltage output by the reference voltage generator;

    the output of the second operational amplifier is coupled to the first ground circuit for conditioning signals of the first ground circuit coupled to ground.
12. The optical receiver of claim 11, wherein the reference voltage generator comprises a third operational amplifier having a first input current source coupled to an input thereof, the first input current source having an adjustable current magnitude.
13. The optical receiver of claim 11, wherein the reference voltage generator comprises a third operational amplifier, an output current source is coupled between an output of the third operational amplifier and the ground, and a current magnitude of the output current source is adjustable.
14. A method of circuit noise reduction, the method being applied to a noise reduction circuit comprising: the first signal detection module, the first earthing circuit, the first transimpedance amplifier, the second operational amplifier and the reference voltage generator; the first signal detection module is used for outputting a first direct current signal and a first alternating current signal; the first grounding circuit is coupled between a grounding end and an output end of the first signal detection module; the first transimpedance amplifier is coupled to the output end of the first signal detection module, and comprises a first operational amplifier and a first resistor, wherein the first resistor is coupled between the input end and the output end of the first operational amplifier, and a signal output by the output end of the first operational amplifier is opposite to a signal received by the input end of the first operational amplifier; the second operational amplifier comprises a positive input end, a negative input end and an output end, and the negative input end of the second operational amplifier is coupled with the output end of the first operational amplifier; the positive input end of the second operational amplifier is coupled with the reference voltage generator and is used for receiving the adjustable reference voltage output by the reference voltage generator; the output end of the second operational amplifier is coupled with the first grounding circuit and is used for adjusting a signal of the first grounding circuit coupled to ground; the method comprises the following steps:

    Acquiring a first direct current signal and a first alternating current signal which are output by the first signal detection module;

    the ratio of the first direct current signal input to the first operational amplifier is adjusted by adjusting an adjustable reference voltage output by the reference voltage generator.
15. A broadband receiving apparatus, the apparatus being applied to a noise reduction circuit, the noise reduction circuit comprising: the first signal detection module, the first earthing circuit, the first transimpedance amplifier, the second operational amplifier and the reference voltage generator; the first signal detection module is used for outputting a first direct current signal and a first alternating current signal; the first grounding circuit is coupled between a grounding end and an output end of the first signal detection module; the first transimpedance amplifier is coupled to the output end of the first signal detection module, and comprises a first operational amplifier and a first resistor, wherein the first resistor is coupled between the input end and the output end of the first operational amplifier, and a signal output by the output end of the first operational amplifier is opposite to a signal received by the input end of the first operational amplifier; the second operational amplifier comprises a positive input end, a negative input end and an output end, and the negative input end of the second operational amplifier is coupled with the output end of the first operational amplifier; the positive input end of the second operational amplifier is coupled with the reference voltage generator and is used for receiving the adjustable reference voltage output by the reference voltage generator; the output end of the second operational amplifier is coupled with the first grounding circuit and is used for adjusting a signal of the first grounding circuit coupled to ground; the device comprises:

    The acquisition unit is used for acquiring the first direct current signal and the first alternating current signal output by the first signal detection module;

    and the adjusting unit is used for adjusting the proportion of the first direct current signal acquired by the acquisition unit to the first operational amplifier by adjusting the adjustable reference voltage output by the reference voltage generator.
16. An electronic device comprising a circuit board comprising a noise reduction circuit according to any one of claims 1 to 9 or an optical receiver according to any one of claims 10 to 13.