JPH0567906A - Automatic setting device for band pass filter - Google Patents

Abstract

PURPOSE:To set a center frequency automatically by inputting a reference signal whose frequency is equal to the center frequency to a band pass filter, converting the reflection frequency into an intermediate frequency, converting the frequency into a same frequency as that from a local oscillator, detecting the signal and controlling the center frequency so as to minimize the level. CONSTITUTION:A reference signal from a signal generator 71 is converted into a 1st intermediate frequency signal at a 1st frequency conversion circuit comprising a mixer 60 and a band pass filter 62 by using a signal having a frequency f1 from a local oscillator 61. On the other hand, when the reference signal is inputted to a band pass filter 30, a detection signal including the reference signal reflected is converted into a 2nd intermediate frequency signal at a 2nd frequency conversion circuit comprising a mixer 64 and a band pass filter 65 as a local oscillation signal, the 2nd intermediate frequency signal is detected to drive a stepping motor 33 so as to vary a variable capacitance VC of a dielectric resonator 31 in the filter 30 thereby almost minimizing the level. Thus, the center frequency of the filter 30 is controlled so as to minimize the level based on the detection signal thereby attaining automatic setting.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention sets the center frequency of a bandpass filter whose center frequency can be changed based on the center frequency of a signal passband to be set (hereinafter, simply referred to as the center frequency). The present invention relates to an automatic setting device for a bandpass filter that automatically sets a center frequency to be set.

[0002]

2. Description of the Related Art FIG. 17 is a block diagram of a first conventional automatic tuning type bandpass filter proposed in JP-A-1-105601.

In FIG. 17, an automatic tuning type bandpass filter of the first conventional example passes an input high frequency signal in one direction and an isolator 101 having a reflected power coupling terminal 111 and an isolator 101. Driving for changing the resonance frequency of the resonator 102 by moving the resonance frequency adjusting element (not shown) in the resonator 102 that operates as a band pass filter that band-filters the high frequency signal. The mechanism 103 and the control circuit 104 that detects the high frequency signal output from the reflected power coupling terminal 111 of the isolator 101 by the diode D1 and controls the drive mechanism 103 based on the detected signal.

In this automatic tuning type band pass filter, when a certain high frequency signal is passed through the band pass filter, a high frequency signal of reflected power detected by the diode D1 (hereinafter referred to as a reflected signal) is detected. Utilizing the fact that the level becomes minimum at the resonance frequency of the resonator 102, the control circuit 104 controls the drive mechanism 103 based on the reflection signal so that the level of the reflection signal becomes minimum. As a result, the resonator 102
The center frequency of the bandpass filter, which is approximately equal to the resonance frequency of, can be tuned to the frequency of the high frequency signal passing through the isolator 101.

[0005]

However, in the above-mentioned first conventional automatic tuning type bandpass filter, the level of the reflected signal is minimized at the resonance frequency of the resonator 102, so that the above-mentioned tuning is performed. Since the operation is performed, for example, when the sneak signal from another channel is input to the automatic tuning type bandpass filter when the automatic tuning type bandpass filter of FIG. When an interference wave signal close to the high frequency signal passing through 101 is input to the automatic tuning bandpass filter, there is a problem that the above tuning operation cannot be performed accurately.

The above-mentioned automatic tuning type bandpass filter is provided with one resonator 102. However, a plurality of resonators having different resonance frequencies and adjacent resonance frequencies are provided between the signal input end and output end. A parallel multistage bandpass filter (hereinafter referred to as a second conventional example) electrically connected in parallel is disclosed in Japanese Patent Laid-Open No. 3-72701.

When adjusting the center frequency and bandwidth of the parallel multistage bandpass filter of the second conventional example, a network analyzer is connected to the input and output ends of the parallel multistage bandpass filter, and the input end thereof is connected. At least after inputting a sweep signal for frequency sweeping the signal pass band of the band pass filter, the center frequency of each band pass filter is adjusted while observing the spectrum of the signal at the output end. That is, there is a problem in that the center frequency and bandwidth of the parallel multistage bandpass filter cannot be automatically adjusted, and they must be manually adjusted.

The first object of the present invention is to solve the above problems and to automatically adjust the center frequency of the bandpass filter to a desired set value with better accuracy than the conventional example. An object is to provide an automatic setting device for a bandpass filter. Further, a second object of the present invention is to provide an automatic tuning type bandpass filter capable of automatically adjusting the center frequency of the bandpass filter to a desired set value with better accuracy than the conventional example. To do. further,
A third object of the present invention is, even when, for example, when an automatic tuning type bandpass filter is used in an antenna sharing apparatus, even when a sneak signal from another channel is input to the automatic tuning type bandpass filter. Another object of the present invention is to provide an antenna sharing apparatus having a plurality of automatic tuning type bandpass filters, which can perform the tuning operation accurately.

A fourth object of the present invention is to automatically adjust the center frequency and bandwidth of the parallel multistage bandpass filter to desired setting values with better accuracy than the conventional example. An object of the present invention is to provide an automatic setting device for a parallel multi-stage bandpass filter that can be used. Further, a fifth object of the present invention is that the center frequency and the bandwidth of the parallel multi-stage band pass filter can be automatically adjusted to desired setting values with good accuracy as compared with the conventional example. An object is to provide a multistage self-tuning bandpass filter.
Still further, a sixth object of the present invention is that, for example, when a parallel multistage automatic tuning type bandpass filter is used in an antenna sharing apparatus, a signal sneaking from another channel is input to the automatic tuning type bandpass filter. Even if
An object of the present invention is to provide an antenna sharing apparatus equipped with a plurality of parallel multistage automatic tuning type bandpass filters capable of performing the above-mentioned tuning operation accurately.

[0010]

An automatic setting device for a bandpass filter according to a first aspect of the present invention has a center frequency of a bandpass filter whose center frequency can be changed to a predetermined set frequency. An automatic setting device for a band-pass filter that is automatically set, comprising: signal generating means for generating a reference signal having the predetermined set frequency; and the reference signal generated by the signal generating means for band-passing the signal. A coupling means for extracting a part of the signal reflected from the band pass filter when input to the filter, and the reference signal generated by the signal generating means, using a local oscillation signal having a predetermined local oscillation frequency. First
Frequency conversion means for converting the intermediate oscillation frequency signal into the intermediate frequency signal, and the signal extracted by the coupling means by using the first intermediate frequency signal converted by the first frequency conversion means. Second frequency conversion means for converting into a second intermediate frequency signal having the same frequency as the above, and the second intermediate frequency signal converted by the second frequency conversion means is detected to output a detection signal. It is characterized by further comprising: detection means; and control means for controlling the center frequency of the band pass filter so that the level of the detection signal is minimized based on the detection signal detected by the detection means.

An automatic setting device according to a second aspect is the automatic setting device according to the first aspect, further comprising input means for inputting the predetermined set frequency.

Further, the automatic setting device according to claim 3 is
The automatic setting device according to claim 1, further comprising receiving means for receiving the information of the predetermined set frequency from an external device.

Still further, the automatic setting device according to claim 4 is the automatic setting device according to claim 1, 2 or 3, wherein
The bandpass filter includes a resonator, the control means, the signal generating means so that the frequency of the reference signal matches the resonance frequency of the resonator based on the detection signal detected by the detection means. The frequency of the reference signal is controlled to change, and the frequency for controlling the bandpass filter so that the center frequency of the bandpass filter matches the predetermined set frequency based on the changed frequency of the reference signal. And a control means.

The automatic setting device according to a fifth aspect of the present invention is the automatic setting device according to the fourth aspect, wherein the bandpass filter is capable of changing an element constant that determines a center frequency of the bandpass filter. A certain frequency variable element, the control means, the element constant changing means for changing the element constant of the frequency variable element of the band pass filter, prior to the control of the center frequency of the band pass filter by the frequency control means. , Based on a pre-measured relationship between the center frequency of the band pass filter and the element constant of the frequency variable element, the element such that the center frequency of the band pass filter substantially matches the predetermined set frequency. Pre-frequency control means for controlling the constant changing means to change the element constant of the frequency variable element of the band pass filter. Characterized in that was.

Further, the automatic setting device according to claim 6 is
The automatic setting device according to claim 1, 2 or 3, wherein the band-pass filter includes a frequency variable element capable of changing an element constant that determines a center frequency of the band-pass filter, and the control means includes: An element constant changing means for changing the element constant of the frequency variable element of the band pass filter, and the element constant changing means for minimizing the level of the detected signal based on the detected signal detected by the detecting means. Is controlled to change the element constant of the frequency variable element of the bandpass filter, thereby controlling the center frequency of the bandpass filter.

Further, the automatic setting device according to claim 7 is the automatic setting device according to claim 6, wherein the control means further precedes the control of the center frequency of the band-pass filter by the frequency control means. , Based on a pre-measured relationship between the center frequency of the band pass filter and the element constant of the frequency variable element, the element such that the center frequency of the band pass filter substantially matches the predetermined set frequency. Pre-frequency control means for controlling the constant changing means to change the element constant of the frequency variable element of the band pass filter is provided.

An automatic tuning bandpass filter according to claim 8 is a bandpass filter capable of changing a center frequency, and the automatic tuning bandpass filter according to claim 1, 2, 3, 4, 5, 6 or 7. And a setting device.

Further, an antenna sharing device according to a ninth aspect is provided with a plurality of the automatic tuning type bandpass filters according to the eighth aspect, and a signal output from each bandpass filter in each of the automatic tuning type bandpass filters. It is characterized in that each of the output terminals of each of the above-mentioned automatic tuning type bandpass filters for outputting is electrically connected together.

According to a tenth aspect of the present invention, there is provided an automatic setting device for a parallel multi-stage band pass filter, wherein a plurality of band pass filters each capable of changing a center frequency are electrically connected in parallel. Based on the center frequency and the bandwidth to be set in the parallel multi-stage band pass filter, the calculating means for calculating the center frequency to be set in the band pass filter, and the center frequency calculated by the calculating means A signal generating means for generating each reference signal having, respectively, each of the reference signals generated by the signal generating means of the respective signals reflected from the respective bandpass filter when input to the respective bandpass filter The coupling means for extracting a part and the reference signals generated by the signal generating means are respectively subjected to predetermined local oscillation. First frequency conversion means for converting each of the first intermediate frequency signals using a local oscillation signal having a wave number, and each signal extracted by the coupling means is converted by the first frequency conversion means. Second frequency conversion means for converting each of the first intermediate frequency signals into each of the second intermediate frequency signals having the same frequency as the local oscillation frequency, and the second frequency conversion means. Based on the detection signals detected by the detection means and the detection means for detecting the second intermediate frequency signals and outputting the detection signals, the level of each detection signal is minimized. And a control means for controlling each center frequency of each band pass filter.

Further, the automatic setting device according to claim 11 is
The automatic setting device according to claim 10 is further provided with input means for inputting a center frequency and a bandwidth to be set in the parallel multistage bandpass filter.

Further, the automatic setting device according to claim 12 is the automatic setting device according to claim 10, further comprising:
The parallel multi-stage band pass filter is characterized by further comprising receiving means for receiving information on a center frequency and a bandwidth to be set from an external device.

Furthermore, an automatic setting device according to a thirteenth aspect is the automatic setting device according to the tenth, eleventh or twelfth aspect, wherein each of the band pass filters has a resonator, and the control means has the detection means. Changing the frequency of each of the reference signals by controlling the signal generating means so that the frequency of each of the reference signals matches the resonance frequency of each of the resonators based on each of the detected signals detected by Frequency control means for controlling the band pass filters so that the center frequencies of the band pass filters match the center frequencies to be set based on the changed frequencies of the reference signals. Is characterized by.

The automatic setting device according to claim 14 is
14. The automatic setting device according to claim 13, wherein each of the band pass filters includes a frequency variable element capable of changing an element constant that determines a center frequency of each of the band pass filters, and the control means includes: Element constant changing means for changing each element constant of the frequency variable element of each band pass filter, and the center of each band pass filter prior to the control of the center frequency of each band pass filter by the frequency control means. Based on a pre-measured relationship between the frequency and the element constant of each frequency variable element, the element constant is changed so that the center frequency of each of the band pass filters substantially matches each center frequency to be set. Pre-frequency control means for controlling the means to change the element constant of the frequency variable element of each band pass filter. And it said that there were pictures.

Furthermore, the automatic setting device according to a fifteenth aspect is the automatic setting device according to the tenth, eleventh or twelfth aspect, wherein each of the band pass filters has an element constant for determining a center frequency of each of the band pass filters. A frequency variable element capable of changing, the control means, the element constant changing means for changing each element constant of the frequency variable element of each of the band pass filter, and the detected by the detection means Based on each detection signal, the element constant changing means is controlled so that the level of each detection signal is minimized to change each element constant of the frequency variable element of each band pass filter, and thereby each band. And frequency control means for controlling each center frequency of the pass filter.

Furthermore, the automatic setting device according to claim 16 is the automatic setting device according to claim 15, wherein the control means further precedes the control of the center frequency of each of the band pass filters by the frequency control means. Based on the pre-measured relationship between the center frequency of each of the bandpass filters and the element constant of each of the frequency variable elements,
Pre-frequency for changing the element constant of the frequency variable element of each band pass filter by controlling the element constant changing means so that the center frequency of each band pass filter substantially matches each center frequency to be set. A control means is provided.

The parallel multistage automatic tuning type bandpass filter according to claim 17 is a parallel multistage bandpass filter in which a plurality of bandpass filters each capable of changing a center frequency are electrically connected in parallel. And claim 1.
The automatic setting device according to 0, 11, 12, 13, 14, 15 or 16 is provided.

Further, the antenna sharing device according to claim 18 is provided with a plurality of parallel multistage automatic tuning type bandpass filters according to claim 17, and each of the parallel multistage automatic tuning type bandpass filters includes The output terminals of the parallel multistage automatic tuning type bandpass filters for outputting the output signals are electrically connected together.

[0028]

In the automatic setting device for the bandpass filter according to claim 1 configured as described above, the signal generating means generates a reference signal having the predetermined setting frequency, and the coupling means is , A part of the signal reflected from the band pass filter when the reference signal generated by the signal generating means is input to the band pass filter. Then, the first frequency conversion means
The reference signal generated by the signal generating means,
After converting into a first intermediate frequency signal using a local oscillation signal having a predetermined local oscillation frequency, the second frequency conversion means converts the signal extracted by the coupling means into the first frequency conversion means. The first intermediate frequency signal converted by is used to convert to the second intermediate frequency signal having the same frequency as the local oscillation frequency. Further, after the detection means detects the second intermediate frequency signal converted by the second frequency conversion means and outputs a detection signal, the control means detects the detection signal detected by the detection means. Based on the signal, the center frequency of the bandpass filter is controlled so that the level of the detected signal is minimized. Here, when an interference wave signal having a frequency component sufficiently distant from the frequency of the reference signal is input to the output end of the bandpass filter, the interference wave signal is input to the input end of the bandpass filter. The frequency component of the interference wave signal is input to the second frequency conversion means via the second intermediate frequency conversion means, and the frequency component of the interference wave signal is sufficiently distant from the frequency of the reference signal. It is removed without being converted into a frequency signal, that is, it does not appear in the detection signal and does not affect the automatic setting operation. Therefore, the center frequency of the bandpass filter can be automatically set to the predetermined set frequency with a simple circuit configuration and with better accuracy than the conventional example.

In the automatic setting device according to the second aspect of the present invention, it is preferable that the automatic setting device further comprises an input means for inputting the predetermined set frequency. Thus, the center frequency to be set in the bandpass filter can be input using the input means.

Further, in the automatic setting device according to the third aspect of the invention, it is preferable that the automatic setting device further comprises a receiving means for receiving the information of the predetermined set frequency from an external device. As a result, information on the center frequency to be set in the bandpass filter can be received from the external device.

Still further, in the automatic setting device according to the fourth aspect, preferably, the bandpass filter includes a resonator, and the frequency control means of the control means has the detection signal detected by the detection means. The frequency of the reference signal is controlled on the basis of the above to change the frequency of the reference signal by controlling the signal generating means so as to match the resonance frequency of the resonator. The band pass filter is controlled so that the center frequency of the band pass filter matches the predetermined set frequency. Therefore, the center frequency of the band pass filter can be automatically set to the predetermined set frequency with better accuracy than in the conventional example.

Further, in the automatic setting device according to the present invention, preferably, the bandpass filter includes a frequency variable element capable of changing an element constant that determines a center frequency of the bandpass filter. , The pre-frequency control means of the control means, between the center frequency of the band pass filter and the element constant of the frequency variable element, prior to the control of the center frequency of the band pass filter by the frequency control means. Based on the pre-measured relationship of, the element constant changing means is controlled so that the center frequency of the band pass filter substantially matches the predetermined set frequency, and the element constant of the frequency variable element of the band pass filter is changed. To change. Therefore, prior to the control of the center frequency of the bandpass filter by the frequency control means, a coarse adjustment process is performed to substantially match the center frequency of the bandpass filter with the predetermined set frequency, whereby the automatic setting is performed. The operation can be performed at higher speed.

Further, in the automatic setting device according to the sixth aspect, preferably, the band pass filter includes a frequency variable element capable of changing an element constant that determines a center frequency of the band pass filter. The frequency control means of the control means controls the element constant changing means to minimize the level of the detection signal based on the detection signal detected by the detection means, and controls the frequency of the band pass filter. The element constant of the variable element is changed to control the center frequency of the bandpass filter. Therefore, the center frequency of the band pass filter can be automatically set to the predetermined set frequency with better accuracy than in the conventional example.

Further, in the automatic setting device according to claim 7, the pre-frequency control means of the control means has the bandpass filter prior to the control of the center frequency of the bandpass filter by the frequency control means. Based on a pre-measured relationship between the center frequency of the pass filter and the element constant of the frequency variable element, the element constant changing means such that the center frequency of the band pass filter substantially matches the predetermined set frequency. Is controlled to change the element constant of the frequency variable element of the band pass filter. Therefore, prior to the control of the center frequency of the bandpass filter by the frequency control means, a coarse adjustment process is performed to substantially match the center frequency of the bandpass filter with the predetermined set frequency, whereby the automatic setting is performed. The operation can be performed at higher speed.

According to an eighth aspect of the present invention, there is provided an automatic tuning type band pass filter, wherein a band pass filter capable of changing a center frequency is used.
Alternatively, an automatic tuning type bandpass filter can be configured by including the automatic setting device described in 7.

Further, in the antenna sharing device according to claim 9, a plurality of automatic tuning type band pass filters according to claim 8 are provided, and output from each band pass filter in each automatic tuning type band pass filter. Output signal,
By electrically connecting the output terminals of each of the automatic tuning type bandpass filters together, each of the automatic tuning type bandpass filters is not affected by a signal sneaking from another channel, and the automatic setting described above is performed. An antenna sharing device that can perform an operation can be configured.

In an automatic setting device for a parallel multistage bandpass filter according to a tenth aspect of the present invention, in the calculation means, a plurality of bandpass filters each capable of changing a center frequency are electrically connected in parallel. The center frequencies to be set in the band pass filters are calculated based on the center frequencies and the bandwidths to be set in the parallel multistage band pass filter. Then, the combining means extracts a part of each signal reflected from each band pass filter when each reference signal generated by the signal generating means is input to each band pass filter. Then, the first frequency converting means converts each of the reference signals generated by the signal generating means into each of the first intermediate frequency signals by using a local oscillation signal having a predetermined local oscillation frequency. And the second frequency conversion means uses the respective first intermediate frequency signals converted by the first frequency conversion means for the respective signals extracted by the coupling means, and has the same local oscillation frequency as the local oscillation frequency. To each second intermediate frequency signal having a frequency of. Further, the detection means detects the second intermediate frequency signals converted by the second frequency conversion means and outputs the detected signals, respectively, and then the control means detects the detection signals by the detection means. Based on the detected signals, the center frequencies of the band pass filters are controlled so that the levels of the detected signals are minimized. Here, when an interference wave signal having a frequency component sufficiently separated from the frequency of each of the reference signals is input to the output end of each of the bandpass filters, the interference wave signal of each of the bandpass filters is The frequency component of the interference wave signal is input to the second frequency conversion means through the input end, but since the frequency of the interference wave signal is sufficiently distant from the frequencies of the reference signals, the frequency component of the interference wave signal is It is removed without being converted into each second intermediate frequency signal, that is, it does not appear in each detection signal and does not affect the automatic setting operation. Therefore, the center frequency and the bandwidth of the parallel multistage bandpass filter can be automatically set to desired setting values with a simple circuit configuration and with better accuracy than the conventional example.

In the automatic setting device according to the eleventh aspect of the present invention, it is preferable that the automatic setting device further comprises input means for inputting a center frequency and a bandwidth to be set in the parallel multistage bandpass filter. Thereby, the center frequency and the bandwidth to be set in the parallel multistage bandpass filter can be input using the input means.

Further, in the automatic setting device according to the twelfth aspect of the present invention, it is preferable that the automatic setting device further comprises a receiving means for receiving information of a center frequency and a bandwidth to be set in the parallel multistage band pass filter from an external device. As a result, the center frequency and bandwidth information to be set in the parallel multistage bandpass filter can be received from the external device.

Still further, in the automatic setting device according to the thirteenth aspect, preferably, each of the band pass filters includes a resonator, and the frequency control means of the control means is detected by the detection means. The frequency of each of the reference signals is controlled based on each of the detected signals so that the frequency of each of the reference signals is changed so as to match the resonance frequency of each of the resonators. Based on the frequency of the reference signal, the band pass filters are controlled so that the center frequencies of the band pass filters match the center frequencies to be set. Therefore, with better accuracy than the conventional example,
The center frequency and the bandwidth of the parallel multistage bandpass filter can be automatically set to desired setting values.

Further, in the automatic setting device according to the fourteenth aspect, preferably, each of the band pass filters is variable in frequency so that an element constant for determining a center frequency of each of the band pass filters can be changed. The front frequency control means of the control means, prior to the control of the center frequency of each of the band pass filters by the frequency control means, the center frequency of each of the band pass filters and each of the frequency variable elements. Based on a pre-measured relationship with the element constant of, the element constant changing means is controlled so that the center frequency of each of the band pass filters substantially matches the center frequency to be set. The element constant of the frequency variable element of the band pass filter is changed. Therefore, prior to the control of the center frequency of each of the bandpass filters by the frequency control means,
Rough adjustment processing is performed to make the center frequencies of the band-pass filters approximately match the center frequencies to be set, whereby the automatic setting operation can be performed at a higher speed.

Further, in the automatic setting device according to the fifteenth aspect, preferably, each of the band pass filters is variable in frequency so that an element constant for determining a center frequency of each of the band pass filters can be changed. The frequency control means of the control means controls the element constant changing means such that the level of each detection signal is minimized based on each detection signal detected by the detection means. Each element constant of the frequency variable element of each band pass filter is changed, and thereby each center frequency of each band pass filter is controlled. Therefore, it is possible to automatically set the center frequency and the bandwidth of the parallel multistage bandpass filter to desired setting values with better accuracy than in the conventional example.

Further, in the automatic setting device according to the sixteenth aspect, preferably, the pre-frequency control means of the control means is prior to the control of the center frequency of each of the band pass filters by the frequency control means. , Based on the pre-measured relationship between the center frequency of each of the band pass filter and the element constant of each of the frequency variable element,
The element constant changing means is controlled to change the element constant of the frequency variable element of each of the band pass filters so that the center frequency of each of the band pass filters substantially matches each of the center frequencies to be set. Therefore, prior to the control of the center frequency of each of the band pass filters by the frequency control means, a coarse adjustment process is performed to substantially match the center frequency of each of the band pass filters with each of the center frequencies to be set. Thus, the automatic setting operation can be performed at higher speed.

Further, in the parallel multistage automatic tuning type bandpass filter according to claim 17, a parallel multistage bandpass filter in which a plurality of bandpass filters each capable of changing a center frequency are electrically connected in parallel. A parallel multistage automatic tuning type bandpass filter can be configured by including a filter and the automatic setting device according to claim 10, 11, 12, 13, 14, 15 or 16.

Further, in the antenna sharing device according to claim 18, a plurality of parallel multistage automatic tuning type bandpass filters according to claim 17 are provided, and each bandpass filter in each parallel multistage automatic tuning type bandpass filter. By electrically connecting the output terminals of each of the parallel multistage automatic tuning type bandpass filters, which outputs the signal output from the It is possible to configure an antenna sharing apparatus capable of performing the above-described automatic setting operation without being affected by the signal of.

[0046]

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

<First Embodiment> FIG. 1 is a block diagram of an automatic tuning type bandpass filter 2d according to a first embodiment of the present invention. The self-tuning bandpass filter 2d of the first embodiment includes a bandpass filter 30 including a dielectric resonator 31 and is to be set in the self-tuning bandpass filter 2d input using a keyboard 81. Based on the data of the center frequency (hereinafter referred to as the set frequency) fd, the built-in signal generator 71 is caused to generate a signal of the set frequency fd, and the signal is used as a reference signal to generate the center frequency of the bandpass filter 30. The feature is that the fc is automatically adjusted so as to substantially match the set frequency fd.

In the tuning operation of the bandpass filter 30 in the automatic tuning type bandpass filter 2d, after the output of the transmission signal output from the transmitter 1 is stopped,
A reference signal generated from the signal generator 71 is used as a first intermediate frequency signal by a first frequency conversion circuit including a mixer 60 and a band pass filter 62 using a local oscillation signal having a frequency f _L output from a local oscillator 61. Frequency signal,
On the other hand, when the reference signal is input to the bandpass filter 30, a signal including the reference signal reflected when reflected from the bandpass filter 30 (hereinafter referred to as a detection signal) is the first intermediate signal. using frequency signal as the local oscillation signal, and converted to a second intermediate frequency signal of frequency f _L by the second frequency converter circuit comprising the mixer 64 and bandpass filter 65 which only passes the frequency f _L, is converted The second intermediate frequency signal is detected, and based on the detected signal after detection, the level of the detected signal is substantially minimized, that is, the center frequency fc of the signal pass band of each band pass filter 30 is the above reference. Drive the stepping motor 33 that changes the variable capacitance VC of the dielectric resonator 31 in the bandpass filter 30 so as to approximately match the frequency fd of the signal. It is characterized by moving.

As shown in FIG. 1, the transmitter 1 outputs a signal having a predetermined constant level, for example, UHF.
The transmission signal of the band frequency f1 is output to the antenna 4 via the automatic tuning type bandpass filter 2d of this embodiment used as a transmission bandpass filter and the feeding line of the antenna system, and the transmission signal is transmitted from the antenna 4 to the antenna 4. Is emitted.

In the automatic tuning type bandpass filter 2d, the transmission signal output from the transmitter 1 is the isolator 1
It is input to the input terminal 20a of the directional coupler 20 via 0. The directional coupler 20 can combine a pass line that passes the distributed transmission signal, a transmission signal that is electromagnetically coupled to the pass line and passes, and a reference signal that is input to the input end 20r of the coupling line. Thus, the reference signal synthesizing coupling line is provided on the output end 20b side of the passing line of the directional coupler 20 at a predetermined distance from the passing line. The signal output from the output end 20b of the pass line of the directional coupler 20 is band-passed through the input end 21a and the output end 21b of the directional coupler 21 having the same configuration as the directional coupler 20. It is input to the input terminal T1 of the filter 30. Here, the directional coupler 21 is the directional coupler 20.
A part of a power of a reflected signal that is reflected from the circuit connected to the output end 21b and that is electromagnetically coupled to the passage line that passes the signal after passing through And a reflection signal detection coupling line for detecting a reflection signal which is provided on the output end 21b side of the directional coupler 21 at a predetermined distance from the passing line so that the reflection signal detection coupling line outputs It has an end 21r. The signal output from the output end 21r of the coupling line is input as a main signal to the main signal input terminal of the mixer 64 via the amplifier 76. Furthermore, the band pass filter 3
The signal output from the output terminal T2 of 0 is output to the antenna 4 via the feed line of the antenna system as described above.

The band pass filter 30 comprises the dielectric resonator 3
1 and has a center frequency fc. As shown in the equivalent circuit of FIG. 2, the dielectric resonator 31 in the band pass filter 30 is composed of two inductors L11 and L12, a variable capacitance VC and a loss resistance Ro which are connected in parallel, The inductance L11 is electromagnetically coupled to the input side coil L1 by inductive coupling + M,
On the other hand, the inductance L12 is electromagnetically coupled to the output side coil L2 of the band pass filter 30 by inductive coupling + M. In addition, one end of the input side coil L1 has an input terminal T1.
And the other end is connected to ground. One end of the output side coil L2 is connected to the output terminal T2, and the other end is connected to the ground. Further, the capacitance of the capacitance VC is controlled by the control circuit 50 as described later in detail.
It is changed by the stepping motor 33, which is controlled via the motor drive circuit 32.

FIG. 3 shows a sectional view of each band pass filter 30 having the dielectric resonator 31. As shown in FIG.
A cylindrical dielectric resonator 211 is placed on a support base 214 having the same linear expansion coefficient as that of the dielectric resonator 211 at the center of the cylindrical shield case 210. The dielectric resonator 211 is, for example, a ceramic dielectric resonator in which ZrSn is mixed with TiO ₂ as a main component, and the dielectric resonator 31 of this embodiment has about 886 in the TE _01δ mode which is the fundamental mode. It has a resonant frequency f _{0 of} 0.4 MHz. In addition, the dielectric resonator 21
Inside the first cylinder, a cylindrical dielectric tuning element 212 is provided supported by a shaft 215. Here, the shaft 215 is moved by the stepping motor 33 in the-direction of the arrow A1 and in the + direction of the arrow A2 opposite thereto. By moving the dielectric tuning element 212 in the electric field gradient of the dielectric resonator 211, the resonance frequency f ₀ of the dielectric resonator 211 can be finely adjusted.

FIG. 4 shows the relationship between the position of the dielectric tuning element 212 of the bandpass filter 30 of FIG. 3 and the center frequency fc of the bandpass filter 30 which is approximately equal to the resonance frequency f ₀ of the dielectric resonator 31. It is a graph. Here, g is the distance from the upper surface of the dielectric tuning element 212 to the inside of the upper surface of the shield case 210. As is clear from FIG.
By moving the dielectric tuning element 212 away from the upper surface of the shield case 210, that is, by increasing the distance g, the resonance frequency f ₀ of the dielectric resonator 211 changes substantially in inverse proportion to the distance g. Therefore, the resonance frequency when the dielectric resonator 211 is at a certain position is f
_{If the} center frequency to be set in the bandpass filter 30 is fss, the dielectric tuning element 212 should be moved in order to set the resonance frequency f ₀ of the dielectric resonator 31 to the set frequency fss. The distance lm is expressed by the following equation 1.

[0054]

[Number 1] lm = k (f ₀ -fss)

Here, k is a constant determined from the graph of FIG. In this embodiment, as will be described later in detail,
Is input to the stepping motor 33 to move the dielectric tuning element 212 in the band pass filter 30, and thereby the dielectric tuning element 212 in the band pass filter 30 is moved. The tuning process of the bandpass filter 30 can be performed so that the center frequency fc substantially matches the set frequency fss.

In FIG. 3, the shield case 210 is shown.
Is formed by baking a silver electrode on the outer surface of a cylindrical casing made of ceramic having the same linear expansion coefficient as that of the dielectric resonator 211 for electromagnetic shielding. As shown in FIG. 3, on the lower surface of the shield case 210, immediately below the outer edge of the cylinder of the dielectric resonator 211, at two positions facing each other and centered on the center of the cylinder, as shown in FIG. , The input side coil L of one turn, for example, so as to be coupled to the magnetic field of the dielectric resonator 211.
1 and an output side coil L2 are provided.

FIG. 5 shows frequency characteristics of the input end reflection coefficient S ₁₁ of the bandpass filter 30 when the output end of the bandpass filter 30 of FIGS. 2 and 3 is terminated by a terminating resistor having a predetermined impedance. It is a graph. As is apparent from FIG. 5, the reflection loss corresponding to the reflection coefficient S ₁₁ at the input end is minimum at the resonance frequency f ₀ of the dielectric resonator 31. In the present embodiment, the center frequency of the bandpass filter 30 is set as will be described later in detail using the characteristics of FIG.

Next, the automatic tuning type band pass filter 2d
Circuits of the signal processing system and the control system will be described with reference to FIG.

As shown in FIG. 1, the signal generator 71 has a PL
The signal generator includes an L circuit and can change the frequency of a generated sine wave reference signal. Signal generator 7
1 generates a reference signal of frequency fs having a predetermined signal level based on the data of frequency fs equal to the set frequency fd input from the CPU 51 of the control circuit 50 through the interface circuit 54, and the reference signal concerned. Is output to the input end 20r of the coupling line of the directional coupler 20 via the amplifier 72, the coupler 73, and the isolator 74.
The combiner 73 includes a branch terminal 73c that extracts a part of the power of the passing signal that is input from the amplifier 72, passes through the combiner 73, and is output to the isolator 74, and outputs a branch signal. The branch signal output from the branch terminal 73c is input to the main signal input terminal of the mixer 60 as the main signal. Further, the local oscillator 61 outputs a local oscillation signal of a sine wave having a predetermined local oscillation frequency f _L lower than the frequency fs of the reference signal and having a predetermined level to the local oscillation signal input terminal of the mixer 60. Mixer 60 composed of multipliers
Is a mixture of the branch signal of the reference signal input from the branch terminal 73 c of the coupler 73 and the local oscillation signal input from the local oscillator 61, and the multiplication is performed. Output to. Here, the mixer 60
The mixed signals output from fs + f _L and fs−f _{L are}
However, the band pass filter 62 includes
After passing only the component of the frequency fs−f _L (hereinafter, referred to as the first intermediate frequency signal) in the input mixed signal, the first intermediate frequency signal is passed through the amplifier 63,
The local oscillation signal is output to the local oscillation signal input terminal of the mixer 64.

In the automatic tuning type bandpass filter 2d, an interference wave signal from another wireless communication system, which is close to the set frequency fd but has a frequency f _I different from the set frequency fd, passes through the antenna 4. When input to the automatic tuning type bandpass filter 2d via
As shown in FIG. 1, the interference wave signal is output from the output end 21r of the bandpass filter 30 and the directional coupler 21 via the coupling line. On the other hand, at this time, the transmitter 1
No transmission signal is transmitted from the signal generator 71 and the signal generator 71 generates the reference signal of the set frequency fs as described above, the reference signal is the amplifier 72, the coupler 73, the isolator 74, and the directional coupling. The signal is input to the input terminal T1 of the bandpass filter 30 via the devices 20 and 21. At this time, as described with reference to FIG. 5, the reflected signal from the bandpass filter 30 is output from the input terminal T1, and the reflected signal is output via the coupling line of the directional coupler 21 at its output end 21r. Is output from. Therefore, in this case, from the output end 21r of the coupled line of the directional coupler 21, the frequency f
The detection signal including the components of s and f _I will be output. This detection signal is input to the main signal input terminal of the mixer 64 via the amplifier 76.

The mixer 64 composed of a multiplier mixes and multiplies the detection signal input from the amplifier 76 and the first intermediate frequency signal input from the amplifier 63, and multiplies the mixed signal. It outputs to the band pass filter 65. here,
The mixed signal output from the mixer 64 is fs + (f
s−f _L ) = − f _L , fs− (fs−f _L ) = f _L , f _I +
_{(Fs-f L), f} I - including (fs-f _L) frequency components, such as, band-pass filter 65, the component of the frequency f _L of the input after mixing signal (hereinafter, the second After passing only the intermediate frequency signal), the second intermediate frequency signal is output to the detection circuit 67 via the amplifier 66.
As described above, no matter what value the frequency fs takes, the frequency component of the second intermediate frequency signal is only the component of the local oscillation frequency f _L.

In the mixer 64, the level of the signal including the various frequencies after mixing is input to the mixer 64 from the output end 21r of the coupling line of the directional coupler 21 via the amplifier 76, as is known. Is proportional to the product of the levels of the detected signals of the frequencies fs and f _I and the level of the local oscillation signal of the local oscillation frequency (fs-f _L ) input from the amplifier 63 to the mixer 64, and Pass filter 65
The level of the second intermediate frequency signal after passing through
Is proportional to the product of the level of the detection signal of the frequency fs input to the mixer 64 from the level of the first intermediate frequency signal input to the mixer 64 from the amplifier 63. On the other hand, since the signal level of the local oscillation signal output from the local oscillator 61 is constant and the signal level of the reference signal output from the signal generator 71 is constant as described above, the second intermediate The level of the frequency signal is changed from the output end 21r of the coupling line of the directional coupler 21 to the mixer 6 via the amplifier 76.
It is proportional to the level of the detection signal of the frequency fs input to 4. Therefore, as described above, the frequency (fs-f _L )
Of the intermediate frequency signal by converting the detection signal into a second intermediate frequency signal by using the generated first intermediate frequency signal as a local oscillation signal. The level is independent of the level of the interference wave signal of frequency f _{I in} the detection signal.

The detection circuit 67 detects the input intermediate frequency signal, and then performs analog / digital conversion (hereinafter referred to as A / It is called D conversion.)
Output to the circuit 70. The A / D conversion circuit 70 converts the analog voltage signal detected from the intermediate frequency signal into a digital voltage signal and outputs the digital voltage signal to the CPU 51 via the interface circuit 57 in the control circuit 50.

As shown in FIG. 1, the control circuit 50 in the automatic tuning type bandpass filter 2d includes a bandpass filter 30.
Of the CPU 51 for executing the tuning process and controlling the dielectric resonator 31 in the band pass filter 30, and a control program for the tuning process and data necessary for executing the control program (for example, the band pass filter 30). Of the dielectric tuning element 212 of the dielectric resonator 31 inside the pre-measured resonance frequency f ₀ at a predetermined position described later, and FIG.
Is a coefficient k or the like in Equation 1 indicating the relationship of ) For storing in advance, and each interface circuit 5 used as a working area of the CPU 51.
R for storing data input via 7,80
AM53. The control circuit 50 further includes an interface circuit 54 connected to the signal generator 71, an interface circuit 56 connected to the stepping motor 33 via the motor drive circuit 32, and an A / D conversion circuit 7.
An interface circuit 57 connected to 0 and an interface circuit 80 connected to a keyboard 81 are provided. In the control circuit 50, the CPU 51 and the ROM 5
2, the RAM 53, and the interface circuits 54 to 57, 80 are connected via a bus 58. In the present embodiment, the center frequency fd to be set in the automatic tuning type bandpass filter 2d is transferred from the keyboard 81 to the RAM 53 via the interface circuit 80.
The process of taking in is performed by the interrupt process of the CPU 51.

The CPU 51 causes the signal generator 71 to generate a reference signal having a frequency fs equal to the set frequency fd, and then sets the resonance frequency f ₀ of the dielectric resonator 31 in the bandpass filter 30 to the frequency of the reference signal. Tuning processing is performed on the band-pass filter 30 that substantially matches fs. That is, in the tuning process, the A / D conversion circuit 70
The motor drive signal for driving the stepping motor 33 is supplied to the CPU 51 via the interface circuit 57 and the motor drive circuit 32 so that the level of the detection signal input to the CPU 51 via the interface circuit 57 becomes substantially minimum. It outputs to 33 and drives. Here, when the motor drive signal of the + polarity pulse is input to the stepping motor 33, the dielectric tuning element 212 in the band pass filter 30 is moved in the direction of arrow A2 as shown in FIG. Motor 33
-When a motor drive signal of negative polarity pulse is input,
The dielectric tuning element 212 in the bandpass filter 30 is moved in the direction of arrow A1. Thus, the capacitance of the variable capacitance VC is changed in the equivalent circuit of FIG. 2, by changing the resonance frequency f ₀ of the dielectric resonator 31, thereby, substantially equal center of the band-pass filter 30 to the resonance frequency f ₀ The frequency fc can be changed.
In the present embodiment, the control circuit 50 drives the stepping motor 33 so that the level of the detection signal output from the detection circuit 67 becomes approximately the minimum, and the resonance of the dielectric resonator 31 in the band pass filter 30. The frequency can be varied so that the center frequency fc of the bandpass filter 30, which is approximately equal to the resonance frequency f ₀ , is approximately equal to the frequency fs of the reference signal generated by the signal generator 71.

FIG. 6 is a flow chart showing the main routine of the tuning process of the control circuit 50 of the automatic tuning type band pass filter 2d shown in FIG. This is a process for automatically setting the center frequency fc of 1 to the set frequency fd input using the keyboard 81. In the initial state before the start of this main routine, the dielectric tuning element 212 of the dielectric resonator 31 in the bandpass filter 30 is located at an arbitrary distance g. In this main routine, step S103 and step S104
Is a coarse tuning process for changing the center frequency fc of the built-in band pass filter 30 to a frequency near the set frequency fd, and the processes from step S105 to step S107 are the band pass filter 3
The center frequency fc of 0 is changed from the frequency in the vicinity of the frequency fd after the coarse tuning processing to obtain the set frequency fd.
This is a fine tuning process for making the values approximately match.

When the power switch (not shown) of the control circuit 50 is turned on, the main routine of the tuning process of FIG. 6 is started. First, in step S101, the dielectric tuning element 212 in the band pass filter 30 is stepped. The motor 33 is driven and moved to a position of g = 4 [mm] (hereinafter referred to as a home position). That is, in this embodiment, the dielectric tuning element 212 in the band pass filter 30 is prevented from moving from the home position in the direction of the arrow A1 in each band pass filter 30 by a dielectric tuning element stopper (see FIG. (Not shown) is provided, and in step S101, the stepping motor 3
When a motor drive signal of a −polarity pulse is continuously input to 3 and each dielectric tuning element 212 is stopped at the home position by the stopper, a micro switch (not shown) provided at the home position. Is turned on, and at this time, the driving of each stepping motor 33 is stopped.
The resonance frequency f ₀ of each dielectric resonator 31 in the band pass filter 30 at the home position is 897 [MHz] which is measured in advance as shown in FIG. 4, and the data is stored in the RAM 53. It

Next, in step S102, it is judged using the keyboard 81 whether or not the data of the set frequency fd to be set in the automatic tuning type bandpass filter 2d is input, and when it is not input (step S102). (NO in step S102), the loop process of step S102 is repeated to enter the standby state. On the other hand, when the input is made (YES in step S102), step S10
Go to 3. Next, in step S103, the resonance frequency f stored in the RAM 53 is stored in order to perform the coarse tuning process.
_{Based on} the data of _{0 and} the data of the set frequency fd (= fss) to be set, the band pass filter 30
The moving distance l for moving the dielectric tuning element 212 in
Calculate m. Next, in step S104, the pulse driving signals having the number of pulses corresponding to the calculated moving distance lm are input to the stepping motor 33 to move the dielectric tuning element 212 in the bandpass filter 30. When the moving distance lm is positive, a pulse drive signal of positive polarity is input to the stepping motor 33, respectively.
Are moved in the direction of the arrow A2 by the moving distance lm, while when the moving distance lm is negative, a pulse driving signal of negative polarity is input to the stepping motor 33, whereby the dielectric tuning element 212 is moved. Is moved in the direction of arrow A1 by the moving distance lm. Thus, the rough tuning process is completed.

Further, in order to perform the fine tuning process, in step S105, the data of the set frequency fd is output to the signal generator 71 as the set frequency fs, and the signal generator 71 is output.
To generate a reference signal of the set frequency fs. Next, in step S106, the data of the set frequency fd is stored in the RAM 53 as the set frequency fss. further,
In step S107, the center frequency fc of the built-in bandpass filter 30 is changed from a frequency in the vicinity of the set frequency fd after the coarse tuning process, and a fine tuning process is performed to substantially match the set frequency fd (FIG. 7 and FIG. 8 and FIG. 9 to FIG. 12) are performed, and the process returns to step S102. Hereinafter, the rough tuning process and the fine tuning process are repeated each time the set frequency of the automatic tuning type bandpass filter 2d is newly input using the keyboard 81.

7 and 8 show the fine tuning process (step S107 in FIG. 6 and step S10 in FIG. 15 which will be described later).
The flowchart of the subroutine of S14) is shown.

As shown in FIG. 7, in step S21, the output voltage V1 input from the A / D conversion circuit 70 is measured and stored in the RAM 53. Then, in step S22, the stepping motor 33 receives one pulse of positive polarity. A minute motor drive signal is input to move the dielectric tuning element 212 in the + direction of arrow A2. Further, step S2
3, the output voltage V2 input from the A / D conversion circuit 70 is measured and stored in the RAM 53, and then it is determined in step S24 whether the output voltage V1 is larger than the output voltage V2 as shown in FIG. To do. After the output voltage V1 is larger than the output voltage V2 in step S24 (YES in step S24), the driving direction of the stepping motor 33, that is, the moving direction of the dielectric tuning element 212 is set to the + direction of arrow A2 in step S25. , And proceeds to step S27. On the other hand, step S24
In step S27, when the output voltage V1 is equal to or lower than the output voltage V2 (NO in step S24), the driving direction of the stepping motor 33, that is, the moving direction of the dielectric tuning element 212 is set to the-direction of arrow A1 in step S26, and then step S27. Proceed to.

Next, in step S27, a motor drive signal for one pulse having a polarity corresponding to the drive direction set in step S25 or S26 is input to the stepping motor 33, and the dielectric tuning element 2
12 is moved in the set driving direction. Then
After measuring the output voltage V3 input from the A / D conversion circuit 70 and storing it in the RAM 53 in step S28,
In step S29, it is determined whether the output voltage V2 is lower than the output voltage V3. In step S29, when the output voltage V2 is equal to or higher than the output voltage V3 (NO in step S29), the center frequency fc of the bandpass filter 30 has not yet become a frequency near the set frequency fs of the reference signal. Therefore, in step S30, the output voltage V3 is set as the output voltage V2 and R
After storing in AM53, the above steps S27 to S2
Since the processing of 9 is repeated, the process proceeds to step S27.

On the other hand, when the output voltage V2 is smaller than the output voltage V3 in step S29 (step S29).
In step S31, the stepping motor 33 is caused to input a motor drive signal for one pulse having a polarity corresponding to the drive direction opposite to the drive direction set in step S25 or S26 to the stepping motor 33. , The dielectric tuning element 212 is moved in a drive direction opposite to the drive direction set above. Accordingly, the center frequency fc of the bandpass filter 30
Is set to the set frequency fs of the reference signal with a frequency accuracy corresponding to one pulse for driving the stepping motor 33.
Almost matches. Thus, the fine tuning process is completed and the process returns to the main routine of FIG.

In the present embodiment, as described above, the first intermediate frequency signal having the frequency (fs-f _L ) is generated from the reference signal of the frequency fs by using the local oscillator 61, the mixer 60 and the band pass filter 62. Generated, the first generated
Of the second intermediate frequency signal by frequency-converting the above detection signal into a second intermediate frequency signal using a frequency conversion circuit including a mixer 64 and a bandpass filter 65 by using the intermediate frequency signal as the local oscillation signal. The level is independent of the level of the signal of the frequency f _I of the interference wave signal. The level of the detection signal obtained by detecting the second intermediate frequency signal is proportional to the output voltage input from the A / D conversion circuit 70 to the CPU 51 of the control circuit 50. Therefore, the output voltage of the A / D conversion circuit 70 is proportional to the level of the component of only the frequency fs in the detection signal output from the output end 21r of the coupling line of the directional coupler 21. That is, the frequency f of the detection signal
Since the dielectric resonator 31 in the bandpass filter 30 is controlled based on the output voltage of the A / D conversion circuit 70 that is proportional to the level of the component of s, as in the conventional example, for example, another wireless communication system. The tuning process can be performed without being affected by the interference wave signal that wraps around.

According to the experiments by the present inventor, by the tuning process composed of the coarse tuning process and the fine tuning process, an accuracy of less than about 10 kHz corresponding to one pulse signal for driving the stepping motor 33 is obtained. The center frequency fc of the built-in bandpass filter 30 can be made to match the set frequency fs of the reference signal output from the signal generator 71.

9 to 12 show fine tuning processing (step S107 in FIG. 6 and step S1 in FIG. 15 described later).
0, S14) shows a flowchart of a modified example of the subroutine.

As shown in FIG. 9, in step S131, the set frequency fss is stored in the RAM 53 as the initial set frequency fp for the signal generator 71. Next, in step S132, the output voltage V0 input from the A / D conversion circuit 70 is measured and stored in the RAM 53. Further, in step S133, the ROM 5 is determined in advance.
After the initial value Δfpo of the frequency change amount stored in 2 is stored in the RAM 53 as the frequency change amount Δfp, the frequency (fp + Δfp) is set to the frequency fs in step S134.
The data of the frequency fs is stored in the RAM 53 and is output to the signal generator 71 to generate the reference signal of the frequency fs. Next, in step S135, the output voltage V1 input from the A / D conversion circuit 70 is measured and the RAM is measured.
After storing in 53, the output voltage V0 is compared with the output voltage V1 in step S136 to determine whether the output voltage V0 is larger than the output voltage V1. If V0> V
If 1 (YES in step S136), in step S137, the frequency change flag FF indicating the changing direction of the frequency fs of the reference signal generated by the signal generator 71 is set to 1, and then step S14 in FIG.
Go to 1. On the other hand, if V0 ≦ V1 (step S1
(NO in 36), after resetting the frequency change flag FF to 0 in step S138, the process proceeds to step S141 in FIG.

As shown in FIG. 10, after the processing parameter J is reset to 0 in step S141, it is determined in step S142 whether the frequency change flag FF is 1. If the frequency change flag FF is 1 (YES in step S142), the frequency (fs + Δfp) is set to the frequency fs in step S143.
Stored in the RAM 53, the frequency fs
Is output to the signal generator 71 to generate the reference signal of the frequency fs, and then the process proceeds to step S145. on the other hand,
When the frequency change flag FF is 0 (step S14
2 is NO), and the frequency (fs-Δfp) is the frequency f
The frequency f is set as s and stored in the RAM 53.
After outputting the data of s to the signal generator 71 to generate the reference signal of the frequency fs, the process proceeds to step S145.

In step S145, the output voltage V2 input from the A / D conversion circuit 70 is measured and the RAM 53 is measured.
Stored in the output voltage V2 in step S146.
Is larger than the output voltage V1. Here, if V2 ≦ V1 (NO in step S146), the signal generator 7 is again moved in the same frequency changing direction.
In order to change the frequency of the reference signal generated by 1, the output voltage V2 stored in the RAM 53 in step S148 is stored in the RAM 53 as the output voltage V1, and then the process returns to step S142, and the step S142 is performed.
The subsequent processing is continued. On the other hand, if V2> V1 (YES in step S146), step S14
At 9, it is determined whether the processing parameter J is 2 or more.

If the processing parameter J is less than 2 (NO in step S149), the frequency fs of the reference signal is increased or decreased in two frequency changing directions (hereinafter referred to as two frequency changing directions). It is determined that the processing from step S142 to step S145 is not performed, and the process proceeds to step S151 in FIG.
It is determined that the processes up to 145 have been performed, and step S150
Proceed to. In step S150, the frequency fs of the reference signal and the set frequency f that substantially match the resonance frequency f _0.
It is determined whether the absolute value | fs-fss | of the difference from ss is smaller than a predetermined frequency error threshold value ε. If | fs-fss | <ε (step S15
If YES, the fine tuning process is completed with a desired accuracy within a predetermined error range, and the process returns to the original main routine. On the other hand, if | fs-fss | ≧ ε (NO in step S150), the frequency fs of the reference signal generated by the signal generator 71 is not within the predetermined error range, and thus step S161 in FIG. move on.

In step S151 of FIG. 11 branching from step S149, it is determined whether or not the frequency change flag FF is 1. If the frequency change flag FF is 1 (YES in step S151), the frequency change flag FF is reset to 0 in step S152, and then the process proceeds to step S154, while if the frequency change flag FF is 0 (step S151). In step S153, the frequency change flag FF is set to 1, and then the process proceeds to step S154.
After changing the frequency changing direction in steps S151 to S153, the value obtained by dividing the frequency changing amount Δfp by 2 is stored in the RAM 53 as the frequency changing amount Δfp to reduce the frequency changing amount Δfp in step S154. In step S155, 1 is added to the processing parameter J, the added value is stored in the RAM 53 as the processing parameter J, the process returns to step S142 in FIG. 10, and the processing from step S142 is repeated.

Further, by changing the frequency fs of the reference signal generated by the signal generator 71 in the processing up to step S150, the band pass filter 3 concerned is changed.
The resonance frequency f ₀ of the dielectric resonator 31 within 0 can be obtained, and the frequency fs of the reference signal before executing the process of step S161 of FIG. 12 branched from step S150 is the dielectric frequency in the band pass filter 30. Body resonator 3
Since it is almost equal to the resonance frequency f _{0 of} 1, the step S
In 161 the difference between the frequency fs of the reference signal generated by the signal generator 71 and the set frequency fss (fs-f
ss), the same formula as in the above equation 1, that is, l
After calculating the moving distance lm for moving the dielectric tuning element 212 using the calculation formula of m = k (fs-fss), pulse driving of the pulse number corresponding to the moving distance lm calculated above in step S162. A signal is input to the stepping motor 33 to move the dielectric tuning element 212. Next, in steps S163 to S165, a process of changing the changing direction of the frequency fs of the reference signal is performed. That is, in step S163, it is determined whether the frequency change flag FF is 1, and if the frequency change flag FF is 1 (YES in step S163), the frequency change flag FF is reset to 0 in step S164. , Go to step S166,
On the other hand, if the frequency change flag FF is 0 (NO in step S163), the frequency change flag FF is set to 1 in step S165, and then step S
Proceed to 166. In step S166, the value obtained by dividing the frequency change amount Δfp by 2 is set as the frequency change amount Δfp and R
After storing in AM53 and reducing the frequency change amount, FIG.
0 returns to step S141.

The modified example of the fine tuning processing shown in FIGS. 9 to 12 has a characteristic that the reflection signal from the band pass filter 30 shown in FIG. 5 becomes minimum at the resonance frequency f ₀ of the dielectric resonator 31. Is used to change the frequency fs of the reference signal generated by the signal generator 71 so that the frequency fs of the reference signal approaches the resonance frequency f _0, and the approached frequency fs is substantially equal to the resonance frequency f _0. After the resonance frequency f ₀ is calculated, the moving distance lm to move the dielectric tuning element 212 based on the calculated resonance frequency f ₀ and the set frequency fss is calculated and moved by the moving distance lm. Fine tuning processing is performed to automatically set the center frequency fc of the pass filter 30 to the set frequency fss.

In the fine tuning process shown in FIGS. 7 and 8, the fine tuning process is performed only by driving the stepping motor 33, but a modification of the fine tuning process shown in FIGS. 9 to 12. Then, the frequency fs of the reference signal generated by the signal generator 71 is changed to obtain the resonance frequency f ₀ of the dielectric resonator 31, and the stepping motor 3
3 is also used. Generally, the processing speed for driving the stepping motor 33 to move the dielectric tuning element 212 is compared with the processing speed for setting the frequency of the reference signal generated by the signal generator 71 including a PLL circuit to a predetermined frequency. Since it is slow, the fine tuning process of the latter modified example can execute the process faster.
Although 2 is used as a divisor for reducing the frequency change amount Δfp in steps S154 and S166, it may be a number larger than 1, such as 3, 4, or 5.

The initial value Δfpo of the predetermined frequency change amount used in step S133 is preferably about 30.
The frequency error threshold value ε used in step S150 is preferably 5 kHz to 10 kHz.
kHz. According to the simulation by the inventor,
When the coarse tuning process in FIG. 6 is completed, the set frequency fss
And the actual center frequency fc of the band-pass filter 30 is about 50 kHz to 100 kHz, but by performing the fine tuning process shown in FIG. 7 and FIG. 8 or FIG. 9 to FIG. The deviation is about 5 kHz to 10 kHz or less, and the center frequency of the bandpass filter 30 can be set more accurately than in the conventional example.

In the automatic tuning type bandpass filter 2d configured as described above, the directional coupler 21 is used to detect the detection signal. For example, the dielectric resonator in the bandpass filter 30 is used. 31 inductance L
It is also technically possible to provide the detection loop 11 with a detection loop so as to be coupled by dense or sparse inductive coupling to detect the detection signal. However, when a dense inductively coupled detection loop is provided, the dielectric resonator 31 including the detection loop is provided.
The unloaded Q (Q ₀ ) of the dielectric resonator 31 increases, which increases the insertion loss of the dielectric resonator 31.
The bandpass filter 30 including 1 has a drawback in that a desired sharp bandpass characteristic cannot be realized. On the other hand, when the detection loop of sparse inductive coupling is provided, the change in the level of the detection signal detected by the detection loop is small, and thus the change in the level of the detection signal input to the mixer 64 is small. Becomes
There is a drawback that the mixer 64 does not operate normally.
In order to avoid these drawbacks, in this embodiment,
A directional coupler 21 is used to detect the detection signal.

Further, in the above-mentioned automatic tuning type bandpass filter 2d, the tuning process of the bandpass filter 30 is not performed using the transmission signal output from the transmitter 1, but a signal is generated in the bandpass filter 2d. The bandpass filter 30 is provided with the converter 71, and the tuning process is performed for each bandpass filter 30 as described above using the reference signal generated by the signal generator 71. On the other hand, in the conventional example shown in FIG. 17, it is necessary to input a high frequency signal from an external circuit. That is, the present embodiment according to the present invention is characterized in that the tuning process can be performed without inputting a signal from an external circuit.

In the above embodiments, the data of the center frequency fd to be set is input by using the keyboard 81, but the present invention is not limited to this, and the center frequency fd of the external frequency control device such as another control circuit is input. An interface circuit of the receiving circuit or the control circuit 50 for receiving data may be provided, and the control circuit 50 may perform the tuning process based on the received data of the center frequency fd.

In the above embodiments, the band pass filter 30 is constructed by using the dielectric resonator 31, but the present invention is not limited to this, and various other bands capable of changing the center frequency are used. A pass filter may be used.

In the above embodiment, after performing the coarse tuning process in steps S103 and S104 of FIG.
Although the fine tuning process of the bandpass filter 30 is performed in steps S105 to S107, the present invention is not limited to this, and the fine tuning process may be performed only.

In the above embodiment, the stepping motor 33 is used to perform the digital tuning process.
The present invention is not limited to this, and a tuning process may be performed by controlling the output voltage of the low-pass filter 68 to a minimum using a motor driven by an analog signal.

In the above embodiment, the band-pass filter 62 applies the first intermediate frequency signal deviated from the frequency fs of the reference signal to the frequency side lower by the local oscillation frequency f _L of the local oscillation signal generated by the local oscillator 61. However, the present invention is not limited to this.
The first intermediate frequency signal deviated from the frequency fs of the reference signal to the higher frequency side by the local oscillation frequency f _L may be band-pass filtered by the band pass filter 62 and generated.

<Second Embodiment> FIG. 13 shows a parallel two-stage automatic tuning type bandpass filter 2 according to a second embodiment of the present invention.
FIG. 14 is a block diagram of an antenna sharing device 2 including a, 2b, and 2c, and FIG. 14 is a block diagram of the parallel two-stage automatic tuning type bandpass filter 2a of FIG. 13 and 14
In FIG. 1, the same components as those in FIG. 1 are designated by the same reference numerals.

Each of the parallel two-stage automatic tuning type bandpass filters 2a, 2b, 2c of this embodiment is electrically connected in parallel using the combiner 11 and the distributor 12, and each has one dielectric resonance. Band pass filter 30 including a filter 31
a, 30b, and each parallel two-stage automatic tuning type band pass filter 2a, 2 input using the keyboard 81.
Based on the center frequency fd of b and 2c and the data of the bandwidth ΔF, the center frequencies f1c and f2c to be set in the respective band pass filters 30a and 30b are calculated, and first based on the calculated center frequency f1c Signal generator 71 to generate a signal having the center frequency f1c, and using the signal as a reference signal, the band pass filter 30
After the center frequency fc of a is approximately matched with the center frequency f1c, the center frequency f2 is then stored in the built-in signal generator 71 based on the calculated center frequency f2c.
c signal is generated and tuned by using the signal as a reference signal so that the center frequency fc of the bandpass filter 30b substantially matches the center frequency f2c, whereby each parallel two-stage automatic tuning type bandpass filter is tuned. 2a, 2
It is characterized in that the center frequencies and bandwidths of b and 2c are automatically adjusted to the input data value.

Further, each bandpass filter 30 in each parallel two-stage automatic tuning type bandpass filter 2a, 2b, 2c.
In each tuning operation of a and 30b, a parallel two-stage automatic tuning type band pass filter (2a, 2b) that performs the tuning operation is performed.
transmitter (1a, 1) corresponding to one of b, 2c)
b, 1c), the output of the transmission signal output from the local oscillator 61 is stopped, and then the reference signal generated from the signal generator 71 is set to the local oscillation signal of the frequency f _L output from the local oscillator 61. Using the mixer 60 and the bandpass filter 6
A parallel two-stage automatic tuning type bandpass filter is used when the first reference frequency signal is converted into a first intermediate frequency signal by the first frequency conversion circuit consisting of two, and the reference signal is input to the respective bandpass filters 30a and 30b. 2b, 2c and the detection signal including the reference signal reflected from the band pass filters 30a, 30b and the signal passing through the band pass filters 30a, 30b from the band pass filter 3, and the first intermediate frequency signal The frequency f _L is used as a local oscillation signal by a second frequency conversion circuit including a mixer 64 and a band pass filter 65 that passes only the frequency f _L.
Of the second intermediate frequency signal, the converted second intermediate frequency signal is detected, and the level of the detected signal is substantially minimized based on the detected signal after detection, that is, each band pass. A stepping motor that changes the variable capacitance VC of the dielectric resonator 31 in each of the band pass filters 30a and 30b so that the center frequency fc of the signal pass band of the filters 30a and 30b substantially matches the frequency of the reference signal. It is characterized by driving 33a and 33b.

As shown in FIG. 14, each transmitter 1a, 1
b, 1c, which are respectively output from b and 1c and have a predetermined constant level, are transmitted signals of different frequencies f1, f2, f3 (f1 <f2 <f3) in the UHF band, respectively. After being passed through the two-stage automatic tuning type bandpass filters 2a, 2b, 2c, they are synthesized. Here, each parallel two-stage automatic tuning type band pass filter 2a, 2
The output terminals of b and 2c are electrically connected together. Next, each of the transmission signals passes through a frequency band including the frequencies f1, f2 and f3, and the transmission band pass filter 3
Each of the above-mentioned frequency-multiplexed transmission signals output to the antenna 4 via the antenna is radiated from the antenna 4. Here, the parallel two-stage automatic tuning type bandpass filters 2a, 2b, 2c have the same configuration. Therefore, the parallel two-stage automatic tuning type bandpass filter 2a will be described below in detail with reference to FIG.

As shown in FIG. 13, the signal output from the transmitter 1a is input to the input terminal of the distributor 11 via the isolator 10. The distributor 11 divides the input transmission signal into two, and outputs the divided transmission signal to the input end 20a of the directional coupler 20 and the input end 22a of the directional coupler 22.

The directional couplers 20 and 21 each have a first
The configuration is similar to those of the embodiment of FIG. Directional coupler 2
The signal output from the output end 20b of the 0 pass line is input to the input terminal T1a of the bandpass filter 30a via the input end 21a and the output end 21b of the directional coupler 21. In addition, the output end 21 of the coupled line of the directional coupler 21
The signal output from r is the switch SW2 as the main signal.
Is input to the main signal input terminal of the mixer 64 via the a-side and the amplifier 76. Further, the signal output from the output terminal T2a of the bandpass filter 30a is input to the first input terminal of the combiner 12.

On the other hand, the directional coupler 22 has a pass line for passing the distributed transmission signal, a transmission signal electromagnetically coupled to the pass line, and an input terminal 2 of the coupling line.
A reference signal synthesizing coupling line is provided on the output end 22b side of the pass line of the directional coupler 22 at a predetermined distance from the pass line so that the reference signal input to 2r can be synthesized. The signal output from the output end 22b of the pass line of the directional coupler 22 is band-passed through the input end 23a and the output end 23b of the directional coupler 23 having the same configuration as the directional coupler 22. It is input to the input terminal T1b of the filter 30b. Here, the directional coupler 23
Is a pass line that allows a signal after passing through the directional coupler 22 to be electromagnetically coupled to the pass line and the output terminal 2
The directional coupler 23 is separated from the passage line by a predetermined distance so that a part of the power of the reflected signal reflected and input from the circuit connected to 3b can be branched and taken out.
And a coupling line for reflection signal detection provided on the output end 23b side for detecting a reflection signal, and the coupling line for reflection signal detection has an output end 23r. Output end 23 of the coupled line
The signal output from r is the switch SW2 as the main signal.
Is input to the main signal input terminal of the mixer 64 via the b side and the amplifier 76. Further, the signal output from the output terminal T2b of the bandpass filter 30b is input to the second input terminal of the combiner 12.

The synthesizer 12 synthesizes the signals input to the first and second input terminals and outputs the synthesized signal to the bandpass filter 3. It should be noted that each band pass filter 30a, 3
0b each include a dielectric resonator 31 and are configured similarly to the bandpass filter 30 of the first embodiment. In addition,
Using a known impedance matching method, the inductance L1 and the input terminal T1a or T1 are connected from the ground end of the inductance L1 in each of the band pass filters 30a and 30b.
b and directional couplers 21, 20 or directional coupler 2
Each electrical length up to the distribution point of the distributor 11 via each of the pass lines 3 and 22, and the inductance L2 from the ground end of the inductance L2 in each band pass filter 30a, 30b.
And each electric length up to the combining point of the combiner 12 via the output terminal T2a or T2b is set to a predetermined electric length.

Next, the circuit of the signal processing system and the control system in the parallel two-stage automatic tuning type bandpass filter 2a is shown in FIG.
This will be described with reference to FIG.

As shown in FIG. 13, the signal generator 71 has P
A control circuit 5 is a signal generator that includes an LL circuit and can change the frequency of a generated sine wave reference signal.
Based on the data of the set frequency fs input from the CPU 51 of 0a via the interface circuit 54, a reference signal of the set frequency fs having a predetermined signal level is generated and the reference signal is supplied to the amplifier 72 and the coupler 73. It outputs to the common terminal of switch SW1 via. Switch S
The reference signal output from the a terminal of W1 is an isolator 7
Input terminal 20r of the coupling line of the directional coupler 20
To the input terminal 22r of the coupling line of the directional coupler 22 via the isolator 75. here,
Each of the switches SW1 and SW2 has a control circuit 50a.
The CPU 51 therein selectively switches to the a side or the b side via the interface circuit 55. Furthermore, the combiner 73 is configured similarly to the first embodiment, and the branch signal output from the branch terminal 73c is input to the main signal input terminal of the mixer 60 as the main signal.

The mixer 60, the local oscillator 61, the bandpass filter 62, and the amplifier 63 are respectively configured in the same manner as in the first embodiment, and the mixer 60 and the bandpass filter 6 are included.
A first intermediate frequency signal having a frequency fs-f _L component obtained by being converted by the frequency conversion circuit configured by 2 is input to the local oscillation signal input terminal of the mixer 64 via the amplifier 63. To be done.

As shown in FIG. 14, since the output terminals of the parallel two-stage automatic tuning type bandpass filters 2a, 2b, 2c are electrically connected together, for example, if the transmitter 1b,
When the respective transmission signals are transmitted from the 1c, the transmission signals are, as shown in FIG. 13, the combiner 12, the bandpass filter 30a or 30b and the directional coupler 21 or 2.
It is output from the output terminals 21r and 23r via the third coupling line. Further, at this time, when the transmission signal is not transmitted from the transmitter 1a and the signal generator 71 generates the reference signal of the set frequency fs as described above, the reference signal is the amplifier 72, the coupler. 73, the switch SW1, the isolator 74 or 75, the directional coupler 20 or 22, and the directional coupler 21 or 23.
0a or 30b, and at this time, as described with reference to FIG. 5, the reflected signal from the bandpass filter 30a or 30b is output from the input terminal T1a or T1b, and the reflected signal is a directional coupler. It is output from the output terminal 21r or 23r via the coupled line 21 or 23. Therefore, in this case, the detection signal including the components of the frequencies fs, f2, and f3 is output from the output end 21r or 23r of the directional coupler 21 or 23. This detection signal is input to the main signal input terminal of the mixer 64 via the switch SW2 and the amplifier 76.

The mixer 64 composed of a multiplier mixes and multiplies the detection signal input from the amplifier 76 with the local oscillation signal input from the amplifier 63, and multiplies the mixed signal by a band pass filter. Output to 65. Here, the mixed signal output from the mixer 64 is fs + (fs-f
_{L) = - f L, fs-} (fs-f L) = f L, f2 + (fs
-F _L ), f2- (fs-f _L ), f3 + (fs-
f _L ), f3- (fs-f _L ), and the like, but the band-pass filter 65 outputs only the second intermediate frequency signal which is the component of the frequency f _{L in} the input mixed signals. After passing, the second intermediate frequency signal is passed through the amplifier 66.
Is output to the detection circuit 67 via. As described above, no matter what value the frequency fs takes, the frequency component of the second intermediate frequency signal is only the component of the local oscillation frequency f _L.

In the mixer 64, the level of the signal including the various frequencies after mixing is, as is well known, the output end 21r or 23 of the coupling line of the directional coupler 21 or 23.
The mixer 6 from r via the switch SW2 and the amplifier 76.
4, the level of the detection signal of each frequency fs, f2, f3, and the first input from the amplifier 63 to the mixer 64
Is proportional to the product of the intermediate frequency signal levels of
The level of the second intermediate frequency signal after passing through the bandpass filter 65 is the level of the detection signal of the frequency fs input from the amplifier 76 to the mixer 64, and the level of the detection signal from the amplifier 63 to the mixer 6.
4 is proportional to the product of the levels of the first intermediate frequency signals input to the signal line 4. On the other hand, as described above, the signal level of the local oscillation signal output from the local oscillator 61 is constant, and
Since the signal level of the reference signal output from the signal generator 71 is constant, the level of the second intermediate frequency signal is
It is proportional to the level of the detection signal of the frequency fs input from the output end 21r or 23r of the coupled line of the directional coupler 21 or 23 to the mixer 64 via the switch SW2 and the amplifier 76. Therefore, as described above, the frequency (fs-f
_L ) is generated, and the detected first signal is frequency-converted into a second intermediate-frequency signal by using the generated first intermediate-frequency signal as a local oscillation signal. The level of the intermediate frequency signal is independent of the levels of the detection signals of the frequencies f2 and f3 of the other channels.

The detection circuit 67 detects the input intermediate frequency signal and then outputs it to the A / D conversion circuit 70 via a low pass filter (LPF) 68 having a predetermined cutoff frequency and an amplifier 69. . A / D conversion circuit 70
Converts the analog voltage signal detected from the intermediate frequency signal into a digital voltage signal and outputs the digital voltage signal to the CPU 51 via the interface circuit 57 in the control circuit 50a.

As shown in FIG. 13, the control circuit 50a in the parallel two-stage automatic tuning type bandpass filter 2a has a switch SW in comparison with the control circuit 50 of the first embodiment.
1, an interface circuit 55 connected to SW2. It should be noted that the CPU 51 uses the band pass filters 30.
The above tuning processes of a and 30b are executed to control the dielectric resonator 31 in the band pass filters 30a and 30b. Further, the interface circuit 56 is connected to the motor drive circuit 32.
a, 32b.

The CPU 51 uses the band pass filters 30a,
When performing each tuning process of 30b, the parallel 2 input by using the keyboard 81 as described later in detail.
Based on the center frequency fd and the bandwidth ΔF to be set in the stage automatic tuning type band pass filter 2a, the center frequencies f1c and f2c to be set in the respective band pass filters 30a and 30b are calculated using the following equations 2 and 3. To calculate. In this embodiment, the center frequency f to be set in the parallel two-stage automatic tuning type bandpass filter 2a.
The process of loading d and the bandwidth ΔF from the keyboard 81 into the RAM 53 via the interface circuit 80 is performed by the CPU
It is performed by the interrupt processing of 51.

[0110]

(2) f1c = fd-2a ₂ ΔF

[0111]

[Formula 3] f2c = fd + 2a ₂ ΔF

Here, a ₂ is preferably 0.8 <a ₂ <
It is in the range of 2.0, and each band pass filter 30a, 30
Depending on the load Q of the dielectric resonator 31 in b (Q _L) is a constant which is predetermined and previously stored in the ROM 52.

Next, the CPU 51 causes the signal generator 71 to generate a reference signal of frequency f1c, and then causes the resonance frequency f ₀ of the dielectric resonator 31 in the band pass filter 30a to approximately match the frequency f1c of the reference signal. After performing the tuning process (hereinafter referred to as the first tuning process) on the bandpass filter 30a, the frequency f2c is fed to the signal generator 71.
The tuning process for the band-pass filter 30b (hereinafter referred to as the second tuning) in which the resonance frequency f ₀ of the dielectric resonator 31 in the band-pass filter 30b is substantially matched with the frequency f2c of the reference signal after the reference signal is generated. Process).

That is, in the first tuning process, A
The motor drive signal for driving the stepping motor 33a is supplied to the interface circuit 56 and the motor drive circuit 32a so that the level of the detection signal input to the CPU 51 from the D / D conversion circuit 70 via the interface circuit 57 becomes substantially minimum. Via stepping motor 3
It outputs to 3a and drives. In the present embodiment, the control circuit 50a controls the stepping motor 33a so that the level of the detection signal output from the detection circuit 67 becomes substantially minimum.
Is driven to change the resonance frequency of the dielectric resonator 31 in the bandpass filter 30a, whereby the center frequency fc of the bandpass filter 30a substantially equal to the resonance frequency f ₀ is generated by the signal generator 71. The frequency f1c of the reference signal can be substantially matched.

In the second tuning process, the level of the detection signal input from the A / D conversion circuit 70 to the CPU 51 via the interface circuit 57 is almost the same as in the first tuning process. As described above, the motor driving signal for driving the stepping motor 33b is output to the stepping motor 33b via the interface circuit 56 and the motor driving circuit 32b to be driven. Here, the control circuit 50a drives the stepping motor 33b so that the level of the detection signal output from the detection circuit 67 becomes substantially minimum, and changes the resonance frequency of the dielectric resonator 31 in the bandpass filter 30b. Which causes the bandpass filter 30 to be approximately equal to the resonant frequency f _0.
The center frequency fc of b can be approximately matched with the frequency f2c of the reference signal generated by the signal generator 71.

By executing the first and second tuning processes, the parallel two-stage automatic tuning type band pass filter 2
The center frequency and the bandwidth of a can be automatically set to the respective data values fd and ΔF input using the keyboard 81.

FIG. 15 is a flow chart showing the main routine of the tuning process of the control circuit 50a of the parallel two-stage automatic tuning type bandpass filter 2a of FIG. 13, and this main routine performs the above-mentioned first and second tuning processes. By executing the center frequency and the bandwidth of the band pass filter 2a,
Each data value fd, ΔF input using the keyboard 81
This is a process for automatically setting to. In the initial state before the start of this main routine, the dielectric tuning element 212 of the dielectric resonator 31 in each of the band pass filters 30a and 30b is located at an arbitrary distance g, and
The output of the transmission signal output from the transmitter 1a is stopped. In this main routine, the processing of step S5 and step S6 is performed by each built-in band pass filter 30.
This is a coarse tuning process for changing the center frequencies fc of a and 30b to frequencies near the center frequencies f1c and f2c to be set, and the processes from step S7 to step S10 are the center of the built-in band pass filter 30a. This is a first fine tuning process for changing the frequency fc from a frequency in the vicinity of the frequency f1c after the rough tuning process to substantially match the frequency f1c, and step S11
The process from step S14 to the step S14 is a second fine adjustment for changing the center frequency fc of the built-in band pass filter 30b from a frequency in the vicinity of the frequency f2c after the coarse tuning process to substantially match the frequency f2c. It is a synchronization process.

When the power switch (not shown) of the control circuit 50a is turned on, the main routine of the tuning process shown in FIG. 15 is started. Element 2
12 is moved to the home position by driving the stepping motors 33a and 33b. That is, in the present embodiment, the dielectric tuning element 212 in each band pass filter 30a, 30b is prevented from moving in the direction of arrow A1 from the home position, so that each band pass filter 30 is not moved.
A dielectric tuning element stopper (not shown) is provided in each of a and 30b, and in step S1, the stepping motors 33a and 33b are continuously input with a negative polarity pulse motor drive signal to adjust each dielectric tuning. When the element 212 is stopped at the home position by the stopper, a micro switch (not shown) provided at the home position is turned on, and at this time, driving of the stepping motors 33a and 33b is stopped. The resonance frequencies f ₀₁ and f ₀₂ of the dielectric resonators 31 in the band pass filters 30a and 30b at the home position are 897 [MHz], which are measured in advance as shown in FIG.

Next, in step S2, 897 [MHz] is set as the data of the resonance frequency f ₀₁ of the dielectric resonator 31 in the current band pass filter 30a, and R is set.
Stored in AM53 and also current bandpass filter 3
897 [MHz] is set as the data of the resonance frequency f ₀₂ of the dielectric resonator 31 in 0b and stored in the RAM 53. Next, in step S3, the keyboard 81
By using the parallel two-stage automatic tuning type bandpass filter 2
In a, it is determined whether or not the data of the center frequency fd and the bandwidth ΔF to be set is input, and when the data is not input (NO in step S3), the loop process of step S3 is repeated to enter the standby state. When it is done (YES in step S3), the process proceeds to step S4. Next, in step S4, based on the input data of the center frequency fd and the bandwidth ΔF, the above-mentioned equation 2
After calculating the center frequencies to be set in the band-pass filters 30a and 30b, that is, the set frequencies f1c and f2c using Equation 3 and Equation 3, these data are stored in the RAM.
Store in 53.

Next, in step S5, in order to perform the coarse tuning process, the same is derived from the above equation 1 based on the data of the resonance frequencies f ₀₁ and f _{02 and} the data of the set frequencies f1c and f2c stored in the RAM 53. Next number 4
And the equation 5 are used to move the dielectric tuning element 212 in each of the band pass filters 30a and 30b, the moving distance lm.
Calculate a, lmb.

[0121]

[Number 4] lma = k (f ₀₁ -f1c)

[0122]

[Number 5] lmb = k (f ₀₂ -f2c)

Then, in step S6, the stepping motors 33a and 33b are supplied with respective pulse drive signals having the number of pulses corresponding to the calculated moving distances lma and lmb.
33b and input to each band pass filter 30a, 30
Move each dielectric tuning element 212 in b. When the moving distances lma and lmb are positive, the pulse drive signals of positive polarity are respectively supplied to the stepping motors 33a and 3b.
3b, which causes the dielectric tuning element 212
Is moved in the direction of the arrow A2 by the moving distances lma and lmb, while when the moving distances lma and lmb are negative, a pulse drive signal of negative polarity is input to the stepping motors 33a and 33b, respectively. , The dielectric tuning element 212 is moved in the direction of arrow A1 by the moving distances lma and lmb. Thus, the rough tuning process is completed.

Further, in order to perform the first fine tuning process, in step S7, the data of the set frequency f1c is output to the signal generator 71 as the oscillation frequency fs and the reference signal of the set frequency f1c is output to the signal generator 71. After generating
In step S8, the switches SW1 and SW2 are both switched to the a side. Then, in step S9,
R of the data of the set frequency f1c is set as the set frequency fss.
After storing in the AM 53, in step S10, the center frequency fc of the built-in bandpass filter 30a is changed from a frequency in the vicinity of the set frequency f1c after the coarse tuning process so as to substantially match the set frequency f1c. Fine tuning processing (FIGS. 7 and 8 and FIGS. 9 to 1)
See 2. ), The process proceeds to step S11.

Next, in order to perform the second fine tuning process, in step S11, the data of the set frequency f2c is output to the signal generator 71 as the oscillation frequency fs, and the signal generator 71 receives the reference signal of the set frequency f2c. After generation, in step S12, the switches SW1 and SW2
Are both switched to the b side. Next, in step S13, the data of the set frequency f2c is set to the set frequency fss.
After that, the center frequency fc of the built-in bandpass filter 30b is stored in the RAM 53 in step S14.
Is changed from a frequency in the vicinity of the set frequency f2c after the rough tuning process to make it substantially match the set frequency f2c (FIGS. 7 and 8 and 9).
See FIG. ), The process returns to step S3. Hereinafter, in the tuning process including the coarse tuning process and the first and second fine tuning processes, the center frequency and the bandwidth of the parallel two-stage automatic tuning type bandpass filter 2a are newly input using the keyboard 81. Every time it is done, it is repeated.

In the present embodiment, as described above, the first intermediate frequency signal having the frequency (fs-f _L ) is generated from the reference signal of the frequency fs by using the local oscillator 61, the mixer 60 and the band pass filter 62. Generated, the first generated
The intermediate frequency signal of 2 is used as a local oscillation signal, and the above detection signal is output to the second frequency by the mixer 64 and the band pass filter 65.
By converting the frequency of the second intermediate frequency signal into the intermediate frequency signal of
It is independent of the signal level of f3. The level of the detection signal detected from this intermediate frequency signal is proportional to the output voltage data input from the A / D conversion circuit 70 to the control circuit 50a. Therefore, the output voltage of the A / D conversion circuit 70 is the output terminal 2 of the coupling line of the directional coupler 21 or 23.
It is proportional to the level of the component of only the frequency fs in the detection signal output from 1r or 23r. That is, A / which is proportional to the level of the frequency fs component of the detection signal
Since the dielectric resonator 31 in the band-pass filters 30a and 30b is controlled based on the output voltage data of the D conversion circuit 70, as in the conventional example, components sneak from other channels, for example, components of frequencies f2 and f3. The tuning process can be performed without being affected by the above.

According to the experiments conducted by the present inventor, the accuracy of less than about 10 kHz corresponding to one pulse signal for driving the stepping motor 33a or 33b is obtained by the tuning process including the coarse tuning process and the fine tuning process. Is the center frequency fc of the built-in band pass filters 30a and 30b.
Can be made to match the set frequency fs of the reference signal output from the signal generator 71.

The parallel two-stage automatic tuning type bandpass filters 2b and 2c have the same configuration as the parallel two-stage automatic tuning type bandpass filter 2a, and each parallel two-stage automatic tuning type bandpass filter 2b. , 2c, the center frequencies of the built-in band pass filters 30a, 30b are respectively set frequencies f1c calculated based on the center frequencies and bandwidths of the band pass filters 2b, 2c input using the keyboard 81. , F2c, the tuning process is executed in the same manner.

In the parallel two-stage automatic tuning type bandpass filter 2a of this embodiment, two bandpass filters 30 are used.
While a and 30b use a parallel two-stage bandpass filter in which they are electrically connected in parallel, for example, a cascade multistage bandpass filter in which a plurality of bandpass filters are electrically connected in cascade is used. Can also be considered. However,
In the case of a cascaded multi-stage band pass filter, as is well known, since the resonance modes of a plurality of band pass filters are combined to realize the entire band pass characteristic, it is possible to realize a parallel two-stage or parallel multi-stage band pass filter. In addition, the band pass characteristics of the respective band pass filters cannot be simply overlapped to realize the entire band pass characteristic, and the tuning processing cannot be performed separately for each band pass filter as in the present embodiment. Therefore, this embodiment according to the present invention cannot be applied to a cascaded multistage bandpass filter.

Further, in the parallel two-stage automatic tuning type band pass filter 2a, the band pass filters 30a and 30b are not tuned by using the transmission signal output from the transmitter 1a, but the band pass filter is not used. Filter 2a
A signal generator 71 is provided therein, and the tuning process is performed on each of the bandpass filters 30a and 30b as described above using a reference signal generated by the signal generator 71. On the other hand, in the conventional example shown in FIG. 17, it is necessary to input a high frequency signal from an external circuit. That is, the present embodiment according to the present invention is characterized in that the tuning process can be performed without inputting a signal from an external circuit.

In the above embodiments, the directional coupler 2
0 and 22 are used as reference signals for each band pass filter 30.
However, the present invention is not limited to this, and the directional coupler 20, as shown in the parallel two-stage automatic tuning type bandpass filter 2aa of the modification shown in FIG.
22 and isolators 74 and 75, respectively,
A directional coupler 2 is provided between the isolator 10 and the distributor 11.
The directional coupler 24 having the same configuration as that of the directional couplers 0 and 22 may be provided, and the isolator 77 may be provided between the input terminal 24r of the reference signal synthesizing coupling circuit of the directional coupler 24 and the amplifier 72. In this case, it is not necessary to provide the switch SW1. In this modification, the transmission signal output from the transmitter 1a is input to the distributor 11 via the isolator 10 and the input end 24a and the output end 24b of the pass line of the directional coupler 24. The signal divided into two by the distributor 11 is directly input to the input end 21a of the directional coupler 21 and the input end 23r of the directional coupler 23. on the other hand,
The reference signal generated by the signal generator 71 is input to the input end 24r of the reference signal combining coupling line of the directional coupler 24 via the amplifier 72 and the isolator 77.

In the above embodiment, the data of the center frequency fd and the bandwidth ΔF to be set is input using the keyboard 81, but the present invention is not limited to this, and the external device such as another control circuit can be used. An interface circuit of the receiving circuit or the control circuit 50a for receiving each data of the center frequency fd and the bandwidth ΔF is provided, and the control circuit 50a, based on the received each data of the center frequency fd and the bandwidth ΔF, sets the frequency f1c, You may make it calculate f2c.

In the above embodiment, the coarse tuning process is performed in steps S5 and S6 of FIG. 15, and then the fine tuning process of each band pass filter 30a, 30b is performed in steps S10 and S14. The invention is not limited to this, and each band pass filter 30a, 30b may be configured to perform only the fine tuning process.

In the above embodiment, the motor drive circuit 32a and the stepping motor 33a necessary for performing the first tuning process, and the motor drive circuit 32b and the stepping motor 33b necessary for performing the second tuning process. However, the present invention is not limited to this, and one circuit and a changeover switch are provided instead of being separately provided, and the changeover switch is used to selectively select the first and second tuning processes. It may be configured to be used for.

In the above embodiment, the antenna sharing apparatus 2 shown in FIG. 14 has two band pass filters 30.
a, 30b are provided with three parallel two-stage automatic tuning type bandpass filters 2a, 2b, 2c, which are connected in parallel.
The present invention is not limited to this, and a plurality of the automatic tuning type bandpass filters 2d of the first embodiment shown in FIG. 1 may be provided and their output terminals may be connected.

In the above embodiments, the parallel two-stage automatic tuning type bandpass filters 2a, 2b and 2c in which the two bandpass filters 30a and 30b are connected in parallel have been described. However, the present invention can be applied to a parallel multistage automatic tuning type bandpass filter in which a plurality of bandpass filters 30 are connected in parallel.

For example, in the case of a parallel three-stage automatic tuning type bandpass filter provided with four bandpass filters 30, based on the center frequency fd to be set and the bandwidth ΔF input using the keyboard 81. , Next 6 and 7
Using Equation 8 and Equation 8, the center frequencies f1c, f2c, and f3c to be set in each band pass filter 30 can be calculated.

[0138]

(6) f1c = fd-2a ₃ ΔF

[0139]

[Formula 7] f2c = fd + 2b ₃ ΔF

[0140]

[Formula 8] f3c = fd + 2c ₃ ΔF

[0141] Here, the constant a _3, b _3, c ₃ is preferably the _{positive, 0.8 <a 3 ≒ c 3} <2.0, and │b ₃ │«a ₃
, The dielectric resonator 3 in each bandpass filter
It is a constant that is predetermined depending on the first load Q (Q _L).

For example, in the case of a parallel four-stage automatic tuning type bandpass filter provided with four bandpass filters 30, based on the center frequency fd and the bandwidth ΔF to be set which are input using the keyboard 81. , The center frequencies f1c, f2c, f3c, f4c to be set in each band pass filter 30 using the following equations 9 to 12.
Can be calculated.

[0143]

[Formula 9] f1c = fd-2a ₄ ΔF

[0144]

[Number 10] f2c = fd-2b ₄ ΔF

[0145]

F3c = fd + 2c ₄ ΔF

[0146]

[Formula 12] f4c = fd + 2d ₄ ΔF

Here, each positive constant a ₄ , b ₄ , c ₄ , d ₄ is preferably in the range of 0.2 <b ₄ ≈c ₄ <a ₄ ≈d ₄ <2.0, and it is a constant that is predetermined depending on the load Q of the dielectric resonator 31 of the band-pass the filter (Q _L).

Similarly, in the case of a parallel multistage automatic tuning type bandpass filter having five or more bandpass filters 30, each center frequency to be set in each bandpass filter 30 is calculated in the same manner. be able to.

In the above embodiments, the bandpass filters 30a and 30b are connected in parallel via the distributor 11 and the combiner 12. Here, the band pass filter 3
The adjustment operation of the center frequency setting process of 0a or 30b is
If the load connected to the band pass filter to be processed is greatly affected, a changeover switch for disconnecting the load may be provided during the setting process of the center frequency. That is, in the embodiment of FIG. 13, the changeover switch for disconnecting the bandpass filter 30a from the load is set to the input terminals of the distributor 11 and the directional coupler 20 in order to set the center frequency of the bandpass filter 30a. 20a and between the output terminal T2a of the bandpass filter 30a and the combiner 12. Further, in order to set the center frequency of the bandpass filter 30b, a changeover switch for disconnecting the bandpass filter 30b from the load is provided at the input end 22a of the distributor 11 and the directional coupler 22.
And the output terminal T2 of the bandpass filter 30b.
It may be provided between b and the combiner 12. Further, in the modification of FIG. 16, the changeover switch for disconnecting the bandpass filter 30a from the load is set to the input terminals of the distributor 11 and the directional coupler 23 for the setting process of the center frequency of the bandpass filter 30a. 23a and between the output terminal T2a of the bandpass filter 30a and the combiner 12. Further, for the setting process of the center frequency of the bandpass filter 30b, the changeover switch for disconnecting the bandpass filter 30b from the load is connected to the distributor 1
1 may be provided between the input terminal 21a of the directional coupler 21 and between the output terminal T2b of the bandpass filter 30b and the combiner 12.

[0150]

As described in detail above, according to the automatic tuning apparatus for the bandpass filter according to the first aspect of the present invention, the automatic tuning device has a predetermined set frequency which is the center frequency to be set in the bandpass filter. A reference signal is generated, a part of the signal reflected from the bandpass filter when the generated reference signal is input to the bandpass filter is extracted, and the generated reference signal is stored in a predetermined local area. After converting to a first intermediate frequency signal using a local oscillation signal having an oscillation frequency, the extracted signal is
The converted first intermediate frequency signal is converted into a second intermediate frequency signal having the same frequency as the local oscillation frequency, and the converted second intermediate frequency signal is detected. Then, the center frequency of the band pass filter is controlled so that the level of the detected signal is minimized based on the detected detected signal. Here, when an interference wave signal having a frequency component sufficiently distant from the frequency of the reference signal is input to the output end of the bandpass filter, the interference wave signal is input to the input end of the bandpass filter. The frequency of the interference wave signal is sufficiently distant from the frequency of the reference signal.
The frequency component of the interference wave signal is removed without being converted into the second intermediate frequency signal, that is, it does not appear in the detection signal and does not affect the automatic setting operation. Therefore, there is an advantage that the center frequency of the band pass filter can be automatically set to the predetermined set frequency with a simple circuit configuration and with better accuracy than the conventional example.

The automatic tuning type band pass filter according to claim 8 is a band pass filter capable of changing the center frequency, and the band pass filter according to claim 1, 2, 3, 4, 5, 6.
Alternatively, an automatic tuning type bandpass filter can be configured by including the automatic setting device described in 7.

Further, in the antenna sharing device according to claim 9, a plurality of automatic tuning type band pass filters according to claim 8 are provided, and output from each band pass filter in each automatic tuning type band pass filter. Output signal,
By electrically connecting the output terminals of each of the automatic tuning type bandpass filters together, each of the automatic tuning type bandpass filters is not affected by a signal sneaking from another channel, and the automatic setting described above is performed. An antenna sharing device that can perform an operation can be configured.

According to the automatic setting device for a parallel multistage bandpass filter according to a tenth aspect of the present invention, a plurality of bandpass filters each capable of changing the center frequency are electrically connected in parallel. Based on the center frequency and the bandwidth to be set in the parallel multi-stage band pass filter, the respective center frequencies to be set in the respective band pass filters are calculated, and each of the center frequencies is calculated. Generating a reference signal, extracting a part of each signal reflected from each of the band pass filters when inputting each of the generated reference signals to each of the band pass filters, and then generating the reference signal Each reference signal is converted into each first intermediate frequency signal by using a local oscillation signal having a predetermined local oscillation frequency, and then the reference signal is extracted. Each of the signals is converted into each second intermediate frequency signal having the same frequency as the local oscillation frequency using each of the converted first intermediate frequency signals, and each of the converted respective After detecting the second intermediate frequency signal and outputting each of the detected signals, based on each of the detected detected signals, the level of each detected signal is minimized in each of the band pass filters. Control the center frequency. Here, when an interference wave signal having a frequency component sufficiently separated from the frequency of each of the reference signals is input to the output end of each of the bandpass filters, the interference wave signal of each of the bandpass filters is The frequency component of the interference wave signal is input to the second frequency conversion means through the input end, but since the frequency of the interference wave signal is sufficiently distant from the frequencies of the reference signals, the frequency component of the interference wave signal is It is removed without being converted into each second intermediate frequency signal, that is, it does not appear in each of the above detection signals,
It does not affect the automatic setting operation. Therefore,
The center frequency and the bandwidth of the parallel multistage bandpass filter can be automatically set to desired setting values with a simple circuit configuration and with better accuracy than the conventional example.

Further, in the parallel multistage automatic tuning type bandpass filter according to claim 17, a parallel multistage bandpass filter in which a plurality of bandpass filters each capable of changing a center frequency are electrically connected in parallel. A parallel multistage automatic tuning type bandpass filter can be configured by including a filter and the automatic setting device according to claim 10, 11, 12, 13, 14, 15 or 16.

Further, in the antenna sharing device according to claim 18, a plurality of parallel multistage automatic tuning type bandpass filters according to claim 17 are provided, and each bandpass filter in each parallel multistage automatic tuning type bandpass filter. By electrically connecting the respective output terminals of the parallel multistage automatic tuning type bandpass filters, which output the signal output from the parallel multistage automatic tuning type bandpass filters, the parallel multistage automatic tuning type bandpass filters are sneaked from other channels. It is possible to configure an antenna sharing apparatus capable of performing the above-described automatic setting operation without being affected by the signal of.

[Brief description of drawings]

FIG. 1 is a block diagram of an automatic tuning type bandpass filter according to a first embodiment of the present invention.

FIG. 2 is a circuit diagram showing an equivalent circuit of a bandpass filter including the dielectric resonator shown in FIG.

3 is a cross-sectional view of the bandpass filter of FIG.

4 is a graph showing the relationship between the position of a dielectric tuning element of the bandpass filter of FIG. 3 and the center frequency.

5 is a graph showing frequency characteristics of an input end reflection coefficient S ₁₁ of the bandpass filters of FIGS. 2 and 3. FIG.

6 is a flowchart showing a main routine of a control flow of a control circuit of the automatic tuning type bandpass filter shown in FIG.

FIG. 7 is a flowchart showing a first part of a sub-routine of the fine tuning process of FIGS. 6 and 15.

FIG. 8 is a flowchart showing a second part of the sub-routine of the fine tuning process of FIGS. 6 and 15.

9 is a flowchart showing a first part of a subroutine of a modified example of the fine tuning process of FIGS. 6 and 15. FIG.

10 is a flowchart showing a second part of a subroutine of a modified example of the fine tuning process of FIGS. 6 and 15. FIG.

FIG. 11 is a flowchart showing a third part of a subroutine of a modified example of the fine tuning process of FIGS. 6 and 15.

FIG. 12 is a flowchart showing a fourth part of a subroutine of a modified example of the fine tuning process of FIGS. 6 and 15.

FIG. 13 is a block diagram of a parallel two-stage automatic tuning type bandpass filter according to a second embodiment of the present invention.

14 is a block diagram of an antenna sharing apparatus provided with three parallel two-stage automatic tuning type band pass filters of FIG. 13. FIG.

15 is a flowchart showing a main routine of a control flow of a control circuit of the parallel two-stage automatic tuning type bandpass filter shown in FIG.

FIG. 16 is a block diagram of a parallel two-stage automatic tuning type bandpass filter which is a modification of the second embodiment of FIG.

FIG. 17 is a block diagram of a conventional automatic tuning type bandpass filter.

[Explanation of symbols]

1, 1a, 1b, 1c ... Transmitter, 2 ... Antenna sharing device, 2a, 2b, 2c, 2aa ... Parallel two-stage automatic tuning type bandpass filter, 2d ... Automatic tuning type bandpass filter, 11 ... Distributor, 12 ... combiner, 20, 21, 22, 23, 24 ... directional coupler, 30, 30a, 30b ... band pass filter (BPF), 31 ... dielectric resonator, 32, 32a, 32b ... motor drive circuit, 33 , 33a, 33b ... Stepping motor, 50, 50a ... Control circuit, 51 ... CPU, 52 ... ROM, 53 ... RAM, 60, 64 ... Mixer, 61 ... Local oscillator, 62, 65 ... Bandpass filter (BPF), 67 ... Detection circuit, 70 ... A / D conversion circuit, 71 ... Signal generator, 73 ... Combiner, 54, 55, 56, 57, 80 ... Interface circuit, 81 ... Keyboard , 211 ... dielectric resonator 212 ... dielectric tuning elements, SW1, SW2 ... switch.

Front page continuation (72) Inventor Hiroyuki Kubo 226-10 Tenjin Tenjin, Nagaokakyo, Kyoto Murata Manufacturing Co., Ltd.

Claims (18)

[Claims] 1. An automatic setting device for a band-pass filter, which automatically sets the center frequency of a band-pass filter capable of changing the center frequency to a predetermined set frequency, wherein Signal generating means for generating a reference signal having, and coupling means for extracting a part of the signal reflected from the bandpass filter when the reference signal generated by the signal generating means is input to the bandpass filter, The reference signal generated by the signal generating means,
First frequency conversion means for converting into a first intermediate frequency signal using a local oscillation signal having a predetermined local oscillation frequency; and the signal extracted by the coupling means is converted by the first frequency conversion means. And second frequency conversion means for converting the first intermediate frequency signal into a second intermediate frequency signal having the same frequency as the local oscillation frequency; and the second frequency conversion means for converting the second intermediate frequency signal. Second
Detecting means for detecting the intermediate frequency signal and outputting the detected signal; and controlling the center frequency of the band pass filter so that the level of the detected signal is minimized based on the detected signal detected by the detecting means. An automatic setting device for a bandpass filter, comprising: 2. The automatic setting device according to claim 1, further comprising input means for inputting the predetermined set frequency. 3. The automatic setting device according to claim 1, further comprising receiving means for receiving information on the predetermined set frequency from an external device. 4. The bandpass filter comprises a resonator,
The control means changes the frequency of the reference signal by controlling the signal generation means so that the frequency of the reference signal matches the resonance frequency of the resonator based on the detection signal detected by the detection means. A frequency control means for controlling the bandpass filter so that the center frequency of the bandpass filter matches the predetermined set frequency based on the changed frequency of the reference signal. The automatic setting device according to claim 1, 2 or 3. 5. The band pass filter includes a frequency variable element capable of changing an element constant that determines a center frequency of the band pass filter, and the control means includes a frequency variable element of the band pass filter. Element constant changing means for changing the element constant of, and prior to the control of the center frequency of the bandpass filter by the frequency control means, between the center frequency of the bandpass filter and the element constant of the frequency variable element Based on the relationship measured in advance, the element constant changing means is controlled to change the element constant of the frequency variable element of the bandpass filter so that the center frequency of the bandpass filter substantially matches the predetermined set frequency. 5. The automatic setting device according to claim 4, further comprising a front frequency control unit for controlling the frequency. 6. The bandpass filter includes a frequency variable element capable of changing an element constant that determines a center frequency of the bandpass filter, and the control means includes a frequency variable element of the bandpass filter. Of the band pass filter by controlling the element constant changing means so that the level of the detection signal is minimized based on the detection signal detected by the detection means. 4. The automatic setting device according to claim 1, further comprising frequency control means for changing the element constant of the frequency variable element to control the center frequency of the bandpass filter. 7. The control means further comprises, prior to the control of the center frequency of the band pass filter by the frequency control means, a pre-set value between the center frequency of the band pass filter and the element constant of the frequency variable element. Based on the measured relationship, the element constant changing means is controlled to change the element constant of the frequency variable element of the bandpass filter so that the center frequency of the bandpass filter substantially matches the predetermined set frequency. 7. The automatic setting device according to claim 6, further comprising front frequency control means. 8. An automatic tuning comprising: a bandpass filter capable of changing a center frequency; and the automatic setting device according to claim 1, 2, 3, 4, 5, 6 or 7. Type bandpass filter. 9. Each of the automatic tuning bandpass filters according to claim 8, comprising a plurality of the automatic tuning type bandpass filters, and outputting a signal output from each bandpass filter in each of the automatic tuning type bandpass filters. An antenna sharing apparatus, wherein each output terminal of a pass filter is electrically connected together. 10. A parallel multistage bandpass filter in which a plurality of bandpass filters each capable of changing a center frequency are electrically connected in parallel, based on a center frequency and a bandwidth to be set. Calculation means for calculating each of the center frequencies to be set in each bandpass filter, signal generating means for generating each reference signal having each center frequency calculated by the calculating means, and signal generation means for generating the reference signals. The reference signal generated by the signal generating means, and a coupling means for extracting a part of each signal reflected from each bandpass filter when each of the reference signals is input to each bandpass filter. A first frequency that is converted into each first intermediate frequency signal by using a local oscillation signal having a predetermined local oscillation frequency. The number conversion means and each signal extracted by the combining means,
Second frequency converting means for converting each of the first intermediate frequency signals converted by the first frequency converting means into each second intermediate frequency signal having the same frequency as the local oscillation frequency; The detection means for detecting the second intermediate frequency signals converted by the second frequency conversion means and outputting the detection signals, and the detection signals detected by the detection means, respectively. An automatic setting device for a parallel multi-stage band pass filter, comprising: a control means for controlling each center frequency of each band pass filter so that the level of each detected signal is minimized. 11. The automatic setting device according to claim 10, further comprising input means for inputting a center frequency and a bandwidth to be set in the parallel multistage bandpass filter. .. 12. The automatic setting device further comprises receiving means for receiving information on a center frequency and a bandwidth to be set in the parallel multi-stage bandpass filter from an external device. Automatic setting device. 13. Each of the band pass filters includes a resonator, and the control means controls the frequencies of the reference signals based on the detection signals detected by the detection means to resonate the resonators. The frequency of each of the reference signals is changed by controlling the signal generating means so as to match the frequency, and the center frequency of each of the band pass filters is set based on the changed frequency of each of the reference signals. 13. The automatic setting device according to claim 10, 11 or 12, further comprising frequency control means for controlling each of the band pass filters so as to match each of the center frequencies to be powered. 14. The band pass filters are respectively
The frequency variable element capable of changing the element constant that determines the center frequency of each of the band pass filters, the control means is an element that changes each element constant of the frequency variable element of each of the band pass filters Prior to the control of the center frequency of each of the band pass filters by the constant changing means and the frequency control means, a pre-measurement between the center frequency of each of the band pass filters and the element constant of each of the frequency variable elements is performed. Based on the relationship, the element constant of the frequency variable element of each band pass filter by controlling the element constant changing means so that the center frequency of each of the band pass filters substantially matches the respective center frequency to be set. 14. The automatic setting device according to claim 13, further comprising front frequency control means for changing the frequency. 15. The band pass filters are respectively
The frequency variable element capable of changing the element constant that determines the center frequency of each of the band pass filters, the control means is an element that changes each element constant of the frequency variable element of each of the band pass filters A constant changing means and a frequency variable element of each band pass filter by controlling the element constant changing means so that the level of each detected signal is minimized based on each detected signal detected by the detecting means. And a frequency control means for controlling each center frequency of each of the band pass filters by changing each element constant of the above.
The automatic setting device according to 0, 11 or 12. 16. The control means further comprises: before the control of the center frequency of each of the bandpass filters by the frequency control means, the center frequency of each of the bandpass filters and the element constant of each of the frequency variable elements. Based on a pre-measured relationship between the band pass filters, the frequency of each band pass filter is controlled by controlling the element constant changing means so that the center frequency of each band pass filter substantially matches the center frequency to be set. 16. The automatic setting device according to claim 15, further comprising front frequency control means for changing the element constant of the variable element. 17. A parallel multistage bandpass filter in which a plurality of bandpass filters each capable of changing a center frequency are electrically connected in parallel, and the multistage bandpass filter according to claims 10, 11, 12, 13, 14, and 15. Or a parallel multistage automatic tuning type bandpass filter, comprising the automatic setting device according to item 16. 18. A plurality of parallel multistage automatic tuning type bandpass filters according to claim 17, each of which outputs a signal output from each bandpass filter in each parallel multistage automatic tuning type bandpass filter. An antenna sharing apparatus characterized in that each output terminal of a parallel multistage automatic tuning type bandpass filter is electrically connected together.