JP2697342B2 - Voltage standing wave ratio measurement device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a voltage standing wave ratio (hereinafter, referred to as "voltage standing wave ratio").
It is called VSWR. ) For measuring a voltage standing wave.

[0002]

2. Description of the Related Art In recent years, a mobile communication system such as an automobile telephone has been put into practical use with the progress of wireless communication technology. As an example of this mobile communication system, there is a cellular mobile communication system. In this cellular mobile communication system, a service area is divided into a plurality of cells, and a base station is provided substantially at the center of each cell, and a plurality of channels are used between the base station and each mobile station. Communication is performed.

A first conventional antenna sharing apparatus 1 provided in a base station of a cellular mobile communication system.
11 and the antenna monitoring device 100 are shown in FIG.

As shown in FIG. 9, a base station is provided with a plurality of transmitters TX1, TX2, TX3 for outputting transmission signals of frequencies f ₁ , f ₂ , f ₃ , respectively, and these transmitters TX1, TX2 , TX3 output from antenna 113 via antenna sharing apparatus 111, antenna monitoring apparatus 100, and wideband bandpass filter F0 that allows all transmission signals transmitted from the base station to pass. And transmitted to each mobile station. Here, the antenna sharing device 111 includes three isolators I1, I2, and I3 each constituted by a three-terminal circulator having one end terminated by a resistor, and a band called a so-called channel filter that passes only each transmission signal. Pass filters F1, F2, and F3 are provided. The input terminals of the circulators I1, I2, I3 are connected to the transmitters TX1, TX2, TX3, respectively, while the output terminals of the band-pass filters F1, F2, F3 are all connected to the directional coupler 112 in the antenna monitoring apparatus 100. Is connected to the input terminal of

In the antenna monitoring apparatus 100, an incident wave output to the antenna 113 and reflected from the antenna 113 are reflected by the directional coupler 112 inserted between the bandpass filter F 0 and the antenna sharing apparatus 111. A reflected wave is detected, and the detected incident wave and reflected wave are detected by detection circuits 114 and 115, respectively, to obtain a DC voltage proportional to the levels of the incident wave and the reflected wave. The detection output of the incident wave and the detection output of the reflected wave are input to the arithmetic circuit 116, and the power and VSWR of the transmission signal radiated from the antenna 113 to the space are calculated, and the calculation result is displayed on the display device 117. . When the calculated VSWR exceeds a predetermined threshold, the display device 1 displays an “abnormal state” of the antenna 113 system.
The information is displayed on the display 17 to inform the maintenance person.

However, in the antenna monitoring apparatus 100 of the first conventional example, a plurality of transmitters TX1, TX2, TX2
The reflected wave and the incident wave of the multiplex wave of each of the transmission signals of the frequencies f ₁ , f ₂ , and f ₃ output from the TX 3 are combined with the directional coupler 1
12, and these incident waves and reflected waves are detected by the detection circuits 114 and 115, respectively. Therefore, the detection outputs of the detection circuits 114 and 115 are added to the nonlinear characteristics of the detection circuits 114 and 115. As a result, a beat signal having a frequency of f ₁ -f ₂ or f ₁ -f ₃ is superimposed and output.
4 and 115 fluctuate with time. Therefore, based on the reflected wave and the incident wave, the power and VS of the transmission signal calculated by the calculation circuit 116 are calculated.
There is a problem that the accuracy of WR is reduced. In addition, when an interference wave of another frequency is input to the antenna 113 from the outside, the interference wave is superimposed on the reflected wave, and the reflected wave and the VSWR cannot be measured accurately.

In order to solve this problem, the present inventor has
In the patent application of Japanese Patent Application No. 2-264236, FIG.
A second conventional antenna monitoring apparatus 104 shown in FIG.

The second conventional antenna monitoring apparatus 10
4, the antenna monitoring device 1 of the first conventional example
In FIG. 12, directional couplers CP1, CP2, and CP3 for extracting incident waves output to the antenna 113 are provided between the transmitters TX1, TX2, and TX3 and the isolators I1, I2, and I3, respectively. An incident wave from one transmitter (one of TX1, TX2, TX3) extracted from the sexual coupler to the antenna 113, and an output wave from the plurality of transmitters TX1, TX2, TX3 and extracted by the directional coupler 112a. After the reflected waves of the multiplex waves of the respective transmission signals are mixed by the double balanced mixer circuit 132 and then low-pass filtered by the low-pass filter 136, the signal of the DC component proportional to the level of the reflected waves is obtained. (Hereinafter, referred to as a DC signal of a reflected wave). Here, one transmitter (T
X1, TX2, TX3) to the antenna 11
3 is taken out by one directional coupler (one of CP1, CP2, CP3) connected corresponding to the transmitter, and then detected through a switch SW. It is input to 135 and detected. The output of the detection circuit 135 is input to the arithmetic circuit 116, and the arithmetic circuit 116 outputs the low-pass filter 1 from the mixer circuit 132.
DC signal of the reflected wave inputted through
A VSWR, which is a voltage ratio between the reflected wave and the incident wave, is calculated based on the 35 detection outputs.

[0009]

However, the level of the DC signal of the reflected wave output from the low-pass filter 136 depends on the level of the reflected wave of the multiplex wave input to the mixer circuit 132 from the directional coupler 112a. Directional couplers (C
P1, CP2, one of CP3) to mixer circuit 1
Since it changes depending on the phase difference from the incident wave input to the input 32, it is difficult to accurately measure the level of the reflected wave. Further, even if the level of the reflected wave taken out by the directional coupler 112a is relatively large, the level of the DC signal of the reflected wave becomes zero depending on the phase of the reflected wave,
There was a problem that the level of the reflected wave could not be measured in some cases.

A first object of the present invention is to solve the above-mentioned problems, and to obtain better accuracy than the conventional example without being affected by an interference wave and without depending on the phase of a reflected wave.
VSWR for a specific high frequency signal on the transmission line
Is to provide a voltage standing wave ratio measuring device capable of measuring the voltage standing wave ratio. A second object of the present invention is to provide the above-described method for a specific high-frequency signal on a transmission line with better accuracy than the conventional example without being affected by an interference wave and without depending on the phase of a reflected wave. An object of the present invention is to provide a reflected wave measuring device capable of measuring the level of a reflected wave.

[0011]

According to a first aspect of the present invention, there is provided a voltage standing wave ratio measuring apparatus comprising a transmission line having one end connected to a load circuit, and transmitting a high frequency signal having a predetermined level to the transmission line. When input to the other end of the line, based on the level of the incident signal passing through the transmission line and the reflected signal input back to the transmission line from the load circuit, the level of the high-frequency signal in the transmission line A voltage standing wave ratio measuring device for measuring a voltage standing wave ratio, comprising: first coupling means provided on the transmission line for extracting a part of the incident signal; Second coupling means for extracting a part of the signal, modulation means for angle-modulating the signal extracted by the first coupling means with a low-frequency signal having a predetermined level, and outputting a modulation signal; Union of two Mixing means for outputting a signal obtained as a result of multiplication according to the phase difference between the signal extracted by the stage and the modulation signal output from the modulation means, and blocking high-frequency components in the signal output from the mixing means Low-pass filtering means for filtering low-frequency components, rectifying means for rectifying a signal filtered by the low-pass filtering means and outputting a signal indicating an absolute value of the filtered signal; Integrating means for integrating a signal indicating the absolute value output from the rectifying means and outputting a signal indicating a peak value of the signal indicating the absolute value; and the incident light based on the signal extracted by the first coupling means. A first calculating means for calculating a signal level, a second calculating means for calculating a level of the reflection signal based on a signal indicating a peak value output from the integrating means, and the first calculating means. Calculation A third calculating means for calculating a voltage standing wave ratio of the high-frequency signal in the transmission line based on the level of the incident signal obtained and the level of the reflected signal calculated by the second calculating means. It is characterized by having.

According to a second aspect of the present invention, there is provided a voltage standing wave ratio measuring apparatus comprising a transmission line having a load circuit connected to one end thereof, and transmitting a high-frequency signal having a predetermined level to the other end of the transmission line. When input to the transmission line, based on the level of the incident signal passing through the transmission line and the reflected signal input back to the transmission line from the load circuit, a voltage standing wave for the high-frequency signal in the transmission line A voltage standing wave ratio measuring device for measuring a ratio, wherein said first and third coupling means are respectively provided on said transmission line and take out a part of said incident signal; Second coupling means for extracting a part of the signal, modulation means for angle-modulating the signal extracted by the first coupling means with a low-frequency signal having a predetermined level, and outputting a modulation signal; Two Mixing means for outputting each signal of a multiplication result according to each phase difference between the signal extracted by the combining means and the signal extracted by the third combining means, and the modulated signal output from the modulation means, A low-pass filtering unit that blocks a high-frequency component and filters a low-frequency component of each signal output from the mixing unit, and rectifies each signal filtered by the low-pass filtering unit. Rectifying means for outputting each signal indicating the absolute value of each of the filtered signals; and integrating the respective signals indicating the absolute value output from the rectifying means to calculate the peak value of each signal indicating the absolute value. Integrating means for respectively outputting the signals indicated by the first and second signals, and a first means for calculating the level of the incident signal and the level of the reflected signal based on each signal indicating the peak value output from the integrating means. Calculating means, and second calculating means for calculating a voltage standing wave ratio of the high-frequency signal in the transmission line based on the level of the incident signal and the level of the reflected signal calculated by the first calculating means. And characterized in that:

Further, the reflection signal measuring device according to claim 3 of the present invention includes a transmission line connected to a load circuit at one end, and a high-frequency signal having a predetermined level is input to the other end of the transmission line. A reflected signal measuring device for measuring the level of a reflected signal input from the load circuit back to the transmission line, provided on the transmission line, wherein the high-frequency signal is input to the other end of the transmission line. A first coupling means for extracting a part of the incident signal passing through the transmission line; a second coupling means provided on the transmission line for extracting a part of the reflected signal; and the first coupling means. A modulating means for angle-modulating the signal extracted by the low-frequency signal having a predetermined level to output a modulated signal; a signal extracted by the second coupling means;
Mixing means for outputting a signal of a multiplication result according to the phase difference with the modulation signal output from the modulation means, and blocking high-frequency components and filtering low-frequency components in the signals output from the mixing means Low-pass filtering means, rectifying means for rectifying the signal filtered by the low-pass filtering means and outputting a signal indicating an absolute value of the filtered signal, and an absolute value output from the rectifying means. Integrating means for integrating the signal indicating the value to output a signal indicating the peak value of the signal indicating the absolute value; and calculating the level of the reflection signal based on the signal indicating the peak value output from the integrating means. And a calculating means.

According to a fourth aspect of the present invention, in the voltage standing wave ratio measuring apparatus, a plurality of high-frequency signals having mutually different frequencies are frequency-multiplexed by frequency multiplexing means, and then the multiplexing includes the plurality of high-frequency signals. A signal is fed to a load circuit via a transmission line, and the transmission line is formed based on an incident signal transmitted from the transmission line to the load circuit and a reflected signal input from the load circuit back to the transmission line. A voltage standing wave ratio measuring device for measuring a voltage standing wave ratio of each of the high-frequency signals, wherein the first coupling means provided on the transmission line and extracting a part of the incident signal; A second coupling means provided on the line for extracting a part of the reflected signal; and a third coupling means provided before the frequency multiplexing means and extracting a part of each of the high-frequency signals. Switching means for selectively switching and outputting each of the high-frequency signals extracted by the third coupling means; and angularly modulating the signal output from the switching means with a low-frequency signal having a predetermined level. A modulating means for outputting a modulating signal in accordance with each phase difference between a signal extracted by the first coupling means and a signal extracted by the second coupling means, and a modulation signal output from the modulating means. Mixing means for outputting each signal of the multiplication result, and low-pass filtering means for blocking high-frequency components and filtering low-frequency components, respectively, among the signals of the multiplication results output from the mixing means, Rectifying means for rectifying each signal filtered by the low-pass filtering means and outputting each signal indicating the absolute value of each of the filtered signals; and Integrating means for integrating each signal indicating the absolute value and outputting each signal indicating the peak value of each signal indicating the absolute value, and based on each signal indicating the peak value output from the integrating means. First calculating means for calculating the level of the incident signal and the level of the reflected signal for each of the high-frequency signals; and the level of the incident signal for each of the high-frequency signals calculated by the first calculating means. A second calculating means for calculating a voltage standing wave ratio for each of the high-frequency signals in the transmission line based on a level of the reflected signal.

Further, according to the reflection signal measuring device of the present invention, after a plurality of high-frequency signals having different frequencies are frequency-multiplexed by the frequency multiplexing means,
A multiplexed signal including the plurality of high-frequency signals is supplied to a load circuit via a transmission line, an incident signal transmitted from the transmission line to the load circuit, and a reflected signal input from the load circuit back to the transmission line. A reflection signal measuring device for measuring the level of the reflection signal with respect to each of the high-frequency signals in the transmission line, the first coupling being provided on the transmission line and extracting a part of the reflection signal. Means, a second coupling means provided before the frequency multiplexing means for extracting a part of each of the high-frequency signals, and selectively switching and outputting each of the high-frequency signals extracted by the second coupling means Switching means for performing an angle modulation of a signal output from the switching means with a low-frequency signal having a predetermined level to output a modulated signal; and the first coupling means Thus, the extracted signal and a mixing unit that outputs a signal of a multiplication result according to a phase difference between the modulation signal output from the modulation unit and a high frequency component in the signal output from the mixing unit Low-pass filtering means for filtering low-frequency components, rectifying means for rectifying a signal filtered by the low-pass filtering means and outputting a signal indicating an absolute value of the filtered signal; Integrating means for integrating a signal indicating an absolute value output from the rectifying means and outputting a signal indicating a peak value of the signal indicating the absolute value;
Calculating means for calculating the level of the reflection signal for each of the high-frequency signals based on the signal indicating the peak value output from the integrating means.

[0016]

In the voltage standing wave ratio measuring apparatus according to the first aspect, the modulating means modulates the signal extracted by the first coupling means by angle-modulating the signal with a low-frequency signal having a predetermined level. A signal is output, and the mixing means outputs a signal obtained as a result of multiplication according to the phase difference between the signal extracted by the second coupling means and the modulation signal output from the modulation means. Next, the low-pass filtering unit filters out low-frequency components while blocking high-frequency components of the signal output from the mixing unit, and the rectifying unit is filtered by the low-pass filtering unit. After rectifying the signal and outputting a signal indicating the absolute value of the filtered signal, the integrating means integrates the signal indicating the absolute value output from the rectifying means and outputs the signal indicating the absolute value. A signal indicating the peak value is output. Further, the first calculating means calculates the level of the incident signal based on the signal extracted by the first coupling means, and the second calculating means calculates the peak value output from the integrating means. Calculating the level of the reflected signal based on the signal indicating the level of the incident signal calculated by the first calculating means and the level calculated by the second calculating means. A voltage standing wave ratio for the high-frequency signal in the transmission line is calculated based on the level of the reflected signal.

In the voltage standing wave ratio measuring device configured as described above, a signal that is a part of the incident signal extracted by the first coupling means is angle-modulated to output a modulated signal. After outputting a signal of a multiplication result according to a phase difference between the signal that is a part of the reflected signal extracted by the second coupling means and the modulation signal, the signal is low-pass filtered and the low-pass filtered signal is output. Rectifies the signal, outputs a signal indicating the absolute value of the filtered signal, integrates the signal, outputs a signal indicating the peak value of the signal indicating the absolute value, and performs the reflection based on the signal indicating the peak value. Since the signal level is calculated, the level of the reflected signal can be accurately measured regardless of the phase difference between the signals input to the mixing means, that is, regardless of the phase of the reflected signal. can do. Further, even when a relatively large interference signal is input to the load circuit, the modulation signal related to the interference signal generated by the mixing means is blocked by the low-pass filtering means, so that the interference signal , And the level of the reflected signal can be accurately measured. Therefore, the VSWR of the high-frequency signal on the transmission line can be accurately measured.

Further, in the voltage standing wave ratio measuring device according to the present invention, the modulating means angularly modulates the signal taken out by the first coupling means with a low frequency signal having a predetermined level. The mixing means outputs a phase difference between the signal extracted by the second coupling means, the signal extracted by the third coupling means, and the modulation signal output from the modulation means. After outputting each signal of the multiplication result according to the above, the low-pass filtering means respectively blocks the high-frequency components and filters the low-frequency components among the signals output from the mixing means. Next, the rectifying means rectifies each signal filtered by the low-pass filtering means and outputs each signal indicating an absolute value of the filtered signal. Each signal indicating the absolute value output from the means is integrated, and each signal indicating the peak value of each signal indicating the absolute value is output. Further, the first calculating means calculates the level of the incident signal and the level of the reflected signal based on each signal indicating the peak value output from the integrating means, and the second calculating means includes: A voltage standing wave ratio for the high-frequency signal in the transmission line is calculated based on the level of the incident signal and the level of the reflection signal calculated by the first calculating means.

In the voltage standing wave ratio measuring device configured as described above, a signal that is a part of the incident signal extracted by the first coupling means is angle-modulated and a modulated signal is output. After outputting a signal of a multiplication result according to a phase difference between the signal that is a part of the reflected signal extracted by the second coupling means and the modulation signal, the signal is low-pass filtered and the low-pass filtered signal is output. Rectifies the signal, outputs a signal indicating the absolute value of the filtered signal, integrates the signal, outputs a signal indicating the peak value of the signal indicating the absolute value, and performs the reflection based on the signal indicating the peak value. Since the signal level is calculated, the level of the reflected signal can be accurately measured regardless of the phase difference between the signals input to the mixing means, that is, regardless of the phase of the reflected signal. can do. Further, even when a relatively large interference signal is input to the load circuit, the modulation signal related to the interference signal generated by the mixing means is blocked by the low-pass filtering means, so that the interference signal , And the level of the reflected signal can be accurately measured. Therefore, the VSWR of the high-frequency signal on the transmission line can be accurately measured.

Further, in the reflection signal measuring device according to the third aspect, the modulating means performs angle modulation of the signal extracted by the first coupling means with a low-frequency signal having a predetermined level and modulates the signal. And the mixing means outputs the signal extracted by the second coupling means,
After outputting the signal of the multiplication result according to the phase difference with the modulation signal output from the modulation means, the low-pass filtering means,
In the multiplication result signal output from the mixing means, high-frequency components are blocked and low-frequency components are filtered. Next, the rectifying unit rectifies the signal filtered by the low-pass filtering unit and outputs a signal indicating an absolute value of the filtered signal, and then the integrating unit outputs the signal from the rectifying unit. The signal indicating the absolute value is integrated, and a signal indicating the peak value of the signal indicating the absolute value is output. Further, the calculating means calculates the level of the reflection signal based on the signal indicating the peak value output from the integrating means.

In the reflection signal measuring device configured as described above, the signal which is a part of the incident signal extracted by the first coupling means is angle-modulated to output a modulated signal, and the second signal is outputted. After outputting a signal of a multiplication result corresponding to the phase difference between the signal that is a part of the reflected signal extracted by the coupling means and the modulation signal, the signal is low-pass filtered, and the low-pass filtered signal is rectified. A signal indicating the absolute value of the filtered signal is output and integrated to output a signal indicating the peak value of the signal indicating the absolute value. Based on the signal indicating the peak value, the level of the reflection signal is determined. Is calculated, so that whatever the phase difference of each signal input to the mixing means becomes, that is, regardless of the phase of the reflected signal, the level of the reflected signal can be accurately measured. it can. Further, even when a relatively large interference signal is input to the load circuit, the modulation signal related to the interference signal generated by the mixing means is blocked by the low-pass filtering means, so that the interference signal Without being affected by
The level of the reflection signal can be accurately measured.

In the voltage standing wave ratio measuring apparatus according to a fourth aspect of the present invention, the switching means selectively switches and outputs each of the high-frequency signals taken out by the third coupling means. In accordance with the switching of the means, the VSWR for each of the above high-frequency signals is sequentially calculated and measured as follows. The modulating means angle-modulates the signal output from the switching means with a low-frequency signal having a predetermined level to output a modulated signal, and the mixing means outputs the signal extracted by the first coupling means. And the second
After outputting each signal of the multiplication result according to each phase difference between the signal extracted by the coupling means and the modulation signal output from the modulation means, the low-pass filtering means includes:
The high-frequency component of each signal of the multiplication result output from the mixing means is blocked, and the low-frequency component is filtered. Next, the rectifying unit rectifies each signal filtered by the low-pass filtering unit and outputs each signal indicating the absolute value of each filtered signal,
The integration means integrates each signal indicating the absolute value output from the rectification means and outputs each signal indicating the peak value of each signal indicating the absolute value. Further, the first calculating means calculates the level of the incident signal and the level of the reflection signal for each of the high-frequency signals based on each signal indicating the peak value output from the integrating means, and The second calculating means includes a voltage standing wave for each of the high-frequency signals in the transmission line based on the level of the incident signal and the level of the reflected signal for each of the high-frequency signals calculated by the first calculating means. Calculate the ratio.

In the voltage standing wave ratio measuring device configured as described above, a signal which is a part of each high-frequency signal extracted by the third coupling means is angle-modulated, and a modulated signal is output. A signal that is a part of the incident signal extracted by the first coupling means and a signal that is a part of the reflected signal extracted by the second coupling means;
After outputting each signal of the multiplication result according to each phase difference with the modulation signal, low-pass filtering is performed, and each low-pass filtered signal is rectified to obtain an absolute value of the filtered signal. After outputting each signal indicating the peak value of each signal indicating the absolute value, each signal indicating the peak value is output. Based on each signal indicating the peak value, the level of the incident signal and the reflection signal are determined. Since the level is calculated, no matter what the phase difference of each signal input to the mixing means becomes, that is, regardless of the phase of the reflection signal, the level of the incident signal for each high frequency signal And the level of the reflected signal can be accurately measured. Further, even when the multiplexed signal passes through the transmission line and a relatively large interference signal is input to the load circuit, a modulation signal and a modulation signal related to the interference signal generated by the mixing unit, respectively. Since the modulated signal related to the high-frequency signal having a frequency different from the high-frequency signal to be measured is blocked by the low-pass filtering means, the level of the reflected signal is not affected by the interference signal and other high-frequency signals. Can be measured accurately. Therefore, the VSWR for each of the high-frequency signals on the transmission line can be accurately measured.

Further, in the reflection signal measuring device according to the fifth aspect, the switching means selectively switches and outputs each of the high-frequency signals extracted by the second coupling means, and switches the switching means. The level of the reflection signal for each of the high-frequency signals is calculated and measured in sequence as follows. The modulating means angle-modulates the signal output from the switching means with a low-frequency signal having a predetermined level to output a modulated signal, and the mixing means outputs the signal extracted by the first coupling means. And, after outputting a signal of a multiplication result corresponding to a phase difference between the modulation signal output from the modulation means and the low-pass filtering means, the low-pass filtering means outputs a high-frequency component of the multiplication result signal output from the mixing means. And filters out low frequency components.
Next, the rectifying unit rectifies the signal filtered by the low-pass filtering unit and outputs a signal indicating an absolute value of the filtered signal, and then the integrating unit outputs the signal from the rectifying unit. The signal indicating the absolute value is integrated, and a signal indicating the peak value of the signal indicating the absolute value is output. Further, the calculation means calculates the level of the reflection signal for each of the high-frequency signals based on the signal indicating the peak value output from the integration means.

In the reflection signal measuring device configured as described above, a signal which is a part of each of the high-frequency signals extracted by the second coupling means is angle-modulated, and a modulated signal is output. After outputting a signal of a multiplication result according to the phase difference between the signal that is a part of the reflected signal extracted by the coupling means and the modulation signal, the signal is low-pass filtered, and the low-pass filtered signal is rectified. Then, after outputting a signal indicating the absolute value of the filtered signal, integrating and outputting a signal indicating the peak value of the signal indicating the absolute value, and calculating the signal of the reflection signal based on the signal indicating the peak value. Since the level is calculated, no matter what the phase difference of each signal input to the mixing means becomes, that is, regardless of the phase of the reflected signal, the level of the reflected signal for each high frequency signal Accurately measure It can be. Further, even when the multiplexed signal passes through the transmission line and a relatively large interference signal is input to the load circuit, a modulation signal and a modulation signal related to the interference signal generated by the mixing unit, respectively. Since the modulation signal related to the high-frequency signal having a frequency different from the high-frequency signal to be measured is blocked by the low-pass filtering means, each of the high-frequency signals is not affected by the interference signal and other high-frequency signals. Can be accurately measured.

[0026]

Embodiments of the present invention will be described below with reference to the drawings.

<First Embodiment> FIG. 1 shows a VSWR measuring apparatus 2 according to a first embodiment of the present invention. VSWR measuring device 2 of the first embodiment
Is used to convert the transmission signal output from the transmitter 1 into a directional coupler 2
After being detected by 0, the signal is phase-modulated by a predetermined low-frequency signal (f _L ), while the directional coupler 30 inserted between the directional coupler 20 and the antenna 3 causes the incident signal and the directional coupler 30 to be modulated. The reflected signal from the antenna 3 connected to the output terminal 30b is detected, and the incident signal or reflected signal (f ₁ ) detected by the directional coupler 30 and the phase-modulated incident signal (f ₁ ′) , After low-frequency filtering, and after full-wave rectification of the filtered low-frequency signal, the peak value is held using a peak hold circuit 45, and based on the peak value, the directional coupler is used. 30 to calculate the levels of the incident signal and the reflected signal, and calculate the VSWR based on the calculated levels of the incident signal and the reflected signal.
Is calculated and measured.

In FIG. 1, a transmission signal of a frequency f ₁ having a predetermined level output from a transmitter 1 is provided with an isolator 10 and a directional coupler 20 for extracting an incident signal.
Is output to the antenna 3 via the passing line 21 of the directional coupler and the passing line 31 of the directional coupler 30 for extracting the incident signal and the reflected signal, and is radiated to free space. Here, the directional coupler 20 can extract a transmission line 21 through which the transmission signal input from the transmitter 1 passes, and a part of the power of the transmission signal that is electromagnetically coupled to the transmission line 21 and passes through. Signal line 2 provided at a predetermined distance from input terminal 20a of directional coupler 20 for detecting the passing transmission signal (hereinafter referred to as an incident signal).
2 is provided. Directional coupler 20 in coupling line 22
Of the directional coupler 2 in the coupling line 22 is terminated by a terminating resistor R1.
The terminal 22a on the input terminal 20a side of 0 is connected to the input terminal of the phase modulator 40.

The directional coupler 20 configured as described above
The transmission signal transmitted from the isolator 10 to the input terminal 20a and passing through the transmission line 21 is
b, the signal is input to the input terminal 30 a of the directional coupler 30, is detected by the coupling line 22, and the detected incident signal is output to the phase modulator 40. Signal generator 70
Generates a low-frequency signal (f _L ) having a predetermined level, for example, a sine wave of 10 kHz, and outputs it to the phase modulator 40. The phase modulator 40 modulates the phase of the incident signal input from the directional coupler 20 with the low-frequency signal (f _L ), and inputs the modulated signal (f ₁ ′) to the local oscillation signal input of the mixer 41. Output to terminal. This phase modulator 40 is, for example,
Conventional literature "Kazuhiro Miyauchi et al.," Microwave circuit for communication ", IEICE, published October 20, 1981."
A three-terminal circulator in which a variable-capacitance diode is connected to a transmission line connected to one terminal of a three-terminal circulator, as disclosed on pages 318 to 320 (hereinafter referred to as a conventional document), or 3 dB. The hybrid circuit can be constituted by a 3 dB hybrid circuit in which variable capacitance diodes are connected to respective transmission lines connected to two terminals that form a pair. here,
The operating point of each of the variable capacitance diodes is biased by a negative DC bias voltage, and the low frequency signal is input to both ends of each of the variable capacitance diodes via a low-pass filter capable of passing the low frequency signal. Thus, the incident signal having the frequency f ₁ passing between the other two terminals of the three-terminal circulator or between the other two terminals of the 3 dB hybrid circuit can be phase-modulated by the low frequency signal. it can.

The directional coupler 30 includes a transmission line 31 for transmitting a transmission signal input from the transmitter 1 and a transmission line 3
1 is provided on the input end 30a side of the directional coupler 30 at a predetermined interval so as to be able to extract a part of the power of the transmitting signal that is electromagnetically coupled to 1 and detects the passing transmitting signal. A reflected signal that is electromagnetically coupled to the incident signal detection coupling line 32 and the passing line 31 and that is reflected and input from the antenna 3 to the output terminal 30b (hereinafter, referred to as a reflection signal)
It is called a reflected signal. And a reflection signal detection coupling line 33 provided on the output end 30b side of the directional coupler 30 so as to be able to take out a part of the power of the directional coupler 30 and detecting the reflection signal. A terminal 32b on the output end 30b side of the directional coupler 30 in the coupling line 32 and a terminal 33a on the input end 30a side of the directional coupler 30 in the coupling line 33 are terminated by terminating resistors R2 and R3, respectively. The terminal 32a on the input side 30a of the directional coupler 30 in the coupling line 32 is connected to the main signal input terminal of the mixer 41 via the a side of the switch SW1, and the output terminal of the directional coupler 30 on the coupling line 33. The terminal 33b on the 30b side is connected to the main signal input terminal of the mixer 41 via the b side of the switch SW1.

The directional coupler 30 configured as described above
In the above, the incident signal of the transmission signal transmitted from the directional coupler 20 to the input terminal 30a and passing through the transmission line 31 is detected by the coupling line 32, and the detected incident signal is transmitted through the a side of the switch SW1. Mixer 4 as main signal
1 is input. The reflected signal of the transmission signal caused by the mismatch of the antenna 3 is detected by the coupling line 33, and the detected reflected signal is input to the mixer 41 as a main signal via the switch SW1 on the side b.

The mixer 41 composed of a multiplier such as a double balance mixer, as disclosed on pages 304 to 306 of the above-mentioned conventional literature, receives a signal (f ₁ ) input to a main signal input terminal and a signal (f ₁ ). , And a signal (f ₁ ′) input to a local oscillation signal input terminal, and multiplies the mixed signal, and outputs the mixed signal to the low-pass filter 42. Here, the mixer 41
Are mixed signals output from the (f ₁ + f ₁ ′) and (f ₁ −f ₁ ′) low-frequency signals, that is, the signal (f _L ) output from the signal generator 70, and the like. The low-pass filter 42 passes only the low-frequency signal among the input mixed signals. The low-frequency signal changes depending on the phase difference and the amplitude of two signals input to the mixer 41, as shown in, for example, Expression (3.154) on page 305 of the above-mentioned conventional document.
It is a result of multiplication of waves. The low-frequency signal is output to a full-wave rectifier 44 including, for example, four bridge-connected rectifying diodes via a low-frequency amplifier 43 that amplifies signals from DC to low-frequency components. Full wave rectifier 44
Performs full-wave rectification on the input low-frequency signal and outputs the signal to a peak hold circuit 45 configured by, for example, an integrating circuit including a circuit in which a capacitor and a resistor are connected in parallel.
The peak hold circuit 45 holds a peak value of the input low-frequency signal, and converts a signal indicating the peak value (hereinafter, referred to as a peak hold signal) into an analog / digital conversion (hereinafter, referred to as A / D conversion) circuit. Output to 46. Next, the A / D conversion circuit 46 converts the analog signal of the peak hold signal into a digital signal,
Output to the CPU 51 via the interface circuit 54 therein.

If the phase modulator 40 is not provided, even if the amplitude of each signal input to the mixer 41 is large, the output voltage of the mixer 41 becomes zero if the phase difference between the two signals is zero. (For details, see pages 304 to 306 of the above-mentioned conventional literature.)

As described with reference to the equation (3.154) in the above-mentioned conventional document, the mixer 41 and the low-pass filter 42
The output voltage of the phase detection circuit composed of the signals changes depending on the phase difference and the amplitude of each signal input to the mixer 41. Here, for example, the incident signal detected by the directional coupler 20 is shifted by the sinusoidal low-frequency signal S1 output from the signal generator 70 so that the phase difference is within the range of -π / 2 to + π / 2. When modulated, the low frequency signal output from the phase detection circuit becomes a sine wave signal S2. Here, as is well known, the level of each frequency component output from the mixer 41 composed of a multiplier is proportional to the product of the level of each signal input to the mixer 41 and is input to the directional coupler 20. Since the level of the transmitted signal is constant, the level of the low-frequency signal S2 output from the low-pass filter 42 when the switch SW1 is switched to the side a is equal to the level of the incident signal detected by the directional coupler 30. The level of the low-frequency signal S2 output from the low-pass filter 42 when the switch SW1 is switched to the b side is equal to the level of the reflected signal detected by the directional coupler 30. Is proportional to

However, as shown in FIG. 5, the phase difference between the signals input to the mixer 41 deviates from the state shown in FIG. 4, and the incident signal detected by the directional coupler 20 is output from the signal generator 70. Sine wave low frequency signal S1a
When the above-mentioned phase difference is phase-modulated in the range from −3 / 4π to + π / 8, the low-frequency signal output from the circuit becomes the signal S2a and does not become a sine wave signal. Therefore, in this embodiment, the low-pass filter 4
2 is amplified by an amplifier 43 and a full-wave rectifier circuit 44 obtains a signal S3a of an absolute value of the low-frequency signal. The peak hold signal is obtained by holding the peak value. As described above, the peak value of the peak hold signal is proportional to the level of the incident signal detected by the directional coupler 30 when the switch SW1 is switched to the a side, and
When W1 is switched to the b side, it is proportional to the level of the reflected signal detected by the directional coupler 30.

As described above, in the present embodiment, the incident signal detected by the directional coupler 20 is phase-modulated by using the phase modulator 40, and the phase-modulated incident signal and the directional coupler 30 are used. After mixing the detected incident signal or reflected signal with the mixer 41, the low-pass filter 4
2, since the full-wave rectifier circuit 44 and the peak hold circuit 45, which are absolute value circuits, are provided, no matter what the phase difference between the signals input to the mixer 41 becomes, The level of the incident signal and the level of the reflected signal can be accurately measured. Therefore, the problem of the second conventional example pointed out in the section of "Problems to be Solved by the Invention" can be solved.

Further, the frequency f ₁ is externally applied to the antenna 3.
The case where an interference signal having a frequency other than the frequency f _it (f ₁ −f _it ) ≫f _L is incident will be described below. In this case, the interference signal and the reflected signal of the frequency f ₁ are
0 is detected by the coupling line 33 and input to the mixer 41 via the b side of the switch SW1. On the other hand, a signal (f ₁ ′) obtained by further phase-modulating the incident signal of the frequency f ₁ detected by the directional coupler 20 is input to the mixer 41. Therefore, the signal after mixing output from the mixer 41 'and the high-frequency _{signal, (f 1 -f 1 (f} 1 + f 1)' the low output from the low-frequency signal, that the signal generator 70) High frequency signal (f _L ), high frequency signal of (f _it + f ₁ ′),
Although the low-pass filter 42 includes a frequency component such as a high-frequency signal (f _it −f ₁ ′), the low-pass filter 42 allows only the low-frequency signal among the input mixed signals to pass. Therefore, since the signal related to the interference signal is blocked by the low-pass filter 42, the VSWR device 2 of the present embodiment can reduce the interference signal even when a relatively large interference signal is input to the antenna 3 from the outside. The VSWR of the transmission signal can be accurately measured without being affected.

The control circuit 50 of the VSWR measuring device 2
A CPU 51 for executing SWR measurement processing;
ROM 52 for storing a control program for measurement processing and data necessary for executing the control program
And a RAM 53 that is used as a working area of the CPU 51 and stores data input through the interface circuits 54 and 56. Control circuit 5
0, the CPU 51, the ROM 52, and the RAM 5
3 and each of the interface circuits 54 to 57 are connected via a bus 59. The interface circuit 55 is connected to the control terminal of the switch SW1, the interface circuit 56 is connected to the ground via the start switch SW2, and the interface circuit 57 is connected to the display 60.

When executing the VSWR measurement process, the CPU 51 selectively switches the switch SW1 via the interface circuit 55 to the a side or the b side, as will be described in detail later.
Side, and outputs the calculation result at the time of the measurement processing to the display 60 via the interface circuit 57 for display.

FIG. 6 shows a VSWR measuring apparatus 2 according to the first embodiment.
Is a flowchart showing a main routine of a VSWR measurement process of the control circuit 50 of FIG.
This is a process of measuring the level of an incident signal of a transmission signal output to the antenna 3 via 0 and 30 and the level of a reflected signal from the antenna 3 and then calculating the VSWR based on each level value.

As shown in FIG. 6, when a power switch (not shown) of the control circuit 50 is turned on, the VSWR of FIG.
The main routine of the measurement process is started. First, it is determined in step S1 whether or not the start switch SW2 has been turned on. After waiting in step S1 until the start switch SW2 is turned on, when the start switch SW2 is turned on (YE
S) Go to step S2. After the switch SW1 is switched to the a side in step S2, in step S3, the effective value power of the incident signal based on the level of the peak hold signal input from the A / D conversion circuit 46 via the interface circuit 54. Is calculated. Next, in step S4, after the switch SW1 is switched to the b side, in step S5, the effective level of the reflected signal is determined based on the level of the peak hold signal input from the A / D conversion circuit 46 via the interface circuit 54. Calculate the value power. Further, in Step S6, after calculating the VSWR based on the calculated effective power of the incident signal and the effective power of the reflected signal, in Step S7, the effective power and V of each of the calculated signals are calculated.
The SWR is displayed on the display 60. Finally, in step S8, the calculated VSWR value is compared with a predetermined threshold value Ts (for example, Ts = 1.3), and when the calculated VSWR value is larger than the threshold value Ts (in step S8). YES), the display 60 indicates that the antenna 3 system is in the “abnormal state”, and a step S1 is performed.
Return to On the other hand, when the calculated VSWR value is equal to or smaller than the threshold value Ts (NO in step S8), the process returns to step S1.

In this embodiment, the effective power of the incident signal, the effective power of the reflected signal, and the VSWR are all converted to respective values at the output terminal 30b of the directional coupler 30 by a known method. After the calculation, the data is displayed on the display 60.

In the above embodiment, the directional coupler 20
However, the present invention is not limited to this. The directional coupler 20 is not provided, and the incident signal output from the output end 32 a of the coupling line 32 of the directional coupler 30 is input to the phase modulator 40. It may be configured as follows. Further, the level of the incident signal may be detected by detecting the incident signal detected by the directional coupler 20 or 30 by a detection circuit, then performing A / D conversion, and inputting the converted signal to the control circuit 50. .

<Second Embodiment> FIG. 2 shows a VSWR measuring device 2a and an antenna sharing device 4 according to a second embodiment of the present invention. In FIG. 2, the same components as those shown in FIG. 1 are denoted by the same reference numerals, the symbols of the directional couplers 20, 23, 26, and 30 are simplified, and each directional coupler is illustrated. The terminating resistors connected to 20, 23, 26 and 30 are omitted.

The VSWR measuring apparatus 2a of the second embodiment
Connects the antenna sharing device 4 of three channels,
The VSWR is measured for each transmission signal transmitted from each of the transmitters 1a, 1b, and 1c using the VSWR measurement principle described in the embodiment. Hereinafter, the description will focus on the differences from the first embodiment.

As shown in FIG. 2, each of the transmitters 1a, 1b,
A constant level determined in advance and is output from 1c, for example, different frequencies f ₁ of the UHF band, f _2, f ₃ (provided _{that, (f 2 -f 1) »f} L, (f 3 -
f ₂ ) ≫f _L , and (f ₃ −f ₁ ) ≫f _L ) are respectively transmitted to the directional couplers 20 and 20 in the VSWR measurement device 2a.
The signal is input to the antenna sharing apparatus 4 via the transmission lines 23, 26, 23, 26. Each directional coupler 20, 2
Reference numerals 3 and 26 have the same configuration as the directional coupler 20 of the first embodiment. That is, the directional coupler 23 includes a transmission line 24 and an incident signal detection coupling line 25, and has an input terminal 23a and an output terminal 23b at both ends of the transmission line 24, and an output terminal 25a at the coupling line 22. Having. The directional coupler 26 includes a transmission line 27 and a coupling line 28 for detecting an incident signal, and has an input terminal 26a and an output terminal 26b at both ends of the transmission line 27, and an output terminal 28a
Having. Each of the incident signals output from the output terminals 22a, 25a, 28a of the coupling lines 22, 25, 28 of the directional couplers 20, 23, 26 respectively correspond to the CP of the control circuit 50.
Switch SW3 selectively switched by U51
Are output to the phase modulator 40 through the a side, the b side, and the c side. Here, the control terminal of the switch SW3 is connected to the control circuit 50.
a is connected to the interface circuit 55 in FIG.

The antenna sharing device 4 has the frequencies f ₁ , f ₂ ,
A multiplexing device that frequency-multiplexes each transmission signal of f ₃ and outputs a multiplexed signal, and an isolator 11 that passes a transmission signal of frequency f _{1 in} a direction from the transmitter 1 a to the antenna 3.
and a, a band-pass filter 12a for passing only the frequency band of the transmission signal of the frequency f _1, an isolator 11b for passing a transmission signal of a frequency f ₂ in the direction from the transmitter 1b to the antenna 3, transmits the frequency f ₂ A band-pass filter 12b for passing only the frequency band of the signal;
an isolator 11c for passing a transmission signal of a frequency f ₃ in the direction of the antenna 3 from c, band-pass filter 12c which passes only the frequency band of the transmission signal of the frequency f ₃
And each band pass filter 12a, 12b, 12c
Are electrically connected to an input terminal 30a of the directional coupler 30. The transmission signal output from the directional coupler 20 is the isolator 1
1a is input to the directional coupler 30 via the bandpass filter 12a, and the transmission signal output from the directional coupler 23 is input to the directional coupler 30 via the isolator 11b and the bandpass filter 12b. , Directional coupler 2
The transmission signal output from 6 is input to the directional coupler 30 via the isolator 11c and the bandpass filter 12c.

A multiplexed signal composed of transmission signals of frequencies f ₁ , f ₂ and f ₃ output from the antenna sharing apparatus 4 is transmitted to the transmission line 31 of the directional coupler 30 and to the frequencies f ₁ , f ₂ , and f ₃ .
The signal is output to the antenna 3 via the transmission band-pass filter 5 that passes only the frequency band including f _3, and the above-mentioned transmission signals of the multiplex signal are radiated from the antenna 3. In the directional coupler 30, the incident signal of the multiplex signal is detected by the coupling line 32, and the detected incident signal of the multiplex signal is output from the output terminal 32a to the mixer 41 via the switch SW1 a side. The reflected signal of the multiplex signal caused by the mismatch of the antenna 3 is detected by the coupling line 33, and the detected reflected signal of the multiplex signal is output from the output terminal 33b to the mixer 41 via the switch SW1 b side. .

The VSWR device 2a configured as described above
In, for example, when the switch SW3 is switched to the a side and the switch SW1 is switched to the a side, the incident signal of the multiplex signal is input to the mixer 41 and detected by the directional coupler 20. A signal (f ₁ ′) obtained by phase-modulating the incident signal of the transmission signal having the frequency f ₁ is input to the mixer 41. Therefore, the signal after mixing output from the mixer 41 'and the high-frequency _{signal, (f 1 -f 1 (f} 1 + f 1)' the low output from the low-frequency signal, that the signal generator 70) Frequency signal (f _L ),
Frequency components such as a (f ₁ ′ + f ₂ ) high frequency signal, a (f ₁ ′ −f ₂ ) high frequency signal, a (f ₁ ′ + f ₃ ) high frequency signal, and a (f ₁ ′ −f ₃ ) high frequency signal. , The low-pass filter 42 outputs the frequency f ₁ of the input mixed signal.
Only the low frequency signal, which is proportional to the level of the incident signal, is passed. Thus, of the incident signal multiplex wave signal, without being affected by the incident signal of a frequency f _2, f ₃ other than the incident signal of a frequency f ₁ which is selected by the switch SW3, the incident signal of a transmission signal of a frequency f ₁ Level can be accurately measured. Further, the switch SW1 is when it is switched to side b, similarly, of the reflected signal multiplexed wave signal, the reflected signal of the frequency f _2, f ₃ other than the incident signal of a frequency f ₁ which is selected by the switch SW3 without being affected, and the level of the reflected signal of the transmission signal of the frequency f ₁ can be measured accurately. Further, regarding the levels of the incident signal and the reflected signal of the other frequencies f ₂ and f ₃ , the switch S
By switching W3 to the b-side or the c-side, accurate measurement can be performed as described above.

Further, the VSWR device 2a of the present embodiment
Is to accurately measure the VSWR of each transmission signal without being affected by the interference signal, as in the first embodiment, even when a relatively large interference signal is externally input to the antenna 3. Can be.

The control circuit 50a of the present embodiment executes a VSWR measurement process described below.

FIG. 7 shows a VSWR measuring apparatus 2 according to the second embodiment.
3 is a flowchart showing a main routine of a VSWR measurement process of the control circuit 50a of FIG. 3A. The main routine includes the directional couplers 20, 23, 26 of the VSWR measurement device 2a and the antennas from the transmitters 1a, 1b, 1c. The level of the incident signal of each transmission signal output to the antenna 3 via the shared device 4, the directional coupler 30 in the device 2 a, and the transmission bandpass filter 5, and the level of each transmission signal from the antenna 3 After measuring the level of the reflected signal, the VSWR for each transmission signal is calculated based on each level value.

As shown in FIG. 7, when a power switch (not shown) of the control circuit 50a is turned on, the VSW of FIG.
The main routine of the R measurement process is started. First, in step S11, it is determined whether or not the start switch SW2 is turned on.
Then, when it is turned on (YES in step S11), the process proceeds to step S12. In step S12, after the switch SW3 is switched to the a side, in step S13, VSWR measurement process of the transmission signal of the frequency f ₁ (see FIG. 8.) Is performed. Next, in step S14, after the switch SW3 is switched to the b side, in step S15, the frequency f
The VSWR measurement processing (see FIG. 8) for the transmission signal of No. ₂ is executed. Further, in step S16, after the switch SW3 is switched to the c side, in step S17, V for transmission signals of the frequency f ₃
After the SWR measurement process (see FIG. 8) is performed, the process returns to step S11.

FIG. 8 is a flowchart of a subroutine of the VSWR measurement process (steps S13, S15, S17) shown in FIG. As shown in FIG.
Steps 22 to S29 are performed in the same manner as steps S12 to S29 shown in FIG.

<Third Embodiment> FIG. 3 is a block diagram of a VSWR measuring device 2b and an antenna sharing device 4 according to a third embodiment of the present invention. The same reference numerals are given to the same components.

The VSWR measuring device 2b of the third embodiment
Does not detect the incident signal of each transmission signal by the directional coupler 30 as in the second embodiment.
The level of the incident signal is measured based on the incident signal of each transmission signal detected by 0, 23, 26. Hereinafter, differences from the second embodiment will be described.

As shown in FIG. 3, the incident signal detecting coupling line 32 and the switch SW1 in the directional coupler 30 are not required as compared with the second embodiment of FIG. After the output incident signal is detected by the detection circuit 47, it is input via the A / D conversion circuit 48 to the interface circuit 58 connected to the bus 59 in the control circuit 50b. The control circuit 50b further includes the above-described interface circuit 58 in the control circuit 50a of the second embodiment. In step S23 in FIG. 8, the detection circuit 47 sends the A / D conversion circuit 48 and the interface 5
8 except that the level of the incident signal of each transmission signal is calculated and measured based on the signal input through
And the subroutine of FIG. 8 are similarly executed.

The VSWR measuring device 2b of the present embodiment
It has the same advantages as the VSWR measurement device 2a of the embodiment.

<Other Embodiments> In each of the above embodiments, the phase modulator 40 is used, but the present invention is not limited to this, and an angle modulator such as a frequency modulator may be used.

Step S8 in FIG. 6 and step S8 in FIG.
At 28, the "abnormal state" of the antenna 3 system is detected by determining the calculated VSWR, but the present invention is not limited to this, and the level of the measured reflected signal is determined to determine the "abnormal state" of the antenna 3 system. An abnormal state "may be detected.

[0061]

As described above in detail, according to the voltage standing wave ratio measuring apparatus of the first aspect of the present invention, the transmission line having one end connected to the load circuit and having a predetermined level is provided. When a high-frequency signal is input to the other end of the transmission line, based on the level of an incident signal passing through the transmission line and a reflection signal input back to the transmission line from the load circuit, A voltage standing wave ratio measuring device for measuring a voltage standing wave ratio of the high-frequency signal, wherein a signal that is a part of an incident signal extracted by a first coupling unit is angle-modulated and a modulated signal is output. Then, a signal that is a part of the reflected signal extracted by the second coupling unit and the modulation signal are mixed by the mixing unit and multiplied, and a multiplication result signal corresponding to the phase difference between the two signals is output. For low-pass filtering The low-pass filtered signal, rectifies the low-pass filtered signal, outputs a signal indicating the absolute value of the filtered signal, and integrates the signal to indicate the peak value of the signal indicating the absolute value. Since the signal is output and the level of the reflection signal is calculated based on the signal indicating the peak value, the phase difference of each signal input to the mixing means becomes any value, that is, the reflection Regardless of the phase of the signal, the level of the reflected signal can be accurately measured, and even when a relatively large interference signal is input to the load circuit, the interference generated by the mixing means is not affected. Since the modulated signal related to the signal is blocked by the low-pass filtering means, the level of the reflected signal can be accurately measured without being affected by the interference signal. Therefore, there is an advantage that the VSWR of the high-frequency signal in the transmission line can be accurately measured.

According to the voltage standing wave ratio measuring device of the second aspect of the present invention, a transmission line having one end connected to a load circuit is provided, and a high-frequency signal having a predetermined level is transmitted to the transmission line. When input to the other end, based on the level of the incident signal passing through the transmission line and the reflected signal input back to the transmission line from the load circuit, a voltage constant for the high-frequency signal in the transmission line is determined. A voltage standing wave ratio measuring device for measuring a standing wave ratio, wherein a signal that is a part of an incident signal extracted by a first coupling unit is angle-modulated to output a modulated signal, and a second coupling unit is provided. A signal that is a part of the reflected signal extracted by the above and the modulation signal are mixed and mixed by the mixing means, a multiplication result signal corresponding to the phase difference between the two signals is output, and then the low-pass filtering means outputs a signal. Filter At the same time, the low-pass filtered signal is rectified, a signal indicating the absolute value of the filtered signal is output, and then integrated to output a signal indicating the peak value of the signal indicating the absolute value. Since the level of the reflected signal is calculated based on the signal indicating the high value, the phase difference of each signal input to the mixing means becomes any value, that is, regardless of the phase of the reflected signal, The level of the reflection signal can be accurately measured. Further, even when a relatively large interference signal is input to the load circuit, the modulation signal related to the interference signal generated by the mixing means is blocked by the low-pass filtering means, so that the interference signal , And the level of the reflected signal can be accurately measured. Therefore, there is an advantage that the VSWR of the high-frequency signal in the transmission line can be accurately measured.

Further, according to the reflection signal measuring device of the third aspect of the present invention, a transmission line having a load circuit connected to one end is provided, and a high-frequency signal having a predetermined level is supplied to the other end of the transmission line. A reflected signal measuring device for measuring the level of a reflected signal input from the load circuit to the transmission line when the signal is input, the signal being a part of the incident signal extracted by the first coupling means. The modulated signal is output after the angle modulation, and a signal, which is a part of the reflected signal extracted by the second coupling means, is mixed with the modulation signal by the mixing means and multiplied. After outputting the signal of the multiplication result, the low-pass filtering means performs low-pass filtering, rectifies the low-pass filtered signal, outputs a signal indicating an absolute value of the filtered signal, and integrates. Indicates the above absolute value. Outputs a signal indicating the peak value of the signal,
Since the level of the reflected signal is calculated based on the signal indicating the peak value, the value of the phase difference between the signals input to the mixing means becomes any value, that is, regardless of the phase of the reflected signal. Therefore, the level of the reflection signal can be accurately measured. Further, even when a relatively large interference signal is input to the load circuit, the modulation signal related to the interference signal generated by the mixing means is blocked by the low-pass filtering means, so that the interference signal There is an advantage that the level of the reflection signal can be accurately measured without being affected by the above.

According to the voltage standing wave ratio measuring device of the fourth aspect of the present invention, after a plurality of high frequency signals having mutually different frequencies are frequency-multiplexed by the frequency multiplexing means, the plurality of high frequency signals are Based on the incident signal transmitted from the transmission line to the load circuit and the reflected signal input back to the transmission line from the load circuit, the multiplexed signal including the power is supplied to the load circuit via the transmission line. A voltage standing wave ratio measuring device for measuring a voltage standing wave ratio of each of the high-frequency signals on a transmission line, wherein the signal that is a part of each of the high-frequency signals extracted by a third coupling unit is angle-modulated. A signal that is a part of the incident signal extracted by the first coupling means and a signal that is a part of the reflected signal extracted by the second coupling means; The modulated signal is mixed and multiplied by the mixing means, and each signal of a multiplication result corresponding to each phase difference of each of the two signals is outputted. After that, the low-pass filtering means performs low-pass filtering and the low-pass filtering. Each of the obtained signals is rectified and each signal indicating the absolute value of each of the filtered signals is output, and then integrated to output each signal indicating the peak value of each signal indicating the absolute value. Since the level of the incident signal and the level of the reflected signal are calculated based on each signal indicating the peak value, no matter what value the phase difference of each signal input to the mixing means has, that is, Regardless of the phase of the reflected signal, it is possible to accurately measure the level of the incident signal and the level of the reflected signal for each of the high-frequency signals. Further, even when the multiplexed signal passes through the transmission line and a relatively large interference signal is input to the load circuit, a modulation signal and a modulation signal related to the interference signal generated by the mixing unit, respectively. Since the modulated signal related to the high-frequency signal having a frequency different from the high-frequency signal to be measured is blocked by the low-pass filtering means, the level of the reflected signal is not affected by the interference signal and other high-frequency signals. Can be measured accurately. Therefore, there is an advantage that the VSWR for each of the high-frequency signals in the transmission line can be accurately measured.

Further, according to the reflection signal measuring apparatus of the fifth aspect of the present invention, after multiplexing a plurality of high-frequency signals having mutually different frequencies by the frequency multiplexing means, the multiplexed signal including the plurality of high-frequency signals is obtained. Is supplied to the load circuit via the transmission line, based on the incident signal transmitted from the transmission line to the load circuit, and the reflected signal input from the load circuit back to the transmission line, based on the transmission line A reflection signal measuring device for measuring a level of the reflection signal with respect to each of the high-frequency signals;
A signal that is a part of each high-frequency signal extracted by the coupling means is angle-modulated to output a modulation signal, and a signal that is a part of the reflection signal extracted by the first coupling means and the modulation signal are After mixing and multiplying by the mixing means and outputting a signal of a multiplication result corresponding to the phase difference between the two signals, the low-pass filtering means performs low-pass filtering, and the low-pass filtered signal is rectified to obtain the signal. After outputting the signal indicating the absolute value of the filtered signal, integrate and output the signal indicating the peak value of the signal indicating the absolute value, and calculate the level of the reflection signal based on the signal indicating the peak value Whatever the value of the phase difference of each signal input to the mixing means, that is, regardless of the phase of the reflected signal, the level of the reflected signal for each of the high-frequency signals can be accurately determined. Can be measured Kill. Further, even when the multiplexed signal passes through the transmission line and a relatively large interference signal is input to the load circuit, a modulation signal and a modulation signal related to the interference signal generated by the mixing unit, respectively. Since the modulation signal related to the high-frequency signal having a frequency different from the high-frequency signal to be measured is blocked by the low-pass filtering means, each of the high-frequency signals is not affected by the interference signal and other high-frequency signals. There is an advantage that the level of the reflection signal can be accurately measured.

[Brief description of the drawings]

FIG. 1 is a block diagram of a VSWR measurement device according to a first embodiment of the present invention.

FIG. 2 is a block diagram of a VSWR measurement device and an antenna sharing device according to a second embodiment of the present invention.

FIG. 3 is a block diagram of a VSWR measurement device and an antenna sharing device according to a third embodiment of the present invention.

FIG. 4 shows a relationship between a phase difference between signals input to a mixer of the VSWR device shown in FIG. 1 and an output voltage of a low-frequency signal output from a low-pass filter, and input to a phase modulator. FIG. 3 is a diagram illustrating a low-frequency signal and a low-frequency signal output from a low-pass filter.

FIG. 5 shows a relationship between a phase difference between signals input to a mixer of the VSWR device shown in FIG. 1 and an output voltage of a low-frequency signal output from a low-pass filter, and input to a phase modulator. FIG. 3 is a diagram illustrating a low-frequency signal, a low-frequency signal output from a low-pass filter, and a low-frequency signal output from a full-wave rectifier circuit.

FIG. 6 is a flowchart illustrating a main routine of a control circuit of the VSWR device illustrated in FIG. 1;

FIG. 7 is a flowchart illustrating a main routine of a control circuit of the VSWR device illustrated in FIG. 2;

FIG. 8 is a flowchart illustrating a subroutine of a VSWR measurement process illustrated in FIG. 7;

FIG. 9 is a block diagram of a VSWR measuring device and an antenna sharing device of a first conventional example.

FIG. 10 is a block diagram of a second conventional VSWR measurement device and antenna sharing device.

[Explanation of symbols]

1, 1a, 1b, 1c ... transmitter, 2, 2a, 2b ... VS
WR measuring device, 3 ... antenna, 4 ... antenna sharing device,
20, 23, 26, 30 ... directional coupler, 31 ... directional coupler passing line, 40 ... phase modulator, 41 ... mixer,
42 low-pass filter, 44 full-wave rectifier, 45 peak hold circuit, 50 control circuit, 51 CPU, 7
0: signal generator, SW3: switch.

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-55-20482 (JP, A) JP-A-53-136875 (JP, A) JP-A-3-30870 (JP, U)

Claims (5)

(57) [Claims] 1. A transmission line having a load circuit connected to one end thereof, wherein when a high-frequency signal having a predetermined level is input to the other end of the transmission line, the level of an incident signal passing through the transmission line is determined by: A voltage standing wave ratio measuring device for measuring a voltage standing wave ratio of the high-frequency signal in the transmission line based on a reflected signal input back from the load circuit to the transmission line, wherein the transmission line A first coupling means provided on the transmission line for extracting a part of the incident signal; a second coupling means provided on the transmission line for extracting a part of the reflected signal; extracted by the first coupling means Means for angle-modulating the signal obtained by the low-frequency signal having a predetermined level to output a modulation signal; a signal extracted by the second coupling means; and a modulation signal output from the modulation means. A mixing unit that outputs a signal of a multiplication result according to a phase difference between the low-frequency filtering unit and a low-band filtering unit that blocks a high-frequency component and filters a low-frequency component of the signal output from the mixing unit. Rectifying means for rectifying the signal filtered by the band-pass filtering means and outputting a signal indicating the absolute value of the filtered signal; and integrating the signal indicating the absolute value output from the rectifying means, and Integrating means for outputting a signal indicating the peak value of the signal indicating the absolute value; first calculating means for calculating the level of the incident signal based on the signal extracted by the first coupling means; and integrating means A second calculating means for calculating the level of the reflection signal based on the signal indicating the peak value output from the first and second calculating means, and the level of the incident signal calculated by the first calculating means and the second calculating means Calculated And a third calculating means for calculating a voltage standing wave ratio for the high-frequency signal in the transmission line based on the level of the reflected signal obtained. 2. A transmission line having a load circuit connected to one end thereof, wherein when a high-frequency signal having a predetermined level is input to the other end of the transmission line, the level of an incident signal passing through the transmission line is determined by: A voltage standing wave ratio measuring device for measuring a voltage standing wave ratio of the high-frequency signal in the transmission line based on a reflected signal input from the load circuit back to the transmission line; First and third coupling means provided on a line for extracting a part of the incident signal; second coupling means provided on the transmission line and extracting a part of the reflected signal; and the first coupling A modulating means for angle-modulating a signal taken out by the means with a low-frequency signal having a predetermined level to output a modulated signal; a signal taken out by the second coupling means and the third coupling means A mixing unit that outputs each signal of a multiplication result according to each phase difference between the signal extracted by the modulation unit and the modulation signal output from the modulation unit; and a high-frequency component among the signals output from the mixing unit. Low-pass filtering means for blocking and filtering low-frequency components, respectively; and rectifying each signal filtered by the low-pass filtering means and forming each signal indicating the absolute value of each filtered signal. A rectifying unit that outputs each signal; an integrating unit that integrates each signal indicating an absolute value output from the rectifying unit and outputs a signal indicating a peak value of each signal indicating the absolute value; First calculating means for calculating the level of the incident signal and the level of the reflected signal based on each of the output peak value signals; and the incident signal calculated by the first calculating means. Voltage standing wave ratio measuring apparatus characterized by comprising level and based on the level of the reflected signal and a second calculating means for calculating a voltage standing wave ratio for the high-frequency signal in the transmission line. 3. A transmission line having a load circuit connected to one end thereof, and when a high-frequency signal having a predetermined level is inputted to the other end of the transmission line, the signal is returned from the load circuit to the transmission line and inputted. A reflection signal measuring device for measuring a level of a reflection signal, wherein a part of the incident signal that passes through the transmission line when the high-frequency signal is input to the other end of the transmission line is extracted from the transmission line. A first coupling unit, a second coupling unit provided on the transmission line, for extracting a part of the reflected signal, and a low-frequency signal having a predetermined level, the signal extracted by the first coupling unit. A modulating means for outputting a modulating signal by performing angle modulation with: a signal obtained as a result of multiplication according to a phase difference between the signal extracted by the second coupling means and the modulating signal outputted from the modulating means. A low-frequency filtering means for blocking high-frequency components and filtering low-frequency components of the signal output from the mixing means; and rectifying the signal filtered by the low-frequency filtering means. Rectifying means for outputting a signal indicating the absolute value of the filtered signal; and integrating the signal indicating the absolute value output from the rectifying means to obtain a signal indicating the peak value of the signal indicating the absolute value. A reflected signal measuring device, comprising: integrating means for outputting; and calculating means for calculating a level of the reflected signal based on a signal indicating a peak value output from the integrating means. 4. A plurality of high-frequency signals having different frequencies are frequency-multiplexed by frequency multiplexing means, and a multiplex signal including the plurality of high-frequency signals is supplied to a load circuit via a transmission line. Voltage standing for measuring a voltage standing wave ratio for each of the high-frequency signals in the transmission line based on an incident signal transmitted to a load circuit and a reflected signal input from the load circuit back to the transmission line. A wave ratio measuring device, comprising: first coupling means provided on the transmission line for extracting a part of the incident signal; and second coupling means provided on the transmission line and extracting a part of the reflected signal. A third coupling means provided before the frequency multiplexing means and extracting a part of each of the high-frequency signals; and the third coupling means extracted by the third coupling means. Switching means for selectively switching and outputting a wave signal; modulation means for angle-modulating a signal output from the switching means with a low-frequency signal having a predetermined level to output a modulation signal; Mixing means for respectively outputting a signal indicating a multiplication result according to each phase difference between the signal extracted by the coupling means and the signal extracted by the second coupling means and the modulation signal output from the modulation means; A low-pass filter for blocking high-frequency components and filtering low-frequency components, respectively, of the signals output from the mixing unit; and rectifying the signals filtered by the low-pass filter. Rectifying means for outputting each signal indicating the absolute value of each of the filtered signals, and each signal indicating the absolute value by integrating each signal indicating the absolute value output from the rectifying means. Integrating means for outputting each signal indicating the peak value of the signal, and the level of the incident signal and the level of the reflected signal for each of the high-frequency signals based on each signal indicating the peak value output from the integrating means. First calculating means for calculating, and a voltage for each of the high-frequency signals in the transmission line based on the level of the incident signal and the level of the reflected signal for each of the high-frequency signals calculated by the first calculating means 2. A voltage standing wave ratio measuring device comprising: a second calculating means for calculating a standing wave ratio. 5. A plurality of high-frequency signals having mutually different frequencies are frequency-multiplexed by frequency multiplexing means, and a multiplexed signal including the plurality of high-frequency signals is supplied to a load circuit via a transmission line, and the transmission line transmits the multiplexed signal to the load circuit. A reflection signal measurement for measuring a level of the reflection signal for each of the high-frequency signals in the transmission line based on an incident signal transmitted to a load circuit and a reflection signal input from the load circuit back to the transmission line. A first coupling means provided on the transmission line for extracting a part of the reflected signal; and a second coupling provided before the frequency multiplexing means and extracting a part of the high-frequency signal. Means, switching means for selectively switching and outputting each of the high-frequency signals taken out by the second coupling means, and output from the switching means Means for angle-modulating a signal with a low-frequency signal having a predetermined level to output a modulation signal; a signal extracted by the first coupling means; and a modulation signal output from the modulation means. Mixing means for outputting a signal of a multiplication result according to the phase difference; low-frequency filtering means for blocking high-frequency components and filtering low-frequency components in the signal output from the mixing means; Rectifying means for rectifying the signal filtered by the means and outputting a signal indicating the absolute value of the filtered signal; and integrating the signal indicating the absolute value output from the rectifying means to obtain the absolute value. Integrating means for outputting a signal indicating the peak value of the signal to be indicated; and calculating means for calculating the level of the reflection signal for each of the high-frequency signals based on the signal indicating the peak value output from the integrating means. Reflected signal measuring apparatus, characterized in that the.