JPH0440119A - Tuner device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a tuner device that converts the frequency of television high frequency signals and satellite broadcasting high frequency signals.

Prior art The tuner device in a conventional television receiver is a VH
Television high frequency signals from the F band to the LIHF band are converted into television intermediate frequency signals (for example, in Japan, 58.
75 MHz). In addition, the tuner device of the satellite broadcasting receiver converts the satellite first intermediate frequency input signal received by the outdoor antenna for satellite reception and frequency-converted by the outdoor converter into the satellite second intermediate frequency signal (for example, 134.26 MHz in Japan, or 402.78 MHz).

The following will be explained based on the drawings.

FIG. 4 shows a schematic block diagram of a television receiver.

Television high-frequency signals are usually transmitted in a terrestrial broadcasting system in a signal band ranging from the VHF band to the UHF band. The high frequency signal received by the antenna 32 is converted into a first intermediate frequency while a desired channel is selected by the tuner device 33 of the television receiver 31 (the audio system is not shown). Next, the video intermediate frequency amplification circuit and detection circuit 34 converts the signal into a baseband signal, and the signal is transmitted to the display 36 via the baseband signal processing circuit 35. In the case of terrestrial broadcasting, the video signal is an amplitude modulated (AM) signal, so the detection circuit 34 performs AM demodulation.

FIG. 5 is a detailed block diagram of the tuner device 33 of FIG. 4. In the figure, the TV high frequency signal is passed through the signal splitter to VH.
The signal is distributed into F band and UHF band signals, and the VHF input signal is input to the input terminal 52. The input signal is sent to an input tuning circuit 41, an RF amplifier circuit 42, and an interstage tuning circuit 43.
The signal is frequency-tuned and amplified to the desired reception channel and input to the mixing circuit 44. In addition, a local oscillation signal for a channel desired to be received is inputted from the local oscillation circuit 46 to the mixing circuit 44, and the high frequency tuned and amplified signal is converted into a TV intermediate frequency signal (for example, 58.75 M in Japan) by the mixing circuit 44.
Hz) and outputs it from the output terminal 54 via the intermediate frequency signal output circuit 45.

On the other hand, the UHF input signal is input to the input terminal 53 like the VHF input signal.
, an input tuning circuit 47, an RF amplification circuit 48, an interstage amplification circuit 49, a mixing circuit 50, and a local oscillation circuit 51 generate a television intermediate frequency signal. Since there is no oscillation component from the local oscillation circuit 46, the intermediate frequency signal is outputted from the output terminal 54 from the output circuit 45 via the output circuit 45 (which operates as an amplifier circuit).

FIG. 6 shows a satellite broadcast signal receiving system. Broadcasting satellite 6
The satellite broadcasting signal from 5 is received by an outdoor antenna 66, and the received weak microwave signal is once converted into a satellite first intermediate frequency signal (Japan: 1035.5) by an outdoor low noise converter 67.
98 to 1331.5M)Iz) and amplified. The satellite first intermediate frequency signal is input to the indoor unit 61, and the desired reception channel is first selected by the satellite broadcast reception tuner device 62, and the satellite second intermediate frequency signal (Japan:
134.26 MHz or 402.78 MHz). Next, the intermediate frequency signal amplification and detection circuit 63 converts the signal into a baseband signal, and the signal is transmitted to the display device 68 via the baseband signal processing circuit 64 .

Note that unlike a terrestrial broadcast television signal, a satellite broadcast signal is a video signal that is frequency modulated (FM), so the detection circuit 64 is an FM demodulation circuit.

FIG. 7 is a detailed block diagram of the satellite broadcast reception tuner device shown in FIG. 6. In the figure, the satellite first intermediate frequency signal is input from input terminal 77, and input matching and filter circuit 71. Mixing circuit 73 via high frequency amplifier circuit 72
flows to On the other hand, since the local oscillation circuit 76 oscillates a local oscillation frequency signal corresponding to the desired reception channel, the mixing circuit 73 extracts the satellite second intermediate frequency signal from the satellite first intermediate frequency signal.

And it is a second intermediate frequency amplification circuit 74° output circuit 75
The configuration was such that the output terminal 78 was taken out via the output terminal 78.

Problems to be Solved by the Invention In such a conventional system, in a television receiver with a built-in satellite broadcasting receiver or a video tape recorder with a built-in satellite broadcasting receiver, the built-in television receiver 8 shown in FIG.
1 as an example, there are independent tuner devices 33 and 62 for television signal reception and satellite broadcast reception, and furthermore, separate detection circuits 34 for AM demodulation and FM demodulation as signal demodulation circuits.
．． 63 is necessary, and signals are transmitted to the baseband signal processing circuit 82 and the display 36 via these. As described above, the reception system requires independent high-frequency signal demodulation circuits, which is disadvantageous in terms of miniaturization and cost reduction of equipment.

The present invention solves the above-mentioned problems, and aims to reduce the size and cost of the tuner device by commonly using the signal conversion system of the tuner device for satellite reception when receiving television signals. This is the purpose.

Means for Solving the Problems and To achieve this object, the present invention provides a system for transmitting terrestrial broadcast television high frequency signals ranging from the VHF band to the UHF band.
an up-converter for up-converting the first intermediate frequency signal for a satellite broadcast receiver to a frequency signal at or near the frequency band; and a down converter that performs down conversion, the up converter is provided with an input terminal for inputting a terrestrial broadcast television high frequency signal, and the down converter is provided with an input terminal for inputting a terrestrial broadcast television high frequency signal, and the down converter is provided with a high frequency signal received by a satellite broadcast antenna and frequency converted by an outdoor converter. a first input terminal into which a satellite first intermediate frequency signal is input; a second input terminal into which an output signal of the up-converter is input; A switching circuit for receiving and selecting input signals from the second input terminal is provided.

According to the above-described configuration, the present invention converts the output signal from the up-converter that receives the terrestrial broadcast television signal into a frequency signal in or near the satellite first intermediate frequency band. Input the signal into a down converter that converts the signal into a satellite second intermediate frequency signal,
Both terrestrial television broadcasting and satellite broadcasting can be processed using the same satellite second intermediate frequency signal.

In other words, when receiving terrestrial broadcast television, the tuner device uses an up-down frequency conversion method that uses an up converter and a down converter, and when receiving satellite broadcasting, it uses a down frequency converter that uses only a down converter without operating an up converter. This is a conversion type tuner device, and the size can be reduced by sharing the component parts.

In particular, the above-mentioned upconverter changes the conversion frequency to VH
Since the signal frequency is selected to be higher than the terrestrial broadcast television frequency from the F band to the UHF band (for example, near the IGHz band), there is no need for a tuning circuit for channel tuning or image interference elimination in conventional tuner devices. It is possible to employ a group conversion method without a tuning circuit, thereby greatly simplifying the circuit configuration, reducing the number of parts, and further promoting miniaturization. In addition, the down converter can be used in common for both terrestrial broadcasting and satellite broadcasting, and the same output frequency can be selected. This is very effective in the circuit system configuration for further amplifying and AM/FM demodulating the output signal of the tuner device, and it is possible to realize miniaturization and cost reduction of equipment such as television receivers or video tape recorders.

EXAMPLE Hereinafter, an example of the present invention will be described based on the accompanying drawings.

FIG. 1 shows an example of a configuration according to the present invention. In the figure, 16 surrounded by a broken line is an up converter, and 17 is a down converter. A signal from an antenna ranging from a VHF band to a UHF band, which is a terrestrial broadcast television high frequency signal, is inputted from an input terminal 13. The input signal is VHF-U
Input filter circuit 1 in which the HF band signal region is appropriately divided
The signal is amplified by the high frequency amplifier circuit 2 and input to the mixing circuit 3. - In the force field section oscillator 5, the oscillation frequency has the relationship shown in the following equation.

f osc+ = f IFI + f RF
--(1) However, + osc + Local oscillation frequency f IFI - Conversion frequency of up converter 16 + RF - Terrestrial broadcast television signal frequency For example, f IFI should be set to 955.75 MHz near the first intermediate frequency of the satellite broadcast receiver. For example, TV channel 1 is f osc+=955.75+91.25=1047
(MHz) TV channel 62 is f osc+ =955.75+765.25=172
1 (MHz), f 08CI is 1047~17
It consists of a 21 MHz local oscillator.

In the conventional example, the frequency change width as a local oscillator is 15
Wide range from 0 MHz to 824 MHz, change ratio N is 5.4
There are also 9. Therefore, in the conventional example, separate local oscillators were used for each of the VHF and UHF bands, and the VHF band required band switching between a low band and a high band. However, in the configuration of one embodiment of the present invention, the frequency change ratio N is as low as 1.64, and one-band oscillation is possible with one circuit, making it possible to greatly simplify the circuit configuration. This signal component of the local oscillator 5 is injected into the mixer 3 and converted to a conversion frequency f IF+ near the first intermediate frequency for the satellite receiver as described above. Note that if the mixer 3 uses a double-balanced mixer circuit using diodes or the like with good nonlinear distortion characteristics, and furthermore, the high-frequency amplifier circuit 2 uses an amplification element with good nonlinear distortion characteristics, channel tuning as in the conventional example can be achieved. No circuit is required,
The input filter circuit 1 may have a simplified configuration that suppresses image interference signals and reduces nonlinear distortion during multichannel reception input. The signal f IF+ converted by the mixer 3 is passed through a bandpass filter 4 to attenuate channels other than the desired reception channel and sent to a terminal 18.
Take it out. Since this bandpass filter 4 is used for receiving terrestrial broadcast television, it is constituted by a narrowband bandpass filter having a bandwidth of approximately 6 MHz (3 dB bandwidth), such as a dielectric resonant filter or a surface acoustic wave filter.

The above explanation uses f IF+ as the first intermediate frequency band for satellite broadcast receivers (Japan 1035.98~1331.5M H
z), but the upper frequency is 1.
It is also possible to set the frequency to around 500 MHz.

Next, the down converter 17 has a configuration surrounded by a broken line. A first intermediate frequency signal for a satellite receiver, which is obtained by receiving a microwave signal from a broadcasting satellite with an outdoor antenna and frequency-converting it with an outdoor converter, is input from the terminal 14 . Note that the signal converted by the up converter 16 described earlier is sent to the down converter 1 via the terminal 18 and the signal switching circuit 6.
When receiving terrestrial broadcasting input to terminal 7, the signal from terminal 14 is cut off. This signal switching circuit 6 can be constructed from a high frequency bin diode, a high frequency relay, or the like. The signal that has passed through the signal switching circuit 6 is sent to the first satellite receiver, which will be described later.
It passes through a wideband input filter circuit 7 that passes the intermediate frequency signal band and the upconverter 16 output signal. The signal is then amplified by a high frequency amplifier circuit 8 and input to a mixer 9.

The local oscillator 12 is set to a fixed frequency when receiving terrestrial broadcasting. That is, in order to select the same frequency as the satellite second intermediate frequency as the Chinaina device output signal, for example, the satellite second intermediate frequency f1.

If 402.78 MHz is selected, the oscillation frequency f 05C2 of the local oscillator 12 is f oscz= f tp+ + f 1F2= 95
5.75 + 402.78 = 1358.53 (M
Minister)...(2). This output signal is taken out from the IP amplifier 10 and the output circuit 1) to the output terminal 15 as a terrestrial broadcast television IF signal.

Next, in the case of satellite broadcast reception, the local oscillator 5 of the up converter 16 is not operated, and the signal switching circuit 6 is connected to the terminal 1.
The signal from terminal 4 is passed through and the signal from terminal 18 is cut off. Therefore, the satellite first intermediate frequency signal from the terminal 14 is input to the input filter circuit 7 via the signal switching circuit 6.

The input filter circuit 7 is composed of a low-pass filter (LPF) that suppresses one image interference signal and one local oscillation signal, using a multi-stage filter configuration using minute inductance and capacitance.

Since this signal has the satellite's first intermediate frequency, it is a multi-channel input signal transmitted from the satellite. The signal is amplified by a wideband high frequency amplification circuit 8 and input to a mixer 9 . When the satellite second intermediate frequency is selected as 402.78 MHz, the oscillation frequency f osc:' of the local oscillation circuit 12 is f05C2=fRF'+f-IF2
-- (31 However, f RF is the satellite's first intermediate frequency. For example, the satellite's first intermediate frequency of the B5-1 channel of satellite broadcasting in Japan is 1049.48 MHz, so fosc2 = 1049.48 + 402.78 = 1452
．． 26MHz, and the B5-15 channel is similarly f.
. sc2-1720, 78MHz.

Therefore, in the case of satellite broadcast reception, the local oscillator 12 becomes a frequency variable oscillation circuit. Here, the local oscillator 12 generates the above-mentioned terrestrial broadcasting oscillation, that is, 1358.53 MHz.
It is necessary to oscillate between 1452.26MHz and 1720.78MHz, but the frequency change ratio is 1720.
78/1358.53=1.27, which is extremely small, and can be configured with a simple circuit using a variable capacitance diode or the like with the same oscillation circuit. This local oscillation signal is injected into the mixer 9,
The output is amplified by IF amplification as a satellite second intermediate frequency component, and outputted from the output terminal 15 via the output circuit 1). Output circuit 1) has a bandwidth of approximately 27 MHz (3 dB bandwidth) as a wide band pass filter for satellite broadcast reception.
It may also be configured with a SAW filter or the like.

The frequency of the local oscillators 5 and 12 can be accurately controlled by using a PLL frequency synthesizer and a microprocessor. In this down converter 17, there are currently only a maximum of 8 channels for satellite broadcast reception in Japan, and adjacent channel interference is prevented by using semiconductor elements and circuits with relatively good nonlinear distortion in the wide band high frequency amplification circuit 8 and mixer 9. If selected, it becomes possible to simplify the circuit, reduce the number of components, and further downsize the circuit without having to tune each channel.

FIG. 2 shows an example of a television receiver incorporating the above embodiment. As is clear from this embodiment, it is greatly different from the conventional one shown in FIG. AM/FM detection circuit 23 and baseband signal processing circuit 2 by common use of one tuner device 22 and satellite second intermediate frequency amplification system.
4, which can greatly contribute to downsizing and lowering the cost of equipment. Note that 25 is a display.

3(a) and 3(b) show a specific example of the circuit shown in FIG. 1.

FIG. 3 (al) is a specific circuit example of the up converter 16, and the sections marked with broken lines indicate the respective circuit blocks explained in FIG. 1. The operation will be explained along the circuit diagram. The terrestrial broadcast television signal is input to the terminal 13 and input to the input filters FLI~3.Here, the switching diodes D1~6 perform on/off operation by the DC bias from the band switching control terminals 91~93.For example, the low band (90 to 108 MHz), switching diodes DI and D4 are conductive, a low-pass filter with a cutoff frequency of 108 M or higher operates, and the input signal is transmitted to the next stage high-frequency amplifier circuit 2. On the other hand, the filter FL2. The switching diodes D2+D3.D5.Ds connected to both ends of FL3 are set to be in a cutoff state, so that the signal is not transmitted to the next stage high frequency amplifier circuit 2.The fill FL2 is in the high band ( It is a pan/do-pass filter that passes the UHF band (170 to 222 MHz) and attenuates the low band and UHF band.
This is a bypass filter that passes the 770 MHz signal and attenuates the VHF channel (low and high-high bands). The high frequency amplifier circuit 2 consists of PIN diodes D7 to D10.
A variable attenuator consisting of
It is configured to perform GC circuit operation. Note that the transistor Q1 is a GaAs MESFET with excellent nonlinear distortion characteristics.
are using. The signal amplified by this high frequency amplification circuit 2 is transmitted through diodes D1) to D14 and balance transformer L5. The signal is inputted to a diode double-balanced mixer type mixer 3 composed of L6. -The force field oscillator 5 consists of a transistor Q2 and a variable capacitance diode D1.
5. Consists of a common collector type oscillator circuit consisting of an inductance line L8, and the oscillation output is provided by a transistor Q3.
The signal is amplified by the buffer amplifier and injected into the mixer 3. The signal frequency-converted by mixer 3 is transferred to capacitor CI
A bypass filter consisting of O, C1l and an inductance L7 suppresses leakage of the television signal in the VHF-UHF band, and the signal is taken out from a terminal 18 via a narrowband bandpass filter FL4 for attenuating unnecessary signals other than the channel desired for conversion. In the figure, capacitors CI, C2, C4,
C6, C8, C9, C12, C13, C14, and C18 are DC blocking or high frequency signal coupling capacitors. Capacitors C3, C5, C7, C17, and C19 are high frequency bypass capacitors, and C15C16 is an oscillation circuit feedback capacitor. Resistors R1 to R23 are DC bias resistors, inductances Ll, L2 . L3. L4 is a high frequency choke coil.

Terminals 95 and 97 are DC power supply terminals for transistors Ql, Q2Q3, and terminal 96 is a DC bias terminal for variable capacitance diode D15 of local oscillator 5.

FIG. 3 fb) is a specific circuit example of the down converter 17. Terminal 14 is an input terminal for a satellite reception first intermediate frequency signal in the case of satellite broadcast reception. Terminal 18 is the conversion signal input terminal of upconverter 16 described above. Each signal is switched by the switch sw1, passed through the input filter FL5, and amplified by the transistor Q31 of the broadband high-frequency amplification circuit 8.
The signal is input to a diode single balance mixer 9 type mixer composed of diodes D31, 32 and balun transformer L34. On the other hand, the intermediate oscillator 12 constitutes an oscillation circuit consisting of a transistor Q33, an inductance line L35, and a variable capacitance diode D33, and the oscillation output is amplified by a buffer amplifier of a transistor Q34, and a mixer 9
is injected into. The signal converted by the mixer 9 is amplified by the transistor Q32 in the IP amplifier 10, and then sent to the output circuit 1.
), the signal is extracted as the satellite second intermediate frequency.

Since the IF amplifier 10 also operates as an AGC circuit when the input electric field level fluctuates during satellite broadcast reception, the AGC driving DC bias can be supplied from the terminal 103 to the transistor Q32. In the figure, capacitors C31, 32
, 33, 36, 37° 39.40, 41.44 are DC blocking or high frequency feeding capacitors. Also, capacitors C3845 and 46 are high frequency bypass capacitors, C42
C43 is a feedback capacitor for the oscillation circuit. Resistor R31
~R43 is a DC bias resistor, inductance L31
．． 32 is a high frequency choke coil. Terminal 102,1
05 is a DC power supply terminal for transistors 031 to 34, terminal 101 is an outdoor converter power supply terminal, and terminal 10
4 is a bias terminal for driving a variable capacitance diode.

Effects of the Invention As described above, according to the present invention, by converting a terrestrial broadcast television signal into a frequency signal in or near the satellite first intermediate frequency band using an up-converter, the satellite first intermediate frequency signal is converted into a satellite second intermediate frequency signal. The down converter that converts to intermediate frequency signals and the signal conversion process can be performed in common, and as a result, the circuit configuration can be significantly simplified, making a significant contribution to reducing the number of parts, downsizing, and lowering costs. Become something.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a tuner device according to an embodiment of the present invention, FIG. 2 is a block diagram showing an embodiment of a television receiver with a built-in satellite broadcasting receiver using the tuner device of FIG. 1, and FIG. Figures ta+ and tb+ are circuit diagrams of the up-converter and down-converter of the tuner device in Figure 1, respectively, Figure 4 is a professional diagram showing an overview of the reception system of a television receiver, and Figure 5 is a diagram of the television reception system. 6 is a block diagram showing an overview of a satellite broadcast receiving system, FIG. 7 is a block diagram of a tuner device for satellite broadcast receivers, and FIG. 8 is a block diagram of a conventional tuner device for satellite broadcast receivers. It is a block diagram. 6... Signal switching circuit, 13.14.18...
...terminal, 15...output terminal, 16...
...up converter, 17...down converter. Name of agent: Patent attorney Shigetaka Awano and one other person 5.12.
・Eibaku #Kuki 6...4 first time S! r 7...χ filter circuit 16

Claims (3)

[Claims] (1) An up-converter that up-converts a terrestrial broadcast television high frequency signal from the VHF band to the UHF band to a frequency signal at or near the first intermediate frequency signal band frequency for a satellite broadcast receiver; a down converter that down-converts a first intermediate frequency signal and its neighboring frequency signal into a satellite second intermediate frequency signal; the up converter is provided with an input terminal for inputting a terrestrial broadcast television high frequency signal; a first input terminal for inputting a satellite first intermediate frequency signal received by a satellite broadcasting antenna and frequency-converted by an outdoor converter; and a second input terminal for inputting an output signal of the up-converter; A tuner device provided with a switching circuit for receiving and selecting input signals from these first and second input terminals. (2) The tuner device according to claim (1), wherein the up-converter and the down-converter are housed in separate metal casings. (3) The tuner device according to claim (1), wherein the up converter and the down converter are housed in the same metal housing.