JPH01251926A - In-phase synthesized space diversity receiver - Google Patents

Abstract

PURPOSE:To prevent stoppage of phase control when the phase of an input signal is nearly opposite to that of another input signal by eliminating a phase control dead zone when the phase relation between the two input signals is nearly opposite. CONSTITUTION:Two signals having a phase difference of 90 deg. against a phase comparator 7 are compared by means of a phase comparator 12 and the threshold voltages of voltage comparators 9 and 10 are changed by means of the output of a voltage comparator 13 which discriminates the output voltage of the phase comparator 12. Then phase control is performed by setting a nonsensitive zone for improving noise characteristics when the phases of the two received input signals are nearly the same and not setting the dead zone when the phases are nearly opposite to each other. Therefore, stoppage of the phase control while signals having opposite phases are set to a synthesized state.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an in-phase synthesis space diversity receiving device, and in particular, when performing phase difference detection, there are two methods for setting a dead zone for improving noise characteristics. The present invention relates to an in-phase synthesis space diversity receiving device that does not set a dead zone when the receiving power is near the opposite phase.

[Prior Art] In general, an in-phase combining space diversity receiver is
A phase comparator is installed to detect the phase difference between the two receivers, and two voltage comparators determine the phase lead or lag from the output to control the phase difference between the receive input signals and perform in-phase synthesis. .

FIG. 3 is a block diagram of a conventional in-phase combining space diversity receiver.

In the same figure, I! , is an infinite phase shifter (EPS), 2 is a power combiner, and the second receiving human power signal is an infinite shifter 1
The phase of the signal is controlled by the power combiner 2, and the signal is always combined in phase with the first received human power signal. The composite signal is then sent to a demodulator (DEM) (not shown) and demodulated into a baseband signal.

The two human input signals are input to the power combiner 2, and at the same time, the two input signals are input to a narrow band pass filter (BPF) 3. which extracts only the components near the center frequency of the modulated wave.
4, and further to an automatic gain control (AGC) amplifier 5.6 which keeps the signal level constant. Then, the output of the automatic gain control amplifier 5 is input to the phase comparator 7 as it is, and the output of the automatic gain control amplifier 6 is input to the phase comparator 7 through a 90' phase shifter 8 that changes the phase by 90''. do.

Here, the phase characteristic of the phase comparator 7 is as shown in FIG. 4(a), and its output becomes 0 when the two signals to be compared are in phase.

The output voltage V8 of this phase comparator 7 is input to two voltage comparators 9°lO having different fixed threshold voltages, and one detects a delay in the input phase and the other detects a lead in the input phase. I am getting a signal (Figure 4(b)
) and (C)).

Then, based on the two control signals having this phase information, the EPS control circuit 11 controls the amount of phase shift of the infinite phase shifter l, changes the phase of the second received human input signal, and performs in-phase synthesis.

By the way, the output voltage vlI of this phase comparator 7 is Vl
>Vll >V2, two voltage comparators 9°1
0, no phase lead or lag is detected (Fig. 4). That is, there is a range in which no phase difference is detected, which is a dead zone in which no phase control is performed.

This is because if the phase of the received human input signal is always controlled using the infinite phase shifter l, it will cause noise in the composite wave, which will cause phase fluctuations that will degrade the error rate characteristics of the entire receiving device. It is.

In this way, the conventional in-phase synthesis space diversity receiver attempts to stabilize the output by setting a dead zone in phase control.

[Problems to be solved] The conventional in-phase synthesis space diversity receiver described above only sets a dead zone in two voltage comparators for the output voltage of one phase comparator. A dead zone occurs not only when the human input signals are in the same phase, but also when they are out of phase, and if for some reason the phase relationship of the receiving input signal jumps into the dead zone near the opposite phase,
There was a problem in that the phase control stopped while remaining in the reverse phase synthesis state.

The present invention has been made in view of the above-mentioned problems. When the two receiver powers are in the same phase, a dead zone is set for improving the noise characteristics, and when the two receiver powers are in the opposite phase, no dead zone is set. An object of the present invention is to provide an in-phase combining space diversity receiving device capable of performing phase control.

[Means for Solving Problems] In order to achieve the above object, the in-phase synthesis space diversity receiving device of the present invention detects the phase difference between the received signals manually input from two antennas, and determines whether the phase leads or lags. a combining means for changing the phase of one of the received signals based on the output of the first phase difference determining means and combining the phase differences between the received signals as being in phase; and second 1a phase difference determining means for determining whether the phase difference between the signals is around the same phase or around the opposite phase, and controlling the dead zone of the first phase difference determining means based on the result. be.

Here, specifically, in order to determine whether the phase difference between the two received human input signals is around the same phase or around the opposite phase, a state where the phase difference is 90'' different from the phase difference when determining phase delay or lead is determined. The phases of the two received input signals are compared, and the result shows that the phase difference (Δθ + 90°) between the two received human input signals is around the same phase (-90"< 90°) or around 90° < Δ
It is determined whether θ<270').

Based on this determination, the threshold voltage of a voltage comparator that determines whether the phase is delayed or advanced is controlled.

[Example code] Hereinafter, the present invention will be explained in detail based on the drawings.

FIG. 1 is a block diagram of an in-phase combining space diversity receiver according to an embodiment of the present invention. . Note that parts common to or corresponding to those of the conventional example are denoted by the same reference numerals.

In the figure, 12 is a phase comparator, and phase comparator 7
Compares three signals with a phase difference of 90 degrees. Also, 1
3 is a voltage comparator that determines the output voltage of the phase comparator 12;
00 threshold voltage can be changed.

In the above configuration, the phase comparator 12 has a phase comparison characteristic (FIG. 2(a)) that is 90 degrees out of phase with the phase comparison characteristic of the phase comparator 7, and the voltage comparator 13 has
Determine whether the output voltage of No. 2 is positive or negative. Then, the voltage comparator 9 and the voltage comparator 10 use the output (FIG. 2(d))
The threshold voltage V, ,V, , is controlled. In other words, the phase difference (Δθ+90°) between the two received human input signals is 90
In the range of °≦△θ+90°≦270°, V, = V2 = O, and in the range of -906≦80≦906, ■, = V2 = constant voltage.

By doing this, no dead zone occurs near the opposite phase. Therefore, unlike the conventional in-phase synthesis space diversity receiver, the phase control does not stop near the opposite phase.

In this way, in this embodiment, in order to control the phase difference of the received input signals coming from the two antennas and combine them in the same phase, the first phase comparator 7 compares the phases of the two received input signals.
A first voltage comparator 9 detects a phase delay between the received human input signals from the output of the first phase comparator 7, and a second voltage comparator 10 similarly detects a phase lead. A phase control circuit 11 that controls the phase difference between the received human input signals based on the phase control information obtained as the output of the first and second voltage comparators 9 and 10. In the in-phase combining space diversity 2 receiving device, which is equipped with a power combiner 2 that combines two signals whose phases are controlled, the first phase comparator 7 is configured to detect the phase difference between the two receiving signals. A second phase comparator 12 whose phase comparison characteristics differ by approximately 90°
and a third voltage comparator 13 that detects from the output of the second phase comparator 12 whether the phase relationship of the received human input signal is near the same phase or near the opposite phase. The threshold voltages of the first and second voltage comparators 9 and 10 are changed by the output of the voltage comparators 9 and 10 to control the phase control dead zone.

[Effects of the Invention] As explained above, the present invention eliminates the dead zone of phase control when the phase relationship of two received human input signals is around the opposite phase, so phase control is stopped during in-phase synthesis.
During anti-phase synthesis, phase control can be performed so that the phase difference is 0°, minimizing the deterioration caused by controlling the infinite phase shifter, and always combining two receiving human input signals near the same phase. This has the advantage that it is possible to provide an in-phase combining space diversity receiving device that can perform

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an in-phase combining space diversity receiver according to an embodiment of the present invention, and FIG.
A diagram showing the phase comparison characteristics of the phase comparator in the in-phase synthesis space diversity receiver shown in Figure 2 (1)),
(C) and (d) are also diagrams showing the output characteristics of the voltage comparator, Figure 3 is a block diagram of a conventional in-phase synthesis space diversity receiver, and Figure 4 (a) is a conventional in-phase synthesis space diversity receiver. Figures 4(b) and 4(c) are diagrams showing the output characteristics of the voltage comparator. 1: Infinite phase shifter (EPS) 2: Power combiner? , 12: Phase comparator 8: 90" phase shifter 9. 10, 13: Voltage comparator lO: Voltage comparator 11: EPS control circuit

Claims (1)

[Claims] A first phase difference determining means detects the phase difference between the received signals inputted from two antennas and determines whether the phase is advanced or delayed; a combining means that changes the phase of one of the received signals and combines the received signals as being in-phase; and determining whether the phase difference between the received signals is around the same phase or around the opposite phase, and based on the result, and second phase difference determining means for controlling a dead zone of the phase difference determining means.