JP2002344367A - Diversity receiving apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a diversity receiving apparatus in which even when the input is interrupted or invalidated in one or more receivers, it does not become a cause of characteristic deterioration or an operation error of the apparatus. SOLUTION: The diversity receiving apparatus comprises a plurality of the receivers connected to different antennas and a composite unit for combining output signals from the respective receivers. Each receiver has a squelch circuit 8, which monitors a state of a reception signal and outputs a control signal which indicates no specified reception signal when the specified reception signal is not obtained. The composite unit combines the output signals from the respective receivers by considering the control signal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diversity receiver.

[0002]

2. Description of the Related Art A diversity receiving apparatus receives the same modulated signal or a signal having information by a plurality of antennas, inputs the received signals to corresponding receiving sections on a one-to-one basis, and receives signals from the plurality of receiving sections. Is synthesized by the synthesis unit and 1
It is known as a receiving device that outputs as a system signal.

[0003]

In a diversity receiving apparatus, when there is no input signal in a certain receiving section or when an interfering wave or the like which is not an original signal is input, noise or an interfering wave is synthesized. There was a possibility that the characteristics would be degraded or the device would malfunction.

[0004] For this reason, signals from a plurality of receiving sections are weighted according to their respective reception states and then combined. However, even when such weighting-based synthesis is performed, if the reception state of a certain receiving unit is extremely deteriorated, it is inevitable that the receiving unit will be affected to some extent.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a diversity receiving apparatus which does not cause deterioration of the characteristics of the apparatus or a malfunction even when the input is interrupted or invalid in one or more receiving sections.

[0006]

According to the present invention, there is provided a diversity receiving apparatus comprising: a plurality of receiving sections connected to different antennas; and a combining section for combining output signals from the respective receiving sections. Circuit, the squelch circuit monitors the state of the received signal and outputs a control signal indicating this when a prescribed received signal is not obtained, and the combining unit considers the control signal from each of the receiving units. Are synthesized.

[0007] In the diversity receiving apparatus, the receiving section further receives the received signal from the antenna, performs gain control, outputs a gain-controlled signal, and detects the level of the received signal to detect the level of the received signal. An AGC circuit that determines the presence or absence of the signal, outputs a level detection signal indicating this, and further outputs an AGC control signal; a demodulation circuit for receiving and demodulating the gain-controlled signal; Alternatively, a synchronous circuit for receiving a demodulated signal, performing synchronous reproduction and outputting a reproduced synchronous signal, and outputting a synchronous state signal indicating lock / unlock of the synchronous signal, and the AGC control signal and the demodulator circuit. And the synchronization state signal, the C / N (Carrier-to-Noise)
a squelch circuit that receives the level detection signal, an output from the demodulation circuit, and the synchronization state signal. Monitoring the state of the received signal. In this case, the squelch circuit indicates that a prescribed reception signal is not obtained when the synchronization state signal indicates the unlock state or when the level detection signal indicates no reception signal. The control unit outputs the control signal as a squelch signal. The combining unit receives the C / N signal and the squelch signal. If the squelch signal indicates the unlocked state or the absence of the received signal, the reception unit outputs the received signal. The demodulated signal from the section is not targeted for synthesis.

[0008] In the diversity receiving apparatus, the receiving section further receives the received signal from the antenna, performs gain control and outputs a gain-controlled signal, and detects the level of the received signal to receive the signal. An AGC circuit for judging the presence or absence of a signal, outputting a level detection signal indicating the signal, and further outputting an AGC control signal; a demodulation circuit for receiving and demodulating the gain-controlled signal; A synchronous circuit for receiving a signal before or after demodulation, performing synchronous reproduction, outputting a reproduced synchronous signal, and outputting a synchronous state signal indicating lock / unlock of synchronization;
In response to the GC control signal, the output from the demodulation circuit, and the synchronization state signal, a C / N (Carrier-to-Noi) signal is received.
a squelch circuit for calculating a level ratio signal, the synchronization state signal, and the C / N signal. And monitoring the state of the received signal. In this case, the squelch circuit determines that a prescribed reception signal is not obtained when the synchronization state signal indicates the unlock state or when the level detection signal indicates no reception signal. The C / N signal included in the C / N signal is output, and the synthesizing unit receives the C / N signal including the control signal indicating the unlock or no reception signal, and outputs the control signal from the receiving unit that outputs the signal. Is characterized in that the demodulated signal is not subject to synthesis.

[0009]

The diversity receiving apparatus according to the present invention detects whether an input signal is interrupted or invalid in a plurality of input systems (hereinafter, referred to as branches) including a receiving section, and detects each branch. Is characterized in that it has a squelch function for controlling a branch whose input is cut off or invalid at the time of combining the squelch so as not to cause a malfunction of the device or a deterioration of characteristics.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 shows the configuration of the diversity receiver. In FIG. 1, a diversity receiving apparatus 1 includes a receiving unit 3 connected to receiving antennas 2-1 to 2-N (N is a positive integer) of each branch.
-1 to 3-N, and a combining unit 4 for combining signals received for each branch. In the diversity receiving apparatus 1, each signal received by each of the antennas 2-1 to 2-N is received and demodulated by each of the receiving units 3-1 to 3-N, and is combined by the combining unit 4 to obtain 1 signal. It becomes a system signal.

FIG. 2 shows the configuration of the receiving section shown in FIG.
The receiving units 3-1 to 3-N have the same configuration. In FIG. 2, the receiving unit A sets the received signal level constant.
A GC circuit 5, a demodulation circuit 6 for demodulating a received signal, a synchronizing circuit 7 for reproducing a synchronizing signal from the received signal, a squelch circuit 8 for monitoring the state of the received signal and controlling it so that characteristics at the time of synthesizing are not degraded, A C / N calculation circuit 9 for calculating a C / N value to be used is included.

More specifically, the AGC circuit 5 receives a signal from an antenna, performs gain control, performs A / D conversion on the gain-controlled signal, outputs the signal to the demodulation circuit 6, and changes the level of the received signal. The squelch circuit 8 detects the presence / absence of the received signal and outputs a level detection signal indicating the presence / absence of the received signal to the squelch circuit 8.
Output to the N calculation circuit 9. The AGC control signal indicates an AGC control voltage corresponding to the input level of the received signal. The demodulation circuit 6 receives the gain-controlled signal and demodulates the signal into a baseband signal. The synchronization circuit 7 receives the signal before or after demodulation in the demodulation circuit 6, performs synchronous reproduction, outputs the reproduced synchronization signal to the demodulation circuit 6, and outputs a synchronization state signal indicating lock / unlock of the synchronization to the squelch circuit. 8. Output to the C / N calculation circuit 9. The C / N calculation circuit 9 receives the AGC control signal, the output from the demodulation circuit 6 and the synchronization state signal, calculates a C / N value, and indicates a C / N value indicating the C / N value.
Output a signal. The C / N calculation circuit 9 does not calculate the C / N value when the synchronization state signal indicates unlock.

The operation of the receiving section will be described below. The gain of the received signal is controlled by the AGC circuit 5 so as to be at a constant level, and then A / D converted. AGC
The circuit 5 also detects the level of the received signal to determine the presence or absence of the received signal, and outputs a level detection signal indicating this to the squelch circuit 8. The demodulation circuit 6 demodulates the input signal into a baseband signal capable of diversity combining. At this time, a synchronization signal from the synchronization circuit 7 is also used. Synchronous circuit 7
Then, the signal before being demodulated by the demodulation circuit 6 is received, and a synchronous signal such as a frame and a clock is reproduced. In order to reproduce the synchronization signal, a signal demodulated by the demodulation circuit 6 is received, and a synchronization signal included in the input signal, for example, MPEG
A -TS synchronization signal (47H or B8H) or the like can also be used. The synchronization circuit 7 also determines the lock / unlock status of the synchronization, and outputs a synchronization status signal indicating the status determination result to each circuit. The squelch circuit 8 controls the demodulated signal based on the level detection signal input from the AGC circuit 5 and the synchronization state signal input from the synchronization circuit 7 so that the device characteristics do not deteriorate. Also, the control signal is output to the synthesizing unit 4 (FIG. 1) as a squelch signal.

That is, the squelch circuit 8 receives the level detection signal, the output from the demodulation circuit 6 and the synchronization state signal and monitors the state of the received signal. When the synchronization state signal indicates unlock, Alternatively, when the level detection signal indicates that there is no reception signal, a control signal indicating that a prescribed reception signal has not been obtained is output to the combining unit 4 (FIG. 1) as a squelch signal. In this case, the squelch circuit 8 may not send the output from the demodulation circuit 6 to the synthesis unit 4. Of course, the squelch circuit 8 outputs the demodulated signal from the demodulation circuit 6 to the synthesizing unit 4 as it is when a prescribed reception signal is obtained.

On the other hand, the synthesizing unit 4 receives the C / N signal and the squelch signal and performs synthesis by referring to the C / N signal from each receiving unit. When the squelch signal indicates unlock or no received signal, In this case, the demodulated signal output from the receiving unit is not targeted for synthesis.

As described above, in the present embodiment, by providing a squelch circuit and performing control, it is possible to improve the characteristic deterioration of the device when there is no received signal or when synchronization is not established. In addition, it is possible to prevent the device from malfunctioning due to the absence of a received signal.

FIG. 3 shows a configuration of a receiving section according to another embodiment of the present invention. 3, the same parts as those in FIG. 2 are denoted by the same reference numerals, and description thereof will be omitted. In this embodiment, the squelch circuit 8 'receives the level detection signal from the AGC circuit 5, the synchronization state signal from the synchronization circuit 7, and the C / N signal from the C / N calculation circuit 9, and monitors the state of the reception signal. I do. In other words, the squelch circuit 8 ′ controls the control signal (squelch signal) indicating that a prescribed reception signal is not obtained when the synchronization state signal indicates unlock or the level detection signal indicates no reception signal. ) Is included in the C / N signal and output. Note that the output of the demodulation circuit 6 is sent directly to the synthesis unit 4 without passing through the squelch circuit 8 '.

On the other hand, when the synthesizing unit 4 (FIG. 1) receives a C / N signal including a control signal indicating unlock or no received signal, the synthesizing unit 4 (FIG. 1) does not target the demodulated signal from the receiving unit that has output the signal. I do.

As described above, in the configuration of FIG. 3, the squelch control signal is included in the C / N signal and output in the configuration of FIG. 2, and the squelch signal may be included in the C / N signal. Therefore, the same effect as in FIG. 2 can be obtained.

It is needless to say that the diversity receiving apparatus according to the present invention can be applied to any modulation scheme of the received signal.

[0021]

According to the present invention, by performing control by providing a squelch circuit in the receiving unit, it is possible to improve the characteristic deterioration of the device when there is no received signal, etc.
A malfunction of the device due to the absence of a received signal can be prevented. Furthermore, since the receiving input system such as an antenna can be replaced during the operation of the diversity receiving apparatus, there is an effect that maintenance workability is greatly improved.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a diversity receiving apparatus to which the present invention is applied.

FIG. 2 is a diagram illustrating a configuration of a receiving unit in FIG. 1;

FIG. 3 is a diagram showing a configuration of a receiving unit according to another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Diversity receiver 2-1-2-N Receiving antenna 3-1-3-N Receiving part 5 AGC circuit 6 Demodulation circuit 7 Synchronization circuit 8, 8 'Squelch circuit 9 C / N calculation circuit

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Tetsuomi Ikeda 1-10-11 Kinuta, Setagaya-ku, Tokyo Inside Japan Broadcasting Corporation Research Institute (72) Inventor Kazuhiko Shibuya 1-110 Kinuta, Setagaya-ku, Tokyo No. Japan Broadcasting Corporation Broadcasting Research Institute (72) Inventor Satoshi Okabe 1-10-11 Kinuta, Setagaya-ku, Tokyo Japan Broadcasting Research Institute F-term (reference) 5K052 AA01 BB01 BB08 DD03 EE11 EE12 EE17 EE30 FF12 FF29 GG13 5K059 CC03 DD32 DD35 DD44

Claims (5)

[Claims] 1. A diversity receiving apparatus comprising: a plurality of receiving sections connected to different antennas; and a combining section for combining output signals from the receiving sections, wherein the receiving section includes a squelch circuit, and the squelch circuit includes The state of the received signal is monitored, and when a prescribed received signal is not obtained, a control signal indicating this is output, and the combining section combines the output signals from the receiving sections in consideration of the control signal. A diversity receiving device. 2. The diversity receiving apparatus according to claim 1, wherein the receiving unit further receives the received signal from the antenna, performs gain control, outputs a gain-controlled signal, and adjusts the level of the received signal. Detects the presence or absence of a received signal, outputs a level detection signal indicating this, and further
An AGC circuit that outputs a control signal; a demodulation circuit for receiving and demodulating the gain-controlled signal; and a synchronous signal that performs synchronous reproduction by receiving a signal before or after demodulation in the demodulation circuit, and reproduces a synchronized signal. A synchronizing circuit for outputting a synchronizing state signal indicating locking and unlocking of the synchronizing signal, and receiving the AGC control signal, the output from the demodulating circuit and the synchronizing state signal, and receiving a C / N (Carrier- to-
Noise ratio) value is calculated, and C /
A squelch circuit that receives the level detection signal, the output from the demodulation circuit, and the synchronization state signal, and monitors the state of the reception signal. Diversity receiver. 3. The diversity receiving apparatus according to claim 2, wherein the squelch circuit is configured to perform a predetermined operation when the synchronization state signal indicates the unlock state or when the level detection signal indicates no reception signal. The control unit outputs the control signal indicating that a received signal has not been obtained as a squelch signal. The combining unit receives the C / N signal and the squelch signal, and determines whether the squelch signal is unlocked or the absence of the received signal. If indicated, the demodulated signal output from the receiving unit is not targeted for synthesis. 4. The diversity receiving apparatus according to claim 1, wherein the receiving unit further receives the received signal from the antenna, performs gain control, outputs a gain-controlled signal, and adjusts the level of the received signal. Detects the presence or absence of a received signal, outputs a level detection signal indicating this, and further
An AGC circuit that outputs a control signal; a demodulation circuit for receiving and demodulating the gain-controlled signal; and a synchronous signal that performs synchronous reproduction by receiving a signal before or after demodulation in the demodulation circuit, and reproduces a synchronized signal. A synchronization circuit for outputting a synchronization state signal indicating lock / unlock of synchronization, and receiving the AGC control signal, the output from the demodulation circuit and the synchronization state signal, and receiving a C / N (Carrier- to-
Noise ratio) value is calculated, and C /
A C / N calculation circuit that outputs an N signal, wherein the squelch circuit receives the level detection signal, the synchronization state signal, and the C / N signal, and monitors a state of the reception signal. Diversity receiver. 5. The diversity receiving apparatus according to claim 4, wherein the squelch circuit is configured to perform a predetermined operation when the synchronization state signal indicates the unlock state or when the level detection signal indicates no reception signal. The C / N signal includes the control signal indicating that a received signal is not obtained, and the C / N signal is output. The combining unit receives the C / N signal including the control signal indicating the unlock or the absence of the received signal. And a demodulated signal output from the receiving unit and output from the receiving unit is not subjected to synthesis.