JPH0628866Y2 - Satellite receiver - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a satellite broadcast receiver, and more particularly to a satellite broadcast receiver in which the azimuth and elevation of the BS antenna can be easily and accurately set.

(Prior Art) FIG. 2 is a block diagram showing a conventional satellite broadcast receiver.

Satellite broadcasting is also called BS (Broadcasting Satellite) broadcasting, and is broadcasting from a broadcasting satellite (space station) launched above the equator.

Television waves from a broadcasting satellite about 38,000 km away are weak and have a high frequency of SHF (12 GHz band), so the reception antenna used in each home has a large parabolic BS with a large gain as shown in Fig. 2. The antenna 1 is used.

The signal in the 12 GHz band received by the BS antenna 1 is BS
The frequency is converted into a 1 GHz band BS-IF signal by the converter 2, and the BS-I of the BS tuner 4 is converted by the coaxial cable 3.
It is supplied to the F signal input terminal 5.

The BS-IF signal supplied to the BS-IF signal input terminal 5 is supplied to the frequency conversion circuit 6 via the capacitor C that passes the high frequency component, and is converted into a signal in the intermediate frequency band.

The output signal of the frequency conversion circuit 6 is supplied to the AGC circuit 7.

The AGC circuit 7 detects the amplitude of the input signal, generates a DC AGC voltage corresponding thereto, controls the gain by the DC AGC voltage, and operates so that the amplitude of the output signal becomes constant.

Therefore, it can be seen that the DC AGC voltage of the AGC circuit 7 is proportional (or corresponding) to the signal level (electric field strength) of the input signal received by the BS antenna 1.

The output signal of the AGC circuit 7 is supplied to the FM demodulation circuit 8, and the video signal to which the FM demodulation is performed and the energy spread signal is added and the four-phase DPSK audio subcarrier are obtained.

The FM demodulated video signal of the FM demodulation circuit 8 is supplied to the video signal processing circuit 9 to be video by a de-emphasis circuit, an energy diffusion signal removal circuit and a video amplification circuit for returning the pre-emphasized video signal to the original waveform. The output signal is taken out and supplied to the video signal output terminal 10.

In addition, the audio subcarrier that has been subjected to 4-phase DPSK output from the FM demodulation circuit 8 is supplied to the audio signal processing circuit 11.
A four-phase DPSK demodulation circuit for demodulating to obtain a PCM signal;
A PCM demodulation circuit that demodulates the PCM signal and extracts a voice signal from the digital signal outputs a 2-channel voice output signal and supplies it to the voice signal output terminals 12 and 13.

Then, the output signals of the video signal output terminal 10 and the audio signal output terminals 12 and 13 are supplied to the television receiver, the video tape recorder, the stereo amplifier, etc., respectively, and utilized.

Since the BS converter 2 handles a weak signal, the operating power is supplied from the BS tuner 4 in order to reduce the influence of hum modulation as much as possible and to further reduce the size and weight of the housing.

The DC power supply voltage (for example, 15 V) generated by the BS converter power supply circuit 14 is superimposed on the BS-IF signal input terminal 5 via the inductance L that blocks high-frequency components, and is transmitted via the coaxial cable 3 to the BS. It is sent to the converter 2.

Further, the DC AGC voltage is taken out from the AGC circuit 7 and supplied to the level check terminal 15 for use in adjusting the direction when the antenna is installed.

(Problems to be solved by the invention) As described above, the distance from Japan to the broadcasting satellite is about 38,
The signal is very weak by the time the radio wave reaches the ground. In addition, the BS antenna has a sharp directivity, and the influence on the video / audio due to the deviation of the direction is remarkable. Therefore, for stable reception for a long period of time, it is important to adjust the direction when the antenna is installed.

As shown in FIG. 2, the BS antenna is generally adjusted by introducing the DC AGC voltage from the level check terminal 15 of the BS tuner 4 to the vicinity of the BS antenna with a cable and connecting the DC voltmeter 16.

That is, as described above, the DC AGC voltage of the AGC circuit 7 is B
It is proportional (or corresponding) to the signal level (electric field strength) of the input signal received by the S antenna 1.

Generally, when the DC AGC voltage is maximum (or minimum), the signal level is maximum.

Therefore, as an adjusting method, the azimuth angle, the elevation angle, etc. of the BS antenna 1 may be adjusted and set so that the DC voltage in the DC voltmeter 16 becomes maximum (or minimum).

However, this adjustment method has a problem that the adjustment accuracy is poor because the adjustment is performed by the deflection of the needle of the DC voltmeter as described above.

In addition, at the time of adjustment, it is necessary to connect the cable from the BS tuner to the vicinity of the BS antenna located at a high place outdoors such as on the roof, and if it is far away, a long cable will be carried, increasing the risk of falling. However, there was also a problem that it took a lot of time to adjust the installation.

The present invention was made by paying attention to the above points, and the azimuth and elevation angles of the BS antenna can be easily adjusted without the need to connect a cable from the BS tuner, and the adjustment can be performed while viewing the actual image. It is an object of the present invention to provide a satellite broadcast receiver that can be adjusted with high accuracy because it can be performed.

(Means for Solving the Problems) In order to achieve the above object, a BS which is received by a BS antenna, frequency-converted by a BS converter, and transmitted.
A BS-IF signal input terminal for inputting an IF signal, a frequency conversion circuit for converting the BS-IF signal into an intermediate frequency band, and an amplitude of an output signal of the frequency conversion circuit is detected and corresponding thereto An AGC circuit for generating a DC AGC voltage, controlling the gain by the DC AGC voltage so that the amplitude of the output signal is constant, and the AGC circuit
An FM demodulation circuit that FM demodulates an output signal of the circuit to separate and output a video signal and an audio signal, and a video signal that is an output signal of the FM demodulation circuit is subjected to processing such as de-emphasis and removal of an energy diffusion signal. A video signal processing circuit for obtaining a video output signal and outputting it to a video signal output terminal, and superimposing the video output signal also on the BS-IF signal input terminal;
The audio signal output from the FM demodulation circuit is converted into a 4-phase DP
An audio signal processing circuit that obtains an audio output signal by processing such as SK demodulation and PCM demodulation, and a BS converter power supply circuit that generates a DC power supply voltage for the BS converter and superimposes it on the BS-IF signal input terminal. The present invention provides a satellite broadcast receiver characterized by having the above.

(Embodiment) FIG. 1 is a block diagram showing a first embodiment of a satellite broadcast receiver of the present invention. The same parts as those in FIG. 2 are designated by the same reference numerals.

The difference from the conventional satellite broadcast receiver shown in FIG. 2 is that the level check terminal 15 is deleted and the video output signal from the video signal processing circuit 9 is also superimposed on the BS-IF input terminal 5.
Since they are connected, the description of the same parts will be omitted and the operations of different parts will be described below.

In FIG. 1, the output signal of the video signal processing circuit 9 is supplied to the video signal output terminal 10 and the filter 17
Is also supplied to.

The filter 17 is a filter that blocks a DC (direct current) component and passes only a required frequency band of a video signal (for example, about 0 to 4.5 MHz in the case of the NTSC system).

The video output signal which is the output signal of the filter 17 is B
It is supplied to the S-IF input terminal 5.

Therefore, the BS-IF input terminal 5 is connected to the BS converter 2
About 1 GHz (1000 MHz) BS-IF signal supplied from the BS converter power supply circuit 14 about 1
This means that the DC signal of 5V and the video output signal of about 0 to 4.5 MHz supplied from the video signal processing circuit 9 are superposed.

However, the frequency bands are different from each other, and by the capacitor C, the inductance L, the filter 17, etc.,
It is possible to prevent the influence of other signals from each other.

At the time of adjusting and setting the angle of the BS antenna 1, as shown in FIG. 1, the BS antenna angle setting jig 18 is connected in the middle of the coaxial cable 3 from the BS converter 2.

The BS antenna angle setting jig 18 is composed of a filter 19 and terminals 20 to 23.

Like the filter 17, the filter 19 is DC (direct current).
The component is blocked, and the required frequency band of the video signal (for example, NT
In the case of the SC system, it is a filter that passes only 0 to 4.5 MHz).

Therefore, as an adjusting method, first, as shown in FIG. 1, the terminals 20 and 21 of the angle setting jig 18 of the BS antenna are
In the vicinity of the antenna 1, it is connected to the middle of the coaxial cable 3 which connects the BS converter 2 and the BS tuner 4.

As shown in the figure, the terminals 20 to 22 are commonly connected internally, and the terminal 23 is connected to the BS tuner 4 via the filter 19.
Therefore, the video output signal can be obtained.

Next, the terminals 22 and 2 of the angle setting jig 18 of the BS antenna
3 is connected to the small television receiver 24. The small television receiver 24 is a small and lightweight television receiver using, for example, a liquid crystal, and can be easily carried to a high place, and the power input terminal can be used. 25 and a video signal input terminal 26.

Therefore, as described above, the small-sized television receiver 24 is supplied with a DC voltage of about 15 V through the terminal 22 of the angle setting jig 18 of the BS antenna, and is also supplied with the video output signal through the terminal 23. The Rukoto.

As a result, the azimuth angle, the elevation angle, etc. of the BS antenna 1 may be adjusted and set so that the image displayed on the small television receiver 24 becomes the best.

According to this adjustment method, since the adjustment can be performed while watching the image obtained from the image output signal of the BS tuner, the azimuth angle, the elevation angle, etc. of the BS antenna 1 can be adjusted with high accuracy, and the BS tuner 4 can be used to make a small television. It is not necessary to separately connect a power supply and a cable for supplying a video signal to the John receiver 24.

The terminal 22 of the angle setting jig 18 of the BS antenna
Although it was explained that a DC voltage of about 15 V was supplied via, the BS-IF signal of about 1 GHz (1000 MHz) and the video output signal of about 0 to 4.5 MHz were also superposed here. It has a high frequency component compared to the DC voltage and does not affect the operation at all.

When it is necessary to remove these high frequency components, the terminal 21 is set inside the angle setting jig 18 of the BS antenna.
It goes without saying that a filter that allows only the DC component to pass may be inserted between points 22 and 22.

(Effect of the Invention) The satellite broadcasting receiver of the present invention is configured as described above,
Setting the azimuth and elevation of the BS antenna does not require connecting a cable from the BS tuner, and since there is no need to carry or connect the cable at high places, the risk of working at high places is reduced, The azimuth angle and elevation angle of the BS antenna can be easily set in a short time, and the adjustment can be performed while watching the actual image, so that the adjustment can be performed with high accuracy, which is an excellent effect in practical use.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a satellite broadcast receiver of the present invention, and FIG. 2 is a block diagram showing a conventional satellite broadcast receiver. 1 ... BS antenna, 2 ... BS converter, 3 ... coaxial cable, 4 ... BS tuner, 5 ... BS-IF signal input terminal, 6 ... frequency conversion circuit, 7 ... AGC circuit, 8 ... FM demodulation circuit, 9 ... video signal Processing circuit, 10 ... Video signal output terminal, 11 ... Audio signal processing circuit, 12, 13 ... Audio signal output terminal, 14 ... BS converter power supply circuit, 15 ... Level check terminal, 16 ... DC voltmeter, 17, 19 ... Filter , 18 ... BS antenna angle setting jig, 20, 2
1, 2, 22, 23 ... Terminal, 24 ... Small television receiver, 25 ... Power input terminal, 26 ... Video signal input terminal, C
… Capacitor, L… Inductance.

Claims (1)

[Scope of utility model registration request] 1. A BS-IF signal input terminal for inputting a BS-IF signal received by a BS antenna, frequency-converted by a BS converter and transmitted, and converting the BS-IF signal into an intermediate frequency band. A frequency conversion circuit and an amplitude of an output signal of the frequency conversion circuit are detected, a corresponding DC AGC voltage is generated, and a gain is controlled by the DC AGC voltage so that the amplitude of the output signal is controlled to be constant. And an FM demodulation circuit that FM demodulates the output signal of the AGC circuit to separate and output a video signal and an audio signal, and a video signal that is the output signal of the FM demodulation circuit is de-emphasized and converted into an energy spread signal. While performing processing such as removal to obtain the video output signal and output it to the video signal output terminal,
A video signal processing circuit that superimposes a video output signal on the BS-IF signal input terminal, and a four-phase DP audio signal that is an output signal of the FM demodulation circuit.
An audio signal processing circuit for obtaining an audio output signal by performing processing such as SK demodulation and PCM demodulation, and generating a DC power supply voltage for the BS converter,
A satellite broadcast receiver comprising a power supply circuit for a BS converter superimposed on an S-IF signal input terminal.