JP6774848B2 - Impedance measuring device - Google Patents

Description

The present invention relates to an impedance measuring device for measuring antenna impedance.

Conventionally, impedance measurement of a transmission antenna in the medium wave band has been performed using equipment such as a shaving bridge circuit, an impedance analyzer, and a network analyzer in an environment where there is no induced voltage to the antenna. The environment in which these devices can be used has restrictions such as the absence or small high-frequency induced voltage to the antenna and the difference between the induced voltage and the frequency of the measurement signal.

Patent Document 1 discloses that biorthogonal detection is used to measure the impedance of an antenna in an environment where a plurality of external waves having different frequencies arrive. Further, Non-Patent Document 1 discloses a method of using the F parameter in order to measure the impedance of the antenna even in an environment where a high high frequency induced voltage is applied to the antenna.

Patent No. 3833565

Ohkita, Okamoto, Yamazoe (March 2013) “Measurement and Application of Medium Wave Antenna Base Impedance in High Induced Voltage Environment of External Waves”, IEICE Technical Report EMCJ2012-132 (2013-3) pp.85-90

When repairing an antenna on a large scale, the induced voltage of the antenna is high and the antenna impedance is adjusted even in an environment where the frequency of the induced voltage and the frequency of the measurement signal are the same in order to grasp the change in the transmitter load and perform matching adjustment. It is required to measure. With the methods disclosed in Patent Document 1 and Non-Patent Document 1, it is difficult to measure the antenna impedance in such an environment.

An object of the present invention made in view of the above problems is to provide an impedance measuring device capable of measuring an antenna impedance at the same frequency as the induced voltage even in an environment where a high high frequency voltage is induced in the antenna. There is.

In order to solve the above problems, the impedance measuring device according to the present invention is an impedance measuring device that measures the antenna impedance, and detects the phase difference between the high frequency induced voltage component and the high frequency induced current component induced in the antenna. The first calculation for calculating the antenna impedance based on the phase difference detector, the phase difference detected by the phase difference detector, the known load resistance connected to the antenna, the high frequency induced voltage component, and the high frequency induced current component. Equipped with a vessel.

Further, in the impedance measuring device according to the present invention, a first adjusting unit that generates a first reference signal whose amplitude and phase of the reference signal are adjusted, and a second reference signal whose amplitude and phase of the reference signal are adjusted. The first reference signal generated by the first adjusting unit and the second adjusting unit for generating the above-mentioned first reference signal are used as the first input, and the high-frequency induced voltage component is used as the second input. The second arithmetic unit that outputs the difference between the signal and the high frequency induced voltage component and the second reference signal generated by the second adjusting unit are used as the first input, and the high frequency induced current component is used as the first input. It is further provided with a third arithmetic unit which has 2 inputs and outputs the difference between the second reference signal and the high frequency induced current component, and the output of the second arithmetic unit is the output of the first adjusting unit. The second adjusting unit is set to be zero, the output of the third arithmetic unit is set to zero, and the phase difference detector is generated by the first adjusting unit. It is desirable to detect the phase difference between the first reference signal as the high frequency induced voltage component and the second reference signal as the high frequency induced current component generated by the second adjusting unit.

Further, in the impedance measuring device according to the present invention, a first adjusting unit that generates a first reference signal whose amplitude and phase of the reference signal are adjusted, and a second reference signal whose amplitude and phase of the reference signal are adjusted. A second arithmetic unit that uses the second adjusting unit that generates the above and the first reference signal generated by the first adjusting unit as the first input and the high frequency induced voltage component as the second input. And a third arithmetic unit that uses the second reference signal generated by the second adjusting unit as the first input and the high-frequency induced current component as the second input, and further comprises the second. Each of the arithmetic unit and the third arithmetic unit performs orthogonal detection of the difference between the first input and the second input based on the reference signal, and the in-phase component and the orthogonal component obtained by the orthogonal detection are performed. And are combined and output, the first adjusting unit is set so that the output of the second arithmetic unit becomes zero, and the second adjusting unit outputs the output of the third arithmetic unit. It is desirable to set it to zero.

According to the impedance measuring device according to the present invention, the antenna impedance can be measured at the same frequency as the induced voltage even in an environment where a high frequency voltage is induced in the antenna.

It is a figure for demonstrating the measurement principle of the antenna impedance by this invention. It is a figure which shows the structure of the impedance measuring apparatus which concerns on 1st Embodiment of this invention. It is a figure which shows the structure of the impedance measuring apparatus which concerns on 2nd Embodiment of this invention. It is a figure which shows the structure of the arithmetic unit shown in FIG.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. It should be noted that the present invention is not limited to the following embodiments, and it goes without saying that various modifications can be made without departing from the spirit of the present invention. Further, in the figure, the same reference numerals indicate the same or equivalent components.

First, the measurement principle of the antenna impedance Z according to the present invention will be described with reference to FIG.

As shown in FIG. 1 (a), a high-frequency induced voltage component Ve induced in the antenna is used as a signal source, and as shown in FIG. 1 (b), a known load resistor R is connected to the antenna impedance Z (antenna impedance). Terminate the base of the antenna for which Z is to be measured with a known load resistor R). Then, based on the current I flowing through the load resistor R, | Z + R | is calculated from the following equations (1) and (2) using the Otori Thevenin's theorem. Further, the real value _Ra and the imaginary value X _a of the antenna impedance Z are calculated by measuring the phase difference between the high frequency induced voltage component Ve and the current I.

(First Embodiment)
FIG. 2 is a diagram showing a configuration of an impedance measuring device 10 according to the first embodiment of the present invention.

The impedance measuring device 10 shown in FIG. 2 includes a distributor 11, amplifiers 12a and 12b, phase shifters 13a and 13b, an arithmetic unit 14 (second arithmetic unit), and an arithmetic unit 15 (third arithmetic unit). ), A phase difference detector 16, and an arithmetic unit 17 (first arithmetic unit). The amplifier 12a and the phase shifter 13a form an adjustment unit 18a (first adjustment unit), and the amplifier 12b and the phase shifter 13b form an adjustment unit 18b (second adjustment unit).

The distributor 11 receives a carrier reference signal E0 (reference signal synchronized with the high frequency induced voltage) for measuring the antenna impedance Z, and distributes the input carrier reference signal E0 to the adjusting unit 18a and the adjusting unit 18b.

The adjusting unit 18a adjusts the amplitude and phase of the carrier wave reference signal E0 output from the distributor 11. Specifically, the adjusting unit 18a includes an amplifier 12a that adjusts the amplitude of the carrier wave reference signal E0, and a phase shifter 13a that adjusts the phase of the carrier wave reference signal E0. Then, the adjusting unit 18a outputs the signal generated by adjusting the amplitude and the phase as the reference signal E1 (first reference signal) to the arithmetic unit 14, the phase difference detector 16, and the arithmetic unit 17.

In the arithmetic unit 14, the reference signal E1 is input from the adjusting unit 18a (first input), and the high frequency induced voltage component Ve induced in the antenna is input as the input signal E2 (second input). As shown in FIG. 1A, the high-frequency induced voltage component Ve is obtained by voltage measurement with the output end of the antenna open. The arithmetic unit 14 operates as a differential amplifier and outputs the difference between the reference signal E1 and the input signal E2 as the signal E5. The adjusting unit 18a sets the amplifier 12a and the phase shifter 13a so that the reference signal E1 and the input signal E2 have the same homologous amplitude, that is, the signal E5 (= E1-E2) becomes zero. Therefore, the reference signal E1 is replaced with the high frequency induced voltage component Ve (having the same homologous amplitude as the high frequency induced voltage component Ve).

The adjusting unit 18b adjusts the amplitude and phase of the carrier reference signal E0 output from the distributor 11. Specifically, the adjusting unit 18b includes an amplifier 12b that adjusts the amplitude of the carrier wave reference signal E0, and a phase shifter 13b that adjusts the phase of the carrier wave reference signal E0. Then, the adjusting unit 18b outputs the signal generated by adjusting the amplitude and the phase to the arithmetic unit 15, the phase difference detector 16 and the arithmetic unit 17 as the reference signal E3 (second reference signal).

In the arithmetic unit 15, the reference signal E3 is input from the adjusting unit 18b (first input), and the high frequency induced current component Vi induced in the antenna is input as the input signal E4 (second input). The high frequency induced current component Vi is obtained by measuring the voltage across the load resistor R. The arithmetic unit 15 operates as a differential amplifier and outputs the difference between the reference signal E3 and the input signal E4 as the signal E6. The adjusting unit 18b sets the amplifier 12b and the phase shifter 13b so that the reference signal E3 and the input signal E4 have the same homologous amplitude, that is, the signal E6 (= E3-E4) becomes zero. Therefore, the reference signal E3 is replaced with the high frequency induced current component Vi (having the same homologous amplitude as the high frequency induced current component Vi).

The phase difference detector 16 has a reference signal E1 (high frequency induced voltage component Ve and homologous amplitude) output from the adjusting unit 18a and a reference signal E3 (high frequency induced current component Vi and homologous amplitude) output from the adjusting unit 18b. ) Is detected, and the detected phase difference θ is output to the arithmetic unit 17. That is, the phase difference detector 16 detects the phase difference θ between the high frequency induced voltage component Ve and the high frequency induced current component Vi.

The arithmetic unit 17 calculates the antenna impedance Z based on the phase difference θ detected by the phase difference detector 16, the load resistance R connected to the antenna, the high frequency induced voltage component Ve, and the high frequency induced current component Vi. Specifically, the arithmetic unit 17 calculates the real value Ra of the antenna impedance Z based on the following equation (3) and outputs it as the signal E7. Further, the arithmetic unit 17 calculates an imaginary value + jXa of the antenna impedance Z based on the following equation (4) and outputs it as a signal E8. As described above, | Z + R | can be calculated from the high-frequency induced voltage component Ve, the high-frequency induced current component Vi, and the load resistance R from the equations (1) and (2).

In this embodiment, the high frequency induced voltage component Ve such as the distributor 11, the adjusting units 18a and 18b, and the arithmetic units 14 and 15 is replaced with the reference signal E1, and the high frequency induced current component Vi is replaced with the reference signal E3. The configuration is not always essential, and the point is that by detecting the phase difference θ between the high frequency induced voltage component Ve and the high frequency induced current component Vi, this phase difference θ, the high frequency induced voltage component Ve, and the high frequency induced current component Vi And the load resistance R can be used to calculate the antenna impedance Z.

As described above, according to the present embodiment, the impedance measuring device 10 detects the phase difference θ between the reference signal E1 corresponding to the high frequency induced voltage component Ve and the reference signal E3 corresponding to the high frequency induced current component Vi. An arithmetic unit 17 that calculates the antenna impedance Z based on the device 16 and the phase difference θ detected by the phase difference detector 16, the known load resistance R connected to the antenna, the high frequency induced voltage component Ve, and the high frequency induced current component Vi. And.

Since the antenna impedance Z can be obtained using the phase difference θ between the high-frequency induced voltage component Ve and the high-frequency induced current component Vi, the known load resistance R, the high-frequency induced voltage component Ve, and the high-frequency induced current component Vi, the antenna is induced. The antenna impedance Z can be measured regardless of the voltage or the frequency of the measurement signal. That is, the antenna impedance Z can be measured at the same frequency as the induced voltage even in an environment where a high frequency voltage is induced in the antenna.

(Second Embodiment)
In the first embodiment, when a plurality of external waves having different frequencies arrive at the antenna, or when a modulated high frequency induced voltage having the same frequency as the measurement frequency arrives at the antenna, the signal E5 and the signal The zero point of E6 cannot be detected, and the antenna impedance Z cannot be measured. In the present embodiment, a configuration for measuring the antenna impedance Z will be described even in such a case.

FIG. 3 is a diagram showing a configuration of an impedance measuring device 10A according to a second embodiment of the present invention.

Compared with the impedance measuring device 10 shown in FIG. 2, the impedance measuring device 10A shown in FIG. 3 is calculated by changing the distributor 11 to the distributor 11A, changing the arithmetic unit 14 to the arithmetic unit 14A, and calculating. It is different from the point that the unit 15 is changed to the arithmetic unit 15A.

The carrier wave reference signal E0 is input to the distributor 11A, and the input carrier wave reference signal E0 is distributed to the adjusting unit 18a and the adjusting unit 18b. Further, the distributor 11A outputs the carrier wave reference signal E0 as the reference signal E9 to the arithmetic unit 14A, and outputs the carrier wave reference signal E0 as the reference signal E10 to the arithmetic unit 15A.

The arithmetic unit 14A performs orthogonal detection of the difference between the reference signal E1 (first input) and the input signal E2 (second input) based on the reference signal E9 input from the distributor 11A. Then, the arithmetic unit 14A synthesizes the in-phase component (I-axis component) and the orthogonal component (Q-axis component) obtained by the orthogonal detection and outputs the signal E5.

The arithmetic unit 15A performs orthogonal detection of the difference between the reference signal E3 (first input) and the input signal E4 (second input) based on the reference signal E10 input from the distributor 11A. Then, the arithmetic unit 15A synthesizes the in-phase component (I-axis component) and the orthogonal component (Q-axis component) obtained by the orthogonal detection and outputs the signal E6.

Next, the configuration of the arithmetic unit 14A will be described with reference to FIG.

The arithmetic unit 14A shown in FIG. 4 includes a differential amplifier 21, a 90-degree phase shifter 22, multipliers 23a and 23b, LPF (Low Pass Filter) 24a and 24b, square circuits 25a and 25b, and a synthesizer. It includes 26.

The differential amplifier 21 receives the reference signal E1 and the input signal E2, and outputs the difference between the input reference signal E1 and the input signal E2 to the multiplier 23a and the multiplier 23b.

In the following, it is assumed that the high frequency induced voltage modulated by the modulated wave is induced in the antenna. In this case, the waveform a of the input signal E2 (high frequency induced voltage component Ve) is represented by the following equation (5). The waveform b of the reference signal E1 is represented by the following equation (6).

In equation (5), A is the carrier amplitude, m is the degree of modulation, ω _p is the modulated wave angular frequency, t is the time, θ ₁ is the carrier phase, and ω _c is the carrier angular frequency. Is. Further, in the equation (6), B is the carrier amplitude and θ ₂ is the carrier phase.

At this time, the output waveform c of the differential amplifier 21 is represented by the following equation (7).

The signal E9 (carrier reference signal) output from the distributor 11A is input to the multiplier 23a and the 90-degree phase shifter 22. The waveform d of the signal E9 is represented by the following equation (8).

In equation (8), D is the carrier amplitude.

The 90-degree phase shifter 22 shifts the phase of the signal E9 (carrier reference signal) output from the distributor 11A by 90 degrees and outputs it to the multiplier 23b. The output waveform e of the 90-degree phase shifter 22 is represented by the following equation (9).

In equation (9), E is the carrier amplitude.

The multiplier 23a multiplies the output of the differential amplifier 21 and the carrier reference signal (signal E9), and outputs the product to the LPF 24a. The output waveform f of the multiplier 23a is represented by the following equation (10).

Of the output of the multiplier 23a, the LPF 24a passes only a frequency band lower than the modulated wave and outputs the output to the square circuit 25a. The output waveform g of the LPF24a is a direct current proportional to the carrier waves of the waveform a, the waveform b, and the waveform d, and is represented by the following equation (11).

The squared circuit 25a squares the output of the LPF 24a and outputs it to the synthesizer 26. Since the output waveform g of the LPF24a is a DC voltage having both polarities of ± g, it is squared by the squared circuit 25a to obtain a value proportional to the positive power. The output waveform h of the squared circuit 25a is represented by the following equation (12).

The multiplier 23b multiplies the output of the differential amplifier 21 and the output of the 90-degree phase shifter 22 and outputs the product to the LPF 24b. The output waveform i of the multiplier 23b is represented by the following equation (13).

The LPF 24b passes only a frequency band lower than the modulated wave among the outputs of the multiplier 23b, and outputs the output to the square circuit 25b. The output waveform j of the LPF24b is a direct current proportional to the carrier waves of the waveform a, the waveform b, and the waveform e, and is represented by the following equation (14).

The squared circuit 25b squares the output of the LPF 24b and outputs it to the synthesizer 26. Since the output waveform j of the LPF24b is a DC voltage having both polarities of ± j, it is squared by the squared circuit 25b to obtain a value proportional to the positive power. The output waveform k of the squared circuit 25b is represented by the following equation (15).

The synthesizer 26 includes the output of the square circuit 25a (in-phase component (I-axis component) obtained by multiplying the difference between the signal E1 and the signal E2 by the carrier reference signal (cos component)) and the output of the square circuit 25b (signal E1 and signal E2). The orthogonal component (Q-axis component) obtained by multiplying the difference between the above by the signal (sin component) whose phase is shifted by 90 degrees from the carrier reference signal is combined (added) and output. The output waveform l of the synthesizer 26 is represented by the following equation (16).

In this way, the arithmetic unit 14A performs orthogonal detection by multiplying the difference between the signal E1 and the signal E2 by signals having different phases of 90 degrees, respectively, and the in-phase component (I-axis component) and the orthogonal component (Q) obtained by the orthogonal detection are performed. Shaft component) and output.

The adjusting unit 18a sets the amplifier 12a and the phase shifter 13a so that the output waveform l of the synthesizer 26 becomes zero. Here, in the equation (16), the component (modulated wave angular frequency ω _p ) caused by the modulated wave is not included, and only the DC component of the target frequency is included. Therefore, even when an external wave other than the desired wave or a modulated induced voltage arrives, the zero point of the signal E5 is detected without being affected by the external wave or the modulated wave, and the induced voltage at the target frequency is detected. Can be used to measure the antenna impedance Z.

The configuration of the arithmetic unit 15A is the same as the configuration of the arithmetic unit 14A. However, in the arithmetic unit 15A, the signal E3 and the signal E4 are input to the differential amplifier 21 instead of the signal E1 and the signal E2, and the signal E10 is used as the multipliers 23a and 90 instead of the signal E9. It is input to the phase shifter 22. By doing so, the output (signal E6) of the arithmetic unit 15A becomes only the DC component of the target frequency, and even when an external wave other than the desired wave or a modulated induced voltage arrives, the external wave or the external wave The zero point of the signal E6 can be detected without being affected by the modulated wave, and the antenna impedance Z can be measured by using the induced voltage of the target frequency.

In the first and second embodiments described above, a signal proportional to the high frequency induced voltage component Ve (a signal obtained by dividing the high frequency induced voltage component Ve by a predetermined voltage division ratio) may be used as the input signal E2. Further, as the input signal E4, a signal proportional to the high frequency induced current component Vi (a signal obtained by dividing the high frequency induced current component Vi by a predetermined voltage division ratio) may be used.

Although the present invention has been described with reference to the drawings and embodiments, it should be noted that those skilled in the art can easily make various modifications or modifications based on the present disclosure. Therefore, it should be noted that these modifications or modifications are within the scope of the present invention.

10,10A Impedance measuring device 11,11A Distributor 12a, 12b Amplifier 13a, 13b Phase shifter 14, 14A Arithmetic unit (second arithmetic unit)
15,15A calculator (third calculator)
16 Phase difference detector 17 Arithmetic unit (first arithmetic unit)
18a Adjustment unit (first adjustment unit)
18b Adjustment section (second adjustment section)
21 Differential amplifier 22 90 degree phase shifter 23a, 23b Multiplier 24a, 24b LPF
25a, 25b squared circuit 26 synthesizer

Claims (3)

An impedance measuring device that measures antenna impedance.
A phase difference detector that detects the phase difference between the high-frequency induced voltage component and the high-frequency induced current component induced in the antenna,
It includes a first arithmetic unit that calculates an antenna impedance based on the phase difference detected by the phase difference detector, a known load resistance connected to the antenna, the high frequency induced voltage component, and the high frequency induced current component. An impedance measuring device characterized in that. In the impedance measuring device according to claim 1,
A first adjusting unit that generates a first reference signal whose amplitude and phase of the reference signal are adjusted, and
A second adjusting unit that generates a second reference signal whose amplitude and phase of the reference signal are adjusted, and
The first reference signal generated by the first adjusting unit is used as the first input, the high frequency induced voltage component is used as the second input, and the difference between the first reference signal and the high frequency induced voltage component. A second arithmetic unit that outputs
The second reference signal generated by the second adjusting unit is used as the first input, the high frequency induced current component is used as the second input, and the difference between the second reference signal and the high frequency induced current component. Further equipped with a third arithmetic unit that outputs
The first adjusting unit is set so that the output of the second arithmetic unit becomes zero.
The second adjusting unit is set so that the output of the third arithmetic unit becomes zero.
The phase difference detector comprises the first reference signal as the high frequency induced voltage component generated by the first adjusting unit and the high frequency induced current component generated by the second adjusting unit. An impedance measuring device characterized by detecting a phase difference from a second reference signal. In the impedance measuring device according to claim 1,
A first adjusting unit that generates a first reference signal whose amplitude and phase of the reference signal are adjusted, and
A second adjusting unit that generates a second reference signal whose amplitude and phase of the reference signal are adjusted, and
A second arithmetic unit that uses the first reference signal generated by the first adjusting unit as the first input and the high frequency induced voltage component as the second input.
Further provided with a third arithmetic unit having the second reference signal generated by the second adjusting unit as the first input and the high frequency induced current component as the second input.
The second arithmetic unit and the third arithmetic unit are each
Based on the reference signal, orthogonal detection of the difference between the first input and the second input is performed, and the in-phase component and the orthogonal component obtained by the orthogonal detection are combined and output.
The first adjusting unit is set so that the output of the second arithmetic unit becomes zero.
The second adjusting unit is an impedance measuring device characterized in that the output of the third arithmetic unit is set to be zero.

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