JP3620964B2 - Phase adjustment device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to, for example, a space diversity receiver, and in particular, receives signals with two spatially separated antennas, controls the phase of a signal received with one antenna, and controls the phase-controlled signal and the other antenna. The present invention relates to a space diversity receiver that reduces the influence of fading that occurs in a wireless communication circuit by synthesizing the signals received by the wireless communication circuit.
[0002]
[Prior art]
The frequency, depth, generation time, and the like of fading generated in the wireless communication circuit vary depending on the place where the receiving antenna is installed. The space diversity reception system uses such a property to install two antennas at a position with little fading correlation, and reduce or reduce fading by combining or switching signals received by the respective antennas.
[0003]
FIG. 5 shows a configuration diagram of a conventional space diversity receiving apparatus of the in-phase synthesis method disclosed in Japanese Patent Laid-Open No. 2-237325. In the figure, the phase of an input signal S2 is controlled by a vector synthesis infinite phase shifter (EPS) 1 and a phase-shifted signal S2a is output. The signal S2a is input to the power combiner 7, and the power combiner 7 always combines in the same phase as the input signal S1. The synthesized signal S3 is sent to a demodulator (DEM) (not shown) and demodulated into a baseband signal. The vector composition type infinite phase shifter 1 includes a power distributor 2, a power combiner 3, a 90 ° phase shifter 4, and multipliers 5 and 6.
[0004]
On the other hand, the two input signals to the power combiner 7 are both branched and passed through the band-pass filters 8 and 9 and the automatic gain control (AGC) amplifiers 10 and 11, respectively. The phase comparator 12 and the phase comparator are input to a second phase comparator that is 90 ° different in phase comparison characteristics with respect to the input phase difference. The bandpass filters 8 and 9 are narrow bandpass filters (BPF) for extracting only components near the center frequency of the modulated wave, and the automatic gain control amplifiers 10 and 11 function to keep the signal level constant at all times. To do.
[0005]
Further, in order to prevent the output of these two phase comparators 12 and 14 from being smoothed and to follow a steep change in the input phase, and to remove the second harmonic component of the carrier wave output from the phase comparator. In addition, low-pass filters 15 and 16 are provided. In addition, linearizers 17 and 18 are provided for linearly changing amplitudes with respect to the control voltages of the multipliers 5 and 6 of the vector synthesis type infinite phase shifter 1.
[0006]
By configuring in this way, the outputs of the phase comparators 12 and 14 are two multipliers 5 for controlling the amplitudes of signals orthogonal to each other on the phase plane constituting the vector synthesis type infinite phase shifter 1. 6 is applied as a control voltage, and phase modulation is performed by using the output of the quadrature detector as the control input of the quadrature modulator to control the phase amount of the vector synthesis type infinite phase shifter 1.
[0007]
That is, as shown in FIG. 6, the phase comparison characteristic of the second phase comparator 14 is 90 ° different from the phase comparison characteristic of the first phase comparator 12. Further, the vector synthesis type infinite phase shifter 1 inputs two orthogonal vectors AcosΔφ and AsinΔφ as control voltages to the two multipliers 5 and 6 of the vector synthesis type infinite phase shifter 1, whereby the phase of the input signal is obtained. Can be shifted by Δφ.
[0008]
Therefore, if the phase shift amount Δφ of the vector combined infinite phase shifter 1 is made the same with respect to the received input phase difference Δθ and the phase shift direction is set so that the phase difference between the received inputs is 0, the vector The combined infinite phase shifter 1 is always controlled to perform in-phase synthesis.
That is, the output of the first phase comparator 12 that generates a voltage of VmcosΔθ with respect to the phase difference Δθ is added to the multiplier 6 that requires a control voltage of VacosΔφ with respect to the phase shift amount Δφ via the linearizer 18, and the phase difference Δθ. By adding the output of the second phase comparator 14 that generates a voltage VmsinΔθ to the multiplier 5 that requires a control voltage VasinΔφ with respect to the phase shift amount Δφ via the linearizer 17, the phase shift amount Δφ = Δθ. The vector synthesis type infinite phase shifter 1 is controlled so that
[0009]
[Problems to be solved by the invention]
In the above-described in-phase synthesis space diversity receiver, the vector synthesis infinite phase shifter 1 forms a loop with the phase comparators 12 and 14, the bandpass filters 8 and 9, the automatic gain control amplifiers 10 and 11, and the linearizers 17 and 18. Since the phase difference detection is performed based on the signal 2Sa phase-shifted by the vector synthesis type vector synthesis type infinite phase shifter 1, the levels of the two input signals are detected in the vector synthesis type infinite phase shifter 1. There is a problem that only half of the input signal phase difference Δθ can be shifted even if the phase shift amount Δφ = Δθ is controlled with respect to the phase difference Δθ. For this reason, when the two input signals are in the opposite phase state, the phase of the signal S2a after the phase shift of the input signal S2 is not reciprocated in the vicinity of + 90 ° or near −90 ° with respect to the input signal S1. In addition to being stable and not synthesized in phase, phase fluctuation occurs in the synthesized wave S3 of the two signals, thereby degrading the error rate characteristics of the entire receiving apparatus.
[0010]
[Means for Solving the Problems]
The phase adjustment apparatus according to the present invention receives a first phase comparator that inputs two input signals and compares the phases of the two input signals, and receives the two input signals, and a first phase comparator Is a second phase comparator for comparing the phases of two input signals with different phase comparison characteristics, and two multiplications for inputting one of the two input signals and controlling the amplitude of the input signal. A phase shifter for adding the outputs of the first and second phase comparators to the two multipliers to shift the phase of the input signal and to control the phase difference between the two input signals. And a vessel.
[0011]
The phase adjusting device further includes a phase controller that stops control of the phase difference by the phase shifter when a phase difference between two input signals is within a predetermined range.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Embodiment 1 FIG.
FIG. 1 is a block diagram showing a first embodiment of the present invention. The same parts as those of the conventional apparatus shown in FIG. 5 are denoted by the same reference numerals, and detailed description thereof is omitted.
In this apparatus, the phase comparison input on the input signal S2 side is taken from the input side of the vector synthesis type infinite phase shifter 1.
[0013]
By taking the input signal S2 for phase comparison with the input signal S1 from the input side of the vector synthesis infinite phase shifter 1, the output signals of the phase comparator 12 and the phase comparator 14 are obtained from the vector synthesis infinite phase shifter 1. Regardless of the phase control result, the signal can always be in accordance with the phase difference between the two input signals.
With this configuration, the outputs of the phase comparators 12 and 14 are two multipliers 5 and 6 for controlling the amplitudes of signals orthogonal to each other on the phase plane constituting the vector synthesis infinite phase shifter 1. The phase shift amount of the vector synthesis infinite phase shifter is controlled by applying phase modulation to the control input of the quadrature modulator at the output of the phase comparator.
[0014]
When the input signal S1 is Acos ωt and the input signal S2 is Bcos (ωt + φ), the output of the first phase comparator 12 is (AB / 2) [sin (2ωt + φ) + sinφ]
The output of the second phase comparator 14 is (AB / 2) [cos (2ωt + φ) + cosφ].
The respective outputs are smoothed by the low-pass filters 15 and 16 to obtain Ksinφ and Kcosφ, respectively. However, K = AB / 2.
As shown in FIG. 2, the phase comparison characteristic of the second phase comparator 14 is 90 ° different from the phase comparison characteristic of the first phase comparator 12. The output of the first phase comparator 12 indicates the direction of the phase difference between the two input signals, while the output of the second phase comparator 14 indicates the amount of the phase difference between the two input signals.
[0015]
An output signal S2a for inputting the two signals (Ksinφ, Kcosφ) to the control inputs of the multipliers 5 and 6 of the vector synthesis infinite phase shifter 1 is as follows.
Kcosφ · Bcos (ωt + φ) + Ksinφ · Bcos (ωt + φ + π / 2) = KBcosωt
Thus, it can be in phase with the input signal S1.
That is, by detecting a phase difference between two input signals on the input side of the vector synthesis infinite phase shifter 1 and adding the detection signal to the control input of the vector synthesis infinite phase shifter 1, The follow-up speed of the phase control is high regardless of the input phase difference, and control can be performed so that the phase is stably in phase regardless of the input phase relationship.
[0016]
Embodiment 2. FIG.
FIG. 3 is a block diagram showing a second embodiment of the present invention, and the same reference numerals are given to the same parts as those of the first embodiment of FIG. The second embodiment is different from the first embodiment in that the phase control is stopped when the phase difference between the two input signals S1 and S2 is in the vicinity of the phase difference of 0 °. The phase controller 29 is provided to prevent the phase fluctuation in the combined signal S3. Others have the same configuration as the first embodiment. The configuration of the phase controller 29 is shown in FIG. The phase controller 29 includes low pass filters 15 and 16, linearizers 17 and 18, a voltage comparator 30, and switches 31 and 32 that are the same as those in the first embodiment.
[0017]
When the phase difference between the two input signals S1 and S2 approaches 0 °, the voltage Va of the output signal a of the first phase comparator 12 approaches 0. Further, the voltage Vb of the output signal b of the second phase comparator 14 approaches the constant value V2. As shown in FIG. 4, the voltage comparator 30 compares the voltage Vb of the output signal b with a preset reference level Vr (Vr <V2), and toggles the switches 31 and 32 when Vr <Vb. Let Then, since the control input of the vector composition type infinite phase shifter 1 is fixed at the preset levels V2 and 0V, the phase control is stopped. When Vr ≧ Vb, the switches 31 and 32 are returned to the state shown in FIG. 4 and the phase control is resumed.
As a result, when the phase difference between the two input signals is not within the predetermined range, the phase control follow-up speed performs high-speed in-phase synthesis control regardless of the input phase difference, and is unnecessary in the vicinity of the phase difference of 0 °. Phase control can be stopped and a stable combined output can be obtained.
[0018]
【The invention's effect】
As described above, the present invention can detect the phase difference between two input signals on the input side of the phase shifter, and add the detection signal to the control input of the phase shifter. The follow-up speed is high regardless of the input phase difference, and control can be performed so that the phase is stably in phase regardless of the phase relationship of any input.
[0019]
In addition, since the present invention includes the phase controller, unnecessary phase control is stopped near the phase difference of 0 °, and a stable combined output can be obtained.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a main configuration of a space diversity device configured by applying a phase adjustment device according to a first embodiment of the present invention.
FIG. 2 is a phase comparison characteristic diagram of a first phase comparator and a second phase comparator.
FIG. 3 is a block diagram showing a main configuration of a space diversity device configured by applying a phase adjustment device according to a second embodiment of the present invention.
4 is a block diagram showing a configuration of a phase controller in FIG. 2. FIG.
FIG. 5 is a diagram illustrating a conventional technique.
FIG. 6 is a phase comparison characteristic diagram of the first phase comparator and the second phase comparator.
[Explanation of symbols]
1 vector synthesis infinite phase shifter, 2 power distributor, 3 power synthesizer, 4 90 ° phase shifter, 5, 6 multiplier, 7 power synthesizer, 8, 9 bandpass filter, 10, 11 automatic gain control amplifier , 12 phase comparator, 13 phase shifter, 14 phase comparator, 15, 16 low pass filter, 17, 18 linearizer, 29 phase controller, 30 voltage comparator, 31, 32 switch.

Claims (1)

A first phase comparator for inputting two input signals and comparing the phases of the two input signals;
A second phase comparator that inputs the two input signals and compares the phases of the two input signals with a phase comparison characteristic different from that of the first phase comparator;
The output signal of the first phase comparator and the output signal of the second phase comparator are input, and the signal having a predetermined first voltage and the output signal of the first phase comparator are switched to whichever A first switch that outputs one of the signals as a first control signal, a signal having a voltage of 0 volts, and an output signal of the second phase comparator to switch one of the signals to the second The second switch output as the control signal, the voltage of the output signal of the first phase comparator is compared with a predetermined second voltage, and the voltage of the output signal of the first phase comparator is the predetermined first voltage. When the voltage is higher than two voltages, switching control for the first switch that outputs a signal having a predetermined first voltage as the first control signal, and a signal having a voltage of 0 volts is output as the second control signal. Switching system for the second switch And when the voltage of the output signal of the first phase comparator is equal to or lower than a predetermined second voltage, the first phase comparator outputs the first control signal as the first control signal. And a voltage converter that performs switching control for the second switch that outputs the output signal of the second phase comparator as a second control signal. A phase controller that outputs a signal, and two multipliers that input one of the two input signals and control the amplitude of the input signal, and the phase controller outputs And a phase shifter that adds the first and second control signals to the two multipliers to control the phase difference between the two input signals by shifting the phase of the input signal. Phase adjustment device.

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