JP2654527B2 - Space diversity reception method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a space diversity reception system, and more particularly to a combined space diversity reception system used for a radio communication device in a microwave band.

[0002]

2. Description of the Related Art As shown in FIG. 2, the phase of a received input signal 2 is controlled by an infinite phase shifter (EPS). Are input to the power combiner 3. On the other hand, the received input signal 1 is split into two by the power divider 4A, input to the power combiner 3, and combined with the received input signal 2 described above. On the other hand, the signals split by the power splitters 4A and 4B pass through band-pass filters 5A and 5B which determine frequency bands to be phase-compared, and are configured by voltage-controlled variable gain amplifiers 6A and 6B and detectors 7A and 7B.
It is amplified to a constant power level by the GC amplifiers 15A and 15B. The phase of the output signal of the AGC amplifier 15B is 9
The phases are compared by a phase comparator 9A through a 90-degree phase shifter 8 for a 0-degree phase shift. The phase difference information removes unnecessary harmonic components with a low-pass filter 10A and outputs a phase difference voltage VO. The characteristics of the phase comparator 9A are shown in FIG.
As shown in (a), it is OV at the in-phase point. This phase difference voltage VO is converted to OV by the voltage comparator 11A.
FIG. 3 (b)
As shown in (1), a detection signal is output depending on whether one input phase is behind or ahead of the other. The signal having this phase information is input to the ESP control circuit 13 as a control signal of the infinite phase shifter (EPS) 1 to control the amount of phase shift of the infinite phase shifter (ESP) 1. That is, if the detected phase difference information is “lag”,
In the case of "advance", in-phase synthesis was performed by changing in the direction of "lag".

[0003]

In the conventional space diversity receiving system described above, the phase shift amount of the infinite phase shifter is controlled so as to control the phase difference between two received input signals and combine them in phase. However, in the transition time until the in-phase synthesis state is established, for example, the phase difference Δθ between the two signals
May be near the reverse phase greater than 120 degrees. In this case, there is a disadvantage that the signal is deteriorated by controlling the original signal level to be lowered rather than by combining.

[0004]

According to the space diversity receiving system of the present invention, two received input signals are inputted,
A 90-degree phase shifter is inserted into one of them, and a first phase comparator for comparing the phases of the two received input signals, and a signal between the output of the first phase comparator and the two received input signals. Phase difference control for controlling a first voltage comparator for detecting whether the phase is delayed or advanced, and an infinite phase shifter for adjusting a phase difference of a received input signal based on phase difference information obtained as an output of these voltage comparators In a space diversity receiving system including a circuit and a power combiner for combining two signals whose phases are controlled, a phase comparison characteristic for a phase difference between two signals compared by the first phase comparator is described. A second phase comparator set so as to differ by 90 degrees, a second voltage comparator for detecting whether the phases of the two reception inputs are near the in-phase or near the reverse phase from the output of the second phase comparator; By the phase difference control circuit First to input your two signals of the power level to the respective control to the power combiner
And a second power attenuator, first and second power detection means for detecting reception input level information of each of the two reception input signals, phase difference information obtained from the second voltage comparator, The amount of attenuation of the first and second power attenuators is controlled based on the input power level information obtained by the first and second power detection means.

[0005]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. FIG. 1 is a block diagram of one embodiment of the present invention, and FIG.
The same reference numerals as those of the conventional example have the same configuration and function. That is, in this embodiment, the phase difference between the phase comparator 9A and the phase comparator 9A is 90.
A power divider 4D is provided on the input side of the 90-degree phase shifter 8 for comparing two signals having different degrees, and the other signal is also branched by the power divider 4C and phase-compared by the phase comparator 9B. . A phase difference voltage VO is obtained from the output through a low-pass filter 10B. Phase difference voltage V of phase comparator 9B
O is, as shown in FIG. 3A, Δθ is −90 degrees to +90 degrees.
The voltage becomes positive near the phase of degree, and Δθ is +90 degrees to +27.
It takes a negative voltage value near the reverse phase of 0 degrees. Voltage comparator 11B
Judge whether the signal is positive or negative, and as shown in FIG. Also, by taking out the output voltages of the detectors 7A and 7B constituting the AGC amplifiers 15A and 15B and providing a voltage comparator 12 for comparing the respective voltage values, the power level of the two received input signals can be reduced. The magnitude is determined to be input power level information. The control circuit 4 receives the input power level information and the phase difference information from the voltage comparator 11B, and controls power attenuation provided for controlling the respective levels of the two signals synthesized by the power synthesizer 3. The amount of attenuation of the devices 2A and 2B is controlled. Control circuit 14
When the phase difference Δθ to be synthesized in step (1) is near the in-phase (Δθ <90 degrees), the synthesis is performed by minimizing the attenuation in the power attenuators 2A and 2B, and when the phase difference is near (Δθ> 90 degrees). Is
The attenuation of the power attenuator with the smaller input power level is increased, and the attenuation of the larger input power level is minimized so that only one signal is input to the power combiner 3 so that the combining is not performed. ing.

[0006]

As described above, according to the present invention, the phase relationship between two received input signals is 90 ° or more by providing the phase comparator of the conventional example and the phase comparing means and the judging means having a phase difference of 90 °. In the case where the two input signals are different from each other, the effect of preventing the lowering of the input level of either of the two received input signals from being combined near the opposite phase to prevent the signal level from being lowered is prevented. There is.

[Brief description of the drawings]

FIG. 1 is a block diagram of one embodiment of the present invention.

FIG. 2 is a block diagram of a conventional space diversity receiving system.

FIG. 3 is an explanatory diagram for comparing and explaining the present embodiment and a conventional example.

[Explanation of symbols]

 Reference Signs List 1 infinite phase shifter (ESP) 2A, 2B power attenuator 3, 4A to 4D power distributor 5A, 5B band pass filter 6A, 6B variable gain amplifier 7A, 7B detector 8 90 degree phase shifter 9A, 9B phase comparison 10A, 10B Low-pass filter 11A, 11B, 12 Voltage comparator 13 EPS control circuit 14 Control circuit 15A, 15B Automatic gain control amplifier

Claims (3)

(57) [Claims] 1. A first phase comparator for inputting two reception input signals, inserting a 90-degree phase shifter into one of them, and comparing the phases of the two reception input signals, and a first phase comparator for comparing the phases of the two reception input signals. A first voltage comparator for detecting whether the phase of the two received input signals is delayed or advanced from the output of the comparator, and a phase difference information obtained as an output of these voltage comparators for detecting the phase of the received input signal. In the space diversity receiving system including a phase difference control circuit for controlling an infinite phase shifter for adjusting a phase difference and a power combiner for combining two signals whose phases are controlled, the first phase comparator And a second phase comparator in which the phase comparison characteristics with respect to the phase difference between the two signals to be compared are set to differ by 90 degrees, and from the output of the second phase comparator, the phases of the two reception inputs are near or in phase. Second to detect near phase And a first and a second for controlling the power levels of the two signals controlled by the phase difference control circuit and inputting them to the power combiner, respectively.
Power attenuator, first and second power detection means for detecting respective reception input level information of two reception input signals, phase difference information obtained from the second voltage comparator, and the first and second power detectors. A space diversity reception system, wherein the amount of attenuation of the first and second power attenuators is controlled based on input power level information obtained by a second power detection means. 2. The method according to claim 1, wherein said first and second power detection means are
2. The space diversity receiving method according to claim 1, wherein said gain control voltage is provided as input power level information, provided in each of the automatic gain control amplifiers for controlling the gain of two reception inputs. 3. When the phase difference between the two reception inputs is greater than 90 degrees and near the reverse phase combination, the amount of attenuation of the first or second power attenuator having the smaller reception input level is changed. 2. The power attenuator according to claim 1, wherein said power attenuator is larger than said power attenuator.
The space diversity reception method described.