Signal processing device and signal processing method

Abstract

SOLUTION: This signal processing device may include: a signal selection unit for receiving an analog signal that indicates the physical quantity detected by each of a plurality of sensors and selectively outputting an analog signal that indicates the physical quantity detected by one of the plurality of sensors; a control unit for controlling the signal selection unit so that a process of causing an analog signal to be sequentially outputted from a sensor which is selected one at a time from among the plurality of sensors in a first order, and thereafter causing an analog signal to be sequentially outputted from a sensor which is selected one at a time from among the plurality of sensors in a second order that is reverse to the first order, is repeated; a conversion unit for converting the analog signals outputted respectively from the plurality of sensors, that are outputted respectively from the signal selection unit by the process, into digital signals; and a derivation unit for deriving the physical quantities detected respectively by the plurality of sensors on the basis of the respective digital signals.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a signal processing device and a signal processing method. [Background technology]

[0002] Patent Document 1 discloses a multiplexer for selectively switching between three-channel input voltages and outputting them to a downstream A / D converter. Patent Document 2 discloses a sensor that simultaneously detects magnetic fields parallel to and perpendicular to a magnetic field concentrator with multiple Hall elements arranged on its end face. Patent Document 3 discloses a magnetic detection device that removes offset voltages of Hall elements and offset voltages inherent in amplifiers. Patent Document 4 discloses providing an amplifier for each magnetic sensor and simultaneously detecting magnetic components with each magnetic sensor. [Prior art document] [Patent Documents] [Patent Document 1] JP 2005-65789 A [Patent Document 2] Japanese Patent Application Laid-Open No. 2002-71381 [Patent Document 3] Japanese Patent Application Laid-Open No. 2005-283503 [Patent Document 4] U.S. Patent No. 6,278,271 Summary of the Invention [Problem to be solved by the invention]

[0003] It is desirable to suppress an increase in circuit size and to suppress deviations in the timing of measurements of physical quantities such as magnetic fields detected by a plurality of sensors. [Means for solving the problem]

[0004] A signal processing device according to one aspect of the present invention may include a signal selection unit that receives analog signals indicating physical quantities detected by each of a plurality of sensors and selectively outputs an analog signal indicating the physical quantity detected by one of the plurality of sensors. The signal processing device may include a control unit that controls the signal selection unit to repeat a process of sequentially outputting analog signals from sensors selected one by one from the plurality of sensors in a first order, and then sequentially outputting analog signals from sensors selected one by one from the plurality of sensors in a second order that is the reverse of the first order. The signal processing device may include a conversion unit that converts each analog signal output from each of the plurality of sensors output from the signal selection unit through processing into a digital signal. The signal processing device may include a derivation unit that derives each physical quantity detected by each of the plurality of sensors based on each digital signal.

[0005] The signal selection section may output, at predetermined intervals, an analog signal indicating a physical quantity detected by one sensor sequentially selected from the plurality of sensors.

[0006] The signal processing device may further include an amplifier that amplifies each analog signal output from the plurality of sensors and output from the signal selection unit after processing. The conversion unit may convert each analog signal amplified by the amplifier into a digital signal.

[0007] The signal processing device may further include an inversion unit that inverts the polarity of analog signals from sensors selected one by one from the plurality of sensors in a second order relative to analog signals from sensors selected one by one from the plurality of sensors in a first order and outputs the inverted signals to the conversion unit.

[0008] The multiple sensors may include a first sensor that outputs an analog signal indicative of the physical quantity of a first axis component, a second sensor that outputs an analog signal indicative of the physical quantity of a second axis component, and a third sensor that outputs an analog signal indicative of the physical quantity of a third axis component. The signal selector may, through processing, output the analog signals in the following order: a first analog signal output from the first sensor at a first time point, a second analog signal output from the second sensor at a second time point following the first time point, and a third analog signal output from the third sensor at a third time point following the second time point, and then output the analog signals in the following order: a fourth analog signal output from the third sensor at a fourth time point following the third time point, a fifth analog signal output from the second sensor at a fifth time point following the fourth time point, and a sixth analog signal output from the first sensor at a sixth time point following the fifth time point. The converter may convert the first analog signal, the second analog signal, the third analog signal, the fourth analog signal, the fifth analog signal, and the sixth analog signal into a first digital signal, a second digital signal, a third digital signal, a fourth digital signal, a fifth digital signal, and a sixth digital signal. The derivation unit may derive the physical quantity of the first axis component based on the first digital signal and the sixth digital signal, derive the physical quantity of the second axis component based on the second digital signal and the fifth digital signal, and derive the physical quantity of the third axis component based on the third digital signal and the fourth digital signal.

[0009] The intervals between the first, second, third, fourth, fifth, and sixth points may be the same.

[0010] The multiple sensors may include a first sensor that outputs analog signals indicating the physical quantity of the first axis component and the physical quantity of the third axis component, a second sensor that outputs analog signals indicating the physical quantity of the first axis component with the polarity reversed and the physical quantity of the third axis component, a third sensor that outputs analog signals indicating the physical quantity of the second axis component and the physical quantity of the third axis component, and a fourth sensor that indicates the physical quantity of the second axis component with the polarity reversed and the physical quantity of the third axis component. The signal selection unit may output the analog signals in the following order: a first analog signal output from the first sensor at a first time point, a second analog signal output from the second sensor at a second time point following the first time point, a third analog signal output from the third sensor at a third time point following the second time point, and a fourth analog signal output from the fourth sensor at a fourth time point following the third time point, and then output the analog signals in the following order: a fifth analog signal output from the fourth sensor at a fifth time point following the fourth time point, a sixth analog signal output from the third sensor at a sixth time point following the fifth time point, a seventh analog signal output from the second sensor at a seventh time point following the sixth time point, and an eighth analog signal output from the first sensor at an eighth time point following the seventh time point. The conversion unit may convert the first analog signal, second analog signal, third analog signal, fourth analog signal, fifth analog signal, sixth analog signal, seventh analog signal, and eighth analog signal into a first digital signal, second digital signal, third digital signal, fourth digital signal, fifth digital signal, sixth digital signal, seventh digital signal, and eighth digital signal. The derivation unit may derive the physical quantity of the first axis component based on the first digital signal, the second digital signal, the seventh digital signal, and the eighth digital signal, derive the physical quantity of the second axis component based on the third digital signal, the fourth digital signal, the fifth digital signal, and the sixth digital signal, and derive the physical quantity of the third axis component based on the first digital signal, the second digital signal, the third digital signal, the fourth digital signal, the fifth digital signal, the sixth digital signal, the seventh digital signal, and the eighth digital signal.

[0011] The multiple sensors may include a first sensor that outputs analog signals indicating the physical quantity of the first axis component and the physical quantity of the third axis component, a second sensor that outputs analog signals indicating the physical quantity of the first axis component with the polarity reversed and the physical quantity of the third axis component, a third sensor that outputs analog signals indicating the physical quantity of the second axis component and the physical quantity of the third axis component, and a fourth sensor that indicates the physical quantity of the second axis component with the polarity reversed and the physical quantity of the third axis component. The signal selection unit may output the analog signals in the following order: a first analog signal output from the first sensor at a first time point, a second analog signal output from the second sensor at a second time point following the first time point, a third analog signal output from the third sensor at a third time point following the second time point, and a fourth analog signal output from the fourth sensor at a fourth time point following the third time point, and then output the analog signals in the following order: a fifth analog signal output from the fourth sensor at a fifth time point following the fourth time point, a sixth analog signal output from the third sensor at a sixth time point following the fifth time point, a seventh analog signal output from the second sensor at a seventh time point following the sixth time point, and an eighth analog signal output from the first sensor at an eighth time point following the seventh time point. The conversion unit may convert the first analog signal, second analog signal, third analog signal, fourth analog signal, fifth analog signal, sixth analog signal, seventh analog signal, and eighth analog signal into a first digital signal, second digital signal, third digital signal, fourth digital signal, fifth digital signal, sixth digital signal, seventh digital signal, and eighth digital signal. The derivation unit may derive the physical quantity of the first axis component based on the first digital signal, the second digital signal, the seventh digital signal, and the eighth digital signal, derive the physical quantity of the second axis component based on the third digital signal, the fourth digital signal, the fifth digital signal, and the sixth digital signal, and derive the physical quantity of the third axis component based on the first digital signal, the second digital signal, the seventh digital signal, and the eighth digital signal or the third digital signal, the fourth digital signal, the fifth digital signal, and the sixth digital signal.

[0012] The intervals between the first, second, third, fourth, fifth, sixth, seventh, and eighth points may be the same.

[0013] Each of the plurality of sensors may be a magnetic sensor that detects a magnetic field as a physical quantity.

[0014] A signal processing method according to one aspect of the present invention may include controlling a signal selection unit to receive analog signals indicating physical quantities detected by each of a plurality of sensors and selectively output an analog signal indicating the physical quantity detected by one of the plurality of sensors, so as to repeat a process of sequentially outputting analog signals from sensors selected one by one from the plurality of sensors in a first order, and then sequentially outputting analog signals from sensors selected one by one from the plurality of sensors in a second order that is the reverse of the first order. The signal processing method may include converting each analog signal output from each of the plurality of sensors output from the signal selection unit through processing into a digital signal. The signal processing method may include a step of deriving each physical quantity detected by each of the plurality of sensors based on the respective digital signals.

[0015] The above summary of the invention does not list all of the features of the present invention, and subcombinations of these features may also be inventions. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a diagram showing a circuit configuration of a signal processing device according to a first embodiment. [Figure 2] FIG. 2 is a diagram showing the timing at which each axis component is measured in the circuit configuration shown in FIG. 1, and the signal of the measurement target for each axis that changes during measurement. [Figure 3] 4A to 4C are diagrams showing the timing at which each axis component is measured in the first embodiment, and the signal of the measurement target for each axis that changes during measurement. [Figure 4] FIG. 10 is a diagram showing a circuit configuration of a signal processing device according to a second embodiment. [Figure 5] FIG. 5 is a diagram showing the timing at which each axis component is measured and the signal of the measurement target for each axis that changes during measurement in the circuit configuration shown in FIG. 4. [Figure 6]10 is a diagram showing the timing at which each axis component is measured in the second embodiment, and the signal of the measurement target on each axis that changes during measurement. FIG. [Figure 7] 10 is a diagram showing the timing at which each axis component is measured in the third embodiment, and the signal of the measurement target for each axis that changes during measurement. FIG. [Figure 8] FIG. 8 is a diagram showing the timing at which each axis component is measured in the circuit configuration shown in FIG. 7, and the signal of the measurement target for each axis that changes during measurement. [Figure 9] 10 is a diagram showing the timing at which each axis component is measured in the third embodiment, and the signal of the measurement target for each axis that changes during measurement. FIG. [Figure 10] FIG. 10 is a diagram showing a circuit configuration of a signal processing device according to a fourth embodiment. [Figure 11] FIG. 11 is a diagram showing the timing at which each axis component is measured and the signal of the measurement target for each axis that changes during measurement in the circuit configuration shown in FIG. [Figure 12] 10 is a diagram showing the timing at which each axis component is measured in the fourth embodiment, and the signal of the measurement target for each axis that changes during measurement. FIG. [Figure 13] 3 is a diagram showing the phase characteristics of measurement data when the magnetic field of each axis is measured at the measurement timing shown in FIG. 2. FIG. [Figure 14] The phase characteristics of the measurement data when the magnetic field of each axis is measured at the measurement timing shown in FIG. 3 are shown. DETAILED DESCRIPTION OF THE INVENTION

[0017] The present invention will be described below through embodiments of the invention, but the following embodiments do not limit the scope of the invention according to the claims. Furthermore, not all of the combinations of features described in the embodiments are necessarily essential to the solution of the invention.

[0018] 1 is a diagram showing the circuit configuration of a signal processing device 100A according to the first embodiment. The signal processing device 100A includes a sensor 10A, a sensor 10B, a sensor 10C, a signal selection unit 20, a switching control circuit 30, an amplifier 40, an ADC 50, and an arithmetic circuit 60.

[0019] Sensors 10A, 10B, and 10C (sometimes collectively referred to as sensor 10) are magnetic sensors that detect magnetic fields. The magnetic sensors may be Hall elements or magnetoresistive elements. Sensor 10A outputs an analog signal indicating the X-axis component of the magnetic field Hx. Sensor 10B outputs an analog signal indicating the Y-axis component of the magnetic field Hy. Sensor 10C outputs an analog signal indicating the Z-axis component of the magnetic field Hz. Note that sensor 10 may be a sensor other than a magnetic sensor as long as it detects physical quantities for each of multiple axis components. Sensor 10 may also be an acceleration sensor, a gyro sensor, or the like.

[0020] The signal selection unit 20 receives the analog signals output by the sensors 10A, 10B, and 10C. The signal selection unit 20 selectively outputs an analog signal indicating a magnetic field detected by one of the sensors 10A, 10B, and 10C. The switching control circuit 30 controls the signal selection unit 20. The switching control circuit 30 is an example of a control unit. The switching control circuit 30 outputs a switching signal SEL_SENSOR to the signal selection unit 20, which switches the sensor 10 to be selected by the signal selection unit 20. The switching control circuit 30 controls the signal selection unit 20 so that the signal selection unit 20 outputs, at predetermined intervals, an analog signal indicating a magnetic field detected by one sensor 10 that is sequentially selected from the multiple sensors 10.

[0021] The amplifier 40 amplifies the analog signal output from the signal selection unit 20 and outputs it to the ADC 50. The ADC 50 is an analog-to-digital conversion circuit. The ADC 50 is an example of a conversion unit. The ADC 50 converts the analog signal amplified by the amplifier 40 into a digital signal. The arithmetic circuit 60 derives the X-axis component of the magnetic field Hx, the Y-axis component of the magnetic field Hy, and the Z-magnetic field component of the magnetic field Hz based on the digital signal indicating the magnetic field detected by each sensor 10 output from the ADC 50. The arithmetic circuit 60 is an example of a derivation unit.

[0022] FIG. 2 shows the timing at which each axis component is measured and the signal of the measurement target for each axis that changes during measurement in the circuit configuration shown in FIG. ΔX, ΔY, and ΔZ indicate the amount of change for each axis per unit measurement time. As shown in FIG. 2, the switching control circuit 30 can control the signal selection unit 20 by sending a switching signal SEL_SENSOR to the signal selection unit 20 so that the signal selection unit 20 selects the sensor 10A, the sensor 10B, and the sensor 10C in that order and repeats the process of outputting an analog signal from each sensor 10. In this case, if the measurement timing of the magnetic field Hx of the X-axis component (1) is taken as the starting point, the measurement data indicating the magnetic field of each axis component taking into account the time change of the magnetic field of each axis component is as follows:

[0023] Doutx=Hx Douty=Hy+ΔY Doutz=Hz+2ΔZ

[0024] As described above, the time changes in the measurement data for each axis are 0, ΔY, and 2ΔZ, so the time changes in the measurement data for each axis do not align. In other words, the timing of measuring the magnetic field for each axis differs.

[0025] Various sensors, such as magnetic sensors and acceleration sensors, are used in a variety of applications. For example, triaxial magnetic sensors and triaxial acceleration sensors are sometimes incorporated into smartphones or devices that realize AR (augmented reality) or VR (virtual reality). Compact magnetic sensors are sometimes used to detect magnetic changes on the order of several tens to hundreds of hertz to determine position. When magnetic sensors and acceleration sensors are used in such applications, timing differences in measurements of physical quantities, such as the magnetic field of each axis component, can lead to errors in position measurements of each axis. Therefore, it is desirable to measure physical quantities, such as the magnetic field of each axis component, at the same time.

[0026] Therefore, in the first embodiment, taking a magnetic sensor as an example, the order of the sensors 10 selected by the signal selection unit 20 is changed in order to eliminate the difference in measurement timing of the magnetic field for each axis.

[0027] 3 shows the timing at which each axial component is measured and the signal of the measurement target for each axis that changes during measurement in the first embodiment. In the first embodiment, the switching control circuit 30 controls the signal selection unit 20 to select the sensors 10A (Hx), 10B (Hy), and 10C (Hz) one by one in a first order of the sensors 10A (Hx), 10B (Hy), and 10C (Hz) to sequentially output analog signals from each sensor 10, and then to select the sensors 10C (Hz), 10B (Hy), and 10A (Hx) one by one in a second order that is the reverse of the first order of the first order of the sensors 10 to sequentially output analog signals from each sensor 10.

[0028] Through this processing, the signal selection unit 20 outputs analog signals in the order of the first analog signal output from sensor 10A at the first time point t1, the second analog signal output from sensor 10B at the second time point t2 following the first time point t1, and the third analog signal output from sensor 10C at the third time point t3 following the second time point t2, and then outputs analog signals in the order of the fourth analog signal output from sensor 10C at the fourth time point t4 following the third time point t3, the fifth analog signal output from sensor 10B at the fifth time point t5 following the fourth time point t4, and the sixth analog signal output from sensor 10A at the sixth time point t6 following the fifth time point t5.

[0029] The intervals between the first time point t1, the second time point t2, the third time point t3, the fourth time point t4, the fifth time point t5, and the sixth time point t6 are the same.

[0030] The first analog signal is converted to a first digital signal indicative of (Hx). The second analog signal is converted to a second digital signal indicative of (Hy+ΔY). The third analog signal is converted to a third digital signal indicative of (Hz+2ΔZ). The fourth analog signal is converted to a fourth digital signal indicative of (Hz+3ΔZ). The fifth analog signal is converted to a fifth digital signal indicative of (Hy+4ΔY). The sixth analog signal is converted to a sixth digital signal indicative of (Hx+5ΔX).

[0031] The arithmetic circuit 60 then averages each component according to the following equation to derive measurement data indicating the magnetic field of each axial component.

[0032] Doutx=((1)+(6)) / 2 =(Hx+Hx+5ΔX) / 2 =Hx+2.5ΔX Douty=((2)+(5)) / 2 =(Hy+ΔY+Hy+4ΔY) / 2 =Hy+2.5ΔY Doutz=((3)+(4)) / 2 =(Hz+2ΔZ+Hz+3ΔZ)=Hz+2.5ΔZ

[0033] As described above, the coefficients of the time changes in the measurement data indicating the magnetic field of each axis component (ΔX, ΔY, ΔZ) are 2.5 for all axes. Therefore, the time changes in the measurement data indicating the magnetic field of each axis component are aligned. In this way, by measuring the magnetic field of each axis component an even number of times in one measurement cycle—two times in the example shown in Figure 3—it is possible to align the time centers of the measurement data after averaging each axis component. Therefore, even when measuring each axis component in a time-division manner, measurement data can be obtained with virtually no measurement timing discrepancy, just like when measuring the axis components in parallel.

[0034] 4 is a diagram showing the circuit configuration of a signal processing device 100B according to the second embodiment. The signal processing device 100B includes sensors 10A, 10B, 10C, and 10D. In the first embodiment, each sensor 10 independently detects the magnetic field of each axial component and outputs an analog signal separately indicating the magnetic field of each axial component. In the second embodiment, each sensor 10 detects the magnetic field of two axial components and outputs an analog signal that is a composite signal indicating the magnetic field of the two axial components.

[0035] The sensors 10A, 10B, 10C, and 10D are disposed on end faces of the magnetic flux concentrator. The sensors 10A and 10B are disposed opposite each other, and the sensors 10C and 10D are disposed opposite each other.

[0036] Sensor 10A outputs an analog signal indicating the X-axis component of the magnetic field Hx and the Z-axis component of the magnetic field Hz. Sensor 10B outputs an analog signal indicating the magnetic field -Hx with the polarity of the X-axis component reversed and the Z-axis component of the magnetic field Hz. Sensor 10C outputs an analog signal indicating the Y-axis component of the magnetic field Hy and the Z-axis component of the magnetic field Hz. Sensor 10D outputs an analog signal indicating the magnetic field -Hy with the polarity of the Y-axis component reversed and the Z-axis component of the magnetic field Hz.

[0037] FIG. 5 shows the timing at which each axis component is measured and the signal of the measurement target for each axis that changes during measurement in the circuit configuration shown in FIG. ΔX, ΔY, and ΔZ indicate the amount of change for each axis per unit measurement time. As shown in FIG. 5, the switching control circuit 30 may control the signal selection unit 20 by sending a switching signal SEL_SENSOR to the signal selection unit 20 so that the signal selection unit 20 sequentially selects sensors 10A, 10B, 10C, and 10D and repeatedly outputs an analog signal from each sensor 10. In this case, if the measurement timing of the magnetic field Hx of the X-axis component (and the magnetic field Hz of the Z-axis component) in (1) is taken as the starting point, the measurement data indicating the magnetic field of each axis component after calculation by the calculation circuit 60, taking into account the time change in the magnetic field of each axis component, is as follows:

[0038] Doutx=((1)-(2)) / 2=Hx+0.5ΔX-0.5ΔZ Douty=((3)-(4)) / 2=Hy+2.5ΔY-0.5ΔZ Doutz=((1)+(2)+(3)+(4)) / 4=Hz+1.5ΔZ-0.25(ΔX+ΔY)

[0039] As described above, the time changes of the measurement data for each axis along the axis being measured are 0.5ΔX, 2.5ΔY, and 1.5ΔZ, so the time changes of the measurement data for each axis do not align. In other words, the magnetic field measurement timing for each axis is different, and the time centers of the measurement data for each axis do not align. Furthermore, when a mixed signal that changes during measurement is acquired for each sensor 10 in a time-division manner and calculated by the calculation circuit 60, the measurement data for the X and Y axes contains an error component of 0.5ΔZ other than the axis being measured, and the measurement data for the Z axis contains an error component of 0.25(ΔX+ΔY) other than the axis being measured.

[0040] Therefore, in the second embodiment as well, the order in which the sensors 10 are selected by the signal selection unit 20 is changed in order to eliminate the difference in measurement timing of the magnetic field for each axis.

[0041] 6 shows the timing at which each axis component is measured and the signal of the measurement target for each axis that changes during measurement in the second embodiment. In the second embodiment, the switching control circuit 30 controls the signal selection unit 20 to select sensors 10A, 10B, 10C, and 10D one by one in a first order of sensors 10A, 10B, 10C, and 10D, and cause each sensor 10 to sequentially output an analog signal, and then to select sensors 10D, 10C, 10B, and 10A one by one in a second order that is reverse to the first order of sensors 10A, 10B, 10C, and 10D, and cause each sensor 10 to sequentially output an analog signal.

[0042] Through this processing, the signal selection unit 20 outputs the analog signals in the order of the first analog signal output from sensor 10A at the first time point t1, the second analog signal output from sensor 10B at the second time point t2 following the first time point t1, the third analog signal output from sensor 10C at the third time point t3 following the second time point t2, and the fourth analog signal output from sensor 10D at the fourth time point t4 following the third time point t3, and then outputs the analog signals in the order of the fifth analog signal output from sensor 10D at the fifth time point t5 following the fourth time point t4, the sixth analog signal output from sensor 10C at the sixth time point t6 following the fifth time point t5, the seventh analog signal output from sensor 10B at the seventh time point t7 following the sixth time point t6, and the eighth analog signal output from sensor 10A at the eighth time point t8 following the seventh time point t7.

[0043] The intervals between the first time point t1, the second time point t2, the third time point t3, the fourth time point t4, the fifth time point t5, the sixth time point t6, the seventh time point t7, and the eighth time point t8 are the same.

[0044] The first analog signal is converted to a first digital signal indicative of (Hx+Hz). The second analog signal is converted to a second digital signal indicative of (-(Hx+ΔX)+Hz+ΔZ). The third analog signal is converted to a third digital signal indicative of (Hy+2ΔY+Hz+2ΔZ). The fourth analog signal is converted to a fourth digital signal indicative of (-(Hy+3ΔY)+Hz+3ΔZ). The fifth analog signal is converted to a fifth digital signal indicative of (-(Hy+4ΔY)+Hz+4ΔZ). The sixth analog signal is converted to a sixth digital signal indicative of (Hy+5ΔY+Hz+5ΔZ). The seventh analog signal is converted to a seventh digital signal indicative of (-(Hx+6ΔX)+Hz+6ΔZ). The eighth analog signal is converted to an eighth digital signal indicative of (Hx+7ΔX+Hz+7ΔZ).

[0045] The arithmetic circuit 60 then averages each component according to the following equation to derive measurement data indicating the magnetic field of each axial component.

[0046] Doutx=((1)-(2)-(7)+(8)) / 4=Hx+3.5ΔX Douty=((3)-(4)-(5)+(6)) / 4=Hy+3.5ΔY Doutz=((1)+(2)+(3)+(4)+(5)+(6)+(7)+(8)) / 8=Hz+3.5ΔZ

[0047] As shown above, the coefficient of the time change in the measurement data indicating the magnetic field of each axis component is 3.5 for all axes. Therefore, the time change in the measurement data indicating the magnetic field of each axis component is consistent. Furthermore, the measurement data does not contain error components of other axes other than the axis being measured. In this way, even when measuring a composite signal using time division, measurement data can be obtained in the same way as when measuring axis components in parallel.

[0048] The arithmetic circuit 60 may derive measurement data indicating the magnetic field of the Z-axis component by averaging each component according to the following formula:

[0049] Doutz=((1)+(2)+(7)+(8)) / 4=Hz+3.5ΔZ or Doutz=((3)+(4)+(5)+(6)) / 4=Hz+3.5ΔZ

[0050] 7 is a diagram showing the circuit configuration of a signal processing device 100C according to the third embodiment. The signal processing device 100C differs from the signal processing device 100A in that it includes a chopper switch 70 for removing offset voltages generated in the amplifier 40 and the ADC 50, and the switching control circuit 30 controls the signal selection unit 20 to select the sensor 10 and also controls the chopper switch 70 to switch between inverting and non-inverting the polarity of the analog signal.

[0051] The chopper switch 70 switches between inverted and non-inverted polarity of the analog signal output from the signal selection unit 20 and inputs the signal to the amplifier 40. The amplifier 40 amplifies the analog signal output from the chopper switch 70 and outputs it to the ADC 50.

[0052] The polarity of the input to the amplifier 40 is switched by the chopper switch 70 in order to remove the offset voltage Oe generated in the amplifier 40 and the ADC 50 .

[0053] For example, a non-inverted signal, which is an analog signal indicating the magnetic field of the X-axis component, indicates Hx + Oe. In an inverted signal, the polarity of the signal from sensor 10A is inverted, but the polarity of the offset voltage Oe is not inverted. Therefore, the inverted signal indicates -Hx + Oe. The offset voltage Oe can be removed by averaging the non-inverted signal and the inverted signal in the calculation circuit 60 as shown in the following equation.

[0054] Dout={(Hx+Oe)-(-Hx+Oe)}×1 / 2=2Hx×1 / 2=Hx

[0055] By performing the same processing for the Y axis and then the Z axis, digital signals indicating the magnetic fields Hx, Hy, and Hz with the offset voltage Oe removed can be obtained.

[0056] Figure 8 shows the timing at which each axis component is measured and the signal to be measured for each axis that changes during measurement in the circuit configuration shown in Figure 7. ΔX, ΔY, and ΔZ indicate the amount of change for each axis per unit measurement time.

[0057] The switching control circuit 30 may control the signal selection unit 20 and the chopper switch 70, as shown in FIG. 8 . That is, the switching control circuit 30 controls the signal selection unit 20 by transmitting a switching signal SEL_SENSOR to the signal selection unit 20 so that the signal selection unit 20 repeats the process of selecting the sensor 10A, the sensor 10B, and the sensor 10C in that order and outputting an analog signal from each sensor 10. Furthermore, the switching control circuit 30 controls the chopper switch 70 by transmitting a switching signal SEL_CHOP to the chopper switch 70 so that, while the sensor 10A is selected, the analog signal output from the sensor 10A is input to the amplifier 40 as a non-inverted signal, and then the analog signal output from the sensor 10A is input to the amplifier 40 as an inverted signal. Similarly, while the sensor 10B is selected, the switching control circuit 30 controls the chopper switch 70 by transmitting a switching signal SEL_CHOP to the chopper switch 70 so that the analog signal output from the sensor 10B is input to the amplifier 40 as a non-inverted signal, and then the analog signal output from the sensor 10B is input to the amplifier 40 as an inverted signal. Next, the switching control circuit 30 controls the chopper switch 70 by sending a switching signal SEL_CHOP to the chopper switch 70 so that, while the sensor 10C is selected, the analog signal output from the sensor 10C is input to the amplifier 40 as a non-inverted signal, and then the analog signal output from the sensor 10C is input to the amplifier 40 as an inverted signal.

[0058] In this case, the arithmetic circuit 60 can derive measurement data indicating the magnetic field of each axial component by averaging each component according to the following equation.

[0059] Doutx=((1)-(2)) / 2={Hx+Oe-(-(Hx+ΔX)+Oe)}×1 / 2=Hx+0.5ΔX Douty=((3)-(4)) / 2={(Hy+2ΔY)+Oe-(-(Hy+3ΔY)+Oe)}×1 / 2=Hy+2.5ΔY Doutz=((5)-(6)) / 2={(Hz+4ΔZ)+Oe-(-(Hz+5ΔZ)+Oe)}×1 / 2=Hz+4.5ΔZ

[0060] However, as mentioned above, the time changes of the measurement data for each axis are 0.5ΔX, 2.5ΔY, and 4.5ΔZ, so the time changes of the measurement data for each axis do not align. In other words, the measurement timing of the magnetic field for each axis is different, and the time centers of the measurement data for each axis do not align.

[0061] Therefore, in the third embodiment, in order to eliminate the difference in measurement timing of the magnetic field for each axis, the order in which the sensors 10 are selected by the signal selection unit 20 and the timing of switching the polarity of the chopper switch 70 are changed.

[0062] 9 shows the timing at which each axial component is measured and the signal of the measurement target for each axis that changes during measurement in the third embodiment. In the third embodiment, the switching control circuit 30 controls the signal selection unit 20 to select the sensors 10A(Hx), 10B(Hy), and 10C(Hz) one by one in a first order of sensor 10A(Hx), sensor 10B(Hy), and sensor 10C(Hz) to sequentially output analog signals from each sensor 10, and then to select the sensors 10C(Hz), 10B(Hy), and 10A(Hx) one by one in a second order that is reverse to the first order of sensor 10A(Hx), sensor 10B(Hy), and sensor 10C(Hz) to sequentially output analog signals from each sensor 10.

[0063] Furthermore, the switching control circuit 30 controls the chopper switch 70 by sending a switching signal SEL_CHOP to the chopper switch 70 so that while sensors 10A, 10B, and 10C are selected in the first order, the analog signals output from sensors 10A, 10B, and 10C are input to the amplifier 40 as non-inverted signals, and then while sensors 10C, 10B, and 10A are selected in the second order, the analog signals output from sensors 10C, 10B, and 10A are input to the amplifier 40 as inverted signals.

[0064] That is, while controlling chopper switch 70 to maintain the analog signal input to amplifier 40 as a non-inverted signal, switching control circuit 30 controls signal selection unit 20 so that analog signals are output from sensor 10A, sensor 10B, and sensor 10C in this order. Next, while controlling chopper switch 70 to maintain the analog signal input to amplifier 40 as an inverted signal, switching control circuit 30 controls signal selection unit 20 so that analog signals are output from sensor 10C, sensor 10B, and sensor 10A in this order.

[0065] The arithmetic circuit 60 then averages each component according to the following equation to derive measurement data indicating the magnetic field of each axial component.

[0066] Doutx=((1)-(6)) / 2={Hx+Oe-(-(Hx+5ΔX)+Oe)}×1 / 2=Hx+2.5ΔX Douty=((2)-(5)) / 2={(Hy+ΔY)+Oe-(-(Hy+4ΔY)+Oe)}×1 / 2=Hy+2.5ΔY Doutz=((3)-(4)) / 2={(Hz+2ΔZ)+Oe-(-(Hz+3ΔZ)+Oe)}×1 / 2=Hz+2.5ΔZ

[0067] As shown above, the coefficient of the time change in the measurement data showing the magnetic field of each axial component is 2.5 for all axes. Therefore, the time change in the measurement data showing the magnetic field of each axial component is consistent. In this way, even when measuring each axial component in a time-division manner, measurement data can be obtained in the same way as when measuring the axial components in parallel.

[0068] 10 is a diagram showing the circuit configuration of a signal processing device 100D according to the fourth embodiment. The signal processing device 100D differs from the signal processing device 100B in that it includes a chopper switch 70 for removing offset voltages generated in the amplifier 40 and the ADC 50, and the switching control circuit 30 controls the signal selection unit 20 to select the sensor 10 and also controls the chopper switch 70 to switch between inverting and non-inverting the polarity of the analog signal.

[0069] Figure 11 shows the timing at which each axis component is measured and the signal to be measured for each axis that changes during measurement in the circuit configuration shown in Figure 10. ΔX, ΔY, and ΔZ indicate the amount of change for each axis per unit measurement time.

[0070] 10 , the switching control circuit 30 may control the signal selection unit 20 and the chopper switch 70. That is, the switching control circuit 30 controls the signal selection unit 20 by sending a switching signal SEL_SENSOR to the signal selection unit 20 so that the signal selection unit 20 repeats the process of selecting the sensor 10A, the sensor 10B, the sensor 10C, and the sensor 10D in that order and outputting an analog signal from each sensor 10. Furthermore, while the sensor 10A is selected, the switching control circuit 30 controls the chopper switch 70 by sending a switching signal SEL_CHOP to the chopper switch 70 so that the analog signal output from the sensor 10A is input to the amplifier 40 as a non-inverted signal, and then the analog signal output from the sensor 10A is input to the amplifier 40 as an inverted signal.

[0071] Similarly, while sensor 10B is selected, the switching control circuit 30 controls the chopper switch 70 by sending a switching signal SEL_CHOP to the chopper switch 70 so that the analog signal output from sensor 10B is input to the amplifier 40 as a non-inverted signal, and then the analog signal output from sensor 10B is input to the amplifier 40 as an inverted signal. Furthermore, while sensor 10C is selected, the switching control circuit 30 controls the chopper switch 70 by sending a switching signal SEL_CHOP to the chopper switch 70 so that the analog signal output from sensor 10C is input to the amplifier 40 as a non-inverted signal, and then the analog signal output from sensor 10C is input to the amplifier 40 as an inverted signal. In addition, while sensor 10D is selected, the switching control circuit 30 controls the chopper switch 70 by sending a switching signal SEL_CHOP to the chopper switch 70 so that the analog signal output from sensor 10D is input to the amplifier 40 as a non-inverted signal, and then the analog signal output from sensor 10D is input to the amplifier 40 as an inverted signal.

[0072] In this case, the arithmetic circuit 60 can derive measurement data indicating the magnetic field of each axial component by averaging each component according to the following equation.

[0073] Doutx={(1)-(2)-((3)-(4))} / 4=Hx+1.5ΔX-ΔZ Douty={(5)-(6)-((7)-(8))} / 4=Hy+5.5ΔY-ΔZ Doutz={((1)-(2))+((3)-(4))+((5)-(6))+((7)-(8))} / 8=Hz+3.5ΔZ-0.5(ΔX+ΔY)

[0074] However, as described above, the time changes of the measurement data for each axis along the axis being measured are 1.5ΔX, 5.5ΔY, and 3.5ΔZ, so the time changes of the measurement data for each axis do not align. In other words, the magnetic field measurement timing for each axis is different, and the time centers of the measurement data for each axis do not align. Furthermore, when a mixed signal that changes during measurement is acquired for each sensor 10 in a time-division manner and calculated by the calculation circuit 60, the measurement data for the X and Y axes contains an error component of ΔZ in addition to the axis being measured, and the measurement data for the Z axis contains an error component of 0.5(ΔX + ΔY) in addition to the axis being measured.

[0075] Therefore, in the fourth embodiment, in order to eliminate the difference in measurement timing of the magnetic field of each axis, the order in which the sensors 10 are selected by the signal selection unit 20 and the timing of switching the polarity of the chopper switch 70 are changed.

[0076] 12 shows the timing at which each axis component is measured and the signal of the measurement target for each axis that changes during measurement in the fourth embodiment. In the fourth embodiment, the switching control circuit 30 controls the signal selection unit 20 to select sensors 10A, 10B, 10C, and 10D one by one in a first order of sensors 10A, 10B, 10C, and 10D, and cause each sensor 10 to sequentially output an analog signal, and then to select sensors 10D, 10C, 10B, and 10A one by one in a second order that is reverse to the first order of sensors 10A, 10B, 10C, and 10D, and cause each sensor 10 to sequentially output an analog signal.

[0077] Furthermore, the switching control circuit 30 controls the chopper switch 70 by sending a switching signal SEL_CHOP to the chopper switch 70 so that while sensors 10A, 10B, 10C, and 10D are selected in a first order, the analog signals output from sensors 10A, 10B, 10C, and 10D are input to the amplifier 40 as non-inverted signals, and then while sensors 10D, 10C, 10B, and 10A are selected in a second order, the analog signals output from sensors 10D, 10C, 10B, and 10A are input to the amplifier 40 as inverted signals.

[0078] That is, while controlling chopper switch 70 to maintain the analog signal input to amplifier 40 as a non-inverted signal, switching control circuit 30 controls signal selection unit 20 so that analog signals are output from signal selection unit 20 in the order of sensor 10A, sensor 10B, sensor 10C, and sensor 10D. Next, while controlling chopper switch 70 to maintain the analog signal input to amplifier 40 as an inverted signal, switching control circuit 30 controls signal selection unit 20 so that analog signals are output from signal selection unit 20 in the order of sensor 10D, sensor 10C, sensor 10B, and sensor 10A.

[0079] The arithmetic circuit 60 then averages each component according to the following equation to derive measurement data indicating the magnetic field of each axial component.

[0080] Doutx={(1)-(8)-((2)-(7))} / 4=Hx+3.5ΔX Douty={(3)-(6)-((4)-(5))} / 4=Hy+3.5ΔY Doutz={((1)-(8))+((2)-(7))+((3)-(6))+((4)-(5))} / 8=Hz+3.5ΔZ

[0081] As shown above, the coefficient of the time change in the measurement data indicating the magnetic field of each axis component is 4 for all axes. Therefore, the time change in the measurement data indicating the magnetic field of each axis component is consistent. Furthermore, the measurement data does not contain error components of any axis other than the axis being measured. In this way, even when measuring in a time-division manner by removing the offset voltage Oe from the composite signal, measurement data can be obtained in the same way as when measuring the axis components in parallel.

[0082] The arithmetic circuit 60 may derive measurement data indicating the magnetic field of the Z-axis component by averaging each component according to the following formula:

[0083] Doutz={((1)-(8))+((2)-(7))} / 4=Hz+3.5ΔZ or Doutz={((3)-(6))+((4)-(5))} / 4=Hz+3.5ΔZ

[0084] Fig. 13 shows the phase characteristics of the measurement data when the magnetic field of each axis is measured at the measurement timing shown in Fig. 2. Fig. 14 shows the phase characteristics of the measurement data when the magnetic field of each axis is measured at the measurement timing shown in Fig. 3.

[0085] As shown in Fig. 13, in the measurement timing shown in Fig. 2, signal processing is performed in the order of the X-axis, Y-axis, and Z-axis, so the phase characteristics of each axis are different. On the other hand, as shown in Fig. 14, in the measurement timing shown in Fig. 3, the phase characteristics of the X-axis, Y-axis, and Z-axis are the same. Therefore, the amount of group delay is the same for all axes. In other words, according to each embodiment, the magnetic field of each axial component can be measured at the same timing in terms of phase characteristics as well.

[0086] As described above, according to each embodiment, it is possible to suppress an increase in circuit size and power consumption, and also to suppress a difference in measurement time of a physical quantity such as a magnetic field detected by a plurality of sensors.

[0087] In the above embodiments, a magnetic sensor has been described as an example of the sensor 10. However, the sensor 10 may be a sensor other than a magnetic sensor as long as it detects a physical quantity for each of a plurality of axial components. The sensor 10 may also be an acceleration sensor, a gyro sensor, or the like.

[0088] Although the present invention has been described above using embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments. It will be apparent to those skilled in the art that various modifications and improvements can be made to the above embodiments. It is clear from the claims that such modifications and improvements can also be included within the technical scope of the present invention.

[0089] It should be noted that the execution order of each process, such as operations, procedures, steps, and stages, in the devices, systems, programs, and methods shown in the claims, specifications, and drawings is not specifically stated as "before," "prior to," etc., and that the processes can be performed in any order unless the output of a previous process is used in a subsequent process. Even if the operational flow in the claims, specifications, and drawings is described using "first," "next," etc. for convenience, this does not mean that the processes must be performed in this order. [Explanation of symbols]

[0090] 10A, 10B, 10C, 10D Sensors 20 Signal selection section 30 Switching control circuit 40 Amplifier 50 ADC 60 Arithmetic circuit 70 Chopper switch 100A, 100B, 100C, 100D Signal processing device

Claims

1. a signal selection unit that receives analog signals indicating physical quantities detected by each of a plurality of sensors and selectively outputs an analog signal indicating the physical quantity detected by one of the plurality of sensors; a control unit that controls the signal selection unit to repeat a process of sequentially outputting analog signals from sensors selected one by one from the plurality of sensors in a first order, and then sequentially outputting analog signals from sensors selected one by one from the plurality of sensors in a second order that is the reverse of the first order; a conversion unit that converts the analog signals output from the plurality of sensors, which are output from the signal selection unit by the processing, into digital signals; a derivation unit that derives each physical quantity detected by each of the plurality of sensors based on each of the digital signals; Equipped with the plurality of sensors include a first sensor that outputs analog signals indicating a physical quantity of a first axis component and a physical quantity of a third axis component, a second sensor that outputs analog signals indicating a physical quantity obtained by inverting the polarity of the first axis component and a physical quantity of a third axis component, a third sensor that outputs analog signals indicating the physical quantity of the second axis component and the physical quantity of the third axis component, and a fourth sensor that indicates the physical quantity obtained by inverting the polarity of the second axis component and the physical quantity of the third axis component, the signal selection unit outputs the analog signals in the order of a first analog signal output from the first sensor at a first time point, a second analog signal output from the second sensor at a second time point subsequent to the first time point, a third analog signal output from the third sensor at a third time point subsequent to the second time point, and a fourth analog signal output from the fourth sensor at a fourth time point subsequent to the third time point, and thereafter outputs the analog signals in the order of a fifth analog signal output from the fourth sensor at a fifth time point subsequent to the fourth time point, a sixth analog signal output from the third sensor at a sixth time point subsequent to the fifth time point, a seventh analog signal output from the second sensor at a seventh time point subsequent to the sixth time point, and an eighth analog signal output from the first sensor at an eighth time point subsequent to the seventh time point; the conversion unit converts the first analog signal, the second analog signal, the third analog signal, the fourth analog signal, the fifth analog signal, the sixth analog signal, the seventh analog signal, and the eighth analog signal into a first digital signal, a second digital signal, a third digital signal, a fourth digital signal, a fifth digital signal, a sixth digital signal, a seventh digital signal, and an eighth digital signal; the derivation unit derives the physical quantity of a first axis component based on the first digital signal, the second digital signal, the seventh digital signal, and the eighth digital signal, derives the physical quantity of a second axis component based on the third digital signal, the fourth digital signal, the fifth digital signal, and the sixth digital signal, and derives the physical quantity of a third axis component based on the first digital signal, the second digital signal, the third digital signal, the fourth digital signal, the fifth digital signal, the sixth digital signal, the seventh digital signal, and the eighth digital signal.

2. The signal processing device according to claim 1 , wherein the signal selection unit outputs, at predetermined intervals, an analog signal indicating a physical quantity detected by one of the plurality of sensors that is sequentially selected.

3. an amplifier that amplifies each of the analog signals output from the plurality of sensors and output from the signal selection unit by the processing; The signal processing device according to claim 1 , wherein the conversion section converts each of the analog signals amplified by the amplifier into a digital signal.

4. 4. The signal processing device according to claim 1, further comprising an inverting unit that inverts the polarity of an analog signal from one of the plurality of sensors selected one by one in the second order from among the plurality of sensors, relative to the polarity of an analog signal from one of the plurality of sensors selected one by one in the first order, and outputs the inverted signal to the converting unit.

5. the plurality of sensors include a first sensor that outputs an analog signal indicative of a physical quantity of a first axis component, a second sensor that outputs an analog signal indicative of a physical quantity of a second axis component, and a third sensor that outputs an analog signal indicative of a physical quantity of a third axis component; the signal selection unit outputs analog signals in the order of a first analog signal output from the first sensor at a first time point, a second analog signal output from the second sensor at a second time point subsequent to the first time point, and a third analog signal output from the third sensor at a third time point subsequent to the second time point, and then outputs analog signals in the order of a fourth analog signal output from the third sensor at a fourth time point subsequent to the third time point, a fifth analog signal output from the second sensor at a fifth time point subsequent to the fourth time point, and a sixth analog signal output from the first sensor at a sixth time point subsequent to the fifth time point, the conversion unit converts the first analog signal, the second analog signal, the third analog signal, the fourth analog signal, the fifth analog signal, and the sixth analog signal into a first digital signal, a second digital signal, a third digital signal, a fourth digital signal, a fifth digital signal, and a sixth digital signal; 5. The signal processing device according to claim 1, wherein the derivation unit derives the physical quantity of a first axis component based on the first digital signal and the sixth digital signal, derives the physical quantity of a second axis component based on the second digital signal and the fifth digital signal, and derives the physical quantity of a third axis component based on the third digital signal and the fourth digital signal.

6. The signal processing device according to claim 5 , wherein the intervals between the first time point, the second time point, the third time point, the fourth time point, the fifth time point, and the sixth time point are the same.

7. A signal selection unit that receives analog signals indicating physical quantities detected by each of a plurality of sensors and selectively outputs an analog signal indicating the physical quantity detected by one of the plurality of sensors; a control unit that controls the signal selection unit to repeat a process of sequentially outputting analog signals from sensors selected one by one from the plurality of sensors in a first order, and then sequentially outputting analog signals from sensors selected one by one from the plurality of sensors in a second order that is the reverse of the first order; a conversion unit that converts the analog signals output from the plurality of sensors, which are output from the signal selection unit by the processing, into digital signals; a derivation unit that derives each physical quantity detected by each of the plurality of sensors based on each of the digital signals; Equipped with the plurality of sensors include a first sensor that outputs analog signals indicating a physical quantity of a first axis component and a physical quantity of a third axis component, a second sensor that outputs analog signals indicating a physical quantity obtained by inverting the polarity of the first axis component and a physical quantity of a third axis component, a third sensor that outputs analog signals indicating the physical quantity of the second axis component and the physical quantity of the third axis component, and a fourth sensor that indicates the physical quantity obtained by inverting the polarity of the second axis component and the physical quantity of the third axis component, the signal selection unit outputs the analog signals in the order of a first analog signal output from the first sensor at a first time point, a second analog signal output from the second sensor at a second time point subsequent to the first time point, a third analog signal output from the third sensor at a third time point subsequent to the second time point, and a fourth analog signal output from the fourth sensor at a fourth time point subsequent to the third time point, and thereafter outputs the analog signals in the order of a fifth analog signal output from the fourth sensor at a fifth time point subsequent to the fourth time point, a sixth analog signal output from the third sensor at a sixth time point subsequent to the fifth time point, a seventh analog signal output from the second sensor at a seventh time point subsequent to the sixth time point, and an eighth analog signal output from the first sensor at an eighth time point subsequent to the seventh time point; the conversion unit converts the first analog signal, the second analog signal, the third analog signal, the fourth analog signal, the fifth analog signal, the sixth analog signal, the seventh analog signal, and the eighth analog signal into a first digital signal, a second digital signal, a third digital signal, a fourth digital signal, a fifth digital signal, a sixth digital signal, a seventh digital signal, and an eighth digital signal; the derivation unit derives the physical quantity of a first axis component based on the first digital signal, the second digital signal, the seventh digital signal, and the eighth digital signal, derives the physical quantity of a second axis component based on the third digital signal, the fourth digital signal, the fifth digital signal, and the sixth digital signal, and derives the physical quantity of a third axis component based on the first digital signal, the second digital signal, the seventh digital signal, and the eighth digital signal or the third digital signal, the fourth digital signal, the fifth digital signal, and the sixth digital signal.

8. 8. The signal processing device according to claim 1, wherein the intervals between the first time point, the second time point, the third time point, the fourth time point, the fifth time point, the sixth time point, the seventh time point, and the eighth time point are the same.

9. The signal processing device according to claim 1 , wherein each of the plurality of sensors is a magnetic sensor that detects a magnetic field as the physical quantity.

10. a step of controlling a signal selection unit that receives analog signals indicating physical quantities detected by each of a plurality of sensors and selectively outputs an analog signal indicating the physical quantity detected by one of the plurality of sensors, so as to repeat a process of sequentially outputting analog signals from sensors selected one by one in a first order from the plurality of sensors, and then sequentially outputting analog signals from sensors selected one by one in a second order that is reverse to the first order from the plurality of sensors; converting the analog signals output from the plurality of sensors output from the signal selection unit into digital signals; deriving a physical quantity detected by each of the plurality of sensors based on the digital signal; Equipped with the plurality of sensors include a first sensor that outputs analog signals indicating a physical quantity of a first axis component and a physical quantity of a third axis component, a second sensor that outputs analog signals indicating a physical quantity obtained by inverting the polarity of the first axis component and a physical quantity of a third axis component, a third sensor that outputs analog signals indicating the physical quantity of the second axis component and the physical quantity of the third axis component, and a fourth sensor that indicates the physical quantity obtained by inverting the polarity of the second axis component and the physical quantity of the third axis component, the signal selection unit outputs the analog signals in the order of a first analog signal output from the first sensor at a first time point, a second analog signal output from the second sensor at a second time point subsequent to the first time point, a third analog signal output from the third sensor at a third time point subsequent to the second time point, and a fourth analog signal output from the fourth sensor at a fourth time point subsequent to the third time point, and thereafter outputs the analog signals in the order of a fifth analog signal output from the fourth sensor at a fifth time point subsequent to the fourth time point, a sixth analog signal output from the third sensor at a sixth time point subsequent to the fifth time point, a seventh analog signal output from the second sensor at a seventh time point subsequent to the sixth time point, and an eighth analog signal output from the first sensor at an eighth time point subsequent to the seventh time point; the converting step includes converting the first analog signal, the second analog signal, the third analog signal, the fourth analog signal, the fifth analog signal, the sixth analog signal, the seventh analog signal, and the eighth analog signal into a first digital signal, a second digital signal, a third digital signal, a fourth digital signal, a fifth digital signal, a sixth digital signal, a seventh digital signal, and an eighth digital signal; the deriving step includes steps of deriving a physical quantity of a first axis component based on the first digital signal, the second digital signal, the seventh digital signal, and the eighth digital signal, deriving a physical quantity of a second axis component based on the third digital signal, the fourth digital signal, the fifth digital signal, and the sixth digital signal, and deriving a physical quantity of a third axis component based on the first digital signal, the second digital signal, the third digital signal, the fourth digital signal, the fifth digital signal, the sixth digital signal, the seventh digital signal, and the eighth digital signal.

11. A step of controlling a signal selection unit that receives analog signals indicating physical quantities detected by each of a plurality of sensors and selectively outputs an analog signal indicating the physical quantity detected by one of the plurality of sensors so that the signal selection unit sequentially outputs analog signals from sensors selected one by one in a first order from the plurality of sensors, and then repeats a process of sequentially outputting analog signals from sensors selected one by one from the plurality of sensors in a second order that is the reverse of the first order from the plurality of sensors; converting the analog signals output from the plurality of sensors output from the signal selection unit into digital signals; deriving a physical quantity detected by each of the plurality of sensors based on the digital signal; Equipped with the plurality of sensors include a first sensor that outputs analog signals indicating a physical quantity of a first axis component and a physical quantity of a third axis component, a second sensor that outputs analog signals indicating a physical quantity obtained by inverting the polarity of the first axis component and a physical quantity of a third axis component, a third sensor that outputs analog signals indicating the physical quantity of the second axis component and the physical quantity of the third axis component, and a fourth sensor that indicates the physical quantity obtained by inverting the polarity of the second axis component and the physical quantity of the third axis component, the signal selection unit outputs the analog signals in the order of a first analog signal output from the first sensor at a first time point, a second analog signal output from the second sensor at a second time point subsequent to the first time point, a third analog signal output from the third sensor at a third time point subsequent to the second time point, and a fourth analog signal output from the fourth sensor at a fourth time point subsequent to the third time point, and thereafter outputs the analog signals in the order of a fifth analog signal output from the fourth sensor at a fifth time point subsequent to the fourth time point, a sixth analog signal output from the third sensor at a sixth time point subsequent to the fifth time point, a seventh analog signal output from the second sensor at a seventh time point subsequent to the sixth time point, and an eighth analog signal output from the first sensor at an eighth time point subsequent to the seventh time point; the converting step includes converting the first analog signal, the second analog signal, the third analog signal, the fourth analog signal, the fifth analog signal, the sixth analog signal, the seventh analog signal, and the eighth analog signal into a first digital signal, a second digital signal, a third digital signal, a fourth digital signal, a fifth digital signal, a sixth digital signal, a seventh digital signal, and an eighth digital signal; the deriving step includes steps of deriving a physical quantity of a first axis component based on the first digital signal, the second digital signal, the seventh digital signal, and the eighth digital signal, deriving a physical quantity of a second axis component based on the third digital signal, the fourth digital signal, the fifth digital signal, and the sixth digital signal, and deriving a physical quantity of a third axis component based on the first digital signal, the second digital signal, the seventh digital signal, and the eighth digital signal or the third digital signal, the fourth digital signal, the fifth digital signal, and the sixth digital signal.

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