JPH0723029A - Space diversity receiving equipment - Google Patents

Abstract

PURPOSE:To obtain an output composite signal of a high level by delaying a signal from plural signal processing systems with a simple constitution and correcting a loss at the time of matching time base. CONSTITUTION:Receiving signals S1a, S1b from parabolic antennas 21, 22 are processed through mixers 23, 24, a local oscillator 25, an infinite phase shifter 26, variable amplifiers 27, 28, and an amplification controller 32, and a level of an IF signal of an input/output end part of delay lines 33, 34 is detected by executing an envelope detection by diodes 40, 41, 44 and 45. By this detected voltage, amplification controllers 42, 46 vary an amplification degree and correct a loss being an input/output end level difference of the delay lines 33, 34. Thereafter, the phase is controlled to the same phase by a phase difference detector 37 and the infinite phase shifter 26, and also, by synthesizing them, a composite output signal so is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a space diversity receiver used in a microwave band radio communication device and delaying signals from a plurality of signal processing systems to correct a loss when matching time axes.

[0002]

2. Description of the Related Art FIG. 2 is a block diagram showing the structure of a conventional space diversity receiver. In FIG. 2, this space diversity receiving apparatus is provided with microwave antenna parabolic antennas 1 and 2 which are spaced apart to perform space diversity reception, and a mixer to which received signals from the parabolic antennas 1 and 2 are input. 3, 4 and a local oscillator 5 for outputting a local oscillation signal for frequency conversion to the mixer 3.
And have. Furthermore, the infinite phase shifter 6 that controls the phase of the local oscillation signal and outputs it to the mixer 4, the mixer 3,
4 has variable amplifiers 7 and 8 for variably amplifying the intermediate frequency signals from the amplifiers 4, and diodes 10 and 11 for detecting the level of the intermediate frequency signals from the variable amplifiers 7 and 8 by envelope detection. .

Further, this space diversity receiver compares an output voltage from the diodes 10 and 11 with an amplification controller 12 which outputs a control signal for making the output level of the intermediate frequency signal from the variable amplifiers 7 and 8 constant. , The intermediate frequency signals from the variable amplifiers 7 and 8 are delayed by a signal in a nearby circuit,
Particularly, delay lines 13 and 14 for correcting the signal delays of the two processing systems when the parabolic antennas 1 and 2 are arranged apart from each other and matching the time axes, and the intermediate frequency signals from the delay lines 13 and 14. And amplifiers 15 and 16 for amplifying.
Further, a phase difference detector 17 that detects the phase difference between the intermediate frequency signals from the amplifiers 15 and 16 and outputs this phase difference signal to the infinite phase shifter 6, and an amplifier whose phase and level are controlled by closed-loop control of these. It has a synthesizer 18 for synthesizing the intermediate frequency signals from 15 and 16 and sending the synthesized output signal.

Next, the operation of this conventional configuration will be described. Received signals from the parabolic antennas 1 and 2 are input to mixers 3 and 4, where they are mixed with a local oscillation signal from a local oscillator 5 and converted into an intermediate frequency signal. The converted intermediate frequency signal is output to the variable amplifiers 7 and 8
It is variably amplified by. This amplification process is performed by diodes 10, 1
The amplification controller 12 controls the variable amplifiers 7 and 8 based on the level of the intermediate frequency signal detected in 1 to automatically make the intermediate frequency signal level of the output from the variable amplifiers 7 and 8 constant in accordance with the higher output level. Gain adjustment (AGC) is performed.

The intermediate frequency signals from the variable amplifiers 7 and 8 are corrected in signal delays by delay lines 13 and 14 to match their time axes, and further amplified by amplifiers 15 and 16 to a phase difference detector 17. Output. The phase difference detector 17 detects the phase difference between the intermediate frequency signals from the amplifiers 15 and 16 and outputs the phase difference signal to the infinite phase shifter 6.
The infinite phase shifter 6 controls the phase of the local oscillation signal based on the input phase difference signal and outputs it to the mixer 4.

The intermediate frequency signals from the amplifiers 15 and 16 whose phase and level are controlled by the closed loop control are combined by a combiner 18 to generate a combined output signal in which fading of radio waves arriving at the parabolic antennas 1 and 2 is suppressed. Send out.

As a proposal of this kind, JP-A-3-06921
There is a "diversity control circuit" disclosed in Japanese Patent No. In this circuit, a correction means is provided to match the characteristics of the respective measurement systems with respect to the received electric field strength, and the same received electric field strength is corrected so as to have the same value as each measurement signal, and the optimum reception is obtained. I am trying to get a signal.

[0008]

However, in the conventional space diversity receiver described above, the delay line 13,
If the delay amount at 14 is large, for example, if the lengths of the transmission paths are largely different because the intervals between the parabolic antennas 1 and 2 are wide, the difference between the attenuation amounts of the delay lines 13 and 14 cannot be ignored and the amplitude is Becomes small, and a high-level output composite signal cannot be obtained even if they are combined in phase. That is, there is a drawback that fading of incoming radio waves cannot be effectively suppressed.

In the example of the publication, the A / D is used as the correction means.
Since the measurement signal is digitized and the received electric field strength characteristic is corrected to the linear characteristic by using the converter, the ROM, the comparator, etc., the signal processing scale and the apparatus scale are increased.

The present invention has been made in view of the above-mentioned circumstances. With a simple configuration, a loss from a signal from a plurality of signal processing systems is corrected when the signals are delayed for time axis matching, and a high level output is obtained. It is an object of the present invention to provide a space diversity receiver that can effectively suppress fading of incoming radio waves by obtaining a composite signal.

[0011]

In order to achieve the above object, a space diversity receiver of the present invention comprises a plurality of frequency conversion means for frequency converting respective reception signals from a plurality of antennas arranged apart from each other. And a local oscillation phase control means for outputting a local oscillation signal for frequency conversion to a plurality of frequency conversion means, and controlling the phase of the local oscillation signal with an input phase control signal for output, and a plurality of frequencies A plurality of variable amplification control means for controlling the signals from each of the conversion means to amplify to a constant level,
A plurality of delay means for delaying the time axis of the signal from each of the plurality of variable amplification control means and a loss which is a difference in signal level between the input and output ends of the plurality of delay means are corrected and output. A plurality of loss correction means, a phase difference detection means for outputting a phase control signal which detects a phase difference between the signals from the plurality of delay line means to the local oscillation phase control means, and a signal from the plurality of loss correction means. And a synthesizing means for synthesizing and outputting.

In this configuration, the plurality of loss correction means are
Based on the difference between the signal levels at the input and output ends of the plurality of delay units and the detection unit that detects the difference between the signal levels at the input and output ends of each of the plurality of delay units The configuration is provided with a plurality of variable amplification means for correcting and outputting loss, which is a difference in signal level between the ends, by variable amplification. Further, the detecting means is configured to include two diodes that detect a difference between voltages detected by the signals at the input and output ends of the plurality of delaying means.

[0013]

In the space diversity receiver of the present invention having the above-mentioned structure, a delay is applied in order to match the time axes of the signals from the plurality of variable amplification control means, and the signal level difference between the input and output ends of the delay means is used. A certain loss is corrected, and the phase is controlled by the local oscillation phase control means to obtain the output combined signal. Therefore, the loss when the signals from the multiple signal processing systems are delayed and aligned on the time axis is corrected, and a high level output composite signal is obtained.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of the space diversity receiver of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing the configuration of an embodiment of a space diversity receiver of the present invention. In FIG. 1, this space diversity receiving apparatus is provided with a parabolic antenna 2 for a microwave band which is arranged apart from each other for performing space diversity reception.
1, 22 and the mixer 2 to which the reception signals S1a and S1b from the parabolic antennas 21 and 22 are input, respectively.
3 and 24, and a local oscillator 25 that outputs a local oscillation signal S2a for frequency conversion to the mixer 23.

Further, this space diversity receiver is provided with an infinite phase shifter 26 which outputs a local oscillation signal S2b in which the phase of the local oscillation signal S2a is controlled to the mixer 24,
Intermediate frequency signals S3 from the mixers 23 and 24, respectively
variable amplifiers 27 and 28 that variably amplify a and S3b, and amplified IF signals S4a and S from the variable amplifiers 27 and 28.
It has diodes 30 and 31 for detecting the level of 4b by envelope detection.

Further, the space diversity receiver compares the output voltages from the diodes 30 and 31 and controls the output levels of the amplified IF signals S4a and S4b from the variable amplifiers 27 and 28 to a constant control signal C1a, C1
The amplification controller 32 which outputs b and the space diversity receiver are the amplification IF signals S from the variable amplifiers 27 and 28.
4a and S4b are delay lines 33 and 34 for correcting the signal delay in the neighboring circuits, in particular, the signal delays of the two transmission processing systems when the parabolic antennas 21 and 22 are arranged apart from each other and aligning the time axes. And the delay IF from the delay lines 33 and 34
Variable amplifiers 35 and 3 for variably amplifying the signals S5a and S5b
6 and 6.

Further, this space diversity receiving apparatus has delay IF signals S5a and S5b from the variable amplifiers 35 and 36.
Phase difference detector 37 that detects the phase difference between the two and outputs the phase difference signal C3 to the infinite phase shifter 26, and the variable amplifiers 35 and 3 whose phase and level are controlled by closed-loop control of these.
It has a synthesizer 38 for synthesizing the delayed IF signals S5a and S5b from S6 and sending a synthesized output signal So in which fading of radio waves individually arrived at the parabolic antennas 21 and 22 is suppressed.

Further, in this space diversity receiver, a diode 40 for detecting the level of the amplified IF signal S4a at the input end of the delay line 33 by envelope detection and an IF signal level at the output end of the delay line 33 are subjected to envelope detection. 41 for detecting by the diode and the diodes 40, 41
The detection voltage from the variable amplifier 3 is input, and the control signal C2a for correcting the difference between the detection voltages, that is, the level difference between the input and output terminals caused by the loss of the delay line 33 is input.
5 and an amplification controller 42 for outputting to the No. 5 circuit.

Further, in this space diversity receiver, the diode 44 for detecting the level of the amplified IF signal S4b at the input end of the delay line 34 by envelope detection and the level of the IF signal at the output end of the delay line 34 are detected. The detection voltage from the diodes 45 and the diodes 44, 45 is input, and the control signal C2b for correcting the difference between the detection voltages, that is, the level difference between the input and output ends caused by the loss of the delay line 34 is changed. It has an amplification controller 46 for outputting to the amplifier 36.

Next, the operation of the configuration of this embodiment will be described. The parabolic antennas 21 and 22 receive radio waves of the same frequency having different phases and electric field strengths at positions separated from each other, and output reception signals S1a and S1b thereof. The received signals S1a and S1b are mixed and converted by the mixer 23 with the local oscillation signal S2a from the local oscillator 25, and are mixed and converted by the mixer 24 with the local oscillation signal S2a from the infinite phase shifter 26. The converted intermediate frequency signals S3a and S3b are output to the variable amplifiers 27 and 2
8 and outputs amplified IF signals S4a and S4b.

The amplification processing here is performed by the diodes 30, 31.
The amplification controller 32 controls the variable amplifiers 27 and 28 on the basis of the levels of the amplified IF signals S4a and S4b detected in step 1 to perform automatic gain adjustment (AGC). That is, according to one of the high output levels of the amplified IF signals S4a and S4b,
Performs closed-loop control that keeps the level constant. Furthermore, the time axes of the amplified IF signals S4a and S4b from the variable amplifiers 27 and 28 are matched by the delay lines 33 and 34. This delay line 3
The delayed IF signals from the amplifiers 3 and 34 are variably amplified by the variable amplifiers 35 and 36, and the delayed IF signals S5a and S5b are output.

In this case, the amplification IF at the input end of the delay line 33
The level of the signal S4a is envelope-detected and detected by the diode 40, and at the same time, the level of the IF signal at the output end of the delay line 33 is envelope-detected and detected by the diode 41. The detection voltage from the diodes 40 and 41 is input to the amplification controller 42, the control signal C2a of the difference between the detection voltages is output to the variable amplifier 35 to change the amplification degree, and the delay line 33
The level difference between the input and output terminals caused by the loss of is corrected.

Further, the level of the amplified IF signal S4b at the input end of the delay line 34 is envelope-detected and detected by the diode 44, and at the same time, the level of the IF signal at the output end of the delay line 34 is envelope-detected and detected by the diode 45. To do.
The detection voltage from the diodes 44 and 45 is input to the amplification controller 46, and the control signal C2b of the difference between the detection voltages is output to the variable amplifier 36 to change the amplification degree, and the delay line 34
The level difference between the input and output terminals caused by the loss of is corrected.

Further, the amplifiers 35 and 36 in which the loss, which is the level difference between the input and output terminals of the delay lines 33 and 34, are corrected.
The phase difference between the delayed IF signals S5a and S5b is detected by the phase difference detector 37, the phase difference signal C3 is output to the infinite phase shifter 26, and the local oscillation signal from the infinite phase shifter 26 is output. S2b is controlled to be in phase with the local oscillation signal S2a supplied to the mixer 23.

The delayed IF signal S5 from the variable amplifiers 35 and 36 whose phase and level are controlled by these closed loop controls.
a and S5b are combined by the combiner 38 to form the parabolic antenna 2
A combined output signal So in which fading of radio waves arriving at 1 and 22 is suppressed is obtained.

[0026]

As described above, the spatial diversity receiving apparatus of the present invention delays the signals from a plurality of variable amplification control means in order to match the time axes, and the signals at the input and output ends of the delay means. Loss when the signals from a plurality of signal processing systems are delayed and time-axis matched by correcting the loss that is the level difference and controlling the phase by the local oscillation phase control means to obtain the output composite signal. Is corrected,
A high-level output combined signal is obtained, and fading of incoming radio waves can be effectively suppressed.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of a space diversity receiving apparatus of the present invention.

FIG. 2 is a block diagram showing a configuration of a conventional space diversity receiver.

[Explanation of symbols]

 21,22 Parabolic antenna 23,24 Mixer 25 Local oscillator 26 Infinite phase shifter 27,28,35,36 Variable amplifier 30,31,40,41,45,45 Diode 32,42,46 Amplification controller 33,34 Delay Line 38 synthesizer

Claims (3)

[Claims] 1. A plurality of frequency conversion means for frequency-converting respective reception signals from a plurality of antennas arranged apart from each other, and a local oscillation signal for frequency conversion is output to the plurality of frequency conversion means, and , A local oscillation phase control means for controlling the phase of a local oscillation signal by an input phase control signal and outputting the same, and a plurality of variable amplifiers for controlling the signals from each of the plurality of frequency conversion means and amplifying them to a constant level It is the difference between the control means and the plurality of delay means for delaying the time axes of the signals from each of the plurality of variable amplification control means, and the signal level of each input / output terminal of the plurality of delay means. A plurality of loss correction means for correcting and outputting loss, and a phase control signal for detecting a phase difference between signals from the plurality of delay line means, the local oscillation phase control means. A space diversity receiving device comprising: a phase difference detecting means for outputting to a plurality of loss compensating means; and a combining means for combining and outputting signals from the plurality of loss correcting means. 2. The plurality of loss correction means include a detection means for detecting a difference in signal level between the input and output ends of the plurality of delay means, and a difference in signal level between the input and output ends obtained by the detection means. 2. A plurality of variable amplifying means for correcting and outputting a loss, which is a difference in signal level between the input and output ends of each of the plurality of delaying means, by variable amplification based on the above. Space diversity receiver. 3. The space diversity receiver according to claim 1, wherein the detecting means includes two diodes for detecting a difference between voltages obtained by detecting signals at respective input and output ends of the plurality of delay means.