JPH0629281U - Satellite receiver - Google Patents

Abstract

(57) [Abstract] [Purpose] With a simple circuit configuration, signals in the band below the satellite broadcast reception band are sufficiently removed. [Configuration] A satellite broadcast signal input terminal 2 to which a satellite broadcast signal is input, a converter drive voltage application terminal 9 to which a converter drive voltage is applied from a DC power source 10, a satellite broadcast signal input terminal 2 and a converter drive voltage LP which is inserted between the voltage application terminal 9 and passes the signal in the band lower than the satellite broadcast reception band to the converter drive voltage application terminal 9 side.
An input unit 20 having an F23 and an HPF 16 having an input end connected to the satellite broadcast signal input terminal 2 and passing signals in a band above the satellite broadcast reception band is provided.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a satellite broadcast receiver that receives satellite broadcasts.

[0002]

[Prior art]

 FIG. 5 is a block diagram showing a configuration example of a conventional satellite broadcast receiver 1. In this figure, 2 is a satellite broadcast signal input terminal to which a satellite broadcast signal is input, and 3 is an amplifier for amplifying the satellite broadcast signal. , An input unit for removing unnecessary signals by selecting with a filter, 4 a local oscillation unit for oscillating a local oscillation signal, and 5 a mixing of the output signal of the input unit 3 with the local oscillation signal for conversion into an intermediate frequency signal in the 400 MHz band This is the mixing section.

Further, 6 is an intermediate frequency section for selecting and amplifying the intermediate frequency signal, 7 is a demodulation section for detecting the intermediate frequency signal and outputting the image detection signal, and 8 is image detection for outputting the image detection signal. A signal output terminal 9 is a converter drive voltage application terminal to which a converter drive voltage of DC 15 V is applied from an external DC power source 10. The converter drive voltage is supplied to the input section 3 and the satellite broadcast signal input terminal 2. It is supplied to a converter (not shown) connected to the preceding stage of the satellite broadcast signal input terminal 2 via. As a result, the converter (not shown) amplifies the weak signal in the 12 GHz band received by the parabolic antenna (not shown), frequency-converts it into a satellite broadcast signal having a frequency of about 1 GHz, and outputs it via the satellite broadcast signal input terminal 2. , To the satellite broadcast receiver 1.

Next, FIG. 6 is a block diagram showing a configuration example of a main part of the input unit 3 constituting the satellite broadcast receiver 1. In this figure, portions corresponding to the respective portions in FIG. 5 are designated by the same reference numerals, and description thereof will be omitted. In FIG. 6, 11 is a choke coil having a value of 22 μH, for example, and supplies the converter drive voltage applied to the converter drive voltage application terminal 9 to the converter (not shown) via the satellite broadcast signal input terminal 2. However, the satellite broadcast signal supplied from the converter (not shown) via the satellite broadcast signal input terminal 2 is blocked. Reference numeral 12 is, for example, a bypass capacitor having a value of 1000 pF, which is provided near the converter drive voltage application terminal 9 and removes unnecessary signal components.

Further, 13 and 14 are capacitors, and 15 is a coil. These circuit elements 13 to 15 constitute a high-pass filter (hereinafter referred to as HPF) 16, and a signal in a band lower than a satellite broadcast reception band. To remove. The value of each of the capacitors 13 and 14 is set to, for example, 2 pF, and the value of the coil 15 is set to, for example, 70 mH. Further, 17 is an output end of the HPF 16, and 18 is a high frequency amplifier for amplifying the satellite emission signal which has passed through the HPF 16. Here, FIG. 7 shows an example of a pass band characteristic between the satellite broadcast signal input terminal 2 and the output end 17 of the HPF 16. In this figure, f _C is the cutoff frequency, which is about 900 MHz when the circuit elements 13 to 15 are set to the above-mentioned values.

[0006]

[Problems to be solved by the device]

 By the way, from the satellite broadcast signal input terminal 2 of the above-described conventional satellite broadcast receiver 1, broadcast signals of various bands are input, as shown in FIG. In FIG. 8, a is a terrestrial VHF band low band (about 90 to 108 MHz), b is a terrestrial VHF band high band (about 170 to 222 MHz), and c is a terrestrial UHF band (about 470 to 770 MHz). ) And d are satellite broadcast receiving bands (about 1030 to 1340 MHz).

Therefore, in the above-described conventional satellite broadcast receiver 1, as described above, the HPF 16 is inserted in the input unit 3 and the band below the satellite broadcast reception band is obtained due to the pass band characteristic shown in FIG. The signal of is removed. However, with the passband characteristics shown in FIG. 7, it is not possible to adequately remove signals in the band below the satellite broadcast reception band, so these signal components may interfere with the circuits after the input section 3 as interference signals. I had entered it.

Therefore, in order to sufficiently remove the signal in the band lower than the satellite broadcast reception band, the attenuation characteristic of the HP F16 with respect to the non-pass band may be improved. For that purpose, the number of circuit elements is increased. It has to be done, and there is a drawback that the circuit becomes complicated. The present invention has been made under such a background, and it is an object of the present invention to provide a satellite broadcast receiver capable of sufficiently removing signals in a band lower than the satellite broadcast reception band with a simple circuit configuration. To aim.

[0009]

[Means for Solving the Problems]

 The satellite broadcast receiver according to the present invention includes a satellite broadcast signal input terminal to which a satellite broadcast signal is input, a converter drive voltage application terminal to which a converter drive voltage of a predetermined voltage is applied from an external DC power source, and A low-pass filter, which is inserted between the satellite broadcast signal input terminal and the converter drive voltage application terminal and passes signals in a band lower than the satellite broadcast reception band to the converter drive voltage application terminal side, and an input terminal. Is connected to the satellite broadcast signal input terminal, and has an input section including a high-pass filter that passes signals in a band above the satellite broadcast reception band.

[0010]

[Action]

 According to the above configuration, the converter driving voltage applied to the converter driving voltage application terminal is supplied to the converter via the low-pass filter and the satellite broadcast signal input terminal. On the other hand, signals in the band below the satellite broadcast reception band input from the converter via the satellite broadcast signal input terminal are passed through the low pass filter to the converter drive voltage application terminal side, and the output terminal of the high pass filter. At, it declines sharply. As a result, signals in the band lower than the satellite broadcast reception band are blocked from being input to the circuit in the subsequent stage from the output end of the high-pass filter, and the interference of these signals in the circuit in the subsequent stage is prevented.

[0011]

【Example】

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a main part of an input unit 20 which constitutes a satellite broadcast receiver 19 according to an embodiment of this idea. In this figure, parts corresponding to those in FIG. 6 are designated by the same reference numerals, and the description thereof will be omitted. In the input unit 20 shown in FIG. 1, instead of the choke coil 11, a low pass filter (hereinafter referred to as LPF) 23 (see FIG. 2) including a coil 21 and a capacitor 22 is newly provided. This LPF 23 has pass band characteristics as shown in FIG. 3 with a cut-off frequency f ′ _C = approximately 800 MHz when the respective values of the coil 21 and the capacitor 22 are set to approximately 150 mH and approximately 1 pF, for example. .

Reference numeral 24 is a floating impedance that exists between the LPF 23 and the bypass capacitor 12. If the stray impedance 24 does not exist, the coil 21 and the capacitor 22 do not operate as the LPF 23. However, in the normal case, the stray impedance 24 is inevitably generated due to the printed wiring pattern. The coil 21 and the capacitor 22 operate as the LPF 23 having the pass band characteristic shown in FIG. Therefore, the pass band characteristic between the satellite broadcast signal input terminal 2 and the output end 17 of the HPF 16 becomes steeper as compared with the conventional pass band characteristic shown in FIG. 7, as shown in FIG.

In such a configuration, the converter drive voltage applied to the converter drive voltage application terminal 9 is not shown in the figure via the floating impedance 24, the coil 21, and the satellite broadcast signal input terminal 2 as in the conventional case. Supplied to the converter. On the other hand, the signal in the band lower than the satellite broadcast receiving band input from the converter (not shown) via the satellite broadcast signal input terminal 2 is passed to the LPF 23, and at the output end 17 of the HP F 16 compared to the conventional one. It decays rapidly. As a result, signals in the band below the satellite broadcasting reception band are blocked from being input to the circuit in the subsequent stage from the output terminal 17 of the HPF 16, and the interference of these signals in the circuit in the subsequent stage is sufficiently reduced compared to the conventional case. Can be prevented.

[0014]

[Effect of device]

 As described above, according to the present invention, it is possible to sufficiently remove the signal in the band lower than the satellite broadcast receiving band with a simple circuit configuration. Therefore, it is possible to prevent these signals from interfering with the circuit in the subsequent stage.

[Brief description of drawings]

FIG. 1 is a satellite broadcast receiver 19 according to an embodiment of the present invention.
FIG. 3 is a block diagram showing a configuration of a main part of an input unit 20 that configures FIG.

FIG. 2 is a circuit diagram showing a configuration of LPF 23.

FIG. 3 is a diagram illustrating an example of pass band characteristics of an LPF 23.

FIG. 4 is a satellite broadcast signal input terminal 2 and an HPF 1 shown in FIG.
It is a figure showing an example of the pass band characteristic between 6 and the output end 17.

FIG. 5 is a block diagram showing a configuration example of a conventional satellite broadcast receiver 1.

FIG. 6 is a block diagram showing a configuration example of a main part of an input unit 3 which constitutes the conventional satellite broadcast receiver 1.

FIG. 7 is a satellite broadcast signal input terminal 2 and HPF1 shown in FIG.
It is a figure showing an example of the pass band characteristic between 6 and the output end 17.

FIG. 8 is a diagram showing an example of a broadcast signal input from a satellite broadcast signal input terminal 2 of a conventional satellite broadcast receiver 1.

[Explanation of symbols]

 1, 19 Satellite Broadcast Receiver 2 Satellite Broadcast Signal Input Terminal 3, 20 Input Section 9 Converter Driving Voltage Applying Terminal 10 DC Power Supply 12 Bypass Capacitor 13, 14, 22 Capacitor 15, 21 Coil 16 HPF 17 Output Terminal 18 High Frequency Amplifier 23 LPF 24 stray impedance

Claims (1)

[Scope of utility model registration request] 1. A satellite broadcast signal input terminal to which a satellite broadcast signal is input, a converter drive voltage application terminal to which a converter drive voltage of a predetermined voltage is applied from an external DC power supply, and the satellite broadcast signal input terminal. A low-pass filter inserted between the converter drive voltage application terminal and passing a signal in a band lower than the satellite broadcast reception band to the converter drive voltage application terminal side, and an input terminal for inputting the satellite broadcast signal input. A satellite broadcast receiver comprising an input unit connected to a terminal, the input unit having a high-pass filter that allows signals in a band above the satellite broadcast reception band to pass therethrough.