Temperature Measuring Device

Abstract

The temperature measuring device includes a signal transmitting / receiving unit (1) having a first antenna (8) and a signal processing unit (3), and a sensor unit (2) having a second antenna (5) and a temperature measuring element (4). The temperature measuring element (4) has a resonant frequency (x * While receiving the transmission radio wave transmitted from the first antenna (8) via the second antenna (5), the resonant frequency (x * The signal processing unit (3) receives the response radio wave through the first antenna (8) while generating the transmission radio wave, and transmits the response radio wave at two or more different transmission frequencies (x i ,x i-1 The signal strength (A i ) based on the resonance frequency (x * (Θ)) and calculate the estimate of the resonant frequency (x * Based on the estimated value of (Θ), the transmission frequency (x i+1 ) to control the

Description

[Technical field]

[0001] The present disclosure relates to a temperature measuring device. [Background technology]

[0002] There has been a proposal for a temperature measuring device that is composed of a sensor unit placed on a measurement target and a signal transmitting / receiving unit placed away from the sensor unit (see, for example, Patent Document 1). This signal transmitting / receiving unit transmits an excitation signal (transmitted radio wave) consisting of a burst wave of a predetermined frequency to the sensor unit during a transmission period, receives a reception signal from the sensor unit during a reception period following the transmission period, detects a resonant reverberation signal due to the excitation signal from the reception signal, detects temperature as a physical quantity from the resonant frequency of the resonant reverberation signal, and reduces the signal strength of the excitation signal when the signal strength of the resonant reverberation signal is higher than a threshold value.

[0003] [Patent Document 1] International Publication No. 2014 / 129071 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the above-mentioned conventional temperature measuring device, an excitation signal is transmitted during a transmission period, a reception signal is received during a reception period, and a resonant reverberation signal is detected from the reception signal, so that the transmission period and the reception period must be separated, and therefore it is not possible to accurately measure the temperature of a measurement object whose temperature fluctuates in a short period of time.

[0005] An object of the present disclosure is to provide a temperature measuring device capable of accurately measuring the temperature of a measurement target. [Means for solving the problem]

[0006] A temperature measuring device according to the present disclosure includes a signal transmitting / receiving unit having a first antenna and a signal processing unit, and a sensor unit having a second antenna and a temperature measuring element, the temperature measuring element having a resonance characteristic in which a resonance frequency changes depending on the temperature of an object to be measured, and while receiving a transmission radio wave transmitted from the first antenna via the second antenna, transmits a response radio wave reflecting the resonance frequency via the second antenna, and the signal processing unit receives the response radio wave via the first antenna while generating the transmission radio wave, calculates an estimate of the resonance frequency of the temperature measuring element based on the signal strength of the response radio wave for each of the transmission radio waves of two or more different transmission frequencies, and controls the transmission frequency based on the estimate of the resonance frequency. the signal transmitting / receiving unit transmits a transmission radio wave of a first frequency lower than the resonant frequency and a transmission radio wave of a second frequency higher than the resonant frequency, measures a first signal strength of a response radio wave from the sensor unit to the transmission radio wave of the first frequency and a second signal strength of a response radio wave from the sensor unit to the transmission radio wave of the second frequency, calculates the estimated value of the resonant frequency based on the first frequency, the second frequency, the first signal strength, and the second signal strength, and controls the first frequency to be lower than the resonant frequency and the second frequency to be higher than the resonant frequency based on the estimated value, and sequentially changes the transmission frequency in accordance with a temperature change of the measurement object. It is characterized by: Effect of the Invention

[0007] According to the device of the present disclosure, the temperature of the measurement target can be accurately measured. [Brief description of the drawings]

[0008] [Figure 1] 1 is a functional block diagram showing a configuration of a temperature measuring device according to an embodiment; [Diagram 2] 2 is a diagram illustrating an example of a hardware configuration of a signal transmitting / receiving unit of a temperature measuring device according to an embodiment. FIG. [Diagram 3] FIG. 13 is a diagram showing how the resonance characteristics of a sensor unit change depending on temperature. [Figure 4] FIG. 1A shows an example of the temperature characteristics of the resonant frequency of the temperature measuring element of the sensor unit, and FIG. 1B shows that the temperature conversion unit of the signal transmitting / receiving unit can estimate the temperature of the object to be measured by calculating the temperature from an estimated value of the resonant frequency of the sensor unit. [Diagram 5] 5(A) and 5(B) are diagrams illustrating the operation of a temperature measuring device of a comparative example. [Figure 6] 5A and 5B are diagrams illustrating the operation of a temperature measuring device according to an embodiment. [Figure 7]4 is a flowchart showing an operation of the temperature measuring device according to the embodiment. [Figure 8] FIG. 8 is a diagram illustrating the processes of steps S1 to S3 in FIG. 7. [Figure 9] 13A and 13B are diagrams illustrating an example of a method for calculating an estimated value of a resonant frequency. [Figure 10] 8(A) and 8(B) are diagrams illustrating the process of step S5 in FIG. 7. [Figure 11] 6A to 6C are diagrams illustrating another example of a method for estimating a resonant frequency. [Figure 12] FIG. 13 is a diagram illustrating an example of calculation of a differential characteristic of a resonance characteristic. [Figure 13] FIG. 13 is a diagram illustrating another example of calculation of the differential characteristic of the resonance characteristic. [Figure 14] 8(A) and 8(B) are diagrams showing an example of setting the frequency of the transmission radio wave in step S7 of FIG. [Figure 15] 8(A) to 8(C) are diagrams showing another example of setting the frequency of the transmission radio wave in step S7 of FIG. [Figure 16] 8(A) to 8(C) are diagrams showing another example of setting the frequency of the transmission radio wave in step S7 of FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, a temperature measuring device according to an embodiment will be described with reference to the drawings. The following embodiments are merely examples, and each embodiment can be modified as appropriate.

[0010] 1 is a functional block diagram showing the configuration of a temperature measuring device according to an embodiment. The temperature measuring device according to the embodiment is composed of a signal transmitting / receiving unit 1 having a first antenna 8 and a signal processing unit 3, and a sensor unit 2 having a second antenna 5 and a temperature measuring element 4. The temperature measuring element 4 is, for example, a quartz crystal oscillator. The signal transmitting / receiving unit 1 is disposed away from the sensor unit 2. The signal transmitting / receiving unit 1 transmits a transmission radio wave to the sensor unit 2, receives a response radio wave from the sensor unit 2, and converts (calculates) the temperature Θ of the measurement object based on the response radio wave.

[0011] The sensor unit 2 is placed on or in the measurement object. The sensor unit 2 (particularly the temperature measuring element 4) is placed in contact with, for example, the device whose temperature is to be measured. The device to be measured is, for example, a moving device, a device in which temperature changes occur in a short period of time, or a device in which temperature changes must be measured instantaneously. A specific example of the device to be measured is the rotor of a motor.

[0012] The temperature measuring element 4 has a resonant frequency x according to the temperature Θ of the object to be measured. * The temperature measuring element 4 has a resonance characteristic in which the resonance frequency x (Θ) changes while receiving the transmission radio wave (excitation signal) transmitted from the first antenna 8 of the signal transmitting / receiving unit 1 via the second antenna 5. * The response radio wave reflecting the resonance frequency (Θ) is transmitted via the second antenna 5. The signal strength distribution of the response radio wave is * Since the peak value is at (Θ), the response wave has a resonant frequency x * (Θ) is reflected.

[0013] The signal processing unit 3 includes a frequency control unit 6, a transmission unit 7, a reception unit 9, a storage unit 10, a resonance frequency estimation unit 11, and a temperature conversion unit 12. In the signal processing unit 3, the transmission unit 7 generates a transmission radio wave, while the reception unit 9 receives a response radio wave via a first antenna 8. In the signal processing unit 3, the resonance frequency estimation unit 11 estimates two or more different transmission frequencies (for example, x i ,x i-1 ) the signal strength of the response radio wave for each of the transmitted radio waves (e.g., Ai ,A i-1 ) based on the resonant frequency x of the temperature measuring element 4 * The estimated (i.e. calculated) value of (Θ)

number

[0014] In this application, the resonant frequency x * Estimate of (Θ)

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[0015] The frequency control section 6 controls the resonant frequency x * The estimated value of (Θ) “x *~ i "The next transmission frequency x of the transmission radio wave is i+1 The temperature conversion unit 12 controls the estimated value of the resonance frequency “x *~ i ” to calculate the measured temperature.

[0016] The frequency control unit 6, the transmission unit 7, the reception unit 9, the memory unit 10, the resonant frequency estimation unit 11, and the temperature conversion unit 12 that constitute the signal processing unit 3 are functional blocks representing the respective functions of the signal processing unit 3, and these functional blocks may be constituted by a common processing circuit.

[0017] The signal transmitting / receiving unit 1 operates, for example, as follows. The signal transmitting / receiving unit 1 has a resonant frequency x * First frequency x less than (Θ) i The transmitted radio wave and the resonant frequency x * (Θ) A second frequency x that is greater than i-1 and transmit the first frequency x i The first signal strength A of the response radio wave from the sensor unit 2 to the transmitted radio wave i and a second signal strength A of a response radio wave from the sensor unit 2 to the transmission radio wave of the second frequency.i-1 and calculating a resonant frequency x based on the first frequency, the second frequency, the first signal strength, and the second signal strength. * The estimated value of (Θ) “x *~ i ” and estimate “x *~ i " based on the first frequency x i is the resonant frequency x * (Θ) is smaller than the second frequency x i-1 is the resonant frequency x * (Θ), and follow the temperature change of the measurement target to change the transmission frequency x i+1 Change it accordingly.

[0018] In addition, the signal transmitting / receiving unit 1 may periodically alternately transmit a transmission radio wave of a first frequency and a transmission radio wave of a second frequency, store the signal strength of the response radio wave from the sensor unit 2 to each of the transmission radio wave of the first frequency and the transmission radio wave of the second frequency, and calculate an estimate of the resonant frequency of the temperature measuring element for each measurement by referring to the measurement results of the first frequency or the second frequency and the measurement results recorded in the memory unit 10.

[0019] In addition, the signal transmitting / receiving unit 1 may transmit a transmission radio wave of a first frequency lower than the resonant frequency, measure a first signal strength of the response radio wave from the sensor unit 2, estimate the difference between the first transmission frequency and the resonant frequency from the first signal strength based on the resonant characteristics of the temperature measuring element 4, and calculate an estimate of the resonant frequency using the difference.

[0020] In addition, the signal transmitting / receiving unit 1 may transmit a transmission radio wave of a second frequency greater than the resonant frequency, measure a second signal strength of the response radio wave from the sensor unit 2, estimate a difference between the second transmission frequency and the resonant frequency from the second signal strength based on the resonant characteristics of the temperature measuring element 4, and use the difference to calculate an estimate of the resonant frequency.

[0021] In addition, the signal transmitting / receiving unit 1 may transmit a transmission radio wave of a first frequency to measure a first signal strength of the response radio wave of the sensor unit 2, transmit a transmission radio wave of a second frequency to measure a second signal strength of the response radio wave of the sensor unit 2, calculate a frequency difference between the first frequency and the second frequency and a signal strength difference between the first signal strength and the second signal strength, and calculate an estimate of the resonant frequency by estimating a frequency difference between the first frequency or the second frequency or the center frequency of the first frequency and the second frequency and the resonant frequency from the signal strength difference based on the differential characteristic of the resonant characteristic of the temperature measuring element.

[0022] The signal transmitting / receiving unit 1 may transmit a transmission radio wave of a first frequency lower than the resonant frequency to measure a first signal strength of the response radio wave of the sensor unit 2, transmit a transmission radio wave of a second frequency higher than the resonant frequency to measure a second signal strength of the response radio wave of the sensor unit 2, calculate a first differential coefficient from the frequency difference between the first frequency and the second frequency and the signal strength difference between the first signal strength and the second signal strength, and calculate an estimate of the resonant frequency by estimating the frequency difference between the first frequency, the second frequency, or the center frequency of the first frequency and the second frequency from the first differential coefficient based on the first differential characteristic of the resonant characteristic of the temperature measuring element.

[0023] The signal transmitting / receiving unit 1 can change the first frequency to a value that is a predetermined frequency smaller than the estimated resonant frequency based on the estimated resonant frequency of the temperature measuring element. Also, the signal transmitting / receiving unit 1 can change the second frequency to a value that is a predetermined frequency larger than the estimated resonant frequency based on the estimated resonant frequency.

[0024] The signal transmitting / receiving unit 1 may operate to compare an average frequency, which is an average value of the first frequency and the second frequency, with the estimated value of the resonant frequency based on the estimated value of the resonant frequency, and if the estimated value is smaller than the average frequency, to decrease the first frequency or the second frequency by a predetermined frequency, and if the estimated value is larger than the average frequency, to increase the first frequency or the second frequency by the predetermined frequency.

[0025] The signal transmitting / receiving unit 1 may convert the resonant frequency into temperature using a conversion table or a conversion formula prepared in advance and stored in the memory unit 10, record the temperature data in chronological order, perform a smoothing process using a low-pass filter, and output the smoothed temperature data.

[0026] The signal transmitting / receiving unit 1 may receive information regarding the heating / cooling of the object to be measured as a control input, and perform control to change the frequency update amount of the transmitted radio wave by predicting the amount of temperature change of the object to be measured and predicting the range of the amount of frequency change.

[0027] The signal transmitting / receiving unit 1 may have a function of sending an alert to the outside via sound, light, display screen, etc. when the calculated temperature is equal to or greater than a predetermined first threshold, or equal to or less than a predetermined second threshold, or both when the temperature is equal to or greater than the predetermined first threshold and when the temperature is equal to or less than the predetermined second threshold.

[0028] 2 is a diagram showing an example of a hardware configuration of a signal transmitting / receiving unit 1 of a temperature measuring device according to an embodiment. The signal transmitting / receiving unit 1 has a processor 101 such as a CPU (Central Processing Unit) that executes a program, a memory 102 as a storage device, a non-volatile storage device 103, a transmitting unit 7, and a receiving unit 9. The signal transmitting / receiving unit 1 may also be configured with a processing circuit such as a single circuit, a composite circuit, or an FPGA (Field Programmable Gate Array). When the signal transmitting / receiving unit 1 is configured with a processing circuit, the processing circuit may include the processor 101 and a memory 102 that stores a program executed by the processor 101.

[0029] The storage device 103 is a storage such as a hard disk drive (HDD) or a solid state drive (SSD), etc. The memory 102 is a semiconductor memory such as a random access memory (RAM).

[0030] 3 is a diagram showing that the resonance characteristic of the sensor unit 2 changes according to the temperature Θ of the temperature measuring element 4 (i.e., the temperature of the object to be measured). The temperature measuring element 4 of the sensor unit 2 changes in resonance frequency x * (Θ) has the property of changing.

[0031] When a transmission radio wave is sent from the first antenna 8 of the signal transmitting / receiving unit 1 to the second antenna 5 of the sensor unit 2, a response radio wave is reflected from the sensor unit 2. The response radio wave has a signal strength distribution with resonance characteristics according to the temperature Θ of the measurement object. In the signal transmitting / receiving unit 1, the receiver 9 receives the response radio wave from the sensor unit 2 via the first antenna 8 and calculates the signal strength or quadrature phase amplitude.

[0032] Figure 3 shows the resonance characteristics of the sensor unit 2 when the temperature Θ of the object to be measured is Θ1 (the resonance frequency is x * (Θ1).) and the resonance characteristic of the sensor unit 2 when the temperature Θ is Θ2 (the resonance frequency is x * (Θ2). Here, the resonance characteristic refers to the distribution of signal strength [au] when a response radio wave reflected from the sensor unit 2 is received by the signal transmitting / receiving unit 1 when a transmission radio wave of each frequency is transmitted from the signal transmitting / receiving unit 1. As shown in FIG. 3, the resonance frequency x * (Θ) changes. In each figure, au indicates an arbitrary unit.

[0033] FIG. 4A shows the resonant frequency x of the temperature measuring element 4 of the sensor unit 2. * FIG. 4(A) is a graph showing an example of the temperature characteristic of (Θ). * (Θ1), and when the temperature Θ rises to Θ2, the resonant frequency is x * This indicates that (Θ2).

[0034] FIG. 4B shows that the temperature conversion unit 12 of the signal transmitting / receiving unit 1 estimates the resonant frequency of the sensor unit 2, “x *~" to temperature (i.e., temperature conversion value)

number

[0035] In this application:

number

[0036] 5(A) and (B) are diagrams showing the operation of the comparative temperature measuring device shown in Patent Document 1. In the comparative temperature measuring device, a transmission signal is transmitted from the signal transmitting / receiving unit to the sensor unit between time 0 and T, and between time T and 2T, the signal transmitting / receiving unit calculates a resonant frequency x based on the intensity of a reverberation signal, which is a response radio wave from the sensor unit. * Next, between times 2T and 3T, the signal transmitting / receiving unit transmits a transmission signal to the sensor unit, and between times 3T and 4T, the signal transmitting / receiving unit estimates the resonant frequency x based on the intensity of the reverberation signal, which is a response radio wave from the sensor unit. * The estimate of x *~ In this way, in the comparative example, the transmission period and the reception period are set separately, so the resonance frequency x is calculated at an interval of 2T, which is the total time of the transmission period and the reception period. * Estimate.

[0037] 6A and 6B are diagrams illustrating the operation of the temperature measuring device according to the embodiment. In the temperature measuring device according to the embodiment, a transmission signal is transmitted from the signal transmitting / receiving unit 1 to the sensor unit 2 between times 0 and T, and the signal transmitting / receiving unit 1 calculates the resonant frequency x based on the intensity of the response radio wave from the sensor unit 2 between times T and 2T. * The estimate of x *~1" is calculated. Then, between time T and 2T, the signal transmitting / receiving unit 1 transmits a transmission signal to the sensor unit 2, and between time 2T and 3T, the signal transmitting / receiving unit 1 calculates the resonant frequency x * The estimated value “x *~ 2”. Next, between times 2T and 3T, the signal transmitting / receiving unit transmits a transmission signal to the sensor unit, and between times 3T and 4T, the signal transmitting / receiving unit calculates the resonant frequency x * The estimated value “x *~ 3" is calculated. In this way, in the temperature measuring device according to the embodiment, the resonant frequency x * In addition, to estimate the resonance frequency of the temperature measuring device according to the embodiment, a transient response signal, not a reverberation signal, of the sensor unit 2 is used.

[0038] 7 is a flowchart showing the operation of the temperature measuring device according to the embodiment. In step S1, the signal processing unit 3 of the signal transmitting / receiving unit 1 first sets the variable i representing the measurement number to 0, and i Then, predetermined initial value frequencies x0 and x1 are set.

[0039] In step S2, the signal processing unit 3 of the signal transmitting / receiving unit 1 measures the signal strengths A0 and A1 of the response radio waves from the sensor unit 2 in response to the transmitted radio waves of frequencies x0 and x1.

[0040] In step S3, the signal processing unit 3 of the signal transmitting / receiving unit 1 sets the frequency x1 as the frequency of the transmission radio wave.

[0041] In loop L1 (start), the signal processing unit 3 of the signal transmitting / receiving unit 1 increments the variable i by 1 (i←i+1) and executes steps S4 to S7.

[0042] In step S4, the signal processing unit 3 of the signal transmitting / receiving unit 1 sets the transmission frequency x i The signal strength A of the response radio wave from sensor unit 2 to the transmitted radio wavei Measure.

[0043] In step S5, the signal processing unit 3 of the signal transmitting / receiving unit 1 outputs the current measurement result (x i ,A i ) and the previous measurement result (x i-1 ,A i-1 ) and the estimated resonant frequency of the sensor unit 2, “x *~ i ”Calculate.

[0044] In step S6, the signal processing unit 3 of the signal transmitting / receiving unit 1 estimates the resonant frequency of the sensor unit 2, “x *~ i "Temperature

number

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[0045] In step S7, the signal processing unit 3 of the signal transmitting / receiving unit 1 calculates the estimated value of the resonant frequency “x *~ i " and the frequency of the transmitted radio wave x i and x i-1 Then, the frequency of the next transmission is x i+1 After that, the process returns to loop L1 (start), and steps S4 to S7, which are the process of loop L1, are repeated until an end command is received.

[0046] Fig. 8 is a diagram showing the processing of steps S1 to S3 in Fig. 7. First, the signal processing unit 3 sweeps the frequency x of the transmission radio wave in the frequency control unit 6, measures the resonance characteristic A(x) of the signal strength of the response radio wave, and calculates a resonance peak value A(x) which is the peak value of the strength distribution of the response signal. * and calculate the half width at half maximum σ.

[0047] In step S1 of FIG. 7, the signal processor 3 of the signal transmitting / receiving unit 1 calculates an initial estimate of the resonant frequency

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[0048] The initial estimate of the resonant frequency, x *~ 0” is, for example, the ambient temperature Θ measured by another temperature sensor. E The following resonance frequency calculated from the temperature characteristic of the resonance frequency of the sensor unit 2 (FIG. 4(A)) may be used.

number

[0049] Alternatively, the initial estimate of the resonant frequency, x *~ 0″ may be the following resonance frequency calculated from the previously obtained resonance characteristic A(x).

number

[0050] Alternatively, if the resonance characteristic is a minimum characteristic, the initial estimate of the resonance frequency, “x *~ 0″ may be the following resonance frequency calculated from the previously obtained resonance characteristic A(x).

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[0051] Furthermore, the signal processing unit 3 sets the initial values ​​x0 and x1 of the transmission frequency to, for example, the resonance frequency x *Using (Θ) and the half-width at half maximum of the resonance characteristic σ, it can be set as follows: x0=x * (Θ)-σ x1=x * (Θ)+σ

[0052] The temperature Θ of the object to be measured changes with time, and the resonant frequency x * (Θ) is also thought to change over time.

[0053] Therefore, the signal processor 3 estimates the resonant frequency “x *~ i In order to accurately calculate ", the value of the transmission frequency is set in the region where the slope of the resonance characteristic is steep, that is, two frequencies (x * +σ) and (x * The frequency control unit 6 updates the first frequency and the second frequency so that they become values ​​close to (-σ) (step S4 and subsequent steps). In a region where the slope of the resonance characteristics is steep, the change in signal strength is large relative to the change in frequency, so that it is easy to estimate the change in frequency from the change in the measured signal strength.

[0054] 9A and 9B show the estimated value of the resonant frequency “x *~ i FIG. 9(A) is a diagram showing an example of a method for calculating the estimated value “x *~ i 9B shows an example of calculating the resonant frequency estimate “x *~ i 9A and 9B show an example of calculating the resonance characteristic of the maximum resonance characteristic.

[0055] In Figure 9(A), x i <x i-1 and x i is the first frequency, and the resonant frequency x * Since the value is set to be sufficiently smaller than (Θ), the signal processor 3 i ≦x * (Θ), the estimated resonant frequency is “x *~i The signal processor 3 calculates the resonance frequency x * Based on the resonance characteristics on the lower frequency side of (Θ), the signal strength A i From x * (Θ) and x i Calculate the frequency difference Δx<0.

[0056] In Figure 9(B), x i-1 <x i and x i is the second frequency, and the resonant frequency x * Since the value is set to be sufficiently larger than (Θ), the signal processor 3 * (Θ)≦x i Assuming that the resonant frequency is estimated as “x *~ i The signal processor 3 calculates the resonance frequency x * (Θ) Based on the resonance characteristics on the higher frequency side, signal strength A i x * (Θ) and x i Calculate the frequency difference Δx>0.

[0057] The estimated resonant frequency “x *~ i " is expressed by the following equation using the frequency difference Δx.

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[0058] The following method can be used to calculate Δx. For example, when the resonance characteristic of the temperature measuring element 4 is a Lorentz function, the resonance characteristic is expressed by the following formula:

number

[0059]

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[0060] 10A and 10B show the estimated value of the resonant frequency “x *~ i 10A shows an example of a method for calculating an estimated resonant frequency from a first frequency, and FIG. 10B shows an example of a method for calculating an estimated resonant frequency from a second frequency. FIGS. 10A and 10B show a case where the resonant characteristics are minimum characteristics. FIGS. 10A and 10B are similar to FIGS. 9A and 9B, which show a case where the resonant characteristics are maximum characteristics, except that they show a case where the resonant characteristics are minimum characteristics.

[0061] 11(A) to (C) are diagrams showing another example of a method for estimating a resonant frequency, where Fig. 11(A) shows the measurement of signal strength, Fig. 11(B) shows the differential characteristic of the resonant characteristic, and Fig. 11(C) shows the estimation of the resonant frequency.

[0062] As shown in FIG. 11(A), the signal processing unit 3 outputs the (i-1)th measurement result (x i-1 ,A i-1 ) and the i-th measurement result (x i ,A i The signal processor 3 obtains the frequency difference w and the signal strength difference ΔA i and are calculated respectively. w indicates the half width of the frequency difference, and is calculated by the following formula:

[0063]

number

[0064] The signal strength difference ΔA is calculated by the following formula: ΔA i =A i -A i-1

[0065] FIG. 11B shows an example of calculating the frequency difference Δx from the differential characteristic B(x;w) of the resonance characteristics.

[0066] Figure 11(C) shows the calculated Δx and average frequency.

number

[0067]

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[0068] 12 is a diagram showing an example of calculation of the difference characteristic B(x;w) of the resonance characteristic. If the resonance characteristic obtained in advance in step S1 is denoted by A(x), then when the resonance characteristic has a Lorentz function form, the resonance characteristic is expressed by the following formula.

[0069]

number

[0070] As a differential characteristic, the detuning ξ is expressed by the following equation: ξ=xx *

[0071] The differential characteristic B(x;w) is defined using the detuning ξ as follows:

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[0072] The following formula:

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[0073] Fig. 13 is a diagram showing another example of calculation of the differential characteristic of the resonance characteristic. As an approximate calculation method of Δx, there is a method of linearizing the differential characteristic at the origin (resonance point). If the gradient of B(ξ;w) at the origin is "a", the following formula is established.

[0074]

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[0075] Also,

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[0076] In addition, the following equation can be used as a solution using differential coefficients:

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[0077] 14A and 14B are diagrams showing an example of setting the frequency of the transmission radio wave in step S7 of FIG. 7. FIG. 14A and 14B show a case where the resonance characteristic is a maximum characteristic. FIG. 14A shows a case where x i <x i-1 In the case of FIG. 14(B), i-1 <x i This shows the case.

[0078] In step S7 of FIG. 7, the estimated value of the resonant frequency

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[0079] If δ is a given frequency update amount, then x i <x i-1 Then, the frequency of the transmitted radio wave x is as follows: i+1 Set.

[0080]

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[0081] If δ is a given frequency update amount, then x i-1 <x i Then, the frequency of the transmitted radio wave x is as follows: i+1 Set.

[0082]

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[0083] Figures 15(A) to (C) and Figures 16(A) to (C) are diagrams showing other examples of setting the frequency of the transmission radio wave in step S7 of Figure 7. Figures 15(A) to (C) and Figures 16(A) to (C) show the case where the resonance characteristic is a maximum characteristic.

[0084] Resonant Frequency Estimation

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[0085]

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[0086]

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[0087]

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[0088]

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[0089] In this method, the transmission radio wave is updated in δ steps, which simplifies the configuration of the transmission unit 7. For example, the predetermined frequency update amount δ may be set to δ=σ / 10.

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[0090] As described above, the temperature measuring device according to the embodiment can measure the temperature transient response of an object. In addition, since the time required for one temperature estimation can be shortened, the temperature transient response of an object whose temperature changes over time in a short period of time can be measured.

[0091] Furthermore, even if the resonant frequency of the temperature measuring element 4 changes due to a change in the temperature of the measurement target, the resonant frequency at the current time can be estimated.

[0092] In addition, since the resonant frequency is estimated from the difference between the strengths of two signals, it is possible to cancel out fluctuations in the offset of the signal strength of the receiving unit (low-frequency noise), improving the accuracy of estimating the resonant frequency.

[0093] Furthermore, since the transmission frequency is successively changed to a value suitable for estimating the resonant frequency, the accuracy of temperature measurement is improved. [Explanation of symbols]

[0094] REFERENCE SIGNS LIST 1 signal transmitting / receiving unit, 2 sensor unit, 3 signal processing unit, 4 temperature measuring element, 5 second antenna, 6 frequency control unit, 7 transmission unit, 8 first antenna, 9 reception unit, 10 storage unit, 11 resonance frequency estimation unit, 12 temperature conversion unit, Θ temperature, x * (Θ) Resonant frequency.

Claims

1. A signal transmission / reception unit having a first antenna and a signal processing unit, A sensor unit having a second antenna and a temperature detection element, characterized by comprising: The temperature detection element has a resonance characteristic in which the resonance frequency changes according to the temperature of the measurement target, while receiving the transmitted radio wave transmitted from the first antenna via the second antenna, transmits a response radio wave reflecting the resonance frequency via the second antenna, The signal processing unit receives the response radio wave via the first antenna while generating the transmitted radio wave, calculates an estimated value of the resonance frequency of the temperature detection element based on the signal intensity of the response radio wave for each of the transmitted radio waves at two or more different transmission frequencies, controls the transmission frequency based on the estimated value of the resonance frequency, The signal transmission / reception unit transmits a transmitted radio wave at a first frequency lower than the resonance frequency and a transmitted radio wave at a second frequency higher than the resonance frequency, respectively, measures a first signal intensity of the response radio wave of the sensor unit with respect to the transmitted radio wave at the first frequency and a second signal intensity of the response radio wave of the sensor unit with respect to the transmitted radio wave at the second frequency, respectively, calculates the estimated value of the resonance frequency based on the first frequency, the second frequency, the first signal intensity, and the second signal intensity, controls so that the first frequency is lower than the resonance frequency and the second frequency is higher than the resonance frequency based on the estimated value, and sequentially changes the transmission frequency following the temperature change of the measurement target A thermometer characterized by the above.

2. The signal transmission / reception unit periodically transmits the transmitted radio wave at the first frequency and the transmitted radio wave at the second frequency alternately, and stores the signal intensity of the response radio wave of the sensor unit with respect to each of the transmitted radio wave at the first frequency and the transmitted radio wave at the second frequency, calculates an estimated value of the resonance frequency of the temperature detection element for each measurement by referring to the measurement result at the first frequency or the second frequency and the measurement result recorded in the storage unit The thermometer according to claim 1, characterized by the above.

3. The signal transmission / reception unit estimates a first difference between the first transmission frequency and the resonance frequency from the first signal intensity and a second difference between the second transmission frequency and the resonance frequency from the second signal intensity based on the resonance characteristic of the temperature detection element, Calculating the estimated value of the resonance frequency using the first difference and the second difference The thermometer according to claim 1, characterized in that.

4. A signal transmission / reception unit having a first antenna and a signal processing unit, A sensor unit having a second antenna and a temperature detection element, Having, The temperature detection element, Has a resonance characteristic in which the resonance frequency changes according to the temperature of the measurement target, While receiving the transmitted radio wave transmitted from the first antenna via the second antenna, transmitting a response radio wave reflecting the resonance frequency via the second antenna, The signal processing unit, Receiving the response radio wave via the first antenna while generating the transmitted radio wave, Calculating an estimated value of the resonance frequency of the temperature detection element based on the signal intensity of the response radio wave for each of the transmitted radio waves at two or more different transmission frequencies, Controlling the transmission frequency based on the estimated value of the resonance frequency, The signal transmission / reception unit, Transmitting a transmitted radio wave having a first frequency lower than the resonance frequency, measuring a first signal intensity of the response radio wave of the sensor unit, Based on the resonance characteristic of the temperature detection element, estimating a difference between the first transmission frequency and the resonance frequency from the first signal intensity, and calculating the estimated value of the resonance frequency using the difference The thermometer characterized by this.

5. A signal transmission / reception unit having a first antenna and a signal processing unit, A sensor unit having a second antenna and a temperature detection element, Having, The temperature detection element, Has a resonance characteristic in which the resonance frequency changes according to the temperature of the measurement target, While receiving the transmitted radio wave transmitted from the first antenna via the second antenna, transmitting a response radio wave reflecting the resonance frequency via the second antenna, The signal processing unit, Receiving the response radio wave via the first antenna while generating the transmitted radio wave, Calculating an estimated value of the resonance frequency of the temperature detection element based on the signal intensity of the response radio wave for each of the transmitted radio waves at two or more different transmission frequencies, Controlling the transmission frequency based on the estimated value of the resonance frequency, The signal transmission / reception unit, Transmitting a transmitted radio wave having a second frequency higher than the resonance frequency, measuring a second signal intensity of the response radio wave of the sensor unit, Based on the resonance characteristics of the temperature detection element, estimate the difference between the second transmission frequency and the resonance frequency from the second signal intensity, and calculate the estimated value of the resonance frequency using the difference. A thermometer characterized by the above. **Claim 6** The signal transmission / reception unit transmits a transmission radio wave of the first frequency to measure the first signal intensity of the response radio wave of the sensor unit, and transmits a transmission radio wave of the second frequency to measure the second signal intensity of the response radio wave of the sensor unit. Calculate the frequency difference between the first frequency and the second frequency and the signal intensity difference between the first signal intensity and the second signal intensity, and based on the differential characteristics of the resonance characteristics of the temperature detection element, estimate the frequency difference between the first frequency or the second frequency or the center frequency of the first frequency and the second frequency and the resonance frequency from the signal intensity difference, thereby calculating the estimated value of the resonance frequency. The thermometer according to claim 1, characterized by the above. **Claim 7** The signal transmission / reception unit transmits a transmission radio wave of a first frequency smaller than the resonance frequency to measure the first signal intensity of the response radio wave of the sensor unit. transmits a transmission radio wave of a second frequency larger than the resonance frequency to measure the second signal intensity of the response radio wave of the sensor unit. Calculate the first-order differential coefficient from the frequency difference between the first frequency and the second frequency and the signal intensity difference between the first signal intensity and the second signal intensity. Based on the first-order differential characteristics of the resonance characteristics of the temperature detection element, estimate the frequency difference between the first frequency, the second frequency, or the center frequency of the first frequency and the second frequency from the first-order differential coefficient, thereby calculating the estimated value of the resonance frequency. The thermometer according to claim 1, characterized by the above. **Claim 8** The signal transmission / reception unit Based on the estimated value of the resonance frequency of the estimated temperature detection element, change the first frequency to a value smaller than the estimated value of the resonance frequency by a predetermined frequency. The thermometer according to claim 1, characterized by the above. **Claim 9** The signal transmission / reception unit Based on the estimated value of the resonance frequency, change the second frequency to a value larger than the estimated value of the resonance frequency by a predetermined frequency. The thermometer according to claim 1, characterized by the above. **Claim 10** The signal transmission / reception unit Based on the estimated value of the resonance frequency, compare the average frequency, which is the average value of the first frequency and the second frequency, with the estimated value of the resonance frequency. When the estimated value is smaller than the average frequency, decrease the first frequency or the second frequency by a predetermined frequency. When the estimated value is larger than the average frequency, increase the first frequency or the second frequency by a predetermined frequency. The thermometer device according to claim 1, characterized in that.

11. The signal transmission / reception unit receives information regarding heating / cooling of the measurement target as a control input, predicts the temperature change amount of the measurement target, and predicts the range of the change amount of the frequency, thereby changing the frequency update amount of the transmission radio wave. The thermometer device according to claim 8 or 9, characterized in that.

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