JPH057172A - Space diversity controller - Google Patents

Abstract

PURPOSE:To prevent a notch in an amplitude of a combined vector from a phase shifter by outputting each waveform data to a memory from an address corresponding to a count of an up-down counter. CONSTITUTION:A ROM 27 is accessed by using a count of an up-down counter 5 as an address and a data changing in a way of a sinusoidal wave superimposed on a rectangular wave whose polarity is inverted at 0 deg. and 180 deg. is read from the ROM 27. Moreover, a ROM 28 is similarly accessed and a data changing in a way of a cosine wave superimposed on a rectangular wave whose polarity is inverted at 00 deg. and 270 deg. is read from the ROM 28. Then D/A converters 10,11 convert the data read from the ROM 27 or 28 into plural analog drive signals. The drive signal is fed to a phase shifter and a balanced modulator is operated without using an area in which the linearity of the transmission impedance is deteriorated even at a phase being an odd number of multiple of 45 deg.. Then a prescribed amplitude characteristic is obtained from an output signal of the phase shifter independently of the phase point.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a space diversity controller for controlling a phase shifter for two-route combining of an in-phase combining space diversity receiver in digital microwave communication.

[0002]

2. Description of the Related Art FIG. 10 is a block diagram showing a conventional space diversity control apparatus. In the figure, reference numeral 1 is input with combining information of an in-phase combining space diversity receiver output from a detector 18 (see FIG. 8). An input terminal 2 is an analog / digital converter (hereinafter referred to as an A / D converter) that digitally converts the composite information input from the input terminal 1, and 3 is a temporary storage of the composite information digitally converted by the A / D converter 2. A holding circuit for storing 4 is a comparison circuit for comparing the current combined information digitally converted by the A / D converter 2 and the combined information before the predetermined time temporarily stored in the holding circuit 3,
Reference numeral 5 is an up / down counter (hereinafter referred to as U / D counter) that counts in an increasing or decreasing direction according to the comparison result of the comparison circuit 4, and 6 is U / D depending on the presence or absence of a signal output from the A terminal of the comparison circuit 4. A U / D conversion circuit for determining the counting direction of the counter 5, and an OR circuit 7 for generating a clock for operating the U / D counter 5 by ORing the signals output from both terminals A and B of the comparison circuit 4. Is.

Reference numeral 8 stores sine wave waveform data in advance,
A memory (hereinafter referred to as a ROM) which is addressed by the count value of the U / D counter 5 and outputs the waveform data at the θ ° step, 9 is the waveform data of the cosine wave is stored in advance, and the memory of the U / D counter 5 is stored. A memory (hereinafter referred to as a ROM) that is addressed by a numerical value and outputs the waveform data at a θ ° step.
.The phase shifter 16 of the in-phase combining space diversity receiver by converting each waveform data output from 9 into analog (see FIG. 8).
A digital / analog converter (hereinafter referred to as a D / A converter), which is supplied as a first and second drive signal to
Reference numeral 12 is an output terminal for outputting the first drive signal, and 13 is an output terminal for outputting the second drive signal.

FIG. 8 is a block diagram showing an example of an in-phase combining space diversity receiver to which the present invention and the conventional space diversity control device are applied.
In the figure, reference numerals 14 and 15 denote input terminals to which received signals from antennas arranged at predetermined intervals are input.
Reference numeral 6 denotes a phase shifter that shifts one of the received signals, for example, the received signal input to the input terminal 15 to perform route combining in the in-phase combining space diversity method. Reference numeral 17 is a synthesizing circuit for synthesizing the reception signal input to the input terminal 14 and the reception signal phase-shifted by the phase shifter 16, and 18 is a detector for detecting the signal output from the synthesizing circuit 17, 19 Is an output terminal from which the detection output of the detector 18 outputs the in-phase combined space diversity combined result as combined information. Reference numeral 20 is a space diversity control device that receives the detection output of the detector 18 and generates the first and second drive signals of the phase shifter 16, and is configured as shown in FIG. 10, for example.

FIG. 9 is a block diagram showing an example of the phase shifter 16. The phase shifter 16 is a vector synthesis phase shifter, and includes a pair of balanced modulators 21 and 22 and a 90 ° distributor 23.
And the in-phase combiner 24. In the figure, 25 is an input terminal to which a received signal from the input terminal 15 is input, 26 is an output terminal to which an output signal to the synthesizing circuit 17 is output, and 27 is a first drive from the space diversity control device 20. Input terminal for signal input, 28
Is also an input terminal to which the second drive signal is input.

Next, the operation will be described. The input terminal 1 of the space diversity control device shown in FIG.
The detection output signal (composite information) of the detector 18 is input. The input combined information is sent to the A / D converter 2, converted into an N-bit digital signal, and temporarily stored in the holding circuit 3.

The output of the A / D converter 2 is the comparison circuit 4
The current data is compared with the previous data temporarily stored in the holding circuit 3 before the fixed time. If the comparison result shows that the current data is smaller than the previous data, a signal is output from the A terminal and the U / D conversion circuit 6 operates, whereby U / D conversion circuit 6 operates.
The D counter 5 counts in the decreasing direction, while the U / D counter 5 counts in the increasing direction when the previous data is larger than the current data.

The count value of the U / D counter 5 is stored in the ROM 8
And 9 sequentially, and the ROMs 8 and 9 read out the stored waveform data addressed by the count value. Therefore, from the ROM 8
The waveform data that changes in a sine wave shape in the step is read out, and from the ROM 9, the waveform data that changes in a sine wave shape in a θ ° step that is 90 ° out of phase with respect to it, that is, the waveform data that changes in a cosine wave shape. Read out.

The waveform data read from the ROMs 8 and 9 are sent to the D / A converters 10 and 11 to be converted into analog signals, and the phase shifter 1 is output from the output terminals 12 and 13.
6 is output as a drive signal. Therefore, the output terminal 12
Outputs a first drive signal based on a sine wave signal, and the output terminal 13 outputs a second drive signal based on a cosine wave signal. The relationship between the first drive signal and the second drive signal is as shown in FIG.

Now, the balanced modulator 2 receives the first and second drive signals shown in FIG. 11 from the input terminals 27 and 28 of the phase shifter 16.
When 1 or 22 is input, the characteristic that the amplitude in each phase has a slight drop in the phase at an odd multiple of 45 ° is obtained as shown in FIG.

This is because the signal voltage of both the first drive signal and the second drive signal is low in the phase of an odd multiple of 45 °, and the balanced modulator 21, because it operates near the diffusion potential of the diode. This is because the region where the linearity in the pass impedance of 22 is deteriorated is used.

Further, the balanced modulator 21 in the phase shifter 16
22 is composed of a lattice type circuit composed of four diodes, and the first drive signal is applied to one side of the lattice type circuit and the second drive signal is applied to the other side. A current determined by the diode impedance corresponding to the applied drive signal voltage flows through the diodes forming the balanced modulators 21 and 22, so that the pass impedance of the balanced modulators 21 and 22 becomes the required impedance, and the balanced modulators As a result of vector combination at the output parts 21 and 22, a signal having a required phase is obtained. In addition, each balanced modulator 21.
The impedance of the diode constituting 2 changes. Therefore, when the ambient temperature rises, the diode impedance decreases, and the pass impedance of the balanced modulators 21 and 22 also decreases. In such a case, the amplitude of the combined vector on the phase plane becomes large, and the amplitude fluctuation at each phase becomes large. On the other hand, when the ambient temperature decreases, the diode impedance increases, so the balanced modulator 21
-The passing impedance of 22 becomes large. In such a case, the amplitude of the combined vector on the phase plane becomes small, and the amplitude fluctuation in each phase becomes large. In Figure 7,
The fluctuation of the composite vector on the phase plane when the ambient temperature changes is shown.

[0013]

Since the conventional space diversity control device is constructed as described above, R
The signal output from the OM is a sine wave whose phase is deviated from each other by 90 °, and since it is used as the first and second drive signals, the amplitude of the composite vector of the phase shifter has a predetermined phase. However, there is a problem in that a drop appears at this point and the control accuracy of the space diversity combining method deteriorates. In addition, since the diode impedance of the balanced modulator changes due to the change in ambient temperature, the pass impedance of the balanced modulator also changes. As a result, the amplitude variation of the combined vector of the phase shifter increases, so the control accuracy of the space diversity combining method is improved. There was a problem such as deterioration.

The present invention has been made to solve the above problems, and prevents the amplitude of the composite vector of the phase shifter from dropping at a predetermined phase point.
An object of the present invention is to obtain a space diversity control device with high control accuracy by suppressing the amplitude fluctuation of the composite vector caused by the fluctuation of the ambient temperature.

[0015]

According to a first aspect of the space diversity control apparatus of the present invention, each waveform data of a sine wave and a cosine wave on which a predetermined constant of positive polarity or negative polarity is preliminarily superimposed according to the phase is stored. A memory is provided which outputs the respective waveform data from the address stored and corresponding to the count value of the up / down counter.

The space diversity controller according to the second aspect of the present invention comprises a resistor connected in series between the digital / analog converter and the phase shifter.

Further, the space diversity control apparatus according to the third aspect of the present invention is provided with a voltage amplification circuit for changing the power level of the drive signal supplied from the digital-analog converter to the phase shifter in accordance with the ambient temperature. It is a thing.

[0018]

According to the space diversity control apparatus of the present invention, a sine wave and a cosine wave in which a predetermined constant of positive polarity or negative polarity is preliminarily superposed according to the phase from the address corresponding to the count value of the up / down counter. By providing the memory for outputting each waveform data of 1), the amplitude of the composite vector falling at a predetermined phase point is compensated by the predetermined constant.

According to the space diversity control device of the present invention, a resistor is connected in series between the digital-analog converter and the phase shifter, so that the balance modulator can operate even if the ambient temperature changes. The current flowing through the diode becomes constant.

Further, in the space diversity control device according to the present invention, a voltage amplifier circuit for changing the voltage level of the drive signal supplied from the digital-analog converter to the phase shifter in accordance with the ambient temperature is provided. Due to
The DC impedance of the diode in the balanced modulator remains constant even if the ambient temperature changes.

[0021]

EXAMPLES Example 1. An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a space diversity control apparatus according to an embodiment of the invention described in claim 1. In the figure, the same reference numerals as those of the conventional one indicate the same or corresponding portions, and therefore the description thereof will be omitted.

27 is a predetermined constant of positive polarity or negative polarity depending on the phase, that is, + Δ in the phase range of 0 ° to 180 °.
Waveform data of a sine wave on which a constant corresponding to the DC voltage of V and a constant corresponding to the DC voltage of -ΔV are superimposed in the phase range of 180 ° to 360 ° is stored and corresponds to the count value of the U / D counter 5. A memory (hereinafter, referred to as a ROM) 28 that outputs the waveform data from the stored address is a predetermined positive or negative constant according to the phase, that is, 0 ° to 90 °.
And a constant corresponding to a DC voltage of + ΔV in the phase range of 270 ° to 360 °, and −Δ in the phase range of 90 ° to 270 °.
This is a memory (hereinafter referred to as a ROM) in which waveform data of a cosine wave on which a constant corresponding to a DC voltage of V is superimposed is stored and which outputs the waveform data from an address corresponding to the count value of the U / D counter 5.

Next, the operation will be described. Here, since the basic operation is the same as that of the conventional case, the description thereof will be omitted.

The ROM 27 is accessed by using the count value of the U / D counter 5 as an address, and the data which is superposed on the rectangular wave whose polarity is inverted at 0 ° and 180 ° and changes in a sine wave shape is read at the θ ° step. Also, ROM
28 is also accessed in the same manner, and the data that is superimposed on the rectangular wave whose polarity is inverted at 90 ° and 270 ° and changes like a cosine wave is read in θ ° steps.

The D / A converters 10 and 11 are the ROMs.
The data read from 27 or 28 is converted into a first drive signal and a second drive signal by analog signals. Therefore, from the output terminals 12 and 13, the waveform thereof is shown in FIG. 4, the first drive signal by the modified sine wave having a stepwise voltage change of 2 · ΔV at 0 ° (360 °) and 180 °, or A second drive signal by a modified cosine wave having a voltage change of 2 · ΔV in steps at 90 ° and 270 ° is sent to the phase shifter 16.

In the phase shifter 16 which receives the first and second driving signals as described above, the balanced modulators 21 and 22 have 45
It operates without using the region near the diffusion potential of the diode where the linearity of the pass impedance deteriorates even in the phase of an odd multiple of °. Therefore, the output signal of the phase shifter 16 is as shown in FIG.
As shown in, a constant amplitude characteristic is obtained regardless of the phase point.

Example 2. 2 is a block diagram showing a space diversity controller according to an embodiment of the present invention. In the figure, 29 and 30 are connected between the D / A converters 10 and 11 and the phase shifter 16. It is a resistor.

Next, the operation will be described. FIG. 6 shows the voltage-current characteristics of the diodes forming the balanced modulators 21 and 22.
It looks like. It is necessary to use the balanced modulators 21 and 22 in a region where the linearity of the voltage-current characteristic is good, but as shown in FIG. 6, the voltage-current characteristic of the diode sensitively changes according to the temperature change, and the ambient temperature changes. When the voltage rises, the diffusion potential decreases, the DC impedance decreases at the same voltage, and the current increases. On the other hand, when the ambient temperature decreases, the diffusion potential increases, the DC impedance increases and the current decreases at the same voltage. Therefore, in order to eliminate the current change due to the ambient temperature change, the drive voltage is supplied through the resistors 29 and 30. As a result, when the temperature rises, the DC impedance of the diode decreases, so that the current increases. However, since the voltage drop occurs in the resistors 29 and 30 by the increase in the current, the DC impedance of the diode increases and the diode increases. The current flowing through it decreases and as a result the current remains constant. On the other hand, when the ambient temperature decreases, the current is kept constant due to the opposite effect of the increase. Since the current is kept constant in this way, the amplitude of the combined vector of the phase shifter 16 is kept constant even if the ambient temperature changes.

Example 3. FIG. 3 is a block diagram showing a space diversity controller according to an embodiment of the invention described in claim 3. In the figure, 31 and 32 are drive signals supplied from the D / A converters 10 and 11 to the phase shifter 16. Voltage amplifier circuit for changing the voltage level of the battery according to the ambient temperature, 31a
32a is a voltage amplifier, and 31b and 32b are heat sensitive elements for voltage feedback.

Next, the operation will be described. Since the voltage-current characteristic of the diode changes sensitively according to the ambient temperature,
When the ambient temperature rises, the DC impedance at the same voltage decreases and the current increases. In this case, by arranging the heat sensitive elements 31b and 32b whose resistance value decreases with the temperature rise in the feedback section of the voltage amplifiers 31a and 32a, the heat sensitive elements 31b and 32b can be connected to the voltage amplifiers 31a and 32b.
The DC impedance is constant because it works so as to decrease the output drive voltage of a. On the other hand, when the ambient temperature decreases, the output voltage works so as to increase, so that the DC impedance becomes constant. In this way, since the DC impedance becomes constant, even if the ambient temperature changes, the phase shifter 16
The amplitude of the composite vector of is kept constant.

[0031]

As described above, according to the first aspect of the invention, the respective waveform data of the sine wave and the cosine wave in which the predetermined constants of the positive polarity or the negative polarity are preliminarily superimposed according to the phase are stored, Since a memory that outputs each waveform data from the address corresponding to the count value of the up-down counter is provided,
Since the amplitude of the composite vector that falls at a predetermined phase point is compensated by the predetermined constant, the composite vector of the phase shifter has a constant amplitude regardless of changes in the phase, and effects such as high control accuracy can be obtained. There is.

According to the second aspect of the present invention, since the resistor is connected in series between the digital / analog converter and the phase shifter, the current flowing through the diode of the balanced modulator does not change even if the ambient temperature changes. Since it becomes constant, the combined vector of the phase shifter has a constant amplitude regardless of the change in the phase, and there is an effect that a high control accuracy can be obtained.

According to the third aspect of the present invention, since the digital-analog converter is provided with the voltage amplifier circuit for changing the voltage level of the drive signal supplied to the phase shifter according to the ambient temperature, the balanced modulator. Since the DC impedance of the diode in is constant, the combined vector of the phase shifter has a constant amplitude regardless of the change in its phase, and there is an effect that a high control accuracy can be obtained.

[Brief description of drawings]

FIG. 1 is a block diagram showing a space diversity controller according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a space diversity control device according to an embodiment of the present invention.

FIG. 3 is a block diagram showing a space diversity control device according to an embodiment of the present invention.

FIG. 4 is a waveform diagram showing a first drive signal and a second drive signal in FIG.

FIG. 5 is a characteristic diagram showing an amplitude characteristic of a combined vector of the phase shifter by the space diversity control device according to the first aspect of the present invention.

FIG. 6 is a characteristic diagram showing a voltage-current characteristic of a diode forming a balanced modulator.

FIG. 7 is a characteristic diagram showing a change in a combined vector on a phase surface when the ambient temperature changes.

FIG. 8 is a block diagram showing an example of an in-phase combining space diversity receiver to which the present invention and the conventional space diversity control device are applied.

FIG. 9 is a configuration diagram showing details of a phase shifter in the in-phase combining space diversity receiver.

FIG. 10 is a block diagram showing a conventional space diversity control device.

FIG. 11 is a waveform diagram showing a first drive signal and a second drive signal by the conventional space diversity control device.

FIG. 12 is a characteristic diagram showing a combined vector amplitude characteristic of a phase shifter by a conventional space diversity control device.

[Explanation of symbols]

2 A / D converter (analog / digital converter) 3 holding circuit 4 Comparison circuit 5 U / D counter (up / down counter) 10, 11 D / A converter 27, 28 ROM (memory) 29,30 resistor 31, 32 Voltage amplification circuit

Claims (3)

[Claims] 1. An analog / digital converter for digitally converting the combined information of the in-phase combined space diversity receiver output from the detector, and a holding circuit for temporarily storing the combined information digitally converted by the analog / digital converter. A comparison circuit for comparing the current synthesis information digitally converted by the analog-digital converter with the synthesis information before the predetermined time temporarily stored in the holding circuit, and increased or increased in accordance with the comparison result of the comparison circuit. The up / down counter that counts in the decreasing direction, and the waveform data of the sine wave and the cosine wave in which a predetermined constant of positive polarity or negative polarity is superimposed in advance according to the phase are stored, and correspond to the count value of the up / down counter. The memory that outputs the waveform data from the specified address and the waveform data that is output from the memory are converted into analog data. A space diversity control device provided with a digital-analog converter that supplies the phase shifter of the in-phase combining space diversity receiver as a drive signal. 2. The space diversity control device according to claim 1, further comprising a resistor connected in series between the digital-analog converter and the phase shifter. 3. The space diversity according to claim 1, further comprising a voltage amplification circuit for changing the voltage level of the drive signal supplied to the phase shifter by the digital-analog converter according to the ambient temperature. Control device.