JPH0495419A - High frequency receiver - Google Patents

Abstract

PURPOSE:To obtain optimum matching between an antenna and a receiver by providing a channel selection section and a video reception section separately and connecting the channel selection section and the video reception section through the use of a transmission line. CONSTITUTION:A broadcast wave signal received by a reception antenna 101 is amplified or attenuated up to a prescribed amplitude by gain control circuits 104,106 and a high frequency amplifier 105 and frequency-converted into an intermediate frequency signal by a frequency converter 107. Moreover, the result is amplified again by a intermediate frequency amplifier 110 and sent to a video reception section 117 via a signal separator 111 and a coaxial cable 102. In the case of channel selection, a channel selection signal generated by a channel setting circuit 114 is superimposed on a high frequency signal by the signal separator 112 and separated from the high frequency signal by the signal separator 111 through the coaxial cable 102. The separated channel selection signal controls an oscillating frequency from the variable oscillator 108 to select a desired channel. By such constitution, the reception antenna and the channel selection section are located closely.

Description

[Detailed Description of the Invention] Industrial Application Fields of the Invention This invention relates to low-noise, high-frequency receiving devices.Conventional Technology: With the spread of high-frequency equipment, Demand for equipment is increasing.

FIG. 3 shows a block diagram of a conventional high frequency receiving system up to the end. In Fig. 3, 101 is a receiving antenna;
102 is a coaxial cable, 103 is a band pass filter, 104, 106 is a gain control circuit 105 is a high frequency amplifier, 107 is a frequency converter 108 is a variable oscillator, 109
110 is an intermediate frequency band pass filter, 110 is an intermediate frequency amplifier, 114 is a channel setting port i, 115 is an intermediate frequency signal output terminal, and 116 is a tuning section.The operation of the above conventional high frequency receiving device will be explained below.

First, a broadcast wave signal received by a receiving antenna 101 is transmitted through a coaxial cable 102, a band pass filter 103,
The high frequency amplifier 10 passes through gain control circuits 104 and 106.
It is amplified by 5. Next, in the frequency conversion circuit 107, the frequency is converted to an intermediate frequency by the local oscillator signal from the variable oscillator 108, and after passing through the intermediate frequency band pass filter 109 and being amplified again by the intermediate frequency amplifier 110, the intermediate frequency signal output terminal 115 The oscillation frequency of the variable oscillator 108 is output from the channel setting circuit 1 to the subsequent video receiving section.
The frequency of the desired channel can be selected by the control voltage from 14. For example, when 2 channels in the 1iVHF band are selected, the oscillation frequency of the variable oscillator 108 is set to 148MH2 by the channel setting circuit 114.
A 90 MH2 signal received by the receiving antenna 101 is frequency-converted to 58 MHz by the frequency conversion circuit 107 and output from the intermediate frequency signal output terminal 115.
The receiving antenna 101 is installed outdoors and the high frequency signal is 10
The signal is transmitted through a coaxial cable 102 having a length of about m to a tuning section 116 installed indoors. FIG. 4 shows a block diagram of a satellite broadcast receiving system up to the tuning section as a second conventional example. In Figure 4, 2
01 is a receiving antenna for satellite broadcasting, 202 is a high frequency amplifier, 203 is a frequency converter, 204 is a local oscillator 20
5, the first intermediate frequency amplifier 206 is a coaxial cable, 20
7 is a high frequency amplifier 208 is a frequency converter, 209 is a variable oscillator, 210 is a second intermediate frequency amplifier, 211 is a band pass filter for the second intermediate frequency, 212 is a channel setting circuit! 2] 3 is a second intermediate frequency signal output terminal.

Further, 213 is a BS converter, and 214 is called a tuning section.The operation of the conventional high frequency receiving device described above will be explained below.
The satellite broadcast signal in the band enters the BS converter section 214, is amplified by the high frequency amplifier 202, is frequency-converted by the frequency conversion circuit 203 to a first intermediate frequency of 950 MHz to 1750 MHz, is amplified again by the first intermediate frequency amplifier 205, and then is coaxially transmitted. The first intermediate frequency signal is sent to the tuning section 215 through the cable 206, where it is amplified again by the high frequency amplifier 207 and the frequency converter 20.
8, the signal is frequency-converted into a second intermediate frequency signal of 600 MHz, passes through the second intermediate frequency amplifier 21O, the second intermediate frequency band-pass filter 211, and then is sent from the second intermediate frequency signal output terminal 213 to the subsequent video reception section. The oscillation frequency of the local oscillator 204 in the BS converter section 214 is fixed, and tuning is performed by the variable oscillator 209 in the tuning section 215.
This is done by changing the oscillation frequency of the Conduction The receiving antenna 201 and the BS converter section 214 are installed outdoors, and the high frequency signal is transmitted through a coaxial cable 206 with a length of about 10 m to the channel selection section 215 installed indoors. Problems to be solved by the invention However, with the configuration of the first conventional example above ((a)) there is a considerable distance between the receiving antenna and the tuning section,
The HF band signal wave has a wide frequency band from 90MHz to 770MHz, and impedance changes and phase rotation caused by the transmission system make it difficult to obtain optimal matching between the antenna and receiver (b) The noise figure deteriorates by the loss in the transmission system from the receiving antenna to the first stage amplifier.4 In addition, in the configuration of the second conventional example, (c) the first intermediate frequency signal wave is 950 MHz to 1750 MHz.
A number with a wide frequency band up to MHz Same as the first conventional example The high frequency characteristics of the receiver deteriorate due to the frequency characteristics of the transmission systema (d) Noise equal to the loss in the transmission system from the BS converter section to the tuning section The index deteriorates.

(e) Since a plurality of frequency converters are required, the number of components increases.The frequency characteristics of the circuit components adversely affect the high frequency characteristics of the receiver.

It has the disadvantage of The present invention aims to solve the above problems.

Means for Solving the Problems To achieve this object The channel selection signal generator is installed separately from the channel selection signal generator, and the channel selection signal generator is connected to the channel selection signal generator using a transmission line.

Effect: With this configuration, the transmission line between the receiving antenna and the tuning section can be made extremely short. No impedance change or phase rotation occurs, and optimal matching between the antenna and receiver can be obtained. A number that can minimize the loss in the transmission system between the receiving antenna and the tuning section
Although the deterioration of the noise figure can be minimized, and since only a single frequency intermediate frequency signal is transmitted, the influence of the frequency characteristics of the transmission system can be eliminated. This is an example of the first embodiment.
In the figure, 101 is a receiving antenna, 102 is a coaxial cable, 103 is a band pass filter, 104,
106 is a gain control circuit 105 is a high frequency amplifier 107
is a frequency converter, 108 is a variable oscillator, 109 is an intermediate frequency band pass filter, and 110 is an intermediate frequency amplifier.
111 and 112 are signal separators 113 is a code decoder 1
14 is a channel setting circuit 117 is a video receiving section 118
The operation of the first embodiment will be explained with reference to the drawings.
After unnecessary signals are removed by band pass filter 103, gain control circuits 104, 106 and high frequency amplifier 1
The signal is multiplied or attenuated to a constant amplitude value in step 05, then frequency-converted to an intermediate frequency signal by a frequency converter 107, and further passed through an intermediate frequency band-pass filter 109, and amplified again by an intermediate frequency amplifier 110, and then a signal separator. 111, the video receiving section 11 via the coaxial cable 102
At the time of channel selection, the channel selection signal generated by the channel setting circuit 114 is superimposed on the high frequency signal by the signal separator 112, passes through the coaxial cable 102, and then is sent to the signal separator 11.
The separated channel selection signal is separated from the high-frequency signal by the code decoder 113 and converted into a voltage value by the variable oscillator 1.
The desired channel is selected by controlling the oscillation frequency of 08.

In this embodiment (the receiving antenna 101 and the tuning section 11
6 is installed outdoors, the distance between each is within 10 cm, and the high frequency signal is transmitted through a coaxial cable 1 with a length of about 10 m.
Even if the video is transmitted to the video receiving unit 117 installed indoors through ζ, no change in impedance or phase rotation occurs, and optimal matching between the antenna and the receiver is achieved. In addition, since there is no loss in the transmission system, the deterioration of the noise figure is minimized, and since only a single frequency intermediate frequency signal is transmitted, the influence of the frequency characteristics of the transmission system is ignored. In this embodiment, the gain control circuits 104, 106,
By integrating the high frequency amplifier 105, frequency converter 107, and variable oscillator 108 on the GaAs substrate,
Figure 2 shows a second embodiment of the present invention, although the connection between each circuit block can be made over extremely short distances, and a high-frequency receiver with low loss and low noise can be realized. In Figure 2, 201 is a receiving antenna for satellite broadcasting, 202 is a high frequency amplifier, 203 is a frequency converter, 209 is a variable oscillation t, and 205 is an intermediate frequency amplifier.
206 is a coaxial cape/210 is an intermediate frequency band pass filter, 212 is a channel setting circuit, 216 is an IC
111 and 112 are signal separators; 114 is a channel setting circuit; and 117 is a video receiving unit. 12G
The Hz-band satellite broadcasting signal is amplified by a high-frequency amplifier 201, directly frequency-converted into a 600 MHz intermediate frequency signal by a frequency converter 202, and then amplified again by a high-frequency amplifier 205, and transmitted through signal separators 111, 112, and a coaxial cable 206 to become an image. The channel selection signal generated by the channel setting circuit 114 is superimposed on the high frequency signal by the signal separator 112, and is separated from the high frequency signal by the signal separator 111 which passes through the coaxial cable 102. be done.

The separated channel selection signal is converted into a voltage value by the code decoder 113, and the oscillation frequency of the variable oscillator 209 is controlled to select the desired channel.In this way, the conventional circuit is used to send the signal to the video receiver. In this example, frequency conversion is performed twice, but in this example, it is performed only once (this is a major difference from the conventional example). This makes it possible to eliminate the influence of the frequency characteristics of the transmission system. Also, in this embodiment, the number of points can be reduced.
By integrating 8 on a GaAs substrate, we have been able to eliminate the influence of the frequency characteristics of circuit components and have realized a high-frequency receiver with even lower loss and lower noise.

Effects of the Invention As described above, the present invention has the advantage that the receiving antenna and the tuning section can be brought close to each other. There is almost no change in impedance or phase rotation, and it is possible to obtain optimal matching between the antenna and the receiver. Since there is no loss in the earth transmission system, the deterioration of the noise figure can be minimized.Also, since only a single frequency intermediate frequency signal is transmitted, the influence of the frequency characteristics of the transmission system can be ignored. By integrating some or all of the components on a semiconductor substrate, it is possible to eliminate the influence of the frequency characteristics of circuit components, and the number of components that make up the receiver can be reduced, which is an excellent effect. .

[Brief explanation of the drawing]

FIG. 1 is a high frequency demodulation circuit according to one embodiment of the present invention. FIG. 2 is a high frequency demodulation circuit according to another embodiment of the present invention @3. FIG. 4 is a circuit diagram of a conventional high frequency demodulation circuit. ...Receiving antenna, 102...Coaxial cable, 103...Band pass filter 104.10
6. Gain control circuit 105... High frequency amplifier 10
7... Frequency conversion edge 108... Variable oscillation edge 10
9... Intermediate frequency band pass filter 110...
Intermediate frequency amplifiers 111, 112...signal separator 11
3. Code decoding image 114...Channel setting circuit 11
5...Intermediate frequency signal output terminal, 116.Tuning section 1
17...Video receiver 118...IC lawsuit

Claims (1)

[Claims] A tuning section consisting of a high frequency amplifier, a frequency converter, a variable oscillator, and a signal separator, and a video reception section including a channel setting circuit and a signal separator are installed separately, and the tuning section and the video reception section are installed separately. A high frequency receiving device characterized in that the two are connected using a transmission line.