JP2830141B2 - Three-sided antenna space diversity receiver - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microwave receiving system, and more particularly to a three-plane antenna space diversity receiving apparatus.

[Conventional technology]

This type of three-plane antenna space diversity receiver conventionally used has a configuration as shown in FIG. In the figure, the AGC control voltage of the variable gain amplifier 206 for amplifying the received signal of the second sub receiving antenna 203 is the variable gain amplifier 2 for amplifying the received signal of the main receiving antenna 201.
The configuration is common to the AGC control voltage of the variable gain amplifier 205 for amplifying the reception signal of the first and second sub receiving antennas 202 and the same control voltage is supplied from the control circuit 209.
Note that in the figure, 207 and 208 are variable gain amplifiers 204 and 205
Detectors 210 and 211 are combiners, the combiner 210 combines the outputs of the variable gain amplifiers 204 and 205, and the combiner 211 combines the output of the combiner 210 and the output of the variable gain amplifier 206. This is a combiner that sends the received output to the terminal 212.

[Problems to be solved by the invention]

However, in such a configuration, when both the reception input levels of the main reception antenna 201 and the first sub reception antenna 202 decrease, the reception signals of these antennas are passed through the respective variable gain amplifiers 204 and 205 and the detectors 207 and 208. The received control circuit 209 outputs an AGC control voltage for increasing the gains of the variable gain amplifiers 204 and 205. However, as mentioned above, the second
When the gain of the variable gain amplifier 206 for amplifying the reception signal of the sub-receiving antenna 203 increases, the linearity of the amplifier cannot be maintained when the reception input level of the second sub-receiving antenna 203 increases, and there is a risk of deteriorating the signal. is there.

SUMMARY OF THE INVENTION An object of the present invention is to provide a three-sided antenna for preventing signal deterioration due to non-linear characteristics of an amplifier when both reception inputs of a main reception antenna and a first sub reception antenna decrease and reception inputs of a second sub reception antenna increase. An object of the present invention is to provide a space diversity receiving device.

[Means for solving the problem]

A three-sided antenna space diversity receiving apparatus according to the present invention includes a first variable gain amplifier for amplifying a received signal of a main receiving antenna, a second variable gain amplifier for amplifying a received signal of a first sub receiving antenna, and a second variable gain amplifier. A third variable gain amplifier for amplifying the reception signal of the sub receiving antenna, a first detector for detecting the output level of the first variable gain amplifier, and a second detector for detecting the output level of the second variable gain amplifier And a third detector for detecting the output level of the third variable gain amplifier.
For simultaneously controlling the gains of the first and second variable gain amplifiers from the outputs of the first and second detectors.
A first control circuit for generating an AGC control voltage, and an AGC for controlling the gain of the third variable gain amplifier based on the AGC control voltage generated by the first control circuit and the output of the third detector.
A second control circuit for generating a control voltage; and means for combining an output of the first variable gain amplifier, an output of the second variable gain amplifier, and an output of the third variable gain amplifier.

[Action]

With such a configuration, the main receiving antenna and the first
Even if the inputs of the sub-receiving antennas are both reduced and the input of the second sub-receiving antenna is increased, it is possible to prevent the conventional signal deterioration due to the non-linear characteristics of the amplifier.

〔Example〕

 Next, the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing one embodiment of the present invention. In the figure, received inputs respectively received by a main receiving antenna 101, a first sub receiving antenna 102, and a second sub receiving antenna 103 are amplified by corresponding first, second, and third variable gain amplifiers 104, 105, and 106, respectively. , The first, second, and third detectors 107, 108, and 109 detect their output levels. The first control circuit 110 controls the gains of the variable gain amplifiers 104 and 105, and determines the magnitudes of the reception input levels of the main receiving antenna 101 and the first sub receiving antenna 102 by the detectors 107 and 1 respectively.
Judgment is made from the output of step 08, an AGC control voltage corresponding to the side having a higher reception input level is generated, and control is performed to make the gains of the variable gain amplifiers 104 and 105 equal at the same time. Second control circuit 111
Controls the gain of the variable gain amplifier 106,
When the reception input of both the main reception antenna 101 and the first sub reception antenna 102 is lower than the reception input of the second sub reception antenna, an AGC control voltage corresponding to the output of the detector 109 is generated,
In other cases, that is, when the reception inputs of both the main reception antenna 101 and the first sub reception antenna 102 are larger than the reception inputs of the second sub reception antenna, the second control circuit 111
Generates an AGC control voltage by the AGC control voltage of the first control circuit 110 so as to have a gain equal to that of the variable gain amplifiers 104 and 105, and controls the variable gain amplifier 106.

FIG. 2 is a specific example of the first and second control circuits 110 and 111, and includes a two-input maximum value output circuit.

The combiners 112 and 113 are, like the combiners 210 and 211 in FIG. 3, a combiner for combining signals received in space diversity.

〔The invention's effect〕

As described above, the present invention includes a detector for detecting the reception input level of the second sub-receiving antenna and a control circuit for controlling the variable gain amplifier for amplifying the reception input of the second sub-receiving antenna. By independently adding the control circuit of the variable gain amplifier for amplifying the reception input of the first sub receiving antenna, both the main receiving antenna and the first sub receiving antenna input are decreased and the second sub receiving antenna input is increased. In this case, there is an effect that signal deterioration due to the non-linearity of the amplifier can be prevented.

Further, according to the present invention, a dedicated control circuit for three-surface antenna space diversity is not necessary, and the two-surface antenna space diversity receiver can be easily and inexpensively changed to a three-surface antenna space diversity receiver.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of a three-plane antenna space diversity receiver according to the present invention, FIG. 2 is a circuit diagram showing a specific example of a control circuit used in FIG. 1, and FIG. It is a block diagram of a receiving device. 101, 201 ... main receiving antenna, 102, 202 ... first sub receiving antenna, 103, 203 ... second sub receiving antenna, 104, 105, 106, 204, 205, 206 ... variable gain amplifier, 107, 108, 109, 207, 208 ... detector, 110 ... first control circuit, 111 ... Second control circuit, 112, 113, 210, 211 ... synthesizer, 114, 212 ... reception output, 209 ... control circuit.

Claims (1)

(57) [Claims] A first amplifying a received signal of a main receiving antenna.
A variable gain amplifier, a second variable gain amplifier for amplifying a received signal of a first sub receiving antenna, a third variable gain amplifier for amplifying a received signal of a second sub receiving antenna, and the first variable gain A first detector for detecting the output level of the amplifier, a second detector for detecting the output level of the second variable gain amplifier, and a third detector for detecting the output level of the third variable gain amplifier A detector, a first control circuit for generating an AGC control voltage for simultaneously controlling the gains of the first and second variable gain amplifiers from the first and second detector outputs, and the first control circuit; A second control circuit for generating an AGC control voltage for controlling a gain of the third variable gain amplifier based on an AGC control voltage generated by a control circuit and an output of the third detector; Gain amplifier output and said second variable gain booster 3 faces the antenna space diversity receiver characterized in that it comprises a means for synthesizing vessel and output an output of said third variable gain amplifier.