JPH05211457A - Receiver - Google Patents

Abstract

PURPOSE:To automatically adjust a polarized wave plane to an optimum position. CONSTITUTION:A radio wave sent from a communication satellite 1 is collected by a primary radiator 2a by using a parabolic antenna 2 and received through the polarized wave plane of the primary radiator 2a, converted into an electric signal and fed to a tuner block 3. The electric signal fed from the primary radiator 2a in the tuner block 3 is detected and outputted to an FM demodulation circuit 4 and a level detection circuit 11. The level detection circuit 11 detects a level of a signal (detected signal) outputted from the tuner block 3 and fed to a channel selection microcomputer 13 through a level measurement circuit 12. A motor (not shown) built in the primary radiator 2a and driving the polarized wave plane is controlled by the channel selection microcomputer 13 so as to increase the level of the signal detected by the level detection circuit 11 and the polarized wave plane is adjusted corresponding to the polarized radio wave.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a receiver suitable for use in, for example, a satellite broadcast receiver.

[0002]

2. Description of the Related Art In conventional satellite communication or satellite broadcasting, horizontal polarization (FIG. 6A), vertical polarization (FIG. 6B), or circular polarization (FIG. 6C) shown in FIG. )) Three types of radio waves are used. Further, in satellite communication in Japan, in order to effectively use the frequency band of radio waves, as shown in FIG.
And the frequency band (channel) of horizontal polarization alternate,
Moreover, the main carriers are arranged (assigned) so as not to overlap each other.

Radio waves from a communication satellite are adjusted by adjusting the direction of an antenna (parabolic antenna) and the plane of polarization of a primary radiator, that is, directing the direction of the antenna to the direction of the satellite transmitting the radio waves. At the same time, it can be received by matching the polarization plane of the primary radiator of the antenna with the polarization (horizontal polarization or vertical polarization) of the radio wave.

[0004]

By the way, since the antenna direction adjustment need only be fixed in the direction of the satellite to be received, it only has to be done once, but the polarization plane of the primary radiator should be adjusted. Depending on the channel used, there are cases of horizontal polarization and cases of vertical polarization.Therefore, it is necessary to adjust the plane of polarization of the primary radiator each time the polarization is different, which poses a problem for the user. there were.

Further, since the polarization plane is generally adjusted while watching the image of the radio wave received by the user on the monitor, the adjustment cannot be made quantitatively.

The present invention has been made in view of such circumstances, and is to adjust the plane of polarization to an optimum position so that a signal with a good S / N can be obtained.

[0007]

The receiving apparatus of the present invention includes a primary radiator 2a as receiving means for receiving a radio wave transmitted in a vertically polarized wave or a horizontally polarized wave by adjusting the polarization plane and receiving the radio wave. Tuner block 3 as a detection means for detecting the radio wave, a level detection circuit 11 as a detection means for detecting the signal level of the output of the tuner block 3, and a primary level corresponding to the signal level detected by the level detection circuit 11. It is characterized by comprising a tuning microcomputer 13 as a control means for controlling the plane of polarization of the radiator 2a.

[0008]

In the receiving device having the above-mentioned structure, the radio wave transmitted in the vertically polarized wave or the horizontally polarized wave is received by the primary radiator 2a, and the received electric wave is detected. Then, the level of the detected signal is detected by the level detection circuit 11, and the polarization plane of the primary radiator 2a is controlled according to the detected signal level. Therefore, the polarization plane is adjusted so as to maximize the signal level without causing the user to feel bothered, so that a good image or sound can always be viewed.

[0009]

1 is a block diagram showing the configuration of an embodiment of a satellite broadcast receiver to which the receiving apparatus of the present invention is applied. The communication satellite 1 receives a radio wave output from a transmitting station (not shown), amplifies it by a transponder provided therein, and retransmits it. The parabolic antenna 2 faces the communication satellite 1 and focuses the radio wave transmitted from the communication satellite 1 on the primary radiator 2a. The primary radiator 2a converts the electric wave supplied from the parabolic antenna 2 into an electric signal having an intermediate frequency of, for example, about 1 GHz, and the tuner block 3
Supply to. Further, the primary radiator 2a has a built-in motor (not shown), and the motor moves the polarization plane of the primary radiator 2a to the right according to a control signal output from the tuning microcomputer 13 as shown in FIG. Or rotate it to the left.

The tuner block 3 detects the electric signal supplied from the primary radiator 2a, that is, the electric signal supplied from the primary radiator 2a corresponds to the operation of an operation unit (not shown) of the tuning microcomputer 13. The frequency band (channel) is taken out (selected) and output to the FM demodulation circuit 4 and the level detection circuit 11. The FM demodulation circuit 4 demodulates the signal output from the tuner block 3. The video / audio separation circuit 5 separates a video signal and an audio signal from a signal demodulated by the FM demodulation circuit 5, that is, a signal in which a 4-phase DPSK-modulated audio signal as a subcarrier is superimposed on the video signal, thereby separating the video signal and the audio signal. The signal is output to the de-emphasis unit 6 and the audio signal is output to the 4-phase DPSK demodulation circuit 8.

The de-emphasis unit 6 de-emphasises the video signal output from the video / audio separation circuit 5.
The energy spread signal removal circuit 7 removes an energy spread signal such as a triangular wave superimposed on the video signal at the transmitting station so that the power (energy) of the radio wave is not concentrated at a predetermined frequency.

The 4-phase DPSK demodulation circuit 8 demodulates the audio signal (subcarrier) output from the video / audio separation circuit 5 into 4-phase DPSK. The PCM demodulation circuit 9 is a 4-phase DPSK
The signal output from the demodulation circuit 8 (PCM audio signal) is demodulated into an audio signal. De-emphasis section 10
De-emphasizes the audio signal output from the PCM demodulation circuit 9.

The level detection circuit 11 detects the level of the signal output from the tuner block 3, that is, the level of the detected signal. For example, as shown in FIG. 4, the level measuring circuit 12 connects one end of the resistor 22 to the negative terminal of the comparator 21, and connects the resistor 22 and the comparator 21 to the other end of the capacitor 23 whose one end is connected to the ground. It can be configured by a circuit whose ends are connected. Comparator 21
Is a voltage (level voltage) proportional to the level of the signal output from the level detection circuit 11 applied to the + terminal.
And a pulse (PWM) applied to the negative terminal and supplied from the tuning microcomputer 13 to a voltage (analog voltage) integrated in a circuit including the capacitor 23 and the resistor 22 are compared, and the comparison result is selected. It is supplied to the station microcomputer 13.

The tuning microcomputer 13 has a level measuring circuit 12
The width of the pulse supplied to the level measuring circuit 12 is adjusted based on the comparison result of the level voltage supplied from the analog circuit and the analog voltage, and the pulse width when the two become equal is calculated based on the signal detected by the level detecting circuit 11. The level is stored in a built-in memory (not shown), and the polarization plane of the primary radiator 2a is set so that the stored value is increased, that is, the level of the signal detected by the level detection circuit 11 is increased. Control the motor to rotate. Further, the tuning microcomputer 13 controls the tuner block 3.

Next, the operation will be described. Radio waves transmitted from the communication satellite 1 are converged by the parabolic antenna 2 to the primary radiator 2a, and in the primary radiator 2a,
The radio wave supplied from the parabolic antenna 2 is received via the plane of polarization of the parabolic antenna 2, converted into an electric signal having an intermediate frequency of, for example, about 1 GHz, and supplied to the tuner block 3. In the tuner block 3, a channel corresponding to the operation of the operation unit of the tuning microcomputer 13 is extracted (selected) from the electric signal supplied from the primary radiator 2a,
It is output to the FM demodulation circuit 4 and the level detection circuit 11.

In the FM demodulation circuit 4, the signal output from the tuner block 3 is demodulated and output to the video / audio separation circuit 5. In the video / audio separation circuit 5, the video signal and the audio signal are separated from the signal that is demodulated by the FM demodulation circuit 5 and the audio signal that is 4-phase DPSK modulated as a subcarrier is superimposed on the video signal, and the video signal is de-emphasised. In the section 6, the voice signal is a 4-phase DPSK demodulation circuit 8
Are output respectively.

In the de-emphasis section 6, the video signal is de-emphasized and the energy spread signal removing circuit 7 is provided.
In, in order to prevent the power (energy) of the radio wave from concentrating on a predetermined frequency, the triangular wave superimposed on the video signal is removed at the transmitting station and supplied to, for example, a CRT (not shown).

The audio signal (subcarrier) output from the video / audio separation circuit 5 is a 4-phase DPSK demodulation circuit 8.
In the above, the four-phase DPSK demodulation is performed, the PCM demodulation circuit 9 performs the PCM demodulation, and the de-emphasis unit 10 is supplied. In the de-emphasis unit 10, the audio signal output from the PCM demodulation circuit 9 is de-emphasized and supplied to, for example, a speaker (not shown).

On the other hand, the level detection circuit 11 detects the level of the detected signal output from the tuner block 3 and supplies a voltage proportional to the level to the level measurement circuit 12 as a level voltage. In the level detection circuit 12 shown in FIG. 4, a voltage (level voltage) applied to the + terminal of the comparator 21 and proportional to the level of the signal output from the level detection circuit 11, and a selection applied to the-terminal thereof. The pulse (PWM) supplied from the station microcomputer 13 is compared with the voltage (analog voltage) integrated by the circuit including the capacitor 23 and the resistor 22, and the comparison result is supplied to the channel selecting microcomputer 13.

In the tuning microcomputer 13, the width of the pulse supplied to the level measuring circuit 12 is adjusted from the comparison result of the level voltage and the analog voltage supplied from the level measuring circuit 12, that is, level voltage> analog voltage. If
When the pulse width is increased and the level voltage is less than the analog voltage, the pulse width is decreased and the pulse width when both (the level voltage and the analog voltage) become equal is the level of the signal detected by the level detection circuit 11. , Stored in the built-in memory, so as to increase the stored value,
That is, the motor for rotating the polarization plane of the primary radiator 2a is controlled so as to increase the level of the signal detected by the level detection circuit 11 (the level of the detected signal).

Next, referring to the flowchart of FIG.
The operation will be further described. First of all, step S1
In, the level of the detected signal is measured (detected) and stored, and the variable flag F _1ST indicating whether or not the plane of polarization is moved is set to a value 1 indicating that the plane of polarization is not yet moved. , And proceeds to step S2. In step S2, the plane of polarization is rotated (fine-tuned) according to a variable F _UPDOWN that indicates the direction in which it is rotated (clockwise or counterclockwise), and in step S3, the level of the detected signal after rotating the plane of polarization. Is measured and the process proceeds to step S4. In step S4, the level of the signal measured in step S3 (the level of the signal measured this time) after the plane of polarization is rotated in step S2, and step S
Before the plane of polarization is rotated in 2, the signal levels measured in step S1 or S3 (levels of previously measured signals) are compared.

When it is determined in step S4 that the level measured this time is equal to or higher than the level measured last time, the process proceeds to step S7, and the variable flag F _1ST is set to a value 0 indicating that the plane of polarization is moved. Set, step S
Go to 8. In step S8, the rotation amount of the polarization plane is
It is determined whether the polarization plane has exceeded a predetermined movement range (rotation range) set to prevent the polarization plane from rotating infinitely when there is no input (no signal). When it is determined in step S8 that the rotation amount of the polarization plane does not exceed the predetermined movement range, the process returns to step S2 and step S2.
Through S4 and steps S7 and S8 are repeated. When it is determined in step S8 that the rotation amount of the polarization plane exceeds the predetermined movement range, step S9
Then, the polarization plane is fixed (set) at the position where the previously measured level is obtained, and the process ends.

When it is determined in step S4 that the level measured this time is smaller than the level measured last time, the process proceeds to step S5, and the variable flag F _1ST is evaluated. When it is determined in step S5 that the variable flag F _1ST is 1, the process proceeds to step S6, and the variable F _UPDOWN that indicates the direction in which the plane of polarization is rotated is set in the opposite direction to the previous direction. That is, in step S6, if clockwise is set far in the variable F _UPDOWN, counterclockwise is set to the variable F _UPDOWN, variable F _{UP DOWN}
If the counterclockwise _rotation has been set up to now, the clockwise _rotation is set in the variable F _UPDOWN . Then, step S7 described above
Proceeds to, at step S5, the variable flag F _{1S T} 1
If not, or in step S8,
The processes of steps S2 to S8 are repeated until it is determined that the rotation amount of the polarization plane exceeds the predetermined movement range.

In step S5, the variable flag F _1ST
When it is determined that is not 1, the process proceeds to step S9, and the polarization plane is fixed (set) at the position where the previously measured level is obtained as described above, and the process ends.

If there is no variable flag F _1ST , the plane of polarization is rotated in the direction indicated by the variable F _{UPD OWN} for the first time in step S2, and if the level measured this time is smaller than the level measured last time, step S4. If it is determined in step S2, that is, if the direction in which the plane of polarization is rotated in step S2 for the first time is the direction in which the level of the detected signal is reduced, the processing ends after performing the processing in step S9.
Thus, the variable flag F _{1S T,} to prevent the direction initially rotate the plane of polarization in this manner when was the direction to reduce the level of the detection signal, operation is complete.

Further, in the embodiment shown in FIG. 1, after the apparatus is started and the processing of FIG. 2 is performed, the operation of the flowchart shown in FIG. 3 is performed at regular intervals by, for example, a timer interrupt. That is, in step S11,
The level of the current detected signal is measured and stored,
Go to step S12. In step S12, the current level stored in step S11 is compared with the level (set level) of the detected signal at the position of the polarization plane set (fixed) in step S9 shown in FIG. When it is determined in step S12 that the set level is lower than the current level, the process proceeds to step S13, and the process of adjusting the polarization plane shown in FIG. 2 is performed again.
When it is determined in step S12 that the set level is higher than the current level, the process ends.

In this way, the polarization plane is adjusted so as to maximize the level of the detected signal.
It can always receive good radio waves.

The case where the receiving apparatus of the present invention is applied to a satellite broadcast receiver has been described above. However, the present invention receives radio waves of both vertical polarization and horizontal polarization in addition to the satellite broadcast receiver. Can be applied to the device.

[0029]

As described above, according to the receiving apparatus of the present invention, the radio wave transmitted in the vertical polarization or the horizontal polarization is received by the receiving means, and the received radio wave is detected and detected. The signal level is detected by the detecting means, and the polarization plane of the receiving means is controlled in accordance with the detected signal level. Therefore, the polarization plane is automatically adjusted so as to maximize the signal level without causing the user to feel bothered, so that a good image or sound can always be viewed.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of a satellite broadcast receiver to which a receiving device of the present invention is applied.

FIG. 2 is a flowchart illustrating an operation of polarization plane adjustment in the embodiment of FIG.

3 is a flowchart illustrating an operation of interrupt processing in the embodiment of FIG.

4 is a circuit diagram showing a configuration of an embodiment of a level measuring circuit 12 of the embodiment of FIG.

5 is a front view showing the plane of polarization of the primary radiator 2a of the embodiment of FIG. 1. FIG.

FIG. 6 is a diagram for explaining polarization of radio waves.

FIG. 7 is a diagram for explaining a channel arrangement for satellite communication.

[Explanation of symbols]

 1 Communication Satellite 2 Parabolic Antenna 2a Primary Radiator 3 Tuner Block 4 FM Demodulation Circuit 5 Video / Audio Separation Circuit 6 De-emphasis Section 7 Energy Spreading Signal Removal Circuit 8 4-Phase DPSK Demodulation Circuit 9 PCM Demodulation Circuit 10 De-emphasis Section 11 Level Detection Circuit 12 Level measurement circuit 13 Tuning microcomputer 21 Comparator 22 Resistance 23 Capacitor

Claims (1)

[Claims] 1. A receiving means for adjusting the polarization plane to receive a radio wave transmitted in a vertically polarized wave or a horizontally polarized wave, a detecting means for detecting the electric wave received by the receiving means, and a detecting means of the detecting means. A receiving device comprising: a detection unit that detects a signal level of an output; and a control unit that controls a polarization plane of the reception unit corresponding to the signal level detected by the detection unit.