JPH02237324A - In-phase synthesis space diversity receiver - Google Patents

Abstract

PURPOSE:To always synthesize around in-phase point by devising the receiver such that the phase hardly enters a dead zone near an opposite phase and a phase error from an in-phase point is decreased near in-phase. CONSTITUTION:The receiver is devised such that the phase hardly enters a dead zone when the relation of phases of two reception inputs is nearly in an opposite phase and a phase error from the in-phase point is decreased near in-phase relation. When the relation of phases of the two reception input signals is at the outside of dead zone of phase control, the width of dead band is decreased, and when the relation of the phases exists within the dead zone, the width of dead zone is increased. Thus, the phase control is stopped in the case of in-phase synthesis and phase control is applied within a range where the phase error is very small from the in-phase point (phase difference is 0 deg.) at the outside in the vicinity of the in-phase. Moreover, the two reception input signals are always synthesized near the in-phase and the deterioration to be caused by controlling an endless phase shifter in an unnecessary way is minimized.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention detects the phase difference between two received input signals in a phase comparator, and determines the phase lead or lag between the received input signals from the output thereof. The present invention relates to an in-phase synthesis space diversity receiver that controls the phase difference of received input signals.

[Conventional technology]

A block diagram of an embodiment of an in-phase combining space diversity receiver in a conventional receiver is shown in FIG. In the figure, the received input signal S2 is input to an infinite phase shifter (EPS) 1.
The phase is controlled by the power combiner 2 so that the signal is always combined in phase with the received input signal S1. This composite signal is sent to a demodulator (DEM) (not shown) and demodulated into a baseband signal.

Meanwhile, the two input signals to the power combiner 2 are branched together and passed through a band pass filter 34 and an automatic gain control (AGC) amplifier 5.6, respectively, and then input to a phase comparator 7. The bandpass filter 3.4 is a narrowband bandpass filter (BPF) for extracting only the components near the center frequency of the modulated wave, and the automatic gain control amplifier 5
, 6 function to always keep the signal level constant.

Also, one signal, here only the received input signal S2 side, is 9
It passes through a 90' phase shifter 8 for changing the phase by 0°.

As shown in FIG. 4(a), the phase comparator 7 has a characteristic such that its output becomes O when the two signals to be compared are in phase, and with this characteristic, the two signals Compare. The output voltage V of this phase comparator 7. are two voltage comparators 9 each having a threshold voltage fixed to a different value.
and 10, to obtain one input phase delay detection signal and one input phase advance detection signal as shown in FIGS. 4(b) and 4(c). Using the two control signals having this phase information, the infinite phase shifter control circuit 11 controls the phase of the received input signal S2 in the infinite phase shifter 1 to perform in-phase synthesis.

[Problems to be Solved by the Invention] In the conventional in-phase synthesis space diharsity receiver described above, the output voltage V of the phase comparator 7 as shown in FIG. When Vl>Vo>V2, there is a phase difference range in which the two voltage comparators 9 and 10 do not detect any phase lead or lag, and this is a dead zone in which no phase control is performed. This is because if a dead band is not provided during in-phase synthesis, the received input signal S2 will always be phase-controlled by the infinite phase shifter 1, which will cause noise to the synthesized wave, or cause phase fluctuations in the entire receiving device. This is because it may cause deterioration of error rate characteristics, and this has been prevented by providing a dead zone.

However, in the conventional method of simply setting a fixed dead zone of the two voltage comparators 9 and 10 with respect to the output voltage of the phase comparator 7, it is difficult not only when the two received input signals are in phase but also when they are in opposite phase. Sometimes, a dead zone occurs due to the phase difference between the two received input signals. For this reason, there is a problem in that if the phase relationship of the received input jumps into a dead zone near the opposite phase for some reason, the phase control will stop while remaining in the opposite phase combination state.

An object of the present invention is to provide an in-phase synthesis space diversity receiver that is difficult to enter a dead zone near the opposite phase, and that makes it possible to always perform synthesis near the in-phase by reducing the phase error from the in-phase point near the in-phase. shall be.

[Means to solve the problem]

The in-phase synthesis space diversity receiving device of the present invention includes:
a phase comparator that compares the phases of two received input signals respectively input from two antennas; and a first phase comparator that detects a phase delay between the two received input signals from the output of the phase comparator.
a voltage comparator, a second voltage comparator that similarly detects a phase lead, and a control circuit that controls the phase difference between the two received input signals using phase control information obtained as the output of these voltage comparators. In the receiving device, the first and second voltage comparators are each provided with a reference voltage generator whose output voltage is changed according to the phase control information,
The output voltage of this reference voltage generator gives each threshold voltage of the first and second voltage comparators a hysteresis characteristic.

[Effect]

In the configuration described above, when the phase relationship between the two received input signals is outside the phase control dead zone, the dead zone width becomes small, and when it is within the dead zone, the dead zone width becomes large. Therefore, phase control is stopped during in-phase synthesis, and when the phase is not near the in-phase, phase control is performed within a range where the phase error from the in-phase point is extremely small.

〔Example〕

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

FIG. 1 is a block diagram of an embodiment of the present invention, and the same parts as those of the conventional device shown in FIG. 3 are given the same reference numerals, and detailed explanation thereof is omitted.

In this device, a reference voltage generation circuit 12 and a reference voltage generation circuit 13 are used to provide a hysteresis characteristic to each threshold voltage of a voltage comparator 9 and a voltage comparator 10 for determining the output voltage of a phase comparator 7. is provided, and the threshold voltage is changed according to the output levels of the voltage comparators 9 and 10.

With this configuration, as shown in FIGS. 2(a) and 2(b), the reference voltage generation circuit 12 and the reference voltage generation circuit 1
Reference numeral 3 denotes a voltage comparator 9 and a voltage comparator 1 that determine whether the input phase is delayed or advanced based on the output voltage obtained by comparing the phase difference Δθ+90° between the two received input signals with the phase comparator 7.
The threshold voltages V, , V2 of 0 are controlled. And 2
The phase difference Δθ+90° between the two received input signals is 0° or 1
Width of dead zone I when it is around 80° V2'Vl'
However, the width of the dead zone ■2''■ in other phase difference regions
,'' is controlled so that it is narrower than .

Here, ■,' are the threshold voltages of the voltage comparator 9 when the input phase comes out of the dead zone ■, and ■2' is the threshold voltage of the voltage comparator 10 when the input phase comes out of the dead zone ■. value voltage,
■1'' is the threshold voltage of voltage comparator 9 when the input phase falls within dead zone I; ■2'' is the threshold voltage of voltage comparator 10 when the input phase falls within dead zone I It is.

That is, when the phase relationship between the two reception inputs is near opposite phases, it is difficult to enter a dead zone, and when near the same phase, the phase error from the in-phase point is made small.

〔Effect of the invention〕

As explained above, in the present invention, when the phase relationship between two received input signals is outside the dead zone of phase control, the dead zone width becomes small, and when it is within the dead zone, the dead zone width becomes large. During in-phase synthesis, phase control is stopped, and when the signal is not in the vicinity of the same phase, the phase control is performed within an extremely small range of phase error from the in-phase point (phase difference is 0°), and the two received input signals are always combined in the vicinity of the same phase. This has the effect of minimizing deterioration caused by unnecessary control of the infinite phase shifter.

[Brief explanation of drawings]

Fig. 1 is a block diagram of an embodiment of the present invention, Fig. 2(a)
and (b) are diagrams showing the phase comparison characteristics of the device in FIG. 1, FIG. 3 is a block diagram of a conventional in-phase combining space diversity receiver, and (a) to (C) in FIG.
FIG. 3 is a diagram of the phase comparison characteristic and its output characteristic in the device shown in the figure. 1... Infinite phase shifter, 2... Power combiner, 3, 4...
・Narrowband bandpass filter, 5.6... Automatic gain control amplifier, 7... Phase shift comparator, 8... 90° phase shifter, 9, 10... Voltage comparator, 11...・Infinite phase shifter control circuit, 12.13...Reference voltage generation circuit. 81st glance

Claims (1)

[Claims] 1. A phase comparator that compares the phases of two received input signals input from two antennas, and a first voltage comparison that detects a phase delay between the two received input signals from the output of this phase comparator. and a second one that similarly detects the phase advance.
and a control circuit that controls the phase difference between the two received input signals using phase control information obtained as outputs of these voltage comparators, wherein the first and second voltage comparison A reference voltage generator whose output voltage is changed according to the phase control information is attached to each of the devices, and the output voltage of the reference voltage generator causes hysteresis characteristics to be applied to each threshold voltage of the first and second voltage comparators. What is claimed is: 1. An in-phase synthesis space diversity receiving device characterized by having: