Measurement device, measurement method, and program

Abstract

To prevent deterioration of measurement accuracy due to a parasitic capacitance on an input resistor.SOLUTION: A measurement device 1 comprises: a first input circuit 11 provided with a first input terminal to which a first signal indicating the magnitude of a potential generated in a measurement object is input; an input resistor 111 having one end connected to the first input terminal; and a first resistor 112 having one end connected to the other end of the input resistor 111 and the other end connected to a reference potential. The measurement device 1 further comprises: a second input circuit 12 provided with a second input terminal to which a second signal indicating the magnitude of a current flowing to the measurement object is input and which calculates a physical quantity of the measurement object on the basis of the output signals of the first input circuit 11 and the second input circuit 12. The measurement device 1 performs processing for compensating the capacitance parasitic Cp to the input resistor 111 and the frequency characteristics of a filter composed of the input resistor 111 and the first resistor 112, for the output signal of the second input circuit 21.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a measurement device, a measurement method, and a program for calculating a physical quantity of a measurement target. [Background technology]

[0002] Patent Document 1 discloses a measuring device that calculates power based on a voltage signal output from a voltage detection section and a current signal output from a current detection section. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2008-175532 A Summary of the Invention [Problem to be solved by the invention]

[0004] Among the measuring devices as described above, there are some in which the amplitude level of the voltage signal is larger than the amplitude level of the current signal, and such measuring devices often have an input resistor arranged as an attenuator to attenuate the amplitude level of the input voltage signal.

[0005] However, when the resistance value of the attenuator is increased, the influence of the frequency characteristic of the filter formed by the resistance and parasitic capacitance of the attenuator becomes large, and the frequency characteristic of the voltage signal is impaired. As a result, in the band where the frequency characteristic of the voltage signal is impaired, a phase shift occurs between the voltage signal output from the voltage detection unit and input to the measurement device through the attenuator, and the current signal output from the current detection unit and input directly to the measurement device, resulting in a problem of a decrease in the measurement accuracy of the physical quantity obtained from the voltage signal and the current signal.

[0006] The present invention has been made in view of the above-mentioned problems, and has an object to suppress a decrease in measurement accuracy caused by a parasitic capacitance in an input resistor such as an attenuator. [Means for solving the problem]

[0007] According to one aspect of the present invention, a measurement device includes a first input circuit having a first input terminal to which a first signal indicating the magnitude of a potential generated in an object to be measured is input, an input resistor having one end connected to the first input terminal, and a first resistor having one end connected to the other end of the input resistor and the other end connected to a reference potential. The measurement device further includes a second input circuit having a second input terminal to which a second signal indicating the magnitude of a current flowing through the object to be measured is input, and a calculation means for calculating a physical quantity of the object to be measured based on output signals from the first input circuit and the second input circuit. The measurement device further includes a compensation means for performing a process on the output signal from the second input circuit to compensate for a capacitance parasitic to the input resistor and a frequency characteristic of a filter formed by the input resistor and the first resistor. Effect of the Invention

[0008] According to the above aspect, the compensation means adds the frequency characteristic of the filter constituted by the input resistance, the first resistance, and the parasitic capacitance of the first input circuit to the output signal of the second input circuit, thereby reducing the deviation in frequency characteristics between the first input circuit and the second input circuit.

[0009] Therefore, the phase shift between the output signal of the first input circuit and the output signal of the second input circuit used in the calculation of the physical quantity is reduced, so that the physical quantity of the measurement target can be measured with high accuracy. In other words, it is possible to suppress the decrease in measurement accuracy caused by the parasitic capacitance of an input resistor such as an attenuator. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram showing the configuration of a measurement device according to the first embodiment. [Diagram 2]FIG. 2 is a circuit diagram showing the circuit configuration of the two channel input sections of the measurement device. [Diagram 3] FIG. 3 is a circuit diagram showing a configuration example of the LPF circuits at the input sections of the two channels. [Figure 4] FIG. 4 is a diagram for explaining the frequency characteristics of a compensation circuit provided at the second input section for compensating for deterioration of the frequency characteristics caused by the parasitic capacitance of an input resistor provided at the first input section. [Diagram 5] FIG. 5 is a flowchart showing an example of a measurement method executed by the measurement device. [Figure 6] FIG. 6 is a diagram showing the configuration of a measurement device according to the second embodiment. [Figure 7] FIG. 7 is a circuit diagram showing a configuration example of a compensation LPF circuit provided at the second input section. [Figure 8] FIG. 8 is a diagram showing the configuration of a measurement device according to the third embodiment. [Figure 9] FIG. 9 is a diagram showing the configuration of a measurement device according to the fourth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In this specification, the same reference numerals are used throughout to refer to the same or equivalent elements.

[0012] First embodiment FIG. 1 is a circuit diagram showing the circuit configuration of the measurement device according to the first embodiment.

[0013] The measurement device 1 of the first embodiment is a device for measuring electrical signals input to multiple channels, and measures the physical quantity of a measurement object. Examples of the measurement object include an electric wire that transmits electric power, a power conversion device, and a power supply device. The measurement object of the first embodiment is an electric wire.

[0014] Physical quantities (measurements) measured by the measurement device 1 include the power and power efficiency of the measurement target, the impedance of the measurement target, and the phase difference between input signals. The measurement quantity in the first embodiment is the magnitude of the power transmitted to the electric wire.

[0015] The measuring device 1 is a computer that includes a processor, a ROM (Read Only Memory), a RAM (Random Access Memory), an input / output interface, and a bus that interconnects these, etc. Examples of the processor include a CPU (Central Processing Unit) and an MPU (Micro Processor Unit).

[0016] The measurement device 1 includes a voltage channel input section 10, a current channel input section 20, a processing section 30, a storage section 40, a display section 50, and an operation section 60.

[0017] The voltage channel input unit 10 converts an analog input signal indicating the magnitude of the potential generated in the measurement target into a digital signal, and outputs the converted digital signal to the processing unit 30 as voltage measurement data.

[0018] The current channel input section 20 converts an analog input signal indicating the magnitude of a current flowing through an object to be measured into a digital signal. The current channel input section 20 outputs the converted digital signal to the processing section 30 as current measurement data.

[0019] The processing unit 30 calculates a physical quantity of the measurement target based on the output signals of the voltage channel input unit 10 and the current channel input unit 20. The processing unit 30 of the first embodiment calculates power transmitted to the electric wire to be measured. The processing unit 30 is configured with one or more processors.

[0020] The storage unit 40 stores, for example, the calculation results obtained by the processing unit 30, the measurement conditions, etc. The storage unit 40 also stores a program for controlling the operation of the measurement device 1. The storage unit 40 is a computer-readable recording medium on which the program is recorded, and is composed of a ROM and a RAM.

[0021] The display unit 50 displays the above-mentioned measurement results or measurement conditions. The display unit 50 is configured, for example, as a touch panel so that the user can visually recognize information and can operate it. Alternatively, the display unit 50 may be configured as a liquid crystal display or an LED display.

[0022] The operation unit 60 is composed of a plurality of push buttons provided around the display screen, a touch sensor arranged within the display screen, or a keyboard and a mouse, etc. The operation unit 60 receives an input operation from a user and generates an operation signal indicating the content of the received input operation.

[0023] Examples of the input operation include an operation of pressing a power button, an operation of setting measurement conditions and display conditions, an operation of instructing the start or end of a measurement process, etc. The operation unit 60 outputs the generated operation signal to the processing unit 30.

[0024] FIG. 2 is a circuit diagram showing an example of the circuit configuration of the voltage channel input section 10 and the current channel input section 20. As shown in FIG.

[0025] As shown in FIG. 2, a voltage signal Sv is input to a voltage channel input section 10 in the first embodiment, and a current signal Si is input to a current channel input section 20.

[0026] The voltage signal Sv is a first signal indicating the magnitude of the potential generated in the measurement target. The voltage signal Sv in the first embodiment is a voltage detection signal output from a clip or a terminal that extracts the voltage of the electric wire. In the first embodiment, the amplitude level of the voltage signal Sv is larger than the amplitude level of the current signal Si.

[0027] The current signal Si is a second signal indicating the magnitude of the current flowing through the object to be measured. The current signal Si in the first embodiment is a current detection signal output from a current sensor that detects the current flowing through the electric wire to be measured. For example, a current sensor that detects the current flowing through the electric wire in a non-contact manner while the electric wire is clamped is used as the current sensor.

[0028] A voltage terminal 1A of the voltage channel input section 10 is a first input terminal to which a voltage signal Sv is input, and a current terminal 1B of the current channel input section 20 is a second input terminal to which a current signal Si is input.

[0029] A voltage signal Sv having a frequency ranging from 1 Hz to several MHz is input to the voltage terminal 1A. The voltage signal Sv in the first embodiment has a high voltage of several hundred V to several kV.

[0030] The voltage channel input unit 10 receives a voltage signal Sv and converts the analog voltage signal Sv into a digital voltage value to output voltage measurement data. The voltage channel input unit 10 of the first embodiment includes an input circuit 11, an LPF circuit 12, and an AD converter 13.

[0031] The input circuit 11 is a first input circuit that includes a voltage terminal 1A to which a voltage signal Sv from a voltage sensor is input, an input resistor 111 having one end connected to the voltage terminal 1A, and a first resistor 112 having one end connected to one end of the input resistor 111 and the other end connected to a reference potential G.

[0032] The input circuit 11 of the first embodiment functions as a voltage measuring circuit that measures the output voltage of the voltage sensor, and includes an input resistor 111, a first resistor 112, and a buffer circuit 113.

[0033] The input resistor 111 is an electric resistor to which a voltage signal Sv is input from a voltage terminal 1A, and a parasitic capacitance Cp that is parasitic on the input resistor 111 is added to the input resistor 111.

[0034] Since the amplitude level of the voltage signal Sv is larger than that of the current signal Si, the input resistor 111 is used to attenuate the amplitude level of the voltage signal Sv so that the amplitude level of the voltage signal Sv falls within the input range of the buffer circuit 113. The resistance values ​​of the input resistor 111 and the first resistor 112 in the first embodiment are determined to be such that the signal level of the voltage signal Sv is attenuated to a level equivalent to the input level of the input circuit 21.

[0035] The input resistor 111 is composed of one or more resistive elements, and is realized by, for example, a general resistor or a high-voltage resistor that can be used at a voltage higher than the withstand voltage of a general resistor. The input resistor 111 in the first embodiment is configured by a high-voltage resistor having a resistance value in the range from several hundred kΩ to several MΩ.

[0036] In the above-mentioned high voltage resistor, in order to increase the resistance value, a meandering resistor pattern having many folded parts between the electrodes is formed so that the path of the resistor pattern is long. As a result, a large number of capacitive couplings are continuously distributed between the many folded parts formed in the resistor pattern and the reference potential G, like a distributed constant circuit.

[0037] In this way, in the high voltage resistor, many electrostatic capacitance components are continuously parasitic along the electrodes, and therefore, a composite capacitance obtained by combining many capacitive couplings is shown as a parasitic capacitance Cp in Fig. 1. The composite value of the parasitic capacitance Cp in the first embodiment has a capacitance value of, for example, several pF.

[0038] The presence of this parasitic capacitance Cp impairs the frequency characteristics of the input resistor 111. Specifically, the flatness of the frequency characteristics of the voltage channel input unit 10 is deteriorated due to the frequency characteristics of a filter (RC circuit) formed by the parasitic capacitance Cp, the input resistor 111, and the first resistor 112. For example, the frequency characteristics of the voltage channel input unit 10 degrades from around several hundred kHz or several MHz.

[0039] The frequency characteristics referred to here include frequency characteristics of amplitude and phase. In the following, the filter formed by the parasitic capacitance Cp, the input resistor 111, and the first resistor 112 is also referred to as a parasitic filter.

[0040] The first resistor 112 is an electric resistor for dividing the voltage signal Sv. The resistance value of the first resistor 112 is designed according to the resistance value of the input resistor 111 so that the level of the attenuated voltage signal Sv divided by the input resistor 111 and the first resistor 112 is within the input range of the buffer circuit 113. The resistance value of the first resistor 112 in the first embodiment is set to a value within a range of several hundred [Ω] to one hundred [kΩ], for example.

[0041] The buffer circuit 113 amplifies the voltage generated across the first resistor 112 as an attenuated voltage signal Sv with a predetermined gain for converting the detected value into a measured value, and outputs the amplified voltage signal Sv to the LPF circuit 12 as a voltage measurement signal.

[0042] Next, a description will be given of the connection configuration of the input circuit 11. In the input circuit 11, the voltage terminal 1A is connected to one end, which is an input terminal, of the input resistor 111, and the other end, which is an output terminal, of the input resistor 111 is connected to one end of the first resistor 112 and an input terminal of the buffer circuit 113. In addition, the other end of the first resistor 112 is connected to a reference potential G.

[0043] The LPF circuit 12 is an analog circuit that functions as a first filter means for performing low-pass filtering on the output signal of the input circuit 11. The LPF circuit 12 is connected to the output terminal of the input circuit 11, and is a filter circuit intended to suppress aliasing noise (anti-aliasing).

[0044] The LPF circuit 12 of the first embodiment is an anti-aliasing filter that serves to suppress the occurrence of aliasing noise in the AD converter 13. The LPF circuit 12 is configured, for example, by a second-order low-pass filter circuit. In the first embodiment, the LPF circuit 12 is realized by an active filter having an active element.

[0045] For example, the LPF circuit 12 is configured by a second-order VCVS (Voltage Controlled Voltage Source) type filter. An example of the configuration of the LPF circuit 12 will be described later with reference to Fig. 3. The LPF circuit 12 outputs the voltage measurement signal after low-pass filtering to the AD converter 13.

[0046] The AD converter 13 converts the output signal of the LPF circuit 12 from an analog signal to a digital signal, and outputs the converted digital signal indicating the measurement value of the voltage signal Sv to the processing unit 30 as voltage measurement data.

[0047] Next, the configuration of the current channel input section 20 will be described.

[0048] The current channel input unit 20 receives the current signal Si and converts the analog current signal Si into a digital voltage value to output current measurement data. The current channel input unit 20 of the first embodiment includes an input circuit 21, a compensation circuit 22, an LPF circuit 23, and an AD converter 24.

[0049] The input circuit 21 is a second input circuit including a current terminal 1B to which a current signal Si from the current sensor is input. The input circuit 21 of the first embodiment functions as a measurement circuit for measuring the output voltage of the current sensor, and includes a buffer circuit 211.

[0050] The buffer circuit 211 amplifies the voltage generated across the first resistor 112 as a current signal Si with a predetermined gain for converting the detected value into a measured value, and outputs the amplified current signal Si to the compensation circuit 22 as a current measurement signal.

[0051] As for the connection configuration of the input circuit 21, an input terminal of a buffer circuit 211 is connected to the current terminal 1B, and an output terminal of the buffer circuit 211 constitutes an output terminal of the input circuit 21.

[0052] The circuit constants of the buffer circuit 211 of the first embodiment are designed so as to have frequency characteristics equivalent to those of the buffer circuit 113. The input circuit 21 may be configured with a shunt resistor instead of the buffer circuit 211. A resistive element may be connected between the input terminal of the buffer circuit 211 and the reference potential G.

[0053] The compensation circuit 22 functions as a compensation means that performs processing on the output signal of the input circuit 21 to compensate for the parasitic capacitance Cp parasitic on the input resistor 111 of the input circuit 11 and the frequency characteristics of a parasitic filter formed by the input resistor 111 and the first resistor 112.

[0054] The compensation circuit 22 in the first embodiment is realized by an analog LPF circuit. It is preferable that the compensation circuit 22 is realized by an active filter that performs a first-order low-pass filter process on the input signal so that the difference in frequency characteristics between the output signals of the input circuits 11 and 21 caused by the parasitic capacitance Cp is reduced.

[0055] As a specific example, the compensation circuit 22 shown in FIG.

[0056] The resistance value of the resistor element 221 and the capacitance value of the capacitor 222 are determined so that the frequency characteristic of the compensation circuit 22 matches the frequency characteristic of a parasitic filter formed by the parasitic capacitance Cp, the input resistor 111 and the first resistor 112.

[0057] For example, the resistance value of the resistive element 221 is set to a value within a range from several kΩ to several tens of kΩ so as to suppress the generation of thermal noise in the resistive element 221. On the other hand, the capacitance value of the capacitor 222 is set to a value of, for example, several tens of pF according to the resistance value of the resistive element 221 so that the frequency characteristics of the compensation circuit 22 are equivalent to the frequency characteristics of the parasitic filter.

[0058] As a specific example, when the circuit constants are designed so that the cutoff frequency of the compensation circuit 22 is 720 [kHz], the resistance value of the resistive element 221 is set to 10 [kΩ] and the capacitance value of the capacitor 222 is set to 22 [pF].

[0059] As for the connection configuration of the compensation circuit 22, one end of a resistor element 221 is connected to the output end of the buffer circuit 211 of the input circuit 21, and the other end of the resistor element 221 is connected to one end of a capacitor 222 and an input end of a buffer circuit 223. The other end of the capacitor 222 is connected to a reference potential G.

[0060] The compensation circuit 22 performs a primary low-pass filter process on the current measurement signal output from the input circuit 21. The compensation circuit 22 then outputs the processed current measurement signal to the LPF circuit .

[0061] The LPF circuit 23 is an analog circuit that performs low-pass filtering on the output signal of the compensation circuit 22. Similar to the LPF circuit 12, the LPF circuit 23 serves as an anti-aliasing filter.

[0062] The configuration of the LPF circuit 23 in the first embodiment is the same as the configuration of the LPF circuit 12. The LPF circuit 23 outputs to the AD converter 24 a current measurement signal that has been subjected to low-pass filtering.

[0063] The AD converter 24 converts the output signal of the LPF circuit 23 from an analog signal to a digital signal, and outputs the converted digital signal indicating the measurement value of the current signal Si to the processing unit 30 as current measurement data.

[0064] The processing unit 30 functions as a calculation means for calculating the physical quantity of the measurement target based on the output signals of the input circuit 11 and the input circuit 21.

[0065] The processing unit 30 of the first embodiment calculates the physical quantity of the object to be measured based on the voltage measurement data output from the voltage channel input unit 10 and the current measurement data output from the current channel input unit 20. Specifically, the processing unit 30 calculates the magnitude of the transmission power of the electric wire to be measured using the voltage value indicated in the voltage measurement data and the current value indicated in the current measurement data.

[0066] Furthermore, the processing unit 30 may calculate the phase difference between the voltage signal Sv and the current signal Si using the voltage value indicated in the voltage measurement data and the current value indicated in the current measurement data.

[0067] For example, when the measurement target is an electricity storage device such as a secondary battery or a fuel cell, the processing unit 30 may calculate the internal impedance of the electricity storage device using the voltage measurement data and the current measurement data.

[0068] In addition, the compensation circuit 22 in the first embodiment is configured as an RC circuit having a resistive element 221 and a capacitor 222, but it may be configured as an RL circuit having a resistor and a coil, or may be configured by combining a resistive element, a capacitor, and a coil.

[0069] Next, the LPF circuit 12 and the LPF circuit 23 will be described with reference to Fig. 3. As described above, the circuit configuration of the LPF circuit 12 and the circuit configuration of the LPF circuit 23 are the same, and therefore the circuit configurations are shown in the same drawing.

[0070] 3 is a circuit diagram showing a circuit configuration of the LPF circuits 12 and 23. Each of the LPF circuits 12 and 23 includes a resistive element 121, a resistive element 122, a capacitor 123, a capacitor 124, and an operational amplifier 125.

[0071] First, in the LPF circuit 12, one end of the resistor element 121 is connected to the output terminal of the buffer circuit 113, and the other end of the resistor element 121 is connected to one end of the resistor element 122 and one end of the capacitor 123. The other end of the resistor element 122 is connected to one end of the capacitor 124 and the non-inverting input terminal (+) of the operational amplifier 125, and the other end of the capacitor 124 is connected to the reference potential G.

[0072] The other end of the capacitor 123 is connected to the inverting input terminal (−) and the output terminal of an operational amplifier 125 , and the output terminal of the operational amplifier 125 is connected to the input terminal of the AD converter 13 .

[0073] Next, the LPF circuit 23 has the same connection configuration as the above-mentioned LPF circuit 12, except that one end of the resistor element 121 is connected to the buffer circuit 211, and the output terminal of the operational amplifier 125 is connected to the AD converter 24.

[0074] In the first embodiment, the resistance value of each of the resistor elements 121 and 122 is set to several kΩ, and the capacitance value of each of the capacitors 123 and 124 is set to several hundred pF.

[0075] As a specific example, when the circuit constants of the LPF circuits 12 and 23 are designed so that the cutoff frequency is 1 [MHz] and the Q value is 0.70, the resistance values ​​of the resistive elements 121 and 122 are set to 1 [kΩ], the capacitance value of the capacitor 123 is set to approximately 200 [pF], and the capacitance value of the capacitor 124 is set to approximately 100 [pF].

[0076] In the first embodiment, the voltage channel input section 10 and the current channel input section 20 are provided with the LPF circuits 12 and 23, respectively, in order to suppress the occurrence of aliasing noise, but these may be omitted. For example, if the circuit configuration does not cause aliasing, the LPF circuits 12 and 23 can be omitted.

[0077] Next, the frequency characteristics of the input circuit 11 obtained by simulation analysis will be described with reference to FIG.

[0078] FIG. 4 is a diagram showing frequency characteristics of the output signals of the input circuit 11 and the compensation circuit 22. As shown in FIG.

[0079] The simulation conditions for the input circuit 11 were as follows: for the input resistor 111 in which five resistor elements are connected in series, the capacitance values ​​of the parasitic capacitances connected in parallel to each resistor element and the parasitic capacitance occurring between each resistor element and the reference potential G were both 0.4 [pF], and the capacitance value of the parasitic capacitance connected in parallel to the first resistor 112 was 0.4 [pF]. In addition, the resistance values ​​of each resistor element and the first resistor 112 were both 100 [kΩ].

[0080] Moreover, the simulation conditions for the compensation circuit 22 were such that the resistance value of the resistor element 221 was 10 [kΩ] and the capacitance value of the capacitor 222 was 22 [pF].

[0081] In Figure 4, the frequency characteristics of the amplitude and phase of the output signal of input circuit 11 are shown by a thick dashed line and a thin dashed line, respectively, and the frequency characteristics of the amplitude and phase of the output signal of compensation circuit 22 are shown by a thick solid line and a thin solid line, respectively.

[0082] As a comparative example, the frequency characteristics of the amplitude and phase of the output signal from the input circuit 21 before compensation processing for the frequency characteristics caused by the parasitic capacitance Cp is performed are shown by a thick dashed line and a thin dashed line, respectively.

[0083] As shown in FIG. 4, the frequency characteristic of the output signal of input circuit 11, indicated by the dashed line, is attenuated in the high frequency band compared to the frequency characteristic of the output signal of input circuit 21, which has not been subjected to compensation processing, indicated by the dotted line as a comparative example.

[0084] As a countermeasure to this, the output signal of the input circuit 21 is filtered by the compensation circuit 22 which constitutes a primary low-pass filter, so that the frequency characteristics of the output signal of the compensation circuit 22 shown by the solid line roughly coincide with the frequency characteristics of the output signal of the input circuit 11.

[0085] The frequency characteristics of the output signal of the input circuit 11 correspond to the frequency characteristics of a parasitic filter composed of the parasitic capacitance Cp, the input resistor 111, and the first resistor 112, and the frequency characteristics of this parasitic filter are accurately approximated by configuring the compensation circuit 22 as a first-order low-pass filter.

[0086] Therefore, the inventors have found that the frequency characteristics of the parasitic filter in the input circuit 11 can be realized with at least the frequency characteristics of a first-order low-pass filter.

[0087] In this way, in the first embodiment, by configuring the compensation circuit 22 with a first-order low-pass filter, it is possible to compensate for the frequency characteristics of the parasitic filter in the output signal of the input circuit 21 so that the frequency characteristics of the parasitic filter are taken into account in the current channel input section 20.

[0088] Next, the operation of the measurement device 1 in the first embodiment will be described with reference to FIG.

[0089] 5 is a flowchart showing an example of the processing procedure of the measurement method executed by the measurement device 1. Here, a voltage signal Sv indicating the magnitude of the voltage generated in the object to be measured is output from the voltage sensor, and a current signal Si indicating the magnitude of the current flowing through the object to be measured is output from the current sensor.

[0090] In step S1, the voltage signal Sv output from the voltage sensor is input to a voltage terminal 1A connected to the input end of the input resistor 111 of the input circuit 11 including the input resistor 111 and the first resistor 112 in the measuring device 1.

[0091] In step S2, the current signal Si output from the current sensor is input to the current terminal 1B of the input circuit 21 in the measuring device 1.

[0092] In step S3, the measurement device 1 performs compensation processing on the output signal of the input circuit 21 to compensate for the parasitic capacitance Cp parasitic on the input resistor 111 and the frequency characteristics of a parasitic filter formed by the input resistor 111 and the first resistor 112. The measurement device 1 of the first embodiment performs primary low-pass filter processing on the output signal of the input circuit 21 as the compensation processing.

[0093] In step S4, the measurement device 1 calculates the physical quantity of the measurement target based on the output signal of the input circuit 11 and the output signal of the input circuit 21 that has been subjected to compensation processing in step S3.

[0094] In the first embodiment, the measurement device 1 performs low-pass filtering on the output signal of the input circuit 11 using the LPF circuit 12, and converts the output signal after the low-pass filtering process into a digital signal using the AD converter 13 to generate voltage measurement data.

[0095] Then, the measuring device 1 performs low-pass filtering on the compensated output signal of the input circuit 21 using the LPF circuit 23, and converts the output signal after the low-pass filtering into a digital signal using the AD converter 24 to generate current measurement data. Furthermore, the measuring device 1 uses the generated voltage measurement data and current measurement data to calculate the magnitude of power transmitted to the electric wire to be measured.

[0096] When the process of step S4 is completed, the series of process steps of the measurement method according to the first embodiment ends.

[0097] Next, the effects of the first embodiment will be described.

[0098] In the first embodiment, the measurement device 1 includes an input circuit 11, an input circuit 21, and a processing unit 30. The input circuit 11 configures a first input circuit including a voltage terminal 1A corresponding to a first input terminal to which a voltage signal Sv is input as a first signal indicating the magnitude of the potential generated in the measurement target, an input resistor 111 having one end connected to the voltage terminal 1A, and a first resistor 112 having one end connected to the other end of the input resistor 111 and the other end connected to a reference potential G.

[0099] The input circuit 21 constitutes a second input circuit having a current terminal 1B corresponding to a second input terminal to which a current signal Si is input as a second signal indicating the magnitude of a current flowing through the object to be measured. The processing unit 30 functions as a calculation means for calculating a physical quantity of the object to be measured based on the output signals of the input circuit 11 and the input circuit 21.

[0100] The measurement device 1 further includes a compensation circuit 22 that functions as a compensation means for performing a process for compensating for the parasitic capacitance Cp parasitic on the input resistor 111 and the frequency characteristic of the filter formed by the input resistor 111, on the output signal of the input circuit .

[0101] Moreover, in the first embodiment, the measurement method includes a first input step (S1) in which a voltage signal Sv is input as a first signal to an input terminal of an input resistor 111 of an input circuit 11 having an input resistor 111 and a first resistor 112, and a second input step (S2) in which a current signal Si is input as a second signal to the input circuit 21.

[0102] The measurement method further includes a compensation step (S3) of performing a process on the output signal of the input circuit 21 to compensate for the frequency characteristics of a filter formed by the parasitic capacitance Cp, the input resistor 111 and the first resistor 112, and a calculation step (S4) of calculating a physical quantity of the object to be measured based on the output signal of the input circuit 11 and the output signal of the input circuit 21 that has been processed in the compensation step (S3).

[0103] Furthermore, the computer of the measuring device 1 that executes the program in the first embodiment acquires an output signal of the input circuit 11 to which a voltage signal Sv is input as a first signal to the input terminal of the input resistor 111, and an output signal of the input circuit 21 to which a current signal Si is input as a second signal. The above program is a program for causing the computer of the measuring device 1 to execute the compensation step (S3) and the calculation step (S4) described above.

[0104] According to these configurations, the compensation circuit 22 or the compensation step (S3) adds the frequency characteristic of a filter formed by the input resistance 111, the first resistance 112, and the parasitic capacitance Cp of the input circuit 11 to the output signal of the input circuit 21. This makes it possible to reduce the difference in frequency characteristics between the input circuit 11 and the input circuit 21.

[0105] Therefore, the phase shift between the output signal of the input circuit 11 and the output signal of the input circuit 21 used for calculating the physical quantity is reduced, so that the physical quantity of the measurement target can be measured with high accuracy. In other words, the deterioration of the measurement accuracy caused by the parasitic capacitance Cp of the input resistor 111 can be suppressed.

[0106] Moreover, the compensation circuit 22 of the first embodiment performs a first-order low-pass filter process on the output signal of the input circuit 21 .

[0107] The reason for adopting such a configuration will be briefly explained. In the input circuit 11, although the frequency characteristic of the input resistor 111 deteriorates due to the presence of the parasitic capacitance Cp, it is possible to accurately approximate it by a first-order low-pass filter as shown in FIG.

[0108] Therefore, as described above, by employing a first-order low-pass filter as compensation circuit 22, it is possible to increase the degree of agreement between the frequency characteristics of the output signal of compensation circuit 22 and the frequency characteristics of the output signal of input circuit 21, compared to a case in which a first-order low-pass filter is not employed. Therefore, it is possible to suppress the phase shift between the measured amount of voltage signal Sv and the measured amount of current signal Si.

[0109] In addition, the resistance values ​​of the input resistor 111 and the first resistor 112 in the first embodiment are determined to be magnitudes such that the input level of the input circuit 11 (voltage signal Sv) is attenuated to a level equivalent to the input level of the input circuit 21 (current signal Si) when output from the other end of the input resistor 111 by voltage division by the input resistor 111 and the first resistor 112.

[0110] This configuration eliminates the need to attenuate the input signal in compensation circuit 22, and makes it possible to set the element values ​​of LPF circuit 23 to the same element values ​​as LPF circuit 12 of voltage channel input section 10, and to use the same AD converter 24 as AD converter 13 of voltage channel input section 10. This makes it easier to design the compensation circuit 22, LPF circuit 23, and AD converter 24.

[0111] Second Embodiment Next, a measurement device according to a second embodiment will be described with reference to FIG.

[0112] 6 is a circuit diagram showing a circuit configuration of a measurement device 2 according to the second embodiment. The second embodiment differs from the first embodiment in that the function of the compensation circuit 22 of the first embodiment is integrated into an LPF circuit .

[0113] The measurement device 2 includes a current channel input section 20A instead of the current channel input section 20 shown in Fig. 1. The same components as those in the measurement device 1 of the first embodiment are denoted by the same reference numerals and will not be described repeatedly.

[0114] The current channel input section 20A includes an input circuit 21 having the same configuration as in the first embodiment, and further includes a compensation LPF circuit 25 instead of the compensation circuit 22 and the LPF circuit 23 in the first embodiment.

[0115] The compensation LPF circuit 25 functions as a compensation unit that performs a process of compensating for the frequency characteristics of a parasitic filter that is configured by the parasitic capacitance Cp, the input resistor 111, and the first resistor 112, similar to the compensation circuit 22 in the first embodiment.

[0116] The compensation LPF circuit 25 of the second embodiment performs low-pass filtering of an order (N+1) that is one greater than the order N of the LPF circuit 12 as the first filter means, on the output signal of the input circuit 21. Note that N indicating the order is a positive integer.

[0117] The compensation LPF circuit 25 is an active filter circuit connected to the output terminal of the input circuit 21 and having an operational amplifier as an active element. The LPF circuit 12 of the second embodiment is configured by a secondary low-pass filter circuit as shown in FIG.

[0118] For example, the compensation LPF circuit 25 is configured by a third-order Geffe-type low-pass filter circuit that is one order larger than the order of the LPF circuit 12. An example of the configuration of the compensation LPF circuit 25 will be described with reference to FIG.

[0119] FIG. 7 is a circuit diagram showing an example of the circuit configuration of the compensation LPF circuit 25. As shown in FIG.

[0120] As shown in FIG. 7, the compensation LPF circuit 25 includes a resistor element 251 and a capacitor 252 in addition to the configuration of the LPF circuit 23 of the first embodiment shown in FIG.

[0121] The circuit constants of the compensation LPF circuit 25 are designed based on the cutoff frequency of a primary transfer function representing the frequency characteristics of the compensation circuit 22 of the first embodiment shown in FIG. 1 and the cutoff frequency and Q value of a secondary transfer function representing the frequency characteristics of the LPF circuit 12.

[0122] Specifically, a third-order transfer function is obtained using the cutoff frequency of the first-order transfer function of the compensation circuit 22 and the cutoff frequency and Q value of the second-order transfer function of the LPF circuit 12. Then, the circuit constant of the compensation LPF circuit 25 is determined using the cutoff frequency and Q value of the third-order transfer function.

[0123] For example, the resistance value of each of resistor elements 121, 122, and 251 is set to several kΩ, the capacitance value of each of capacitors 123 and 252 is set to several hundred pF, and the capacitance value of capacitor 124 is set to several tens of pF.

[0124] As a specific example, it is assumed that the circuit constants are designed so that the cutoff frequency of the primary characteristic of the compensation circuit 22 is 720 [kΩ], the cutoff frequency of the secondary characteristic of the LPF circuit 12 is 1 [MHz], and the Q value is 0.70. In this case, the resistance values ​​of the resistive elements 121, 122, and 251 are each set to 1 [kΩ], the capacitance value of the capacitor 123 to about 350 [pF], the capacitance value of the capacitor 124 to about 60 [pF], and the capacitance value of the capacitor 252 to about 260 [pF].

[0125] The compensating LPF circuit 25 of the second embodiment may be configured with a coil and a resistive element instead of the resistive element 251 and the capacitor 252, or may be configured with a circuit combining a resistive element, a capacitor, and a coil.

[0126] Next, the effects of the second embodiment will be described.

[0127] The measurement device 2 of the second embodiment includes an input circuit 11 and an input circuit 21, similar to the first embodiment. The measurement device 2 further includes an LPF circuit 12 and a compensation LPF circuit 25.

[0128] At this time, the LPF circuit 12 functions as a first filter means for performing low-pass filtering on the output signal of the input circuit 11. Furthermore, the compensation LPF circuit 25 functions as a compensation means for performing low-pass filtering on the output signal of the input circuit 21, the order of which is one level higher than that of the LPF circuit 12.

[0129] According to this configuration, the compensation LPF circuit 25 has an order one higher than that of the LPF circuit 12, so it is possible to take into account the frequency characteristics of a first-order parasitic filter constituted by the parasitic capacitance Cp, the input resistance 111, and the first resistance 112 to the frequency characteristics of the LPF circuit 12.

[0130] This makes it possible to apply low-pass filtering equivalent to that of the LPF circuit 12 to the output signal of the input circuit 21 while taking into account the frequency characteristics of the parasitic filter. Therefore, as in the first embodiment, the difference between the frequency characteristics of the output signal of the compensation LPF circuit 25 and the frequency characteristics of the output signal of the LPF circuit 12 becomes small, thereby improving the measurement accuracy.

[0131] In the second embodiment, the LPF circuit 12 is a filter circuit connected to the input circuit 11 to suppress the occurrence of aliasing noise. The compensation LPF circuit 25 is an active filter circuit connected to the input circuit 21 and has an operational amplifier 125 as an active element.

[0132] According to this configuration, the LPF circuit 12 suppresses the occurrence of aliasing noise, while the compensation LPF circuit 25 suppresses the influence of the parasitic capacitance Cp, thereby improving the measurement accuracy.

[0133] In addition, by employing an active filter circuit as the compensation LPF circuit 25, it becomes possible to form a complex frequency characteristic. Therefore, even if the LPF circuit 12 has a frequency characteristic of second order or higher, it is possible to accurately approximate the frequency characteristic of the output signal of the LPF circuit 12. Therefore, it is possible to suppress a decrease in measurement accuracy caused by the adjustment accuracy of the frequency characteristic of the compensation LPF circuit 25.

[0134] More specifically, in the second embodiment, the LPF circuit 12 is configured as a second-order low-pass filter circuit, and the compensation LPF circuit 25 is configured as a third-order Geffe-type low-pass filter circuit.

[0135] According to this configuration, the compensation LPF circuit 25 can be realized by including only one operational amplifier 125 as an active element, as shown in Fig. 7. In contrast, the compensation circuit 22 and the LPF circuit 23 (see Fig. 2) of the first embodiment having the two functions of the compensation LPF circuit 25 require two active elements, the buffer circuit 223 and the operational amplifier 125.

[0136] In this way, by employing a third-order Geffe-type low-pass filter circuit as the compensation LPF circuit 25, the number of active elements is reduced compared to the circuit configuration of the first embodiment, making it possible to reduce an increase in offset and the introduction of noise in the circuit. In addition, since the number of active elements is minimized, it is possible to reduce the size of the measurement device 2 and suppress an increase in manufacturing costs.

[0137] Third embodiment Next, a measurement device according to a third embodiment will be described with reference to Fig. 8. The third embodiment differs from the first embodiment in that the compensation circuit 22, the LPF circuit 12, and the LPF circuit 23 of the first embodiment shown in Fig. 1 are omitted, and the function of the compensation circuit 22 is provided in a processing unit 30.

[0138] FIG. 8 is a diagram showing the configuration of a measurement device 3 according to the third embodiment.

[0139] The measurement device 3 includes a voltage channel input unit 10A from which the LPF circuit 12 of the first embodiment has been deleted, a current channel input unit 20B from which the compensation circuit 22 and the LPF circuit 23 of the first embodiment have been deleted, and a processing unit 30A having the function of the compensation circuit 22. In the following, in order to avoid redundant description, only the functional configuration of the processing unit 30A will be described.

[0140] The processing unit 30A includes one or more processors that perform digital processing. The processing unit 30A of the third embodiment includes a compensation unit 31 and a measurement amount calculation unit 32.

[0141] The compensation unit 31 functions as a compensation means that performs processing on the output signal of the input circuit 21 to compensate for the parasitic capacitance Cp parasitic on the input resistor 111 of the input circuit 11, and the frequency characteristics of the parasitic filter formed by the input resistor 111 and the first resistor 112.

[0142] Similar to the first embodiment, the compensation unit 31 of the third embodiment performs a first-order low-pass filter process on the current measurement data output from the current channel input unit 20B. For example, the compensation unit 31 executes a compensation process equivalent to the process performed in the circuit configuration of the compensation circuit 22 shown in FIG. 1. The compensation unit 31 outputs the current measurement data after the compensation process to the measurement quantity calculation unit 32.

[0143] The measurement quantity calculation section 32 functions as a calculation means for calculating the physical quantity of the measurement target based on the output signals of the input circuit 11 and the input circuit 21.

[0144] In the third embodiment, the measured quantity calculation unit 32 acquires voltage measurement data from the voltage channel input unit 10A, and acquires compensated current measurement data from the compensation unit 31. Then, the measured quantity calculation unit 32 calculates the magnitude of power transmitted to the electric wire to be measured, using the voltage value indicated in the voltage measurement data and the current value indicated in the compensated current measurement data.

[0145] The measured quantity calculation unit 32 may also calculate the phase difference between the voltage signal Sv and the current signal Si using a voltage value indicated in the voltage measurement data and a current value indicated in the compensated current measurement data. For example, when the measurement target is a power storage device, the measured quantity calculation unit 32 may calculate the internal impedance of the power storage device using the voltage measurement data and the compensated current measurement data.

[0146] Next, the effects of the third embodiment will be described.

[0147] The measurement device 3 of the third embodiment includes an input circuit 11, an input circuit 21, and a processing unit 30A including a compensation unit 31 and a measured quantity calculation unit 32. The measured quantity calculation unit 32 functions as a calculation means that calculates a physical quantity of the measurement target based on the output signals of the input circuit 11 and the input circuit 21. The compensation unit 31 functions as a compensation means that performs a process to compensate for the frequency characteristics of a parasitic filter formed by the parasitic capacitance Cp, the input resistance 111, and the first resistance 112, on the output signal of the input circuit 21 input to the measured quantity calculation unit 32.

[0148] According to this configuration, as in the first embodiment, it is possible to suppress a decrease in measurement accuracy caused by the parasitic capacitance Cp of the input resistor 111, compared to a functional configuration in which the compensation unit 31 does not execute compensation processing.

[0149] In addition, since the processing of the compensation circuit 22 is performed in the processing unit 30A that performs digital processing, unlike the first embodiment, there is no need to provide the compensation circuit 22. This makes it possible to suppress increases in the size and manufacturing costs of the measurement device 3.

[0150] (Fourth embodiment) Next, a measurement device according to a fourth embodiment will be described with reference to Fig. 9. The fourth embodiment differs from the third embodiment in that, in addition to the functional configuration of the processing unit 30A of the third embodiment, a functional configuration for performing low-pass filter processing on both the voltage measurement data and the current measurement data is added.

[0151] FIG. 9 is a diagram showing the configuration of a measurement device 4 according to the fourth embodiment.

[0152] The measurement device 4 includes a processing unit 30B instead of the processing unit 30A of the measurement device 3 of the third embodiment shown in Fig. 8. The processing unit 30B includes an LPF unit 311 and a compensation LPF unit 312 instead of the compensation unit 31 of the processing unit 30A. Note that the same components of the measurement device 4 as those of the measurement device 3 of the third embodiment shown in Fig. 8 are denoted by the same reference numerals and redundant explanations will be omitted.

[0153] The LPF unit 311 functions as a first filter means that performs low-pass filtering on the output signal of the input circuit 11. The LPF unit 311 plays a role in removing high-frequency noise contained in the voltage measurement data.

[0154] The LPF unit 311 of the fourth embodiment performs secondary low-pass filtering on the voltage measurement data output from the voltage channel input unit 10A. As a specific example, the LPF unit 311 performs low-pass filtering on the voltage measurement data, which is executed by the same circuit configuration as the LPF circuit 12 of the first embodiment.

[0155] The compensating LPF unit 312 functions as a compensation unit that performs processing to compensate for the frequency characteristics of a parasitic filter formed by the parasitic capacitance Cp, the input resistor 111 and the first resistor 112, on the output signal of the input circuit 21.

[0156] For example, the compensation LPF unit 312 performs low-pass filtering on the output signal of the input circuit 21 with an order one step larger than the order of the LPF unit 311. As a specific example, the compensation LPF unit 312 executes low-pass filtering performed by a third-order Geffe-type low-pass filter circuit.

[0157] Next, the effects of the fourth embodiment will be described.

[0158] In the fourth embodiment, the LPF unit 311 functions as a first filter means that performs low-pass filtering on the output signal of the input circuit 11. The compensation LPF unit 312 functions as a compensation means that performs low-pass filtering on the output signal of the input circuit 21, the order of which is one order larger than that of the LPF unit 311.

[0159] According to this configuration, the LPF unit 311 can remove high-frequency noise that is mixed into the output signal of the input circuit 11 from around the electric wire to be measured, or high-frequency noise that occurs in the input resistor 111 and the AD converter 24. Therefore, the measurement accuracy can be improved compared to a configuration that does not have the function of the LPF unit 311.

[0160] In addition, as in the second embodiment, the compensation LPF section 312 applies low-pass filtering to the output signal of the input circuit 21 in the same manner as the LPF section 311, and also takes into account the frequency characteristics of the parasitic filter caused by the parasitic capacitance Cp of the input resistor 111.

[0161] This removes high frequency noise from each of the output signals from the input circuits 11 and 21, and reduces the phase shift between the output data from the LPF unit 311 and the compensation LPF unit 312, compared to the phase shift between the output signals from the input circuits 11 and 21. This makes it possible to improve the measurement accuracy of the physical quantity calculated based on the output signals from the input circuits 11 and 21.

[0162] Although each embodiment of the present invention has been described above, the above-mentioned embodiments merely illustrate some of the application examples of the present invention, and it is not intended that the technical scope of the present invention be limited to the specific configurations of the above-mentioned embodiments.

[0163] For example, in the above embodiment, the number of the current channel input unit 20, 20A or 20B is one, but a plurality of the current channel input units 20, 20A or 20B may be provided. Even in this case, the phase shift between the voltage channel input unit 10 or 10A and the plurality of current channel input units 20, 20A or 20B or the processing unit 30A or 30B is suppressed, so that it is possible to perform calculation of the measured quantity with high accuracy.

[0164] In the first and second embodiments, the compensation circuit 22 and the compensation LPF circuit 25 are configured with active filters, but the present invention is not limited to this. For example, if the frequency characteristics of the compensation circuit 22 and the compensation LPF circuit 25 can be approximated to the frequency characteristics of a parasitic filter consisting of the parasitic capacitance Cp, the input resistor 111, and the first resistor 112 using a passive filter, the compensation circuit 22 and the compensation LPF circuit 25 may be a passive filter.

[0165] In addition, in the first and second embodiments, the LPF circuit 12 is configured as a second-order low-pass filter, but this is not limited thereto, and a third-order or higher-order low-pass filter may be adopted as the LPF circuit 12. In this case, the compensation LPF circuit 25 may be a fourth-order or higher-order low-pass filter, and a low-pass filter other than a Geffe type may be adopted. [Explanation of symbols]

[0166] 1~4 Measuring equipment 1A voltage terminal (first input terminal) 1B Current terminal (second input terminal) 11 Input circuit (first input circuit) 111 Input Resistance 112 First resistance Cp Parasitic capacitance (parasitic capacitance of input resistor) 12 LPF circuit (first filter means, filter circuit, secondary low-pass filter circuit) 21 Input circuit (second input circuit) 22 Compensation circuit (compensation means) 25 Compensation LPF circuit (compensation means, active filter circuit, third-order Geffen type low-pass filter circuit) 30, 30A, 30B Processing section (calculation means) 31 Compensation Department (Compensation Means) 32 Measured quantity calculation section (calculation means) 311 LPF section (first filter means) 312 Compensation LPF section (compensation means) S1~S4 (first input step, second input step, compensation step, calculation step)

Claims

1. a first input circuit including a first input terminal to which a first signal indicating the magnitude of a potential generated in an object to be measured is input, an input resistor having one end connected to the first input terminal, and a first resistor having one end connected to the other end of the input resistor and the other end connected to a reference potential; a second input circuit including a second input terminal to which a second signal indicating a magnitude of a current flowing through the object to be measured is input; a calculation means for calculating a physical quantity of the measurement target based on output signals of the first input circuit and the second input circuit, a compensation means for performing a process for compensating for a parasitic capacitance of the input resistor and a frequency characteristic of a filter formed by the input resistor and the first resistor, with respect to an output signal of the second input circuit; Measuring equipment.

2. 2. The measuring device according to claim 1, The compensation means performs a first-order low-pass filter process on the output signal of the second input circuit. Measuring equipment.

3. 2. The measuring device according to claim 1, a first filter means for performing low-pass filtering on the output signal of the first input circuit; the compensation means subjects the output signal of the second input circuit to low-pass filtering having an order one level higher than the order of the first filter means; Measuring equipment.

4. The measuring device according to claim 3, the first filter means is a filter circuit connected to the first input circuit and configured to suppress aliasing noise; the compensation means is an active filter circuit connected to the second input circuit and having an active element; Measuring equipment.

5. The measuring device according to claim 4, the filter circuit is a second-order low-pass filter circuit, The active filter circuit is a third-order Geffe-type low-pass filter circuit. Measuring equipment.

6. 2. The measuring device according to claim 1, the compensation means is a processor that performs low-pass filtering on the output signal of the second input circuit as a process for compensating for the frequency characteristics of the filter. Measuring equipment.

7. The measuring device according to any one of claims 1 to 6, the resistance values ​​of the input resistor and the first resistor are determined to be such that the input level of the first signal is attenuated to a level equivalent to the input level of the second input circuit when it is output from the other end of the input resistor; Measuring equipment.

8. a first input step in which a first signal indicating a magnitude of a potential generated in a measurement target is input to an input end of a first input circuit including an input resistor and a first resistor having one end connected to one end of the input resistor and the other end connected to a reference potential; a second input step of inputting a second signal indicating a magnitude of a current flowing through the object to be measured to a second input circuit; a compensation step of performing a process for compensating for a parasitic capacitance of the input resistor and a frequency characteristic of a filter formed by the input resistor and the first resistor, with respect to an output signal of the second input circuit; a calculation step of calculating a physical quantity of the object to be measured based on the output signal of the first input circuit and the output signal of the second input circuit that has been subjected to the processing in the compensation step; Measurement methods including:

9. a first input circuit having an input resistor and a first resistor having one end connected to one end of the input resistor and the other end connected to a reference potential, the first input circuit receiving a first signal indicating a magnitude of a potential generated in an object to be measured and inputting the first signal to the other end of the input resistor, and the second input circuit receiving a second signal indicating a magnitude of a current flowing through the object to be measured, the first input circuit receiving an output signal from the first input circuit and inputting the second signal to the other end of the input resistor; a compensation step of performing a process for compensating for a parasitic capacitance of the input resistor and a frequency characteristic of a filter formed by the input resistor and the first resistor, with respect to an output signal of the second input circuit; a calculation step of calculating a physical quantity of the object to be measured based on the output signal of the first input circuit and the output signal of the second input circuit that has been subjected to the processing in the compensation step; A program for executing the above.

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