JP2007232451A - Plural frequency driven measuring instrument of spherical surface elastic wave element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To change a drive frequency at a high speed and to simultaneously output a plurality of frequencies. <P>SOLUTION: The plural frequency driven measuring instrument of a spherical surface elastic wave element comprises: a drive line circuit for impressing a drive signal on the wave element at a plurality of frequencies; and a measurement system circuit for measuring a go-around reception signal of a plurality of frequencies outputted from the wave element. The measuring instrument of the wave element is characterized by being equipped with a plurality of series resonance circuits and a plurality of parallel resonance circuits respectively resonating at the plurality of frequencies between the drive system circuit and the wave element. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a driving device for a spherical surface acoustic wave element and a measurement device for a circular received signal, and more particularly to a driving measuring device for a spherical surface acoustic wave element using a plurality of frequencies.

  2. Description of the Related Art In recent years, a spherical surface acoustic wave element is known in which interdigital electrodes are formed on the surface of a spherical piezoelectric crystal base material instead of a flat plate shape (see, for example, Patent Document 1).

  In this spherical surface acoustic wave device, when a high-frequency burst signal is applied to the interdigital electrode as a drive signal, the surface acoustic wave is excited from the interdigital electrode, and the surface acoustic wave is formed in an annular shape on the substrate surface. Cycle around the area multiple times.

  Here, the speed at which the surface acoustic wave multi-circulates changes according to the state of the substrate surface. Similarly, the resonance frequency of the surface acoustic wave changes when the circumference of the annular region becomes an integral multiple of the wavelength of the surface acoustic wave due to adhesion of molecules to the surface of the substrate.

  For this reason, spherical surface acoustic wave devices have been proposed for applications such as detecting the adhesion between molecules attached to the annular region of the substrate surface and the reaction film formed on the annular region with environmental gas, etc. Yes.

  The frequency of the high-frequency burst signal applied to the spherical surface acoustic wave device as the drive signal depends on the shape of the interdigital electrode on the spherical surface acoustic wave device, the deposit on the substrate surface, the reaction film formed on the annular region, etc. In some cases, drive measurement is performed at multiple frequencies.

Patent documents and the like are as follows.
International Publication No. WO 01/45255

  By the way, an impedance matching circuit for efficiently performing signal transmission is required between the drive system circuit and the measurement system circuit and the spherical surface acoustic wave element, and the circuit constant of the impedance matching circuit is determined by the frequency. .

  Therefore, when driving at a plurality of frequencies, it is necessary to perform drive measurement with means for switching a plurality of impedance matching circuits corresponding to each frequency according to the driving frequency or means for changing impedance matching circuit constants.

  As a means for switching the impedance matching circuit or a means for changing the impedance matching circuit constant, when the switching time is sufficiently slow, a switch having a mechanical contact may be manually switched, or the mechanical contact may be electrically connected by an electromagnetic relay. Switching may be performed, but high-speed switching cannot be performed at several ms or less.

  However, in high-accuracy measurement, it is necessary to switch the driving frequency at high speed due to the drift problem. High-speed switching is possible by using an electronic switch or a photo moss relay. However, when the driving frequency of the spherical surface acoustic wave element is higher than 10 MHz, the circuit is cut off due to the capacitance of the switch element. Even in this state, there is a problem that the drive signal and the round reception signal leak, and it is difficult to switch a plurality of high-frequency drive frequencies at high speed.

  Furthermore, in order to improve measurement accuracy, a method of synthesizing and outputting a plurality of frequencies instead of switching them has been considered, but this cannot be realized by a switching method using a switch.

  The present invention has been made in consideration of the above circumstances, and in a device that drives and measures a spherical surface acoustic wave element at a plurality of frequencies, the drive frequency can be changed at a high speed and a plurality of frequencies can be output simultaneously. An object of the present invention is to provide a multi-frequency driving measurement device for a spherical surface acoustic wave element that can be realized.

  The invention corresponding to claim 1 measures a driving system circuit for applying a driving signal to a spherical surface acoustic wave element at a plurality of frequencies, and a circular reception signal having a plurality of frequencies output from the spherical surface acoustic wave element. A measurement surface circuit, and a multi-frequency drive measurement device for a spherical surface acoustic wave element, wherein the plurality of frequencies are provided between the drive system circuit and the measurement system circuit and the spherical surface acoustic wave element. And a plurality of series resonant circuits that resonate with each other and a plurality of parallel resonant circuits.

  The invention corresponding to claim 2 is the spherical surface acoustic wave device according to claim 1, wherein the plurality of frequencies for driving measurement are separated by at least 1.3 times or more. It is a multi-frequency drive measurement device for an acoustic wave element.

  The invention corresponding to claim 3 is the multi-frequency drive measurement device for spherical surface acoustic wave elements according to claim 1 or claim 2, wherein the drive signals for drive measurement output a single frequency simultaneously. A multi-frequency drive measuring apparatus for spherical surface acoustic wave elements, which is sequentially switched.

  The invention corresponding to claim 4 is the multi-frequency drive measurement device for spherical surface acoustic wave device according to claim 1 or claim 2, wherein the drive signals of multiple frequencies for driving measurement simultaneously output a composite drive signal of multiple frequencies. This is a multi-frequency drive measuring device for a spherical surface acoustic wave device.

The invention corresponding to claim 5 is the multi-frequency drive measuring device for spherical surface acoustic wave elements according to any one of claims 1 to 4,
A spherical surface characterized in that drive signals of a plurality of frequencies for driving measurement are drive system circuits for applying to the same path, and the outgoing measurement system circuit is a measurement system circuit for measuring a circulating reception signal of the same path It is a multi-frequency drive measurement device for an acoustic wave element.

The invention corresponding to claim 6 is the multi-frequency drive measuring device for spherical surface acoustic wave elements according to any one of claims 1 to 4,
A drive signal of a plurality of frequencies for driving measurement is a drive system circuit for applying to different paths for each frequency, and an output measurement system circuit is a measurement system circuit for measuring each round reception signal of a different path for each frequency. This is a multi-frequency drive measuring device for a spherical surface acoustic wave device.

  Therefore, in the invention corresponding to claims 1 to 6, for example, when the spherical surface acoustic wave device is driven and measured at two frequencies, the first frequency is set to f1 and the second frequency is set to f2 (where f1 <1.3). × f2 or f1> 1.3 × f2), a series resonance circuit that is in a resonance state at f1 and a parallel resonance circuit that is in a resonance state at f1 between the driving system circuit and the measurement system circuit and the surface acoustic wave element. A circuit in which a circuit coupled by a coil, a series resonant circuit that enters a resonance state at f2 and a parallel resonance circuit that enters a resonance state at f2 are coupled by a coil are configured in parallel.

  The parallel resonant circuit that resonates at f1 and the parallel resonant circuit that resonates at f2 also serve as an impedance matching circuit for the spherical surface acoustic wave element.

  Thus, the series resonant circuit that is in the resonance state at f1 and the series resonance circuit that is in the resonance state at f2 have selectivity of the passing frequency, and the drive measurement signal is sent to the impedance matching circuit suitable for the passing frequency. Can communicate.

  In addition, since the impedance matching circuit is configured by the parallel resonant circuit that resonates at f1 and the parallel resonant circuit that is in a resonant state at f2, the frequency that does not match impedance matching is on the side that matches impedance matching. Compared to the impedance of the parallel resonant circuit being close to infinity, the impedance is sufficiently low, and its presence can be ignored electrically.

  This indicates that an impedance matching circuit suitable for the drive measurement frequency is passively and automatically selected.

  As a result, in an apparatus for driving and measuring a spherical surface acoustic wave device at a plurality of frequencies, it is no longer necessary to switch a plurality of impedance matching circuits that respectively match the plurality of frequencies with a switch or the like.

  As described above, according to the present invention, in a device for driving and measuring a spherical surface acoustic wave device at a plurality of frequencies, the driving measurement frequency can be changed at a high speed, and a plurality of driving frequencies can be synthesized and output simultaneously. Became possible.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

<First Embodiment>
FIG. 1 is a schematic diagram showing the configuration of the spherical surface acoustic wave element multi-frequency drive measuring apparatus according to the first embodiment of the present invention, and FIG. 2 is a schematic diagram showing the configuration of this spherical surface acoustic wave element. .

  This multi-frequency drive measurement apparatus includes a spherical surface acoustic wave element 10, a frequency selection unit 20, an impedance matching unit 30, a separation unit 40, a high frequency burst signal generation unit 50, and a measurement unit 60.

  Here, the spherical surface acoustic wave element 10 includes a spherical member 12 having a propagation surface 11 and an interdigital electrode 13. The propagation surface 11 has an annular surface made of a continuous curved surface, and surface acoustic waves SAW1 and SAW2 propagating in opposite directions excited by the interdigital electrode 13 are formed on at least a part of the annular surface. There is a circulation path for circulation. The spherical member 12 is a three-dimensional substrate having a propagation surface 11 in which a surface acoustic wave once excited can circulate multiple times. In this embodiment, a single crystal quartz material processed into a spherical shape having a diameter of 10 mm is used. .

  The frequency selection unit 20 is a series resonant circuit in which a coil and a capacitor are connected in series. The frequency selection unit 20 has a frequency selectivity with respect to the drive signal from the high frequency burst signal generation unit 50 or the reception loop signal from the spherical surface acoustic wave element 10. It is intended to pass through.

The impedance matching unit 30 is a parallel resonance circuit in which a coil and a capacitor are connected in parallel. The impedance matching between the driving system circuit from the high frequency burst signal generation unit 50 and the measurement unit 60 and the spherical surface acoustic wave device 10 is performed at a frequency. This is done with selectivity.

  The separation unit 40 prevents the drive signal from the high frequency burst signal generation unit 50 from flowing to the measurement unit 60 and prevents the circulation reception signal from flowing to the high frequency burst signal generation unit 50.

  The high-frequency burst signal generator 50 intermittently generates a burst signal having an arbitrary frequency and applies it to the interdigital electrode 13 of the spherical surface acoustic wave element 10 as a drive signal.

  The measuring unit 60 is for amplifying the detection signals of the surface acoustic waves SAW1 and SAW2 during multiple rounds outputted from the interdigital electrode 13 by the amplifier 61 and measuring the intensity of the detection signal.

  Next, the operation of the multi-frequency driving measurement apparatus for the spherical surface acoustic wave element configured as described above will be described in detail.

  In the present embodiment, a plurality of frequencies are set to two frequencies of a first frequency f1 and a second frequency f2 (where f1 <1.3 × f2 or f1> 1.3 × f2).

  The reason why 1.3 or more is preferable is that it is not possible to make use of the merit at a frequency near that high-precision measurement can be performed by detecting a difference due to a different frequency, that is, a difference does not occur so much.

  In addition, in this method, it is difficult to separate frequencies of 1.3 times or less due to electrical characteristics. This can be done theoretically, but in practice, this method cannot be used effectively unless the Q (good resonance) is limited and 1.3 times or more from experience.

  The high frequency burst signal generator 50 alternately and intermittently generates burst signals of the first frequency f1 and the second frequency f2.

  In the frequency selection unit 20, a frequency selection circuit 21 having a pass frequency f1 and a frequency selection circuit 22 having a pass frequency f2 are connected in parallel.

  The frequency selection circuit 21 forms a series resonance circuit in which a coil L21 and a capacitor C21 are connected in series, and resonates at a frequency f1.

  The frequency selection circuit 22 forms a series resonance circuit in which a coil L22 and a capacitor C22 are connected in series, and resonates at a frequency f2.

  Here, it is assumed that the burst signal having the frequency f1 is output from the high-frequency burst signal generator 50.

The burst signal having the frequency f1 is applied to the frequency selection circuit 21 and the frequency selection circuit 22, respectively. However, since the frequency selection circuit 21 performs series resonance at the frequency f1, the impedance becomes almost zero (theoretically in the series resonance circuit). In the resonance state, the impedance becomes zero, but in reality, since the pure resistance component of the coil remains, it has a slight impedance), whereas the frequency selection circuit 22 has an impedance because it does not enter the resonance state. FIG. 3 is an equivalent representation of this state, and the frequency selection circuit 21 in the series resonance state is in a short-circuit state 21a with substantially zero impedance, in other words, equivalent to a simple electric wire. For this reason, most of the burst signal having the frequency f 1 output from the high-frequency burst signal generator 50 passes through the frequency selection circuit 21.

  Next, the burst signal having the frequency f 1 that has passed through the frequency selection circuit 21 is applied to the impedance matching unit 30.

  In the impedance matching unit 30, an impedance matching circuit 31 having a resonance frequency f1 and an impedance matching circuit 32 having a resonance frequency f2 are connected in series.

  The impedance matching circuit 31 forms a parallel resonance circuit in which a secondary coil L31a and a secondary coil L31a, a coil L31b constituting a transformer, and a capacitor C31 are connected in parallel, and resonates at a frequency f1. .

  The impedance matching circuit 32 forms a parallel resonance circuit in which a secondary coil L32a, a secondary coil L32a, a coil L32b constituting a transformer, and a capacitor C32 are connected in parallel, and resonates at a frequency f2. .

  Here, a supplementary explanation will be given for impedance matching to the spherical surface acoustic wave device.

  The spherical surface acoustic wave element 10 used in this embodiment has a very high operating impedance, whereas the high-frequency electronic equipment such as the high-frequency burst signal generator 50 and the measurement unit 60 used in this embodiment has an input / output impedance. Is generally 50Ω. Further, the characteristic impedance of the high-frequency coaxial cable for connection not shown is 50Ω. If the spherical surface acoustic wave element 10 having a very high operating impedance is directly connected to a 50Ω circuit in this way, the energy loss is large and the spherical surface acoustic wave element 10 cannot be driven efficiently.

  Therefore, by inserting an impedance matching circuit between the high frequency burst signal generator 50 and the measuring unit 60 and the spherical surface acoustic wave element 10, the operating impedance of the spherical surface acoustic wave element 10 is converted to 50Ω or a low impedance in the vicinity thereof. Thus, the spherical surface acoustic wave element 10 can be driven efficiently while suppressing energy loss.

  Specifically, the impedance matching circuit is configured by a parallel resonance circuit including a coil L31b and a capacitor C31 or a parallel resonance circuit including a coil L32b and a capacitor C32, and the impedance viewed from the spherical surface acoustic wave element 10 when the parallel resonance state is obtained. The matching circuit has a very high impedance, and impedance matching can be achieved with the spherical surface acoustic wave element 10 having a very high operating impedance.

  On the other hand, the secondary coil L31a is provided so as to form a transformer in the impedance matching coil L31b, one end of the secondary coil L31a is grounded, and the other end is connected to the high-frequency burst signal generator 50 and the measurement unit 60. The impedance of the impedance matching circuit viewed from the burst signal generator 50 and the measuring unit 60 is set to 50Ω. Further, the number of turns of the secondary coil L31a is much smaller than the number of turns of the impedance matching coil L32b.

  As described above, the impedance matching circuit according to the present embodiment can perform impedance matching between the high-frequency burst signal generation unit 50 and the measurement unit 60 and the spherical surface acoustic wave device 10 when the resonance state is achieved.

  The burst signal having the frequency f1 that has passed through the frequency selection circuit 21 enters the parallel resonance state in the impedance matching circuit 31 having the resonance frequency f1, and the impedance of the impedance matching circuit 31 becomes very high (theoretically in the parallel resonance circuit). In the resonance state, the impedance becomes infinite, but in reality, it does not become infinite because the pure resistance component of the coil remains), and impedance matching can be achieved with the spherical surface acoustic wave device 10 having a very high operating impedance. .

  On the other hand, the burst signal having the frequency f1 that has passed through the frequency selection circuit 21 also flows to the impedance matching circuit 32 that is connected in series with the impedance matching circuit 31 and has a resonance frequency f2, but the impedance matching circuit 32 is in a parallel resonance state. Therefore, the value is sufficiently lower than the very high impedance of the impedance matching circuit 31 in the parallel resonance state. FIG. 4 shows this state equivalently, and the impedance matching circuit 31 can be regarded as being grounded via a sufficiently low resistance 32a.

  As a result, the burst signal having the frequency f1 is impedance-matched via the impedance matching circuit 31 that is optimal for the frequency f1, and a drive signal can be applied to the spherical surface acoustic wave device 10.

  Next, the interdigital electrode 13 excites the surface acoustic waves SAW1 and SAW2 propagating in opposite directions to the surface of the spherical member 12 by applying a burst signal having the frequency f1, propagates along the surface, and propagates the surface. A synthetic wave SAW (not shown) of the elastic waves SAW1 and SAW2 is received, and a circular received signal can be excited and output. The surface acoustic waves SAW 1 and SAW 2 make multiple rounds on the surface of the spherical member 12 while passing through the interdigital electrode 13.

  After the application of the burst signal having the frequency f1, the interdigital electrode 13 outputs an excited circulation reception signal. The round received signal is returned at the same frequency as the applied burst signal. Therefore, the frequency of the round received signal is f1.

  The circular reception signal passes through the impedance matching circuit 31 and the frequency selection circuit 21 based on the operation principle, amplifies the detection signal by the amplifier 61 through the separation unit 40, and is input to the measurement unit 60.

  Next, it is assumed that a burst signal having a frequency f2 is output from the high frequency burst signal generator 50.

  The burst signal having the frequency f2 is applied to the frequency selection circuit 21 and the frequency selection circuit 22, respectively. Since the frequency selection circuit 22 resonates in series at the frequency f2, the impedance becomes almost zero. Since it does not become a resonance state, it has impedance. FIG. 5 is an equivalent representation of this state, and the frequency selection circuit 22 in a series resonance state is in a short-circuit state 22a with substantially zero impedance. For this reason, most of the burst signal having the frequency f 2 output from the high frequency burst signal generator 50 passes through the frequency selection circuit 22.

  Next, the burst signal having the frequency f2 that has passed through the frequency selection circuit 22 is applied to the impedance matching unit 30 to be in a parallel resonance state by the impedance matching circuit 32 having the resonance frequency f2, and the impedance of the impedance matching circuit 32 becomes very high. Impedance matching can be achieved with the spherical surface acoustic wave element 10 having a very high operating impedance.

  On the other hand, the burst signal having the frequency f2 that has passed through the frequency selection circuit 22 also flows to the impedance matching circuit 31 that is connected in series with the impedance matching circuit 32 and has a resonance frequency f1, but the impedance matching circuit 31 is in a parallel resonance state. Therefore, the value is sufficiently lower than the very high impedance of the impedance matching circuit 32 in the parallel resonance state. FIG. 6 shows this state equivalently, and the impedance matching circuit 32 can be regarded as being connected to the spherical surface acoustic wave device 10 via a sufficiently low resistance 31a.

  As a result, the burst signal having the frequency f2 is impedance-matched via the impedance matching circuit 32 optimum for the frequency f2, and a drive signal can be applied to the spherical surface acoustic wave device 10.

  Next, the interdigital electrode 13 excites the surface acoustic waves SAW1 and SAW2 propagating in opposite directions to the surface of the spherical member 12 by applying a burst signal of the frequency f2, and propagates along the surface and propagates the surface. The synthesized wave SAW of the elastic waves SAW1 and SAW2 is received, and the circulation reception signal can be excited and output. The surface acoustic waves SAW 1 and SAW 2 make multiple rounds on the surface of the spherical member 12 while passing through the interdigital electrode 13.

  After the application of the burst signal of frequency f2, the interdigital electrode 13 outputs an excited round reception signal. The round received signal is returned at the same frequency as the applied burst signal. Therefore, the frequency of the round received signal is f2.

  The circular reception signal passes through the impedance matching circuit 32 and the frequency selection circuit 22 based on the operating principle, amplifies the detection signal by the amplifier 61 through the separation unit 40, and is input to the measurement unit 60.

  As described above, according to the present embodiment, the high-frequency burst signal output from the high-frequency burst signal generation unit 50 is subjected to impedance matching by passively automatically selecting a matching circuit suitable for the frequency, and thus having a spherical surface. The acoustic wave element 10 is driven.

  The circular reception signal output from the spherical surface acoustic wave device 10 is passively and automatically selected an impedance matching circuit suitable for the frequency, impedance-matched, and input to the measuring unit 60.

  Although the above description has been made in the case where the circulation path is a single path, a signal may be applied to a different path for each frequency and measured.

  Next, Example 1 related to the present embodiment will be described.

<Example 1>
The spherical surface acoustic wave element was driven with a plurality of frequencies set to two frequencies of 20 MHz and 45 MHz, and the round reception signal was measured by the measuring unit 60.

  The schematic diagram showing the configuration of the present example is as shown in FIG. 1 and is the same as that of the first embodiment, and the description thereof will be omitted.

  FIG. 7 is a schematic diagram showing the configuration of a spherical surface acoustic wave element used in this example.

The interdigital electrodes used for the spherical surface acoustic wave element 10S are two interdigital electrodes 13a and 13a.
b is formed in contact with the spherical member 12. The interdigital electrode 13a has an electrode pattern in which surface acoustic waves are generated at 20 MHz, and 13b has 45 MHz, and excites surface acoustic waves on the same propagation surface 11. The two interdigital electrodes 13a and 13b are electrically connected in parallel.

  When a surface acoustic wave is excited on the same propagation surface with a driving signal in which one frequency is an integral multiple of the other frequency, such as 15 MHz and 45 MHz, in the interdigital electrodes 13a and 13b, one interdigital electrode The other interdigital electrode may inhibit the circulation of the surface acoustic wave excited. Therefore, a combination such as 20 MHz and 45 MHz is more desirable than a combination of 15 MHz and 45 MHz.

  The high frequency burst signal generator 50 alternately outputs a 20 MHz high frequency burst signal and a 45 MHz high frequency burst signal as drive signals. In either case, the output power is 20 dBm.

  First, a 20 MHz burst signal is transmitted at a gate time of 100 μS, and after waiting for a measurement time of 50 μS, a high frequency burst signal of a frequency of 45 MHz is transmitted at a gate time of 100 μS and a measurement time of 50 μS is waited. Thereafter, the above timing is repeated.

  Therefore, the high frequency burst signal of the two frequencies is switched every 150 μS.

  The measurement unit 60 is in a state in which reception is possible continuously, and can measure the cyclic reception signal intensity for an arbitrary time. In this embodiment, the cyclic reception signal intensity 20 μs after the burst signal is transmitted was measured. .

  As a result, when a high frequency burst signal of 20 MHz is applied, the circulating reception signal averages 0.3 dBm. When a high frequency burst signal of 45 MHz was applied, the circulating reception signal was an average of 4.6 dBm.

  When the switching time of high frequency signals of 20 MHz and 45 MHz is as fast as 150 μS, it cannot be switched naturally with a switch having a mechanical contact such as an electromagnetic relay, or even an electronic switch such as a photo mos relay Switching takes a time of mS unit or more due to the capacity relationship, and even if drive measurement is performed in such a state, correct impedance matching is not performed, and the received circular received signal strength is −30 dBm or less.

  Therefore, the experiment of Example 1 shows that it is operating satisfactorily while switching at a high speed of 150 μS.

<Second Embodiment>
Next, a second embodiment will be described.

  The schematic diagram showing the configuration of the present embodiment is the same as FIGS. 1 and 2 in the first embodiment, and a description thereof will be omitted. The operation of the multi-frequency drive measuring device for the spherical surface acoustic wave device configured as described above will be described.

  In the present embodiment, a plurality of frequencies are set to two frequencies of a first frequency f1 and a second frequency f2 (where f1 <1.3 × f2 or f1> 1.3 × f2).

  The high frequency burst signal generator 50 synthesizes and simultaneously generates burst signals of the first frequency f1 and the second frequency f2.

  The burst signal obtained by synthesizing the first frequency f1 and the second frequency f2 is applied to the frequency selection unit 20, but the burst signal passing through the frequency selection circuit 21 has only the frequency f1 due to the action of the frequency selection circuit 21. Only the frequency f2 passes through the burst signal passing through the selection circuit 22 due to the action of the frequency selection circuit 22.

  The burst signal having the frequency f1 that has passed through the frequency selection circuit 21 enters a parallel resonance state in the impedance matching circuit 31 having a resonance frequency f1, and the impedance of the impedance matching circuit 31 becomes very high, and the spherical surface having a very high operating impedance. Impedance matching can be achieved with the acoustic wave element 10.

  The burst signal having the frequency f2 that has passed through the frequency selection circuit 22 enters a parallel resonance state in the impedance matching circuit 32 having a resonance frequency f2, and the impedance of the impedance matching circuit 32 becomes very high, and the spherical surface having a very high operating impedance. Impedance matching can be achieved with the acoustic wave element 10.

  Next, the interdigital electrode 13 excites the surface acoustic waves SAW1 and SAW2 propagating in opposite directions to the surface of the spherical member 12 by applying each burst signal having the frequencies f1 and f2, and propagates along the surface. The synthesized wave SAW of the propagated surface acoustic waves SAW1 and SAW2 is received, and the circular received signal can be excited and output. The surface acoustic waves SAW 1 and SAW 2 make multiple rounds on the surface of the spherical member 12 while passing through the interdigital electrode 13.

  After the application of the composite burst signal having the frequencies f1 and f2, the interdigital electrode 13 outputs the excited round reception signal. The round received signal is returned at the same frequency as the applied burst signal. Therefore, the frequency of the round received signal is a combination of f1 and f2.

  The circular reception signal passes through the impedance matching unit 30 and the frequency selection unit 20 based on the operation principle, amplifies the detection signal by the amplifier 61 via the separation unit 40, and is input to the measurement unit 60.

  As described above, according to the present embodiment, the high frequency synthesized burst signal output from the high frequency burst signal generator 50 is passively automatically selected by the impedance matching circuit suitable for the frequency, and impedance matching is performed. The spherical surface acoustic wave element 10 is driven.

  The circular reception signal output from the spherical surface acoustic wave device 10 is passively and automatically selected an impedance matching circuit suitable for the frequency, impedance-matched, and input to the measuring unit 60.

  Next, Example 2 related to the present embodiment will be described.

<Example 2>
The spherical surface acoustic wave element was driven with a plurality of frequencies set to two frequencies of 20 MHz and 45 MHz, and the round reception signal was measured by the measuring unit 60.

  The schematic diagram showing the configuration of this example is the same as that of FIG. 1 in the first embodiment, and a description thereof will be omitted.

  Further, the schematic diagram showing the configuration of the spherical surface acoustic wave element used in this embodiment is the same as that in FIG.

  The high frequency burst signal generator 50 synthesizes and outputs a 20 MHz high frequency burst signal and a 45 MHz high frequency burst signal as drive signals. The output power is 20 dBm.

  The measurement unit 60 is in a state in which reception is possible continuously, and can measure the cyclic reception signal intensity for an arbitrary time. In this embodiment, the cyclic reception signal intensity 20 μs after the burst signal is transmitted was measured. .

  Since the round received signal intensity received by the measuring unit 60 is a combined wave of 20 MHz and 45 MHz, fast Fourier transform was performed by a computer (not shown) to separate it into a 20 MHz component and a 45 MHz component.

  As a result, the average frequency of the 20 MHz round received signal is -1.0 dBm. The average number of 45 MHz round received signals was 3.6 dBm.

  Even if drive measurement is performed without performing impedance matching suitable for each frequency component as in this embodiment, the energy loss is large, and the received round-trip received signal intensity is -40 dBm or less.

  Therefore, the experiment of Example 2 shows that it is operating well while simultaneously driving two frequencies.

As described above, in the device for driving and measuring the spherical surface acoustic wave element at a plurality of frequencies, it is not necessary to switch a plurality of impedance matching circuits respectively adapted to the plurality of frequencies by using a switch or the like. In addition, the present invention is not limited to the above-described embodiments as they are, but is within the scope not departing from the gist thereof at the implementation stage. The component can be modified and embodied. Moreover, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.

It is a schematic diagram which shows the structure of the multi-frequency drive measuring device of the spherical surface acoustic wave element concerning the 1st Embodiment of this invention. It is a schematic diagram which shows the structure of the spherical surface acoustic wave element concerning the embodiment. FIG. 6 is an equivalent circuit diagram for explaining an operation according to the embodiment. FIG. 6 is an equivalent circuit diagram for explaining an operation according to the embodiment. FIG. 6 is an equivalent circuit diagram for explaining an operation according to the embodiment. FIG. 6 is an equivalent circuit diagram for explaining an operation according to the embodiment. It is a schematic diagram which shows the structure of the spherical surface acoustic wave element concerning Example 1 of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Spherical surface acoustic wave element, 11 ... Propagation surface, 12 ... Spherical member, 13, 13a, 13b ... Interdigital electrode, 20 ... Frequency selection part, 21, 22 ... Frequency selection circuit, 21a, 22a ... Equivalent circuit, 30 ... impedance matching section 31, 32 ... impedance matching circuit, 31a, 32a ... equivalent circuit, 40 ... separation section, 50 ... high frequency burst signal generation section, 60 ... measurement section, 61 ... amplifier, C21, C22, C31, C32 ... Capacitor, L21, L22, L31a, L31b, L32a, L32b ... Coil, R ... Resistance

Claims (6)

A drive circuit for applying drive signals at a plurality of frequencies to the spherical surface acoustic wave device;
A measurement system circuit for measuring a circular reception signal of a plurality of frequencies output from the spherical surface acoustic wave element;
A multi-frequency driving measurement device for a spherical surface acoustic wave device comprising:
A plurality of series resonance circuits and a plurality of parallel resonance circuits each resonating at the plurality of frequencies are provided between the driving system circuit and the measurement system circuit and the spherical surface acoustic wave device. Multi-frequency drive measuring device for spherical surface acoustic wave device. In the multiple frequency drive measuring device of the spherical surface acoustic wave device according to claim 1,
A multi-frequency drive measurement apparatus for a spherical surface acoustic wave device, wherein a plurality of frequencies for drive measurement are at least 1.3 times apart from each other. In the multiple frequency drive measuring device of the spherical surface acoustic wave device according to claim 1 or 2,
A multi-frequency driving measurement apparatus for a spherical surface acoustic wave device, wherein a plurality of driving signals for driving measurement simultaneously output one frequency and sequentially switch between them. In the multiple frequency drive measuring device of the spherical surface acoustic wave device according to claim 1 or 2,
A multi-frequency drive measurement apparatus for a spherical surface acoustic wave device, wherein a drive signal of a plurality of frequencies for driving measurement outputs a composite drive signal of a plurality of frequencies simultaneously. In the multiple frequency drive measuring device of the spherical surface acoustic wave device according to any one of claims 1 to 4,
A spherical surface characterized in that drive signals of a plurality of frequencies for driving measurement are drive system circuits for applying to the same path, and the outgoing measurement system circuit is a measurement system circuit for measuring a circulating reception signal of the same path Multi-frequency drive measurement device for acoustic wave elements. In the multiple frequency drive measuring device of the spherical surface acoustic wave device according to any one of claims 1 to 4,
A drive signal of a plurality of frequencies for driving measurement is a drive system circuit for applying to different paths for each frequency, and an output measurement system circuit is a measurement system circuit for measuring each round reception signal of a different path for each frequency. A multi-frequency driving measurement apparatus for a spherical surface acoustic wave device.

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