JP4399314B2 - Method and apparatus for driving measurement of surface acoustic wave device - Google Patents

Description

  The present invention particularly relates to a driving measurement method and apparatus for a revolving surface acoustic wave device.

  In recent years, spherical surface acoustic wave elements (hereinafter referred to as ball SAW devices) in which interdigital electrodes are formed on the surface of a piezoelectric crystal base material having a spherical shape (ball shape) instead of a flat plate shape have been developed (for example, referred to as a ball SAW device). , See Patent Document 1).

  When an impulse signal or a radio frequency (RF) burst signal as a driving signal is applied to the interdigital electrode, the ball SAW device may be called a surface acoustic wave (SAW) or surface acoustic wave from the interdigital electrode. Is excited, and the surface acoustic wave circulates around the annular region of the substrate surface in multiple layers. In other words, surface acoustic waves are diffused from the geometric characteristics of the sphere surface by propagating the surface acoustic waves to a part of the sphere surface in the annular shape in the vicinity of the beam width determined by the diameter of the sphere or the wavelength of the surface acoustic wave. Is suppressed and circulates multiple times.

  In addition to the ball SAW device, for example, a cylindrical SAW device or the like may be generically called a revolving surface acoustic wave device. Here, the ball SAW device will be described as a representative.

  In the present invention, what is called a surface acoustic wave is a generic term for an acoustic wave that propagates by concentrating energy on the surface or boundary. Even a corridor wave that propagates along a spherical surface inside a sphere is a Rayleigh wave. Further, it is assumed here that a boundary wave propagating on a spherical boundary may be propagated because the surface of the sphere is covered with another substance. As described above, various types of spherical surface acoustic waves have been proposed.

  Here, the surface acoustic wave changes the speed of multiple laps depending on the state of the substrate surface, the adhesion of molecules to the substrate surface, and the like. Similarly, the resonance frequency of the surface acoustic wave changes such that the time required to go around the annular region is an integral multiple of the period of the surface acoustic wave.

  The device can be used by applying an impulse signal or an RF burst signal and measuring the phase of the electrical signal output from the interdigital electrode when it is repeatedly circulated (multiple laps). A sensor such as a meter can be configured. In addition, there have been proposed uses such as a gas sensor for detecting a molecule adhering to the annular region on the surface of the substrate or a reaction between a reaction film formed on the annular region and an environmental gas.

  By the way, since the ball SAW device uses a crystal sphere such as quartz to form an annular region having a spherical substrate or a spherical surface, it only circulates along a predetermined path determined by the crystal axis. Unlike devices, it is difficult to reduce temperature dependence. In a planar SAW device, it is relatively easy to reduce the temperature dependence by selecting a cut surface.

In the ball SAW device, when a circular path is formed using a quartz Z-axis cylinder, which is a spherical base material, the propagation speed of the surface acoustic wave has a temperature dependency of the circular time of about 25 to 26 ppm / ° C. In order to suppress this temperature dependency, there is also a method of arranging the device in a thermostatic bath, but the range of application when used as a sensor is limited.
International Publication No. WO 01/45255

  As measures against temperature dependence, a method of mounting a thermometer on the surface of the crystal sphere can be considered. However, this measure is not practical because the measurement accuracy of the device is limited by the detection accuracy of the thermometer, and the sensitivity of the original device cannot be fully utilized.

  As another countermeasure, for example, using a crystal sphere such as LiNbO3 and using a crystal having a plurality of paths on the sphere surface as a base material, or preparing a plurality of individual crystal spheres in the same environment There is a method to measure it. However, in such a method, when a plurality of crystal spheres are used, the circumferences of the crystal spheres to be created are not necessarily the same. Similarly, in the case of a plurality of paths formed on the same base material, it is difficult to ensure the same circulation time.

  In particular, a plurality of crystal spheres are used to simultaneously input RF burst signals to each device, circulate the multi-circulation signal a number of times, and then interfere with each other to detect each phase difference. The measurement method has the following problems. That is, when the phase is detected, since RF burst signals exist at different time points, the interference phenomenon due to the sum of the signals cannot be observed, resulting in difficulty in phase comparison.

  As a countermeasure to solve such problems, there is a method of using a delay element in order to observe simultaneously different signals in time, but as a result, it is necessary to cope with the delay element causing measurement errors. Become.

  Furthermore, it is effective to use a measuring device and a calibration device to prepare a transmission source of a specific frequency and measure the resonance frequency associated with the circulation, but the general purity is high and the frequency is stable. It is difficult to prepare a signal source, and the measurement apparatus is increased in size.

  Moreover, there were the following practical problems. Usually, particularly in the case of a ball SAW device using a crystal, the efficiency of conversion from an electric signal to the energy of a surface acoustic wave (referred to as an electromechanical coupling constant) is small, so the surface acoustic wave makes one round of the circuit. The RF burst signal is continuously applied for a longer time. This makes it possible to circulate a strong surface acoustic wave, and as a result, when the circulatory signal is observed with the interdigital electrode, it can be observed as a larger voltage value.

  However, in the case of this method, since the signals for each round of the RF burst signal are continuously connected, it is difficult to specify the number of rounds of the signal. In addition, since it becomes difficult to specify a signal around a specific turn on two or more devices on the time axis, measurement using a method that uses two devices, one of which is used for calibration. Calibration with the system becomes difficult.

  Furthermore, when applying an RF burst signal having a long duration of one or more rounds, it may be difficult to measure the phase difference between the two devices even if the number of rounds in two devices can be specified. is there. In other words, when an RF burst signal having a long duration is used, it interferes with the signal of one cycle before itself, and as a result, it becomes difficult to rotate the surface acoustic wave energy on the circuit loop with sufficient strength. . For this reason, it is difficult to secure both signals with sufficient strength to interfere with signals from two devices or two peripheral circuits.

  In short, in order to put a measurement system using a ball SAW device into practical use, a system using a plurality of devices or a system in which a plurality of circulation paths are formed by one device is effective. In other words, a measurement system that prepares measurement devices (or loop paths) and calibration devices (or loop paths) to remove environmental factors such as ambient temperature, and detects their output difference (phase difference). is there.

  However, in order to put such a measurement system into practical use, it is necessary to adjust the delay time of the signal due to the path length of the spherical base material or the temperature dependence of the reaction film, or to generate an RF burst signal having a particularly long duration. It is necessary to devise a method for obtaining the number of rounds of the signal when using it, and to perform accurate phase measurement while resonating with itself when the duration of the input signal is long.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a surface acoustic wave device drive measurement method and apparatus for realizing practical use of a measurement system that detects an output difference between a measurement output signal and a calibration output signal.

  An aspect of the present invention according to claim 1 is an elasticity in which a high-frequency signal is generated and input to an acoustic wave device, and response characteristics are measured based on a circular reception signal repeatedly output from the acoustic wave device at a constant time interval. A method of measuring a driving of a wave device, the step of generating the high-frequency signal, the step of specifying a position on the time axis of the circular reception signal, and the duration of the high-frequency signal based on the specified position A method for measuring the drive of an acoustic wave device.

  According to a second aspect of the present invention, there is provided an acoustic wave device that measures response characteristics based on a circular reception signal that is repeatedly output with a high-frequency signal superimposed on a high-frequency signal at predetermined time intervals. A driving measurement method comprising: generating the high-frequency signal; analyzing and measuring a response of the elastic wave device to the input of the high-frequency signal; adjusting a duration of the high-frequency signal; And a step of identifying the position of the received signal on the time axis.

  According to a third aspect of the present invention, the surface acoustic wave device includes a surface acoustic wave element having an electroacoustic transducer formed on a piezoelectric surface, and a surface acoustic wave that responds to the high-frequency signal is specified. 3. The elastic wave device drive measurement method according to claim 1, wherein the elastic wave device drive measurement method according to any one of claims 1 and 2, wherein the output is repeated at a predetermined time by repeatedly propagating through the medium. is there.

  According to a fourth aspect of the present invention, the elastic wave device is configured of a surface acoustic wave element having a circular path, and outputs the circular reception signal based on the circular rotation of the surface acoustic wave propagating on the surface. It is comprised, The drive measurement method of the elastic wave device of any one of Claims 1-3 characterized by the above-mentioned.

  The aspect of the present invention according to claim 5 is characterized in that the surface acoustic wave device includes a spherical surface acoustic wave element provided with a circular path having a spherical surface. The driving measurement method for an acoustic wave device according to claim 1.

  According to a sixth aspect of the present invention, a high-frequency signal is generated and input to a surface acoustic wave device, and response characteristics are measured based on a circular reception signal repeatedly output from the surface acoustic wave device at a constant time interval. A surface acoustic wave device drive measurement method comprising: generating the high frequency signal; and having a time width shorter than a repetition period of repeated output, and extracting a high frequency signal for gate timing detection from the high frequency signal. The step of inputting to the surface acoustic wave device, the step of flattening the intensity of the round received signal that becomes weaker as the number of rounds overlaps, and the number of rounds of the rounded round received signal are counted. A step of generating a gate timing signal that operates at a specified time defined by a specific number of laps, and a duration of the high-frequency signal for gate timing detection It has a long gate width is a driving method for measuring a surface acoustic wave device characterized by comprising a step of extracting a high-frequency signal for measurement in response to the gate timing signal.

  The aspect of the present invention according to claim 7 is the driving of the surface acoustic wave device according to claim 6, wherein the duration of the high-frequency signal for gate timing detection is shorter than the impulse or the repetition period. This is a measurement method.

  According to an eighth aspect of the present invention, a high-frequency signal is generated and input to a surface acoustic wave device, and response characteristics are measured based on a circular reception signal repeatedly output from the surface acoustic wave device at a constant time interval. A surface acoustic wave device drive measurement apparatus comprising: means for generating the high-frequency signal; and a gate timing signal for detecting a position of the circular received signal at a specified circular using the high-frequency signal. Based on the rounded received signal responsive to the high frequency signal for measurement per round, and means for separating the high frequency signal for round round measurement using the gate timing signal A surface acoustic wave device drive measurement apparatus comprising: means for measuring response characteristics of the surface acoustic wave device.

  According to a ninth aspect of the present invention, a high-frequency signal is generated and input to a plurality of surface acoustic wave devices, and each round reception signal is repeatedly output from each surface acoustic wave device at a constant time interval. A surface acoustic wave device driving measurement method for measuring a phase difference, comprising: a step of generating the high frequency signal; and a plurality of gate means for branching and inputting the high frequency signal to the surface acoustic wave devices. Controlling at least one gate timing in step, analyzing and measuring the response of each surface acoustic wave device, and performing phase comparison based on the response signal of each surface acoustic wave device, And a step of adjusting the gate timing so as to adjust the input time of each branched high-frequency signal. A.

  The aspect of the present invention according to claim 10 is that each of the branched high-frequency signals is a continuous high-frequency signal in which the phases coincide with each other, and the step of adjusting the gate timing includes: 10. The surface acoustic wave device drive measurement method according to claim 9, wherein the gate timing is adjusted in order to mutually adjust time zones having the high-frequency signal intensity.

  An aspect of the present invention according to claim 11 is characterized in that each of the branched high-frequency signals has a period longer than a repetition period of the surface acoustic wave excited by each surface acoustic wave device. Alternatively, the driving measurement method for the surface acoustic wave device according to claim 10.

  According to a twelfth aspect of the present invention, each of the surface acoustic wave devices includes a surface acoustic wave element having a circular path, and outputs the circular reception signal based on the circular rotation of the surface acoustic wave propagating on the surface. It is comprised as follows, It is a drive measurement method of the surface acoustic wave device of any one of Claim 9 or Claim 10 characterized by the above-mentioned.

  According to a thirteenth aspect of the present invention, each of the surface acoustic wave devices comprises a spherical surface acoustic wave element provided with a circular path having a spherical surface. 10. The driving measurement method for a surface acoustic wave device according to claim 10.

  According to a fourteenth aspect of the present invention, a high-frequency signal is generated and input to a plurality of surface acoustic wave devices, and each round reception signal is repeatedly output from each surface acoustic wave device at a constant time interval. A surface acoustic wave device drive measurement apparatus for measuring a phase difference, the means for generating the high frequency signal, a plurality of gate means for branching the high frequency signal and inputting it to the surface acoustic wave devices, Measuring means for analyzing and measuring the response of each surface acoustic wave device; and when performing phase comparison based on the response signal of each surface acoustic wave device in the measurement means, A surface acoustic wave device drive measurement apparatus comprising: means for adjusting a gate timing of the gate means so as to adjust an input time.

  According to the present invention, in a measurement system using a repetitive output type acoustic wave device typified by a ball SAW device, the measurement device (or the circulation path) and calibration for removing environmental factors such as ambient temperature. A device (or a circulation path) is prepared, and a measurement system that detects an output difference (phase difference) between them can be put to practical use.

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

(First embodiment)
FIG. 1 is a block diagram showing a configuration of a ball SAW device drive measurement apparatus according to the first embodiment.

  As shown in FIG. 1, the drive measurement apparatus includes a single ball SAW device (hereinafter sometimes simply referred to as a device) 10, a high-frequency signal generator 20, gates 21 and 31, an amplifier 22, a signal Analysis unit 23, measurement value calculation unit 24, measurement result display unit 25, pulse number counting unit 26, gate timing calculation unit 27, system control unit 28, measurement cycle number designating unit 29, and gate width change Part 30.

  In this embodiment, the case where the ball SAW device 10 that performs transmission and reception using the same interdigital electrode is used will be described. However, the same effect can be obtained when a device that performs transmission and reception using separate interdigital electrodes is used. is there.

  The device 10 is, for example, a ball-shaped surface acoustic wave element that is made of a quartz sphere having a diameter of 1 cm, and interdigital electrodes that are circular paths (measurement and calibration paths) are formed on the Z-axis cylinder path. In this embodiment, the ball SAW device will be described. However, for example, a cylindrical SAW device included in a multiple output type or circular surface acoustic wave device is also included in the applicable range.

  The high frequency signal generator 20 generates a 45 MHz RF (high frequency) signal, for example, as shown in FIG. The gate 21 passes an RF burst signal as shown in FIG. 2B and inputs it to the device 10 for a time corresponding to the gate width (window gate) adjusted by the gate width changing unit 30 described later.

  The amplifier 22 amplifies the circular reception signal output from the device 10 and outputs the amplified signal to the gate 31, the measurement system signal analysis unit 23, and the pulse number counting unit 26. Here, the circular reception signal has a signal waveform as shown in FIG. 2C, for example, or is an interference signal obtained by interference between the measurement circular reception signal and the calibration circular reception signal. .

  The signal analysis unit 23, the measurement value calculation unit 24, and the measurement result display unit 25 are components constituting a measurement system. The signal analysis unit 23 analyzes the round reception signal cut out by the gate 31. The measurement value calculation unit 24 calculates various measurement values from the analysis results analyzed by the signal analysis unit 23. This measured value includes the intensity of the interference signal, the phase difference between the measurement and calibration circular reception signals included in the interference signal, and the difference in the propagation speed of the surface acoustic wave. The measurement result display unit 25 is an element that displays and outputs the measurement value calculated by the measurement value calculation unit 24.

  In response to an instruction from the system control unit 28, the gate width changing unit 30 is instructed to reduce the gate width, and then the pulse number counting unit 26 outputs the number of pulses of the circular reception signal (pulse train) output from the amplifier 22. Is output to the gate timing calculation unit 27. As will be described later, the gate timing calculation unit 27 calculates the generation timing of a wind gate for specifying the Nth round received signal specified by the measurement cycle number specifying unit 29 and controls the gate 31.

  The system control unit 28 is an element that executes control of the entire measurement apparatus, and outputs a window gate at the generation timing calculated by the gate timing calculation unit 27 in the Nth cycle specified by the measurement cycle number specifying unit 29. The gate 31 is controlled as described above, and control such as narrowing the gate width at the time of counting is executed.

(Operational effects of the first embodiment)
The measurement apparatus of the present embodiment inputs, for example, an RF burst signal of 45 MHz as shown in FIG. 2B to the device 10, and the attenuation rate of the Nth round received signal output from the device 10 and the A phase difference from the frequency of the RF burst signal is detected.

  Here, as shown in FIG. 2C, the time T of the signal (ultrasonic signal) excited on the device 10 and making one round is, for example, 9.97 μs. The sound velocity V of the surface acoustic wave of the crystal of the device 10 is 3150 m / s, for example. The diameter D of the crystal sphere is, for example, 1 cm (10 mm).

  The measurement apparatus of the present embodiment outputs a window gate at the generation timing calculated from the gate timing calculation unit 27 in order to detect the position of the N-th round reception signal specified by the measurement cycle number specifying unit 29. Thus, the gate width changing unit 30 is controlled.

  Here, as shown in FIG. 3 (A), when burst transmission is performed, the signal resolution of the signal output each time it circulates is long because the time resolution of the circulation reception signal in the Nth cycle deteriorates. It will be connected in the waveform of the high number of laps. For this reason, as shown in FIG. 3D, the S / N of the cyclic reception signal in the Nth cycle is improved by performing short burst transmission of the circular reception signal. FIG. 3B shows the generation timing of a trigger signal for generating an impulse. FIG. 3C shows the short burst generation timing synchronized with the trigger signal.

  Further, the amplifier 22 has an AGC (Auto Gain Control) function and an STC (Sensitivity Time Control) function for correcting the attenuation of the circular reception signal (ultrasonic wave) output from the device 10, and FIG. An output signal having a signal waveform as shown in FIG.

  Next, the generation operation of the window gate for specifying the N-th round received signal by the pulse number counting unit 26 and the gate timing calculating unit 27 will be described with reference to the timing charts of FIGS. explain.

  The pulse number counting unit 26 includes a comparator and an up / down counter, envelopes the output signal waveform from the amplifier 22 (see FIG. 3E), and sets the comparator level (see FIG. 4A). .

  The output signal of the comparator shown in FIG. 4B is input to the down input terminal of the up / down counter. Here, the up / down counter is set with a count value N corresponding to the Nth cycle specified by the measurement cycle number specifying unit 29 by the system control unit 28. When the output signal (pulse) of the comparator is down-counted by the count value N, the up / down counter outputs a borrow signal as shown in FIG.

  On the other hand, the up / down counter up-counts, for example, a 10 MHz clock signal as shown in FIG. 4E only during the period until the output of the borrow signal, and measures the count value m (in the N gate) (FIG. 4). 4 (D)).

  Next, the up / down counter sets a count value (m−m1) obtained by subtracting m1 from the count value m, counts down, and outputs a borrow signal as shown in FIG. . The up / down counter sets a count value (m + m2) obtained by adding m2 to the count value m, down-counts, and outputs a borrow signal as shown in FIG.

  The gate timing calculation unit 27 performs the operation shown in FIG. 4 (H) according to the output timings of the borrow signal shown in FIG. 4F and the borrow signal shown in FIG. The timing for generating the window gate as shown in FIG. 4 is calculated, the gate 31 is controlled, and a predetermined signal to be analyzed is cut out by the gate as shown in FIG.

  In the present embodiment, m1 and m2 are count units, and the gate timing is calculated by the gate timing calculation unit 27 with a repetition period as one unit. However, m1 and m2 may be designated by actual times. . That is, if the signal position of the Nth round is specified and a gate having a time width specified before or after or in one direction is applied, only the intended signal can be cut out more accurately.

  Furthermore, by shortening the gate width, the pulse number counting unit 26 that counts the number of laps is operated to obtain the operation timing of the gate 31, so that in actual measurement, a high S / N ratio with a long gate width is obtained. Can be measured.

  The system control unit 28 controls the gate width changing unit 30 so that the pulse number counting unit 26 can count the circulating wave pulses.

  As described above, in the measurement apparatus according to the present embodiment, an RF burst signal having a short width for gate timing detection is first generated, and the number of rounds corresponding to a predetermined number of rounds is measured by the measurement round number designation unit 29. A received signal can be received.

  In other words, in the measurement apparatus according to the present embodiment, the response signal from the device 10 for each designated Nth round, that is, each round (measurement round reception signal), is only required by adjusting the duration of the RF burst signal. Can be separated. Therefore, for example, even when an RF burst signal having a duration of less than one round is used, even when the waveform collapses in time or spreads on the time axis due to an increase in the reflection component, the received signal of the specified number of rounds The position on the time axis can be reliably identified. This makes it possible to detect a response signal for a specific round digitally, so that a measurement system using the ball SAW device 10 can be easily put to practical use.

  FIG. 5 shows a timing chart when measuring the attenuation characteristic of the Nth cycle in the measurement system according to this embodiment. That is, as shown in FIG. 5A, the measurement system inputs the burst reception waveform output from the device 10 to a log amplifier included in the signal analysis unit 23. The log amplifier outputs a signal waveform as shown in FIG.

  Here, as shown in FIG. 5C, the measurement system can detect the position of the burst reception waveform in the Nth cycle designated by the window gate, and therefore, the waveform peak in the Nth cycle from the output waveform of the log amplifier. Is detected. As a result, the measuring apparatus can measure the attenuation characteristic of the burst reception waveform on the Nth cycle as a result.

(Second Embodiment)
FIG. 6 is a block diagram showing a configuration of a ball SAW device drive measurement apparatus according to the second embodiment.

  The drive measurement apparatus of this embodiment uses two ball SAW devices 10A and 10B, and the first and second gates 21A and 21B to which the RF burst signal output from the high-frequency signal generator 20 is branched and input. , First and second amplifiers 22A and 22B, and a measurement system.

  The high-frequency generator 20 and the measurement system are branched into two systems, a measurement system and a calibration system. In other words, the measurement system includes the first gate 21A, the measurement device 10A, and the first amplifier 22A. On the other hand, the calibration system includes a second gate 21B, a calibration device 10B, and a second amplifier 22B. In the calibration system, the gate timing of the second gate 21 </ b> B is adjusted by the gate timing adjustment unit 32.

  The measurement system includes a phase comparison unit 310 in addition to the measurement value calculation unit 24 and the measurement result display unit 25. The phase comparison unit 310 measures the phase difference between the measurement and calibration circular reception signals included in the interference signal in which the output signals from the first and second amplifiers 22A and 22B interfere. The measurement value calculation unit 24 calculates the difference in the propagation speed of the surface acoustic wave on each device 10A, 10B based on the phase difference.

(Operational effects of the second embodiment)
Hereinafter, the operational effects of the present embodiment will be described with reference to FIGS.

  As shown in FIG. 7, a 45 MHz RF burst signal 70 is generated from the high frequency generator 20 in a narrow band with a pulse width of, for example, 2 μs, and is branched to split the first gate 21A of the measurement system and the calibration system. Input to the second gate 21B.

  In the measurement system, a response signal of the RF burst signal 70A is output from the measurement device 10A, and a measurement reception signal 71A is output from the first amplifier 22A. On the other hand, in the calibration system, a response signal of the RF burst signal 70B is output from the measuring device 10B, and a calibration loop reception signal 71B is output from the second amplifier 22B. In the measurement system, the phase comparison unit 310 measures the phase difference between the measurement and calibration circular reception signals included in the interference signal in which the output signals from the first and second amplifiers 22A and 22B interfere.

  Here, when the phase difference ΔP of the phase of each output signal is 0 radians, the amplitude value of the interference signal is maximized. Conversely, when the phase difference is shifted by π radians, the intensity of the interference signal is minimized. In this case, when the phase shifts by 2π radians, the change in the signal intensity interfered with exactly the same period is repeated, so that the correct phase difference can be obtained when the number of turns is small. Furthermore, by calculating the phase difference at the time when the number of laps is large, the change from the previous phase difference is re-measured, and the phase difference when the number of laps is small is correct even when the change is an integral multiple of 2π. The phase difference can be obtained. As such a phase difference measurement method, there is a known method called phase unwrap.

  When mixing the output signals from the measurement system and the calibration system when obtaining the phase difference using the above method, the RF burst signal output that circulates to the signal at the same time is input to each device 10A, 10B. It is necessary to However, it is difficult to set the time due to various factors such as the size and surface state of the sphere of each device 10A, 10B, or the temperature difference of the surface of the sphere.

  For example, as shown in FIG. 7, even when the second gate 21B of the calibration system is adjusted with a fixed time dT by the gate time adjustment unit 40, particularly when the duration of the RF burst signal is long. Since signal portions having different numbers of turns are mixed, it is difficult to detect a phase difference with high accuracy. Specifically, as shown in FIG. 8A, the timings of the round reception signals 71A and 71B in the measurement system and the calibration system are shifted, resulting in an interference signal as shown in FIG. 8B. For this reason, it is difficult for the measurement system to measure the amplitude of the interference signal using an electric circuit.

  In the present embodiment, as shown in FIG. 9, the gate timing adjustment unit 32 variably adjusts the gate timing of the second gate 21B of the calibration system. That is, when the RF burst signals 70A and 70B are applied to the devices 10A and 10B, the gate timing adjustment unit 32 adjusts the time at which the gate of the second gate 21B is opened. In this case, the gate timing of the first gate 21A of the measurement system is made constant, and the gate timing of the gate of the second gate 21B of the calibration system is changed.

  As a result, the timing of the circular reception signal 71B output from the calibration device 10B also moves in accordance with the change in the gate time (dT). That is, as shown in FIG. 10A, the calibration-related circular reception signal 71B changes to a signal 71C with the timing adjusted.

  Here, the internal phase of the RF burst signal applied to each of the measurement system and calibration system devices 10A and 10B is constant with respect to the movement of the gate. Accordingly, as shown in FIG. 10B, the measurement system observes the intensity change due to interference from the interference signals obtained by mixing the respective round received signals 71A and 71C of the phase measurement system and the calibration system, and stabilizes the phase change. Can be measured.

  In addition, it is hardly influenced by the fluctuation | variation of the time which observes a signal from a trigger. Even if there is some jitter in the gate timing, it is only necessary to observe the relative phase change of the output signals from the two devices 10A and 10B, and the jitter in the gate timing has little effect on the phase difference detection. do not do.

  Further, the adjustment time dT executed by the gate timing adjustment unit 32 can be obtained by various methods. For example, the circulation signal from the device 10B may be observed, and the arrival time difference between the signals may be directly obtained as dT. Alternatively, when mixing is performed and an interference signal is output, a gate timing at which the waveform of the interference signal becomes smooth may be obtained.

(Concrete example)
Hereinafter, a specific example when the measurement apparatus of the present embodiment is applied to a measurement system (sensor apparatus) that detects a hydrogen concentration will be described.

  Each of the devices 10A and 10B is a surface acoustic wave element that is a quartz sphere having a diameter of 1 cm, forms interdigital electrodes on the equator path (Z-axis cylinder) with the Z axis as the ground axis, and multiplexes Rayleigh waves. is there. One measurement system device 10A is formed by depositing palladium in a thickness of 20 nm along the equator path to form a hydrogen sensitive film. The other calibration system device 10B has no film such as the hydrogen-sensitive film formed on the surface. This calibration system device 10B has a temperature dependence of the circulation time, and is used for the purpose of calibrating a temperature change of about 25 ppm / degree.

  In this measurement system, a detection operation is performed in which a change in the difference in the circulation time between the devices 10A and 10B is interpreted as a change in the circulation speed caused by the palladium film absorbing hydrogen. That is, it has a detection function expressed by the relational expression “circumferential speed change due to hydrogen absorption = (signal phase difference at the number of laps S) / (2π * time to the number of laps S * frequency F)”.

  In this measurement system, the frequency of the RF burst signal, which is a continuous wave output from the high frequency generator 20, is 15.0 MHz and is fixed. The gate width of each of the gates 21A and 21B is 5 μs, thereby generating an RF burst signal input to each device 10A and 10B. The gate 21A of one measurement system has a phase shifter with a phase of 360 degrees immediately before it. The gate timing of the other calibration system gate 21B is adjusted by a digital gate timing adjustment unit 32 that can adjust the gate open time (dT) every 50 ns.

  A high-speed switch is arranged before connection to each device 10A, 10B, and is electrically insulated by impedance exchange immediately after the RF burst signal is applied to each device 10A, 10B. As a result, no signal is returned to the high-frequency signal generator 20 side. This not only prevents noise from being mixed into the signals for driving, but also serves to prevent the energy of the elastic surface network that circulates on the surfaces of the devices 10A and 10B from being consumed as electrical energy.

  Further, as described above, each device 10A, 10B has an electrode structure with a pair of interdigital transducers, which excites a surface acoustic wave with the same interdigital electrode and outputs from the same interdigital electrode. Measure the signal. A signal repeatedly output by the circulating surface acoustic wave is output to the amplifiers 22A and 22B through the switch. The switch is used in order to suppress damage to the amplifiers 22A and 22B due to the RF burst signal for excitation and not to consume energy along the wiring of the measurement system in the circulation process until the phase is observed.

  When this measurement system is placed in an environment with a hydrogen concentration of 0%, the RF burst signal is shifted by about 4 μs at about 200 laps (near 1997 μs after the gate OPEN time of the gate 21B). The output signals from the devices 10A and 10B have a time difference. Therefore, it has been found that even if each output signal is mixed as it is, it is difficult to measure the phase difference from the interference signal.

  Therefore, the gate timing adjustment unit 32 is used to change the gate OPEN time of about 4 μs of the gate 21B. As a result, the interference intensity of the interference signal could be measured as 1.5 radians from the intensity change caused by changing the phase by the phase shifter. Since this measured phase difference is considered to incorporate a phase change of an integer multiple N of 2π radians, the value of N was determined by the following method.

  Since the RF burst signal has a time lag of about 4 μs, 4 μs corresponds to a deviation of 60 times the period of the 15 MHz signal (about 66.6 nanoseconds). The same phase comparison was performed to obtain the phase difference. Next, when the phase difference in the fourth cycle is sequentially multiplied by four times the phase difference in the first cycle, the phase difference near the RF burst signal output in the 200th cycle is N = I was able to clarify the equivalent of 62. The method of obtaining the N value when the phase difference is a multiple of 2π (N times) can be realized by a known method called phase unwrapping.

  Therefore, what is the phase difference at the 200th lap? The calculation was successful as “2π * 62 + 1.5 = 391.046 radians”.

  Next, when the devices 10A and 10B were actually exposed to an environment with a hydrogen concentration of 1% and the same measurement was performed, the phase difference was found to be 391.048 radians, and 0.002 radians was the hydrogen concentration at the 200th lap. It was possible to measure that it changed due to the influence. Therefore, from the relational expression, it was possible to measure the change in the circulation speed as “0.002 radians / (2π * 1997 μsec / 66.6 nanoseconds) = 10.6 ppm”. Further, it was possible to measure that the change in the rotation speed of 10.6 ppm was about 1% of hydrogen from the hydrogen reaction of this device.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, 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.

The block diagram which shows the structure of the drive measurement apparatus of the ball | bowl SAW device regarding the 1st Embodiment of this invention. The figure which shows an example of RF burst signal regarding 1st Embodiment, and a circumference reception waveform. The timing chart which shows the circulation reception waveform in the measuring apparatus regarding 1st Embodiment, and the output signal waveform of an amplifier. The timing chart for demonstrating the generation timing of the window gate regarding 1st Embodiment. The timing chart for demonstrating the measurement process of the attenuation characteristic of the Nth periphery regarding 1st Embodiment. The block diagram which shows the structure of the drive measurement apparatus of the ball | bowl SAW device regarding 2nd Embodiment. The figure for demonstrating operation | movement of the drive measuring apparatus regarding 2nd Embodiment. The figure for demonstrating the measurement process of the phase difference regarding 2nd Embodiment. The figure for demonstrating the gate timing adjustment regarding 2nd Embodiment. The figure for demonstrating the measurement process of the phase difference regarding 2nd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Ball-shaped surface acoustic wave (SAW) device, 10A ... SAW device for measurement,
10B ... SAW device for calibration, 20 ... high frequency signal generator, 21,31 ... gate,
21A ... first gate, 21B ... second gate, 22 ... amplifier,
22A ... 1st amplifier, 22B ... 2nd amplifier, 23 ... Signal analysis part,
24 ... Measured value calculation unit, 25 ... Measurement result display unit, 26 ... Pulse number counting unit,
27... Gate timing calculation unit, 28... System control unit, 29.
30: Gate width changing unit, 310: Phase comparing unit, 32: Gate timing adjusting unit.

Claims (14)

A method for driving and measuring an acoustic wave device that generates and inputs a high-frequency signal to an acoustic wave device and measures response characteristics based on a circular reception signal that is repeatedly output from the acoustic wave device at a constant time interval.
Generating the high-frequency signal;
Identifying a position on the time axis of the round reception signal;
And a step of adjusting the duration of the high-frequency signal based on the specified position. A method for measuring and driving an acoustic wave device that measures response characteristics based on a circular reception signal that is repeatedly output by superimposing a high-frequency signal at a constant time interval with respect to an input of a high-frequency signal,
Generating the high-frequency signal;
Analyzing and measuring the response of the acoustic wave device to the input of the high frequency signal;
And adjusting the duration of the high-frequency signal to specify the position of the circular reception signal on the time axis.   The surface acoustic wave device is composed of a surface acoustic wave element having an electroacoustic transducer formed on a piezoelectric surface, and a surface acoustic wave responding to the high-frequency signal repeatedly propagates through a specific medium, thereby maintaining a constant value. The drive measurement method for an acoustic wave device according to any one of claims 1 and 2, wherein the output is repeatedly output at a period of time.   The said acoustic wave device is comprised from the surface acoustic wave element which has a circumference path | route, It is comprised so that the said circumference reception signal may be output based on the circumference | surroundings of the surface acoustic wave which propagates the surface. The drive measurement method for an acoustic wave device according to any one of claims 1 to 3.   5. The acoustic wave device according to claim 1, wherein the acoustic wave device includes a spherical surface acoustic wave element provided with a circular path having a spherical surface. 6. Drive measurement method. A surface acoustic wave device drive measurement method that generates and inputs a high-frequency signal to a surface acoustic wave device, and measures response characteristics based on a circular reception signal repeatedly output from the surface acoustic wave device at a constant time interval. And
Generating the high-frequency signal;
Having a time width shorter than a repetition period of repeated output, extracting a high-frequency signal for gate timing detection from the high-frequency signal, and inputting the high-frequency signal to the surface acoustic wave device;
A step of flattening the intensity of the circulating reception signal that becomes weaker as the circulation is repeated;
Counting the number of laps of the flattened round reception signal and generating a gate timing signal that operates at a specified time defined by a specific number of rounds;
A driving measurement of a surface acoustic wave device, comprising: a gate width longer than a duration of the high-frequency signal for gate timing detection, and a step of extracting a high-frequency signal for measurement according to the gate timing signal Method.   7. The surface acoustic wave device drive measurement method according to claim 6, wherein a duration of the gate timing detection high-frequency signal is shorter than an impulse or the repetition period. A surface acoustic wave device drive measurement device that generates and inputs a high-frequency signal to a surface acoustic wave device and measures response characteristics based on a circular reception signal repeatedly output from the surface acoustic wave device at a constant time interval. And
Means for generating the high-frequency signal;
Means for generating a gate timing signal for detecting the position of the round reception signal of a specified round using the high frequency signal;
Means for using the gate timing signal to separate the high frequency signal for measurement per round;
A driving and measuring apparatus for a surface acoustic wave device, comprising: means for measuring a response characteristic of the surface acoustic wave device based on the circulation reception signal that responds to the high-frequency signal for measurement for each revolution. . Driving a surface acoustic wave device that generates and inputs a high-frequency signal to a plurality of surface acoustic wave devices and measures a phase difference based on each round received signal repeatedly output from each surface acoustic wave device at a constant time interval A measuring method,
Generating the high-frequency signal;
Controlling at least one gate timing among a plurality of gate means for branching the high frequency signal and inputting it to each of the surface acoustic wave devices;
Analyzing and measuring the response of each surface acoustic wave device;
Adjusting the gate timing so as to adjust the input time of each branched high-frequency signal when performing phase comparison based on the response signal of each surface acoustic wave device. Drive measurement method for a surface acoustic wave device. Each of the branched high-frequency signals is a continuous high-frequency signal in phase with each other,
The step of adjusting the gate timing adjusts the gate timing in order to mutually adjust the time zones having the strengths of the high-frequency signals when performing mutual phase comparison. A driving measurement method for a surface acoustic wave device according to claim 1.   11. Each of the branched high-frequency signals has a period longer than the repetition period of the surface acoustic wave excited by the surface acoustic wave device. Drive measurement method for a surface acoustic wave device.   Each of the surface acoustic wave devices is composed of a surface acoustic wave element having a circular path, and is configured to output the circular reception signal based on the rotation of the surface acoustic wave propagating on the surface. The driving measurement method for a surface acoustic wave device according to any one of claims 9 and 10.   11. The surface acoustic wave device according to claim 9, wherein each of the surface acoustic wave devices comprises a spherical surface acoustic wave element provided with a circular path having a spherical surface. Wave drive drive measurement method. Driving a surface acoustic wave device that generates and inputs a high-frequency signal to a plurality of surface acoustic wave devices and measures a phase difference based on each round received signal repeatedly output from each surface acoustic wave device at a constant time interval A measuring device,
Means for generating the high-frequency signal;
A plurality of gate means for branching the high-frequency signal and inputting it to each of the surface acoustic wave devices;
Measuring means for analyzing and measuring the response of each surface acoustic wave device;
Means for adjusting the gate timing of the gate means so as to adjust the input time of each branched high-frequency signal when performing phase comparison based on the response signal of each surface acoustic wave device in the measuring means; An apparatus for measuring and driving a surface acoustic wave device, comprising:

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