JPH02283128A - Signal detection circuit for satellite broadcast reception antenna adjustment - Google Patents

Abstract

PURPOSE:To attain the setting of an elevating angle and an azimuth angle of a satellite broadcast reception antenna accurately by using a signal detection circuit for adjusting a satellite broadcast reception antenna integrated to a device so as to detect the presence of a satellite broadcast signal in a received signal thereby applying data processing. CONSTITUTION:A signal received by a satellite broadcast reception antenna is led to a converter, a 1st intermediate signal converted therein is inputted to an input terminal 1, a reception channel is selected by a tuner 2, converted further into a signal with a 2nd intermediate frequency and the signal is outputted to a 2nd intermediate frequency amplifier 3. The amplifier 3 amplifies the signal and the noise component of the signal is eliminated by a filter 4 and the result is outputted to an AGC detection circuit 5, where the signal is converted into a DC voltage in response to the reception signal level, led to the tuner 2 as an AGC voltage, and used for gain control. On the other hand, the signal whose noise component is eliminated by the filter 4 is detected by an FM detector 8 and the signal is detected by signal detection circuits 11-15 based on the detected and demodulated video and PSK audio signal to obtain the signal for adjusting a satellite broadcast transmission reception antenna.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a system in which a satellite broadcast reception tuner, a device incorporating the same, and a satellite broadcast reception antenna are used in combination, and is used for antenna adjustment when installing a satellite broadcast reception antenna. The present invention relates to a signal detection circuit for adjusting a satellite broadcast receiving antenna used to obtain a signal.

[Prior art] In order to receive satellite broadcasting, it is necessary to point the antenna in the direction of the satellite and adjust the elevation and azimuth angles correctly.
AG of the main circuit diagram of the satellite broadcasting receiver shown in Figure 5
A tester is connected to the C output terminal (6), and the orientation of the satellite broadcasting antenna is set at the position where the tester's indication is maximum.

Alternatively, a level checker is used to set the direction of the satellite broadcast receiving antenna at a position where the output of the converter incorporated in the satellite broadcast receiving antenna is maximized.

[Problem to be solved by the invention]

Since satellite broadcasting antennas receive weak radio waves, they are affected by the noise received from the antenna and the noise generated from within the receiving system, and the antenna rotation of the AGC voltage used as an antenna adjustment signal is affected. As shown in Figure 1, the amount of change caused by
The degree is small. Furthermore, compared to general VHF broadcast receiving antennas, the antenna's directional characteristics are very sharp, and as shown in Figure 3, the deviation from the satellite's true direction can be suppressed to within 1 degree, making it possible to receive satellite broadcasts stably. It is desirable to
This makes it extremely difficult to install the receiving antenna.

Therefore, in the method of the present invention, the presence or absence of a satellite broadcasting signal is detected from the received signal by utilizing the very sharp directional characteristics of the antenna as shown in FIGS. 2 and 4, and data processing is performed.
By using the output as an antenna adjustment signal, the influence of noise can be eliminated and the pointer of the indicator can be changed significantly.
By clearly drawing the reception limit point when adjusting the antenna's elevation and azimuth in the direction of the satellite, and setting the direction of the satellite broadcasting antenna at the center, adjustments can be made easily and accurately. It is an object of the present invention to do so.

[Means for Solving the Problems] One of the signal detection circuits 11, 12, 13, and 14, 15 as shown by the section Gω showing the circuit portion according to the present invention in FIG. 5 is incorporated into the equipment, and FM detection Based on the video and PSK audio signals that have been processed, the signals are input to the signal detection circuit directly or via a video signal separation circuit or PSK audio signal separation circuit, and the circuit output is used as the signal output for antenna adjustment. It is something.

Each signal detection circuit includes a synchronous separation circuit, a filter circuit,
Consisting of a detection circuit, an amplifier, or a synchronous separation circuit,
A monomulti circuit, a comparator circuit, an amplifier, a detection circuit, an amplifier, a 4-phase DPSK demodulation circuit, a PCM demodulation circuit, and an amplifier are used.

(Function) Based on the video and PSK audio signals after FM detection, a signal detection circuit consisting of a sync separation circuit, a filter circuit, a detection circuit, and an amplifier, or a signal consisting of a sync separation circuit, a monomulti circuit, and a comparator circuit. Since it uses a signal detection circuit consisting of a detection circuit, an amplifier, a detection circuit, and an amplifier, unlike conventional methods, it does not suffer from noise and can respond to changes in the rotation angle of the antenna, as shown in Figure 2. It is possible to generate an antenna adjustment signal output that greatly changes the pointer of the indicator.

As shown in Figure 3, the parabolic antenna is gradually rotated toward the satellite, and when the center line of the parabolic antenna reaches the limit point where it can receive data, the signal detection circuit outputs an output voltage as shown in Figure 2. Occur. As the parabolic antenna is further rotated, this output voltage remains constant until the center line of the parabolic antenna passes through the true direction of the satellite and reaches the limit point where reception is possible on the opposite side. The output voltage decreases rapidly.

When installing a satellite broadcasting antenna, find the installation angle of these two limit points while changing the antenna direction, and set the antenna in the correct direction by aligning the center line of the antenna with the center that bisects the angle. can be done.

Further, as the signal detection circuit, a 4-phase DPSK demodulation circuit,
By using a PCM demodulation circuit and an amplifier to amplify the PCM error signal obtained from the PCM demodulation circuit, it is possible to respond to changes in the rotation angle of the antenna without being affected by noise, as shown in Figure 4. It is possible to generate an antenna adjustment signal output that greatly changes the pointer of the indicator.

This PCM error signal has the characteristic that it almost disappears when the center line of the parabolic antenna is facing the true direction of the satellite, but increases when the antenna direction deviates from the satellite direction, and this characteristic can be utilized. By doing this, the above two limit points can be found. When installing a satellite broadcasting antenna, find the installation angle of these two limit points while changing the direction of the antenna, and place the center of the antenna at the center that bisects the angle. By matching the lines, you can orient the antenna in the correct direction.

〔Example〕

The details of the present invention will be explained below with reference to one embodiment of the present invention.

FIG. 5 is a diagram showing the main circuit configuration of an embodiment of the present invention.

The signal received by the satellite broadcasting antenna is guided to the converter built in the same part, and the first intermediate frequency signal converted by the converter is sent to the input terminal (1) of the satellite broadcasting receiver.
), the reception channel is selected by the tuner (2), further converted to a second intermediate frequency, and output to the second intermediate frequency amplifier (3).

This signal is amplified by the second intermediate frequency amplifier (3), and the noise component of the amplified signal is removed by the filter (4).
It is output to the GC detection circuit (5), where it is converted to a DC voltage according to the received signal level, and is led to the tuner (2) as an AGC voltage and used for gain control.
Buffer amplifier (7) which is an impedance conversion amplifier
In the prior art, this voltage was used as a signal for adjusting the satellite broadcasting antenna.

In the present invention, the signal from which noise components have been removed by the filter (4) is detected by the FM detector (8), and each signal detection circuit detects the signal based on the detected and demodulated video and PSK audio signals. and obtained the signal for adjusting the satellite broadcasting antenna.

FIG. 6 is a block diagram showing an embodiment of a signal detection circuit for adjusting a satellite broadcast receiving antenna according to claims (2) and (4).

The FM detected and demodulated video and PSK audio signals, or signals separated as video signals by passing these signals through a video signal separation circuit, are input to the synchronization separation circuit 07) consisting of a limiter circuit, and the separated synchronization signals are After being led to a filter circuit 08) consisting of LC or RC to remove noise, it is led to a detection circuit, detected by a diode, and smoothed by a capacitor QΦ to generate a DC voltage. This DC voltage is amplified by an amplifier (21) and used as an antenna adjustment signal output.

FIG. 7 is a block diagram showing an embodiment of the satellite broadcast receiving antenna adjustment signal detection circuit according to claim (3).

The FM detected and demodulated video and PSK audio signals are further passed through the video signal separation circuit (9) and separated as a video signal.The signal is input to the synchronization signal separation circuit (22) consisting of a limiter circuit, and the separated synchronization The signal is input to a monomulti circuit (23), which generates a pulse signal synchronized with the synchronization signal. This pulse signal is sent to the comparator (24
), and the comparator (24) outputs a pulse signal corresponding to the portion of the pulse signal that exceeds the bias voltage applied to the comparator (24). This is used as a signal output for antenna adjustment.

FIG. 8 is a block diagram showing an embodiment of a signal detection circuit for adjusting a satellite broadcast receiving antenna according to claim (5).

The FM detected and demodulated video and PSK audio signals are
PSK audio signal separation circuit 00 for separating SK audio signals
and the separated PSK audio signal is input to the amplifier (26).
The amplified signal is detected by a diode (27), and further smoothed by a capacitor (28) to generate a DC voltage. This DC voltage is amplified by an amplifier (29) and used as an antenna adjustment signal output.

FIG. 9 is a block diagram showing an embodiment of a signal detection circuit for adjusting a satellite broadcast receiving antenna according to claim (6).

The separated PSK audio signal is passed through the PSK audio signal separation circuit 00) and guided to the four-phase DPSK demodulation circuit (30), where it is demodulated into a PCM code string digital signal, and this demodulated signal is Furthermore, PCM demodulation circuit (31)
During transmission, the erroneous error signal is corrected and demodulated back to the original digital audio signal at the transmitting end.

This error signal is taken out from the PCM demodulation circuit (31), inputted to the amplifier (32), amplified to a required level, and used as an antenna adjustment signal output.

The amplifiers (21, 29, 32) are used to amplify the signal output for antenna adjustment to a required level, and can be omitted if the pointer of the indicator can be swung sufficiently.

These antenna adjustment signal outputs can be connected to measurement terminals on the device, and can be measured by connecting a meter from outside the device, or can be displayed using a meter or lamp built into the device. good.

〔Effect of the invention〕

As described above, the present invention makes use of the characteristic that the directional characteristics of satellite broadcast antennas are very sharp, and detects the presence or absence of satellite broadcast signals in received signals using a signal detection circuit for adjusting satellite broadcast antennas built into equipment. Since the detection and data processing are performed, the influence of noise is eliminated and the circuit output
It is possible to greatly change the pointer of the indicator, and by rotating the satellite broadcast receiving antenna, the two limit points of reception are clearly drawn, and the satellite broadcast receiving antenna is placed in the center of the limit points. By installing it, you can accurately set the elevation angle and azimuth angle of the satellite broadcasting antenna.

[Brief explanation of drawings]

FIG. 1 is a characteristic diagram showing the amount of change in the AGC voltage due to rotation of the antenna in the conventional example, and FIGS. 2 and 4 are characteristic diagrams showing the amount of change in the antenna adjustment signal due to rotation of the antenna according to the method of the present invention. Fig. 3 is a diagram showing the direction of the antenna and satellite for explanation with respect to Figs. 2 and 4, Fig. 5 is a main circuit configuration diagram showing a satellite broadcast receiver, and Figs. 1 is a circuit configuration diagram of a main part showing an embodiment of the present invention. FIG. 1-...-Satellite broadcast signal input terminal, 2- Tuner,
3--Intermediate frequency amplifier, 4.18--Filter circuit, 5-A GC detection circuit, 6-A GC voltage measurement terminal, 7--Buffer amplifier, 8--FM detection circuit , 9- video signal separation circuit, 10-PSK audio signal separation circuit, 11.12, 13, 14, 15. - Signal detection circuit, 16- Division showing parts related to the present invention,
17.22 Synchronous separation circuit, 19.27...Diode, 20.28 Capacitor, 29.32 Amplifier, Mono multi circuit, Comparator circuit, 4-phase DP SK demodulation circuit, PCM demodulation circuit.

Claims (6)

[Claims] (1) A tuner that receives a satellite broadcast signal, an intermediate frequency amplifier that amplifies the output of this tuner, and a filter that removes unnecessary noise components from the output of this intermediate frequency amplifier.
An FM detector that detects the output of this filter, and an FM detector that detects the output of this filter.
It consists of a video signal separation circuit that separates the video signal from the video and PSK audio signals detected by the wave detector, and a signal detection circuit that detects the output of this video signal separation circuit. A signal detection circuit for adjusting a satellite broadcast receiving antenna, characterized in that two receivable limit points are determined by the detection signal of the signal detection circuit, and the direction of the satellite broadcast receiving antenna is adjusted to approximately the center of the two limit points. . (2) Claim (1) wherein the signal detection circuit comprises a sync separation circuit that separates a sync signal from the output of the video signal separation circuit, and a detection circuit that detects the output of the sync separation circuit.
The signal detection circuit for adjusting the satellite broadcast receiving antenna described above. (3) The signal detection circuit includes a sync separation circuit that separates a sync signal from the output of the video signal separation circuit, a monomulti circuit that generates a pulse signal synchronized with the sync signal from the output of the sync separation circuit; A signal detection circuit for adjusting a satellite broadcast receiving antenna according to claim 1, comprising a comparator circuit that discriminates the pulse signal of the monomulti circuit and outputs a signal. (4) a tuner that receives a satellite broadcast signal, an intermediate frequency amplifier that amplifies the output of this tuner, and a filter that removes unnecessary noise components from the output of this intermediate frequency amplifier;
An FM detector that detects the output of this filter, and an FM detector that detects the output of this filter.
The orientation of the satellite broadcasting antenna is determined from the detection signal of the signal detection circuit, which consists of a sync separation circuit that separates the sync signal from the video and PSK audio signals detected by the detector, and a detection circuit that detects the output of this sync separation circuit. A signal detection circuit for adjusting a satellite broadcast receiving antenna, characterized in that the signal detection circuit for adjusting a satellite broadcast receiving antenna is characterized in that the satellite broadcast receiving antenna is rotated to find two limit points at which reception can be received, and the direction of the satellite broadcast receiving antenna is adjusted to approximately the center of these two limit points. (5) a tuner that receives a satellite broadcast signal, an intermediate frequency amplifier that amplifies the output of the tuner, and a filter that removes unnecessary noise components from the output of the intermediate frequency amplifier;
An FM detector that detects the output of this filter, and an FM detector that detects the output of this filter.
PSK the video and PSK audio signals detected by the detector.
The PSK audio signal is separated through an audio signal separation circuit, and the separated PSK audio signal is detected by a signal detection circuit consisting of a wave detector. A signal detection circuit for adjusting a satellite broadcast receiving antenna, characterized in that two limit points are determined by the detection signal of the signal detection circuit, and the direction of the satellite broadcast reception antenna is adjusted to approximately the center of the two limit points. (6) The signal detection circuit includes a 4-phase DPSK demodulation circuit that demodulates the PSK audio signal separated by the PSK audio signal separation circuit into a PCM code string digital signal, and a 4-phase DPSK demodulation circuit that demodulates the PSK audio signal separated by the PSK audio signal separation circuit. 6. A signal detection circuit for adjusting a satellite broadcast receiving antenna according to claim 5, comprising a PCM demodulation circuit that demodulates a digital signal of a PCM code string into a digital audio signal.