WO2023035663A1 - Digitally controlled vector modulator - Google Patents

Abstract

The present invention provides a digitally controlled vector modulator, comprising port 1, an I/Q splitter, a digital control signal amplitude adjustment unit, a digital control inverter, a power divider, and port 2 which are connected in sequence. The I/Q splitter is used to divide a radio frequency signal inputted from port 1 into an I-channel signal and a Q-channel signal which are orthogonal and equal in amplitude. The digital control signal amplitude adjustment unit is used to separately control the amplitude of the I-channel and Q-channel signals, and after undergoing vector synthesis, adjust the amplitude and phase of the signals in quadrants thereof. According to quadrant differences required by vectors, the digital control inverter is used to perform phase processing on the I and Q-channel signals processed by the digital control signal amplitude adjustment unit. Beneficial effects of the present invention are as follows: it is easy for the digitally controlled vector modulator described in the present invention to achieve the design of a wide operating frequency band and perform technology transplanting between frequency bands. Performance parameters of the modulator are not sensitive to temperature, and the response speed is fast.

Description

CNC vector modulator technical field

The invention belongs to the field of radio frequency technology, in particular to a numerically controlled vector modulator.

Background technique

In the fields of modern radar TR components, external interference cancellation, self-interference cancellation, instrumentation, UHF radio frequency identification, feedforward linear power amplifier, mobile communication, etc., it is often necessary to adjust the amplitude and phase of microwave and radio frequency signals. The vector modulator can adjust the amplitude and phase at the same time, which is one of the preferred schemes.

Traditional analog vector modulators usually use PIN diode technology and are controlled by an analog voltage (usually a DAC output). Its control voltage needs to be filtered to avoid clutter modulation on the RF signal, so the response speed is slow, and it is not suitable for scenarios that require fast switching of operating frequency points or working states (such as frequency hopping communication); the more fatal problem is that due to random As the temperature changes, the equivalent resistance of the PIN diode changes significantly, and because the control slope is large (especially in the high resistance area), and the device parameters drift discretely over time, it is difficult to guarantee long-term operation even if it is factory calibrated reliability. It is precisely because of its shortcomings that it is difficult to overcome, so the vector modulator is often only used in slow, closed-loop control work scenarios. In other application scenarios, a digitally controlled attenuator plus a digitally controlled phase shifter is often used to control the amplitude and phase separately. However, the existing various digitally controlled phase shifter technologies, such as switch line technology, load line technology, reflective technology, switch filter technology, etc., are difficult to simultaneously satisfy broadband, 360° all-phase adjustment, high precision, Low insertion loss performance, or there may be problems of high cost and large volume, and it is difficult to perform technology transplantation between various frequency bands.

Contents of the invention

In view of this, the present invention aims to propose a numerically controlled vector modulator to solve the deficiencies in the above problems.

In order to achieve the above object, technical solution of the present invention is achieved in that way:

Digitally controlled vector modulator, including port 1, I/Q splitter, digitally controlled signal amplitude adjustment unit, digitally controlled inverter, power divider, and port 2 connected in sequence;

I/Q splitter, used to divide the RF signal input from port 1 into I-channel signal and Q-channel signal which are orthogonal and equal in amplitude;

The numerical control signal amplitude adjustment unit is used to control the amplitude of the I-channel and Q-channel signals respectively, and after vector synthesis, adjust the amplitude and phase of the signal in the quadrant;

The digitally controlled inverter is used to perform phase processing on the I-channel and Q-channel signals processed by the numerically controlled signal amplitude adjustment unit according to the different quadrants required by the vector;

The power divider is used to combine the signals of the I channel and the Q channel and then output them through port 2.

Further, the I/Q splitter includes a 3dB directional coupler and an isolation resistor.

Further, the I/Q splitter includes a high/low pass rheostat filter.

Further, the digitally controlled signal amplitude adjustment unit includes a digitally controlled attenuator.

Further, the digitally controlled signal amplitude adjustment unit includes a numerically controlled variable gain amplifier.

Further, the digitally controlled inverter includes two working states:

The reference state is defined as a phase of 0°, and the phase is flipped to 180° in another state.

Further, the digitally controlled inverter includes a 3dB directional coupler and a pair of simultaneously on/off SPST RF switches.

Further, the digitally controlled inverter includes a pair of SPDT radio frequency switches for switching high/low pass filters.

Further, the radio frequency switch includes a radio frequency switch based on a PIN diode, a radio frequency switch IC based on various semiconductor processes, and a MEMS radio frequency switch, and the IC represents an integrated circuit.

Further, the power divider includes a non-phase power divider or a reverse-phase power divider.

Compared with the prior art, the digitally controlled vector modulator of the present invention has the following beneficial effects:

The numerical control vector modulator of the invention is easy to realize the design of wide working frequency band, easy to transplant technology between frequency bands, its performance parameters are not sensitive to temperature, and the response speed is fast.

Description of drawings

The drawings constituting a part of the present invention are used to provide a further understanding of the present invention, and the schematic embodiments and descriptions of the present invention are used to explain the present invention, and do not constitute an improper limitation of the present invention. In the attached picture:

Fig. 1 is the structural representation of numerical control vector modulator of the present invention;

Fig. 2 is the structural representation of traditional analog vector modulator;

Fig. 3 is the structural representation of the narrowband IQ splitter of the present invention;

Fig. 4 is the quadrant adjustment schematic diagram of the signal vector of the present invention;

Fig. 5 is the structural representation of the narrowband digital control inverter of the present invention;

Explanation of reference signs

101, I/Q splitter; 102, numerical control attenuator (I road); 103, numerical control attenuator (Q road); 104, numerical control inverter (phase is 0 °); 105, numerical control inverter (phase is 180°); 106, power divider.

Detailed ways

It should be noted that, in the case of no conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other.

The present invention will be described in detail below with reference to the accompanying drawings and examples.

A numerically controlled vector modulator as shown in FIG. 1 includes: port 1, port 2, I/Q splitter, numerically controlled signal amplitude adjustment unit, numerically controlled inverter, and power divider.

The I/Q splitter 101 divides the radio frequency signal into an I-channel signal and a Q-channel signal which are orthogonal and equal in amplitude.

The I/Q splitter can be completed using a 3dB directional coupler (90° bridge) and isolation resistors;

In some narrowband applications, an I/Q splitter can also be completed in the form of a high/low pass rheostat filter, as shown in Figure 3. And any other circuit form that can split the signal into equal amplitude and phase difference of ±90° can be used as an I/Q splitter.

The digital control signal amplitude adjustment units 102 and 103 respectively control the amplitudes of the I-channel and Q-channel signals, and after vector synthesis, can adjust the amplitude and phase of the signals in the quadrants they are in. The lowest gear of the numerical control signal amplitude adjustment unit affects the accuracy of the amplitude and phase adjustment of the vector modulator. For example, the circuit designed based on the NC signal amplitude adjustment unit with the lowest gear of 0.25dB has an amplitude adjustment accuracy of 0.25dB or better, and an all-phase control accuracy of 0.825° or better; The circuit designed by the signal amplitude adjustment unit has an amplitude adjustment accuracy of 0.5dB or better, and an all-phase control accuracy of 1.65° or better. Compared with a 6-bit 360° digitally controlled phase shifter, its gears (180°, 90°, 45°, 22.5°, 11.25°, 5.625°) are at least 5.625°. It can be seen that this design is easier to achieve higher adjustment accuracy.

The core function of the numerically controlled signal amplitude adjustment unit is to adjust the amplitude of the signal, so a numerically controlled attenuator can be used, or a numerically controlled variable gain amplifier can be used instead.

The digitally controlled inverters 104 and 105 have two working states. One is the reference state, which is defined as a phase of 0°; in the other state, the phase is flipped to 180°.

A 3dB directional coupler and a pair of SPST RF switches that are turned on or off at the same time can be used to complete the function of the digitally controlled inverter. For each signal (I signal, Q signal), when the radio frequency switch is not conducting (open circuit state), it is defined that the signal is in the reference phase at this time, that is, the phase is 0°; then when the radio frequency switch is conducting (short circuit state), the signal phase of this channel will be reversed by 180°. Define the I-channel signal as the X-axis, the Q-channel signal as the Y-axis, and when the RF switches are not turned on, the signal vector is in the first quadrant, then the corresponding relationship between the signal vector quadrant and the switch state is shown in Figure 4. That is, by switching the working state of the radio frequency switch, the signal vector can be mapped from the first quadrant to any quadrant from the first to the fourth quadrant, and the 360° all-phase adjustment of the signal vector can be completed.

In some narrowband applications, a pair of SPDT radio frequency switches can also be used to switch the high/low pass filter to complete the function of the digitally controlled inverter, and its functional block diagram is shown in Figure 5. And any other circuit form that can control the signal vector to a phase difference of 180° can be used as a digitally controlled inverter.

RF switches can be realized by a variety of technologies, such as RF switches based on PIN diodes, RF switch ICs based on various semiconductor processes (GaN, GaAs, SiGe, etc.), MEMS RF switches, etc.

The power divider 106 may be composed of an in-phase (0° phase difference) power divider or an inverting phase power divider (180° phase difference/BULUN). The difference is only the mirror image of the quadrant where the vector is located, and does not affect the realization of the overall function.

In the vector modulator, the numerically controlled signal amplitude adjustment unit and the numerically controlled inverter are connected in series, so the positions can be interchanged without affecting the realization of the functions.

In the vector modulator, other circuits, including but not limited to amplifiers, filters, equalizers, etc., can be symmetrically inserted into the I and Q circuits without affecting the realization of functions.

In the vector modulator, if no unidirectional transmission device (such as an amplifier, etc.) is used in the I-way and Q-way circuits, then port 1 and port 2 are reciprocal, that is, the signal flow direction is arbitrary, and can be obtained from port 1 Flow to port 2, or flow from port 2 to port 1, without affecting the realization of the function.

When the phase only needs an adjustment range not greater than 90°, the digitally controlled inverter can be deleted.

Those of ordinary skill in the art can realize that the units and method steps of the examples described in conjunction with the embodiments disclosed herein can be implemented by electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the relationship between hardware and software Interchangeability. In the above description, the composition and steps of each example have been generally described according to their functions. Whether these functions are executed by hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art may use different methods to implement the described functions for each specific application, but such implementation should not be regarded as exceeding the scope of the present invention.

In the several embodiments provided in this application, it should be understood that the disclosed method and system may be implemented in other ways. For example, the division of the above-mentioned units is only a logical function division, and there may be other division methods in actual implementation, for example, multiple units or components can be combined or integrated into another system, or some features can be ignored, or Not implemented. The above units may or may not be physically separated, and components shown as units may or may not be physical units, that is, they may be located in one place, or may be distributed to multiple network units. Part or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment of the present invention.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than limiting them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: It is still possible to modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the technical solutions of the various embodiments of the present invention. All of them should be covered by the scope of the claims and description of the present invention.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the scope of the present invention. within the scope of protection.

Claims (8)

The digitally controlled vector modulator is characterized in that: it comprises a port 1, an I/Q splitter, a digitally controlled signal amplitude adjustment unit, a numerically controlled inverter, a power splitter, and a port 2 connected in sequence; I/Q splitter, used to divide the RF signal input from port 1 into I-channel signal and Q-channel signal which are orthogonal and equal in amplitude; The numerical control signal amplitude adjustment unit is used to control the amplitude of the I-channel and Q-channel signals respectively, and after vector synthesis, adjust the amplitude and phase of the signal in the quadrant; The digitally controlled inverter is used to perform phase processing on the I-channel and Q-channel signals processed by the numerically controlled signal amplitude adjustment unit according to the different quadrants required by the vector; The power divider is used to combine the signals of the I channel and the Q channel and then output them through port 2. The numerically controlled vector modulator according to claim 1, characterized in that: the I/Q splitter includes a 3dB directional coupler, an isolation resistor, and a high/low pass rheostat filter. The numerically controlled vector modulator according to claim 1, wherein the numerically controlled signal amplitude adjustment unit includes a numerically controlled attenuator and a numerically controlled variable gain amplifier. The digitally controlled vector modulator according to claim 1, wherein the digitally controlled inverter includes two working states: The reference state is defined as a phase of 0°, and the phase is flipped to 180° in another state. The digitally controlled vector modulator according to claim 1, characterized in that: the digitally controlled inverter comprises a 3dB directional coupler and a pair of simultaneously on/off SPST radio frequency switches. The digitally controlled vector modulator according to claim 1, characterized in that: the digitally controlled inverter comprises a pair of SPDT radio frequency switches for switching high/low pass filters. According to the numerical control vector modulator described in any one of claims 5 and 6, it is characterized in that: the SPDT radio frequency switch includes a radio frequency switch based on PIN diodes, a radio frequency switch IC based on various semiconductor processes, and a MEMS radio frequency switch, and the IC represents integrated circuit. The digitally controlled vector modulator according to claim 1, wherein the power divider comprises a non-phase power divider or an inverting phase power divider.

Images