Electronic devices, electronic equipment, electronic equipment systems, air conditioning systems and air conditioning equipment

Abstract

To provide an electronic device that can itself improve a frequency accuracy of an operation clock generated by the electronic device.SOLUTION: An electronic device 1 has: an oscillation circuit 16 for generating an operation clock; a reception circuit 11 for receiving a communication signal synchronized with a high-accuracy clock from an upstream device 3 that operates with a high-accuracy clock having a frequency accuracy higher than a frequency accuracy of the operation clock; a measurement circuit 17 for measuring a pulse width, which is a width of a pulse included in the communication signal, based on the operation clock; a memory 13 for storing a reference value of the pulse width; and a correction circuit 18 for correcting a frequency of the operation clock based on a result of comparing a measured value of the pulse width measured by the measurement circuit 17 with the reference value.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to an electronic device, an electronic apparatus, an electronic apparatus system, an air conditioning system, and an air conditioner.

Background Art

[0002] There is known a technique for correcting the oscillation frequency of a driver IC based on the result of measuring the frequency of a clock output from the driver IC with a microcomputer using an oscillator with low accuracy in the oscillation circuit of the driver IC (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the conventional technology, there has been a problem that the processing load of another device that controls an electronic device to be corrected for the oscillation frequency of a clock increases.

[0005] The present disclosure has been made in view of these points, and an object thereof is to enable an electronic device to improve the frequency accuracy of a clock generated by the electronic device itself.

Means for Solving the Problems

[0006] An electronic device according to a first aspect of this disclosure includes: an oscillator circuit that generates an operating clock; a receiving circuit that receives a communication signal synchronized with the high-precision clock from an upstream device that operates with a high-precision clock having a higher frequency accuracy than the frequency accuracy of the operating clock; a measurement circuit that measures the pulse width, which is the width of the pulses included in the communication signal, based on the operating clock; a memory that stores a reference value of the pulse width; and a correction circuit that corrects the frequency of the operating clock based on a comparison between the measured value of the pulse width measured by the measurement circuit and the reference value. This allows the electronic device itself to improve the frequency accuracy of the operating clock it generates.

[0007] The oscillation circuit may have a trimming circuit that changes the frequency of the operating clock based on the input voltage, and the correction circuit may correct the frequency of the operating clock by inputting a voltage based on the difference between the measured value and the reference value to the trimming circuit. This allows the electronic device to correct the frequency over a wide frequency range.

[0008] The oscillation circuit includes a reference clock generation circuit that generates a reference clock with a different frequency from the operating clock, and a phase synchronization circuit that generates the operating clock by dividing or multiplying the reference clock. The correction circuit may correct the frequency of the operating clock by changing the internal parameters of the phase synchronization circuit based on the result of comparing the measured value with the reference value. This allows the electronic device to correct the frequency with high precision.

[0009] The oscillation circuit includes a trimming circuit that changes the frequency of the operating clock based on an input voltage, a reference clock generation circuit that generates a reference clock with a different frequency from the operating clock, and a phase-locking circuit that generates the operating clock by dividing or multiplying the reference clock. The correction circuit may correct the frequency of the operating clock by inputting a differential voltage based on the difference between the measured value and the reference value to the trimming circuit, and then correct the frequency of the operating clock by changing the internal parameters of the phase-locking circuit based on the result of comparing the measured value obtained by the measurement circuit measuring the pulse width of the new communication signal with the reference value. This allows the electronic device to correct the frequency with high accuracy over a wide frequency range.

[0010] The correction circuit may, after correcting the operating clock frequency with a first resolution by inputting the differential voltage to the trimming circuit, correct the operating clock frequency with a second resolution higher than the first resolution by changing the internal parameters of the phase-locking circuit. This allows the electronic device to correct the frequency with high resolution and high precision over a wide frequency range.

[0011] The system may further include a data acquisition circuit that acquires the setting data for the aforementioned reference value and stores the acquired reference value in the memory. This allows the electronic device to correct the frequency regardless of the communication speed of the communication signal transmitted by the upstream device.

[0012] The memory may store a plurality of reference value candidates, and the correction circuit may compare the reference value selected from the plurality of reference value candidates based on the pulse width measured by the measurement circuit with the measured value. This allows the electronic device to correct the frequency even when multiple communication speeds are assumed as the communication speed of the communication signal transmitted by the upstream device.

[0013] The system further includes a data acquisition circuit that acquires instruction data including an instruction to correct the frequency of the operating clock, and the correction circuit may correct the frequency of the operating clock in response to the receiving circuit receiving the instruction data. This allows the electronic device to correct its frequency when a user of an electronic device equipped with the electronic device wants the electronic device to correct its frequency.

[0014] The electronic device further includes a temperature sensor for measuring the internal temperature, and the correction circuit may correct the frequency of the operating clock when the deviation of the temperature measured by the temperature sensor from a reference temperature exceeds a threshold. This makes it possible to reduce the frequency deviation of the operating clock of the electronic device caused by the temperature deviation.

[0015] The memory further stores the cumulative period during which the electronic device is operating, and the correction circuit may correct the frequency of the operating clock when the cumulative period reaches a predetermined period. This makes it possible to reduce the frequency deviation of the operating clock of the electronic device caused by aging.

[0016] An electronic device according to a second aspect of this disclosure includes a first electronic device that operates with a high-precision clock of first frequency accuracy, and a second electronic device that generates an operating clock with a second frequency accuracy lower than the first frequency accuracy, wherein the second electronic device includes an oscillator circuit that generates the operating clock, a receiving circuit that receives a communication signal synchronized with the high-precision clock from the first electronic device, a measurement circuit that measures the pulse width, which is the width of a pulse included in the communication signal, based on the operating clock, a memory that stores a reference value of the pulse width included in the communication signal, and a correction circuit that corrects the frequency of the operating clock based on a comparison between the measured value of the pulse width measured by the measurement circuit and the reference value. This makes it possible to improve the frequency accuracy of the electronic devices in the electronic device while suppressing an increase in the cost of the electronic device.

[0017] An electronic device system according to a third aspect of the present disclosure comprises a first electronic device and a second electronic device capable of communicating with the first electronic device, wherein the first electronic device has a first electronic device that operates with a high-precision clock of first frequency accuracy, and the second electronic device has a second electronic device that generates an operating clock with a second frequency accuracy lower than the first frequency accuracy, the second electronic device having an oscillator circuit that generates the operating clock, a receiving circuit that receives a communication signal synchronized with the high-precision clock from the first electronic device, a measurement circuit that measures the pulse width, which is the width of a pulse included in the communication signal, based on the operating clock, a memory that stores a reference value of the pulse width included in the communication signal, and a correction circuit that corrects the frequency of the operating clock based on a comparison between the measured value of the pulse width measured by the measurement circuit and the reference value. This makes it possible to improve the frequency accuracy of the electronic device of the second electronic device while suppressing an increase in the cost of the second electronic device.

[0018] A fourth aspect of the present disclosure is an air conditioning system comprising an indoor unit and an outdoor unit, wherein one of the indoor unit and the outdoor unit has a first electronic device that operates with a high-precision clock of first frequency accuracy, and the other of the indoor unit and the outdoor unit has a second electronic device that generates an operating clock with a second frequency accuracy lower than the first frequency accuracy, the second electronic device comprising: an oscillation circuit that generates the operating clock; a receiving circuit that receives a communication signal synchronized with the high-precision clock from the device having the first electronic device; a measurement circuit that measures the pulse width, which is the width of a pulse included in the communication signal, based on the operating clock; a memory that stores a reference value of the pulse width included in the communication signal; and a correction circuit that corrects the frequency of the operating clock based on a comparison between the measured value of the pulse width measured by the measurement circuit and the reference value. This makes it possible to improve the frequency accuracy of the electronic device in the indoor unit or the outdoor unit while suppressing an increase in the cost of the indoor unit or the outdoor unit in the air conditioning system.

[0019] The air conditioner according to the fifth aspect of the present disclosure is an air conditioner capable of communicating with a communication device provided with a first electronic device operating with a high-precision clock having a first frequency accuracy. The air conditioner has a second electronic device that generates an operating clock having a second frequency accuracy lower than the first frequency accuracy. The second electronic device includes an oscillation circuit that generates an operating clock, a reception circuit that receives a communication signal synchronized with the high-precision clock from the communication device, a measurement circuit that measures a pulse width, which is the width of a pulse included in the communication signal, based on the operating clock, a memory that stores a reference value of the pulse width included in the communication signal, and a correction circuit that corrects the frequency of the operating clock based on a result of comparing a measured value of the pulse width measured by the measurement circuit with the reference value. Thereby, it is possible to improve the frequency accuracy of the electronic device while suppressing an increase in the cost of the air conditioner.

Brief Description of Drawings

[0020] [Figure 1] It is a diagram for explaining an overview of the electronic device 100. [Figure 2] It is a diagram showing the configuration of the electronic device 1. [Figure 3] It is a diagram showing a configuration example of the phase synchronization circuit 163. [Figure 4] It is a diagram showing an example of a pulse to be measured by the measurement circuit 17. [Figure 5] It is a flowchart showing the flow of a process for correcting an operating clock in the electronic device 1. [Figure 6] It is a diagram showing another configuration example of the electronic device 1. [Figure 7] It is a diagram showing an example of the electronic device 1. [Figure 8] It is a diagram showing another example of the electronic device 1. [Figure 9] It is a diagram showing the configuration of the electronic device 200. [Figure 10] It is a diagram showing the configuration of the electronic device 300. [Figure 11] It is a diagram showing the configuration of the electronic device 400. [Figure 12] This is a diagram showing the configuration of the air conditioning system S1. [Figure 13] This is a diagram showing the configuration of the air conditioning system S2. [Figure 14] This diagram shows the configuration of the air conditioning system S3. [Modes for carrying out the invention]

[0021] [Overview of Electronic Device 100] Figure 1 is a diagram illustrating the overview of electronic equipment 100. Electronic equipment 100 is a device having an electrical circuit that operates based on a clock, such as an air conditioner. Electronic equipment 100 includes an electronic device 1, an oscillator 2, an upstream device 3, and an oscillator 4.

[0022] Electronic device 1 is a semiconductor device that operates based on an operating clock generated by, for example, the oscillation of oscillator 2. Electronic device 1 generates an operating clock by dividing or multiplying the oscillation signal generated by oscillator 2, and operates its internal circuitry with the operating clock. By correcting the frequency of the operating clock using a communication signal input from upstream device 3, electronic device 1 can make the frequency accuracy of the operating clock higher than the frequency accuracy of oscillator 2.

[0023] Oscillator 2 oscillates while connected to electronic device 1. Oscillator 2 is, for example, a ceramic oscillator. The accuracy of the oscillation frequency of oscillator 2 is lower than that of oscillator 4, for example, ±0.5%.

[0024] The upstream device 3 is a device capable of transmitting communication signals to the electronic device 1. The upstream device 3 operates with a high-precision clock that has a higher frequency accuracy than the operating clock generated by the electronic device 1. The upstream device 3 generates communication signals based on the high-precision clock generated by causing the oscillator 4 to oscillate. The communication signals are serial signals such as UART (Universal Asynchronous Receiver Transmitter) and SPI (Serial Peripheral Interface).

[0025] Oscillator 4 provides an oscillation signal to the upstream device 3. Oscillator 4 is, for example, a crystal oscillator. The frequency accuracy of oscillator 4 is higher than that of oscillator 2, for example, ±0.001%. Oscillator 4 may be a temperature-compensated crystal oscillator (TCXO) or a crystal oscillator with a constant temperature chamber. Alternatively, a crystal resonator with higher frequency accuracy than oscillator 2 may be used instead of oscillator 4. The upstream device 3 operates using a high-precision clock based on the oscillation signal provided by oscillator 4.

[0026] Upstream device 3 generates communication signals using a high-precision clock. When the design value of the communication speed of the communication channel between electronic device 1 and upstream device 3 is 9600 bps, the design value of the minimum pulse width of the communication signal is 104.16 μs. When the communication speed of the communication channel is 19200 bps, the design value of the minimum pulse width of the communication signal is 52.08 μs. In the following explanation, the design value of the pulse width of the communication signal transmitted by upstream device 3 is referred to as the reference value.

[0027] Electronic device 1 measures the pulse width of the received communication signal based on the operating clock generated by oscillating oscillator 2. If the operating clock of electronic device 1 has the same precision as the high-precision clock of upstream device 3, the measured pulse width will match the above reference value. However, if the frequency of the operating clock of electronic device 1 is lower than the design frequency, the pulse width measured by electronic device 1 will be shorter than the reference value. If the frequency of the operating clock of electronic device 1 is higher than the design frequency, the pulse width measured by electronic device 1 will be longer than the reference value. Electronic device 1 compares the measured pulse width with the reference value and corrects the operating clock based on the magnitude of the difference between the measured value and the reference value.

[0028] With this configuration, even if the frequency accuracy of the oscillator 2 used by electronic device 1 to generate the operating clock is low, electronic device 1 can achieve a higher frequency accuracy for the operating clock it generates based on the oscillator than for the oscillator 2. As a result, high frequency accuracy is not required for the oscillator 2, thus reducing the cost of the oscillator 2.

[0029] [Configuration of Electronic Device 1] Figure 2 shows the configuration of electronic device 1. Electronic device 1 includes a receiving circuit 11, a data acquisition circuit 12, a memory 13, a temperature sensor 14, an AD converter 15, an oscillation circuit 16, a measurement circuit 17, and a correction circuit 18. Some or all of the functions of the receiving circuit 11, the data acquisition circuit 12, the measurement circuit 17, and the correction circuit 18 may be implemented by a processor that executes a program, or by hardware logic circuits.

[0030] The receiving circuit 11 receives a communication signal from the upstream device 3 that is synchronized with the high-precision clock generated by the upstream device 3. The receiving circuit 11 has, for example, a receive buffer and inputs a digital signal to the measurement circuit 17 while maintaining the rising and falling timings of the received communication signal. Based on the operating clock output from the oscillation circuit 16, the receiving circuit 11 extracts the data contained in the communication signal and inputs the extracted data to the data acquisition circuit 12.

[0031] The data acquisition circuit 12 acquires the data output by the receiving circuit 11. For example, the data acquisition circuit 12 acquires the setting data for the reference value of the pulse width of the communication signal transmitted by the upstream device 3. The data acquisition circuit 12 stores the reference value included in the acquired setting data in the memory 13.

[0032] The data acquisition circuit 12 may acquire instruction data that includes an instruction to correct the frequency of the operating clock. This instruction is input, for example, by a user of the electronic device 100 operating the control panel of the electronic device 100. The data acquisition circuit 12 acquires the instruction data input at the control panel of the electronic device 100. The data acquisition circuit 12 also acquires instruction data included in the communication signal transmitted by the upstream device 3 that acquired the instruction data input at the control panel.

[0033] Memory 13 is, for example, RAM (Random Access Memory). Memory 13 may also include ROM (Read Only Memory). Memory 13 stores, for example, a reference value for the pulse width of a communication signal transmitted by the upstream device 3. Memory 13 may further store the cumulative period during which the electronic device 1 is operating.

[0034] The temperature sensor 14 is a sensor that measures the temperature around or inside the electronic device 1. The temperature sensor 14 includes, for example, a silicon diode and outputs a voltage corresponding to the temperature.

[0035] The AD converter 15 converts the voltage output by the temperature sensor 14 into temperature data, which is digital data indicating temperature. The AD converter 15 inputs the temperature data to the correction circuit 18.

[0036] The oscillation circuit 16 outputs an operating clock based on the oscillation signal generated by causing the oscillator 2 to oscillate. The oscillation circuit 16 includes a reference clock generation circuit 161, a trimming circuit 162, and a phase synchronization circuit 163.

[0037] The reference clock generation circuit 161 has an amplifier for causing the oscillator 2 to oscillate, and generates a reference clock by causing the oscillator 2 to oscillate at its oscillation frequency. The reference clock generation circuit 161 generates a reference clock with a frequency different from the operating clock output by the phase-locking circuit 163. The reference clock generation circuit 161 inputs the generated reference clock to the phase-locking circuit 163.

[0038] The trimming circuit 162 changes the frequency of the operating clock based on the input voltage. The trimming circuit 162 is a circuit for adjusting the frequency of the reference clock generated by the reference clock generation circuit 161, and for example, has a variable capacitance diode whose capacitance decreases as the applied voltage increases. The trimming circuit 162 changes the frequency of the reference clock by changing the capacitance of the oscillation loop formed by the amplifier of the reference clock generation circuit 161 in response to the voltage input from the correction circuit 18.

[0039] The phase-locked circuit 163 generates an operating clock by dividing or multiplying the reference clock generated by the reference clock generation circuit 161. The phase-locked circuit 163 has a PLL (Phase Locked Loop) which has, for example, a VCO (Voltage Controlled Oscillator). The phase-locked circuit 163 has a register in which the internal parameters of the PLL are set, and the VCO outputs an operating clock with a frequency corresponding to the internal parameters set in the register. The phase-locked circuit 163 can adjust the frequency with a higher resolution than the frequency adjustment resolution of the trimming circuit 162, and can adjust the operating clock with a resolution of, for example, 0.3 ppm.

[0040] Figure 3 shows an example of the configuration of a phase-locked circuit 163. The phase-locked circuit 163 shown in Figure 3 includes a frequency divider 31, a frequency divider 32, a phase comparator 33, an LPF 34, and a VCO 35.

[0041] Frequency divider 31 divides the reference clock by a division ratio M (where M is a natural number). Frequency divider 31 inputs the divided clock to phase comparator 33. Frequency divider 32 divides the operating clock output by VCO 35 by a division ratio N (where N is a natural number). Frequency divider 32 inputs the divided clock to phase comparator 33.

[0042] The phase comparator 33 calculates the phase difference between the clock input from the frequency divider 31 and the clock input from the frequency divider 32, and inputs a voltage corresponding to the phase difference to the LPF 34. The LPF 34 is a low-pass filter that removes the high-frequency components of the voltage input from the phase comparator 33.

[0043] The VCO35 outputs an operating clock with a frequency corresponding to the voltage input from the LPF34. The frequency of the operating clock output by the VCO35 is determined by the frequency of the reference clock × the division ratio N / division ratio M. The division ratio M and division ratio N are internal parameters of the phase-lock circuit 163, and the correction circuit 18 can fine-tune the operating clock frequency by setting the division ratio M and division ratio N in the registers of the phase-lock circuit 163.

[0044] The measurement circuit 17 measures the pulse width contained in the communication signal based on the operating clock output by the oscillation circuit 16. The measurement circuit 17 has, for example, a timer that counts up based on the operating clock, and by counting up between one level change point of the communication signal and another level change point, it measures the time between multiple level change points as the pulse width. The measurement circuit 17 inputs the measured value of the pulse width to the correction circuit 18.

[0045] Figure 4 shows an example of a pulse that the measurement circuit 17 measures. The measurement circuit 17 measures, for example, the time T1 from the falling edge to the rising edge of a communication signal. The measurement circuit 17 may also measure the time T2 from the rising edge to the falling edge of a communication signal, or it may measure the time T3 from one falling edge to the next falling edge of a communication signal.

[0046] The measurement circuit 17 may measure the cumulative period during which the electronic device 1 is operating. The measurement circuit 17 measures the cumulative time since the start of operation using, for example, a timer that operates based on an operating clock, and periodically (for example, every day) stores the measured cumulative time in the memory 13.

[0047] The correction circuit 18 corrects the operating clock frequency based on the result of comparing the measured pulse width value measured by the measurement circuit 17 with a reference value. For example, the correction circuit 18 corrects the operating clock frequency by inputting a voltage based on the difference between the measured value and the reference value to the trimming circuit 162.

[0048] The correction circuit 18 determines that if the measured value is greater than the reference value, the operating clock frequency is higher than the high-precision clock frequency. Therefore, the correction circuit 18 applies a voltage to the trimming circuit 162 that is smaller than the voltage applied to the trimming circuit 162 immediately before, thereby increasing the capacitance of the variable capacitance diode and lowering the frequency of the reference clock generated by the reference clock generation circuit 161. As a result, the operating clock frequency also decreases.

[0049] The correction circuit 18 assumes that if the measured value is smaller than the reference value, the operating clock frequency is lower than the high-precision clock frequency. Therefore, the correction circuit 18 applies a voltage to the trimming circuit 162 that is higher than the voltage applied to the trimming circuit 162 immediately before, thereby reducing the capacitance of the variable capacitance diode and increasing the frequency of the reference clock generated by the reference clock generation circuit 161. As a result, the operating clock frequency also increases. If the difference between the measured value and the reference value is within a predetermined range where changing the operating clock frequency is unnecessary, the correction circuit 18 maintains the voltage applied to the trimming circuit 162 immediately before, thereby not changing the operating clock frequency.

[0050] The frequency range that the trimming circuit 162 can change is greater than the frequency range that can be changed by changing the internal parameters of the PLL. Therefore, using the trimming circuit 162 to correct the operating clock frequency by the correction circuit 18 is suitable when the deviation of the operating clock from the reference value is relatively large.

[0051] The correction circuit 18 can also correct the operating clock frequency by changing the internal parameters of the phase-lock circuit 163 based on the result of comparing the measured value with a reference value. If the measured value is greater than the reference value, the correction circuit 18 increases the operating clock frequency, for example, by increasing the frequency division ratio N / M of the phase-lock circuit 163. If the measured value is smaller than the reference value, the correction circuit 18 decreases the operating clock frequency, for example, by decreasing the frequency division ratio N / M of the phase-lock circuit 163.

[0052] The frequency resolution of the frequencies that can be corrected by changing the internal parameters of the phase-lock circuit 163 is higher than the frequency resolution of the frequencies that can be corrected by changing the voltage applied to the trimming circuit 162. Therefore, the correction circuit 18 correcting the operating clock frequency using the internal parameters of the phase-lock circuit 163 is suitable for fine-tuning the frequency.

[0053] The correction circuit 18 may first correct the operating clock frequency by inputting a differential voltage based on the difference between the measured value and the reference value to the trimming circuit 162, and then correct the operating clock frequency by changing the internal parameters of the phase-locking circuit 163 based on the result of comparing the measured value obtained by the measurement circuit 17 measuring the pulse width of the new communication signal with the reference value. In other words, the correction circuit 18 corrects the operating clock frequency with a first resolution by inputting a differential voltage to the trimming circuit 162, and then corrects the operating clock frequency with a second resolution higher than the first resolution by changing the internal parameters of the phase-locking circuit 163.

[0054] With the correction circuit 18 operating in this manner, even if the frequency difference requiring correction exceeds the frequency range that the phase-locking circuit 163 can correct with its second resolution, it becomes possible to correct the frequency difference corresponding to the difference between the measured value and the reference value. Furthermore, the correction circuit 18 can correct the operating clock frequency with high precision using its second resolution.

[0055] Incidentally, the communication speed of the communication path between electronic device 1 and upstream device 3 may vary depending on the electronic device 100. Also, the communication speed may change depending on the operating mode. Furthermore, the pulse width measured by the measurement circuit 17 may be the pulse width of one bit of the communication signal, or it may be the pulse width corresponding to two or more bits. Therefore, the memory 13 may store multiple reference value candidates, and the correction circuit 18 may compare the measured value with a reference value selected from the multiple reference value candidates based on the pulse width measured by the measurement circuit 17.

[0056] For example, if the communication speed of the communication path between electronic device 1 and upstream device 3 is assumed to be one of 9600bps, 14400bps, or 19200bps, memory 13 stores the following as candidate reference values: 104.16μs for a 1-bit pulse width at 9600bps, 208.32μs for a 2-bit pulse width at 9600bps, 69.44μs for a 1-bit pulse width at 14400bps, and 138.88μs for a 2-bit pulse width at 14400bps.

[0057] The correction circuit 18 uses the reference value candidate that shows the pulse width closest to the pulse width shown by the measured value from among multiple reference value candidates stored in the memory 13 as the reference value, and compares the measured value with the reference value. With the correction circuit 18 configured in this way, even when the pulse width of the communication signal is variable, the correction circuit 18 can correct the operating clock based on the communication signal.

[0058] The correction circuit 18 corrects the operating clock frequency when preset conditions are met. For example, the correction circuit 18 corrects the operating clock frequency in response to the receiving circuit 11 receiving instruction data. This makes it possible for a user of the electronic device 100 to improve the accuracy of the operating clock of the electronic device 1 by performing a correction operation when using the electronic device 100 in applications requiring high precision.

[0059] The correction circuit 18 may correct the operating clock frequency when the deviation of the temperature measured by the temperature sensor 14 from the reference temperature exceeds a threshold. This allows the accuracy of the operating clock frequency of the electronic device 1 to be maintained at a high level even when the temperature of the environment in which the electronic device 100 is used changes. The correction circuit 18 does not need to compare the measured value with the reference value when the temperature deviation is less than the threshold. By not performing the correction process when the temperature deviation is small, the power consumed by the correction circuit 18 can be reduced.

[0060] The correction circuit 18 may correct the operating clock frequency when the cumulative period since the electronic device 1 started operating reaches a predetermined period. For example, the correction circuit 18 corrects the operating clock frequency every month since the electronic device 1 started operating. This allows the correction circuit 18 to maintain a high level of accuracy in the operating clock frequency of the electronic device 1 even if the electrical characteristics of the electronic device 1 or oscillator 2 change over time.

[0061] [Processing flow in electronic device 1] Figure 5 is a flowchart showing the process for correcting the operating clock in electronic device 1. The process shown in the flowchart of Figure 5 is executed by a processor or circuit that functions as a measurement circuit 17 and a correction circuit 18. This process may also be executed by the processor and the circuit working together.

[0062] The correction circuit 18 determines whether the data acquisition circuit 12 has acquired instruction data that includes an instruction to correct the frequency (S11). If the data acquisition circuit 12 has acquired instruction data (YES in S11), the correction circuit 18 causes the measurement circuit 17 to measure the pulse width of the communication signal (S14).

[0063] If the data acquisition circuit 12 has not acquired instruction data (NO in S11), the correction circuit 18 compares the temperature indicated by the temperature data input from the AD converter 15 with the reference temperature and calculates the temperature deviation. The correction circuit 18 determines whether the temperature deviation is greater than or equal to the first threshold (S12). If the temperature deviation is greater than or equal to the first threshold (YES in S12), the correction circuit 18 causes the measurement circuit 17 to measure the pulse width of the communication signal (S14).

[0064] If the temperature deviation is less than the first threshold (NO in S12), the correction circuit 18 determines whether a predetermined period has elapsed since the last frequency correction by referring to the cumulative period stored in the memory 13 (S13). If the predetermined period has elapsed (YES in S13), the correction circuit 18 causes the measurement circuit 17 to measure the pulse width of the communication signal (S14).

[0065] When the measurement circuit 17 measures the pulse width of the communication signal, the correction circuit 18 compares the measured value with the reference value stored in the memory 13 and calculates the difference value (S15). If the difference value is greater than or equal to the second threshold (YES in S16), the correction circuit 18 corrects the frequency of the reference clock generated by the reference clock generation circuit 161 with a first resolution by changing the voltage input to the trimming circuit 162 according to the difference value (S17). If the difference value is less than the second threshold (NO in S16), the correction circuit 18 terminates the correction process.

[0066] The correction circuit 18 corrects the frequency of the reference clock and then causes the measurement circuit 17 to measure the pulse width of the communication signal (S18). If the difference between the measured value and the reference value is greater than or equal to the second threshold (YES in S19), the correction circuit 18 corrects the frequency of the operating clock with a second resolution by changing the internal parameters of the PLL (S20). If the difference between the measured value and the reference value is less than the second threshold in S19 (NO in S19), the correction circuit 18 terminates the correction process.

[0067] Of the processes shown in Figure 5, whether or not to execute processes S11, S12, and S13, and the order in which these processes are performed, is arbitrary. Electronic device 1 may continue to execute processes S14 to S20 without executing processes S11 to S13.

[0068] [Other configuration examples of electronic device 1] Figure 6 shows another example of the configuration of the electronic device 1. In the electronic device 1 shown in Figure 2, the case in which the data acquisition circuit 12 acquires setting data and instruction data via the receiving circuit 11 is illustrated, but the data acquisition circuit 12 may acquire the setting data and instruction data via a communication path different from the communication path through which the communication signal is transmitted.

[0069] [Example of Electronic Device 1] Figure 7 shows an embodiment of the electronic device 1. The electronic device 1 shown in Figure 7 has a CPU (Central Processing Unit) 20, and a receiving circuit 11, memory 13, AD converter 15, oscillator circuit 16, measurement circuit 17, and correction circuit 18 are connected to the data bus DB1 of the CPU 20. In this embodiment, the correction circuit 18 acquires a measured value indicating the pulse width from the measurement circuit 17 via the data bus DB1, and sets data for correcting the operating clock to the oscillator circuit 16 via the data bus DB1.

[0070] Figure 8 shows another embodiment of the electronic device 1. The electronic device 1 shown in Figure 8 differs from the electronic device 1 shown in Figure 7 in that, in addition to the data bus DB1, it has a data bus DB2. The data bus DB2 is connected to an oscillation circuit 16, a measurement circuit 17, and a correction circuit 18.

[0071] The oscillation circuit 16, measurement circuit 17, and correction circuit 18 transmit and receive data for correcting the operating clock via the data bus DB2, and transmit and receive other data via the data bus DB1. Specifically, the measurement circuit 17 notifies the correction circuit 18 of the measured pulse width of the communication signal via the data bus DB2, and the correction circuit 18 notifies the oscillation circuit 16 of data for correcting the operating clock via the data bus DB2. By using the data bus DB2 to correct the frequency of the operating clock, the CPU 20 and data bus DB1 are not used for the frequency correction process, thus preventing a decrease in the performance of the CPU 20.

[0072] [Comparative Examples of Electronic Device Configurations] Figure 9 shows the configuration of the electronic device 200. The electronic device 100 shown in Figure 1 had one electronic device 1, but the electronic device 200 differs from the electronic device 100 in that it further has electronic devices 1A and 1B. Electronic device 1A generates a reference clock based on oscillator 2A, which has lower frequency accuracy than oscillator 4, similar to oscillator 2, and electronic device 1B generates a reference clock based on oscillator 2B, which has lower frequency accuracy than oscillator 4, similar to oscillator 2.

[0073] Electronic device 1 functions as an upstream device to electronic device 1A, and electronic device 1A corrects the frequency of its operating clock based on the measurement of the pulse width of the communication signal input from electronic device 1. Electronic device 1A also functions as an upstream device to electronic device 1B, and electronic device 1B corrects the frequency of its operating clock based on the measurement of the pulse width of the communication signal input from electronic device 1. According to the configuration shown in electronic device 200, even if there are more electronic devices 1 installed than the number of communication signals that the upstream device 3 can output, the frequency accuracy of the operating clocks of each of the multiple electronic devices 1 can be improved.

[0074] Figure 10 shows the configuration of the electronic device 300. Like the electronic device 200, the electronic device 300 also has electronic devices 1A and 1B, but differs from the electronic device 200 shown in Figure 9 in that electronic devices 1A and 1B are directly connected to the upstream device 3. Electronic devices 1A and 1B, like electronic device 1, correct the operating clock based on oscillator 2A by measuring the pulse width of the communication signal received from the upstream device 3. With the configuration shown in the electronic device 300, even if electronic device 1 does not have the function of outputting a communication signal, the frequency accuracy of the operating clocks of each of the multiple electronic devices 1 can be improved.

[0075] Figure 11 shows the configuration of the electronic device 400. In the electronic device 400, electronic device 1 functions as an upstream device for electronic devices 1A and 1B. Electronic devices 1A and 1B correct their operating clocks by measuring the pulse width of the communication signal output by electronic device 1. With the configuration shown in the electronic device 400, even if the upstream device 3 can only output one communication signal and electronic devices 1A and 1B cannot output communication signals, the frequency accuracy of the operating clocks of each of the multiple electronic devices 1 can be improved.

[0076] [First example of an air conditioning system] Figure 12 shows the configuration of an air conditioning system S1. The air conditioning system S1 is an example of an electronic equipment system having an indoor unit 500, which is a first electronic device, and an outdoor unit 600, which is a second electronic device. The indoor unit 500 has a first electronic device that operates with a high-precision clock of first frequency accuracy, and the outdoor unit 600 has a second electronic device that operates with an operating clock of second frequency accuracy, which is lower than the first frequency accuracy. The first electronic device corresponds to the upstream device 3 in Figure 1, and the second electronic device corresponds to electronic device 1 in Figure 1.

[0077] The outdoor unit 600 has a compressor device 610 and a fan device 620 as second electronic devices. The outdoor unit 600 also has an oscillator 630 and an oscillator 640. The compressor device 610 is an electronic device for controlling the compressor. The fan device 620 is an electronic device for controlling the fan. The compressor device 610 operates with an oscillator 630 having a frequency accuracy lower than that of the oscillator in the indoor unit 500. The fan device 620 operates with an oscillator 640 having a frequency accuracy lower than that of the oscillator in the indoor unit 500.

[0078] The compressor device 610 has the same function as the electronic device 1 shown in Figure 1, and corrects the frequency of the operating clock generated by the oscillation of the oscillator 630 by measuring the pulse width of the communication signal received from the indoor unit 500. The fan device 620 also has the same function as the electronic device 1 shown in Figure 1, and corrects the frequency of the operating clock generated by the oscillation of the oscillator 640 by measuring the pulse width of the communication signal received from the compressor device 610.

[0079] The indoor unit 500 operates based on an oscillator with higher frequency accuracy than oscillators 630 and 640, similar to the upstream device 3 shown in Figure 1. The indoor unit 500 has a PLL that generates an oscillation signal synchronized with a clock or signal supplied from the communication network, and may generate a communication signal based on the oscillation signal generated by the PLL. Since the frequency accuracy of the clock or signal supplied from the communication network is extremely high, the frequency accuracy of the oscillation signal synchronized with the clock or signal will be higher than the frequency accuracy of oscillators 630 and 640.

[0080] For example, upon receiving an operation to start the indoor unit 500, it transmits a communication signal containing instruction data for frequency correction to the compressor device 610. Once the compressor device 610 has completed the correction of the frequency of its own operating clock, it transmits a communication signal containing instruction data for frequency correction to the fan device 620. This reduces the cost of the oscillator in the outdoor unit 600, while enabling the devices in the outdoor unit 600 (e.g., the inverter) to operate at an appropriate operating clock frequency. As a result, the compressor and fan operate at the appropriate speed, making it possible to reduce power consumption.

[0081] The compressor device 610 and the fan device 620 may correct the operating clock when they detect that the temperature of the outdoor unit 600 has become too high or too low outside a predetermined range. For example, the compressor device 610 may request the indoor unit 500 to send a communication signal when the temperature deviation is above a first threshold, and correct the frequency of the operating clock based on the measured pulse width of the communication signal sent by the indoor unit 500. Such a configuration is suitable for the outdoor unit 600 used outdoors where temperature fluctuations are drastic.

[0082] Furthermore, the indoor unit 500 is connected to a communication network, and the first electronic device may have a PLL that generates an oscillation signal synchronized with a clock or signal supplied from the communication network. In this case, the first electronic device generates a communication signal based on the oscillation signal of first frequency accuracy generated by the PLL.

[0083] Furthermore, the indoor unit 500 may have an upstream device 3 and an electronic device 1. In this case, the indoor unit 500 transmits a first communication signal based on a high-precision clock generated by the upstream device 3 to the electronic device 1, and transmits a second communication signal based on a high-precision clock generated by the upstream device 3 to the outdoor unit 600.

[0084] In addition, in the outdoor unit 600, the fan device 620 may receive a communication signal from the indoor unit 500, and the compressor device 610 may receive a communication signal from the fan device 620.

[0085] [Second example of an air conditioning system] Figure 13 shows the configuration of the air conditioning system S2. The air conditioning system S2 differs from the first embodiment in that the outdoor unit 600 has a first electronic device that operates with a high-precision clock based on a first frequency accuracy, and the indoor unit 500 has a second electronic device that operates with an operating clock with a second frequency accuracy lower than the first frequency accuracy, but is otherwise the same.

[0086] The outdoor unit 600 has a compressor device 610 and a fan device 620. For example, the frequency accuracy of the oscillator 650 connected to the compressor device 610 is higher than that of the oscillator 640 connected to the fan device 620, and the compressor device 610 functions as the upstream device 3 shown in Figure 1. The fan device 620 functions as the electronic device 1 shown in Figure 1.

[0087] The compressor device 610 transmits a first communication signal based on a high-precision clock to the fan device 620, and also transmits a second communication signal based on a high-precision clock to the indoor unit 500. The fan device 620 has the same function as the electronic device 1 shown in Figure 1, and corrects the frequency of the operating clock generated by the fan device 620 by measuring the pulse width of the communication signal received from the outdoor unit 600.

[0088] The second electronic device in the indoor unit 500 has the same function as electronic device 1 shown in Figure 1, and corrects the frequency of the operating clock generated by the second electronic device by measuring the pulse width of the communication signal received from the outdoor unit 600. This makes it possible to operate at an appropriate frequency while keeping the cost of the oscillator of the indoor unit 500 down.

[0089] Alternatively, the frequency accuracy of the oscillator 640 connected to the fan device 620 may be higher than that of the oscillator 650 connected to the compressor device 610, allowing the fan device 620 to function as the upstream device 3 shown in Figure 1. In this case, the fan device 620 transmits a communication signal, and the compressor device 610 and the indoor unit 500 correct their operating clocks based on the communication signal.

[0090] [Third embodiment of the air conditioning system] Figure 14 shows the configuration of the air conditioning system S3. The air conditioning system S3 includes an indoor unit 500, which is an air conditioning device connected to a communication device 700, and an outdoor unit 600, which is an air conditioning device that can communicate with the indoor unit 500. For example, the communication device 700 is a router or access point connected to a communication network (e.g., the Internet or a local area network) and transmits data indicating the status of the indoor unit 500 or the outdoor unit 600 to a server.

[0091] The communication device 700 has an upstream device 3 shown in Figure 1 as a first electronic device operating with a high-precision clock of first frequency accuracy. The communication device 700 has a PLL that generates an oscillation signal synchronized with a clock or signal supplied from the communication network, and generates a communication signal based on the oscillation signal generated by the PLL. Since the frequency accuracy of the clock or signal supplied from the communication network is extremely high, the frequency accuracy of the oscillation signal generated by the PLL is higher than the frequency accuracy of the operating clock of the indoor unit 500 or the outdoor unit 600.

[0092] The indoor unit 500 and the outdoor unit 600 each have an electronic device 1, shown in Figure 2, as a second electronic device that operates at an operating clock lower than the first frequency accuracy. The electronic device 1 of the indoor unit 500 corrects the frequency of the operating clock based on the oscillator of the indoor unit 500 based on a communication signal received from the communication device 700. The electronic device 1 of the outdoor unit 600 corrects the frequency of the operating clock based on the oscillator of the outdoor unit 600 based on a communication signal received from the indoor unit 500. With this configuration, the air conditioning system S2 can use an oscillator with low frequency accuracy, thereby reducing costs while increasing the frequency accuracy of the operating clock.

[0093] In Figure 14, the outdoor unit 600 is connected only to the indoor unit 500, but the outdoor unit 600 may also be connected to a communication device 700, and the outdoor unit 600 may correct the frequency of its operating clock based on the communication signal received from the communication device 700.

[0094] [Effects of Electronic Device 1] As described above, the electronic device 1 includes a measurement circuit 17 that measures the pulse width, which is the width of the pulses included in the communication signal transmitted from the upstream device, based on the operating clock, and a correction circuit 18 that corrects the frequency of the operating clock based on the result of comparing the measured pulse width measured by the measurement circuit 17 with a reference value. With the electronic device 1 configured in this way, the electronic device 1, which has an oscillator 2 with relatively low frequency accuracy, can improve the frequency accuracy of the operating clock it generates based on the oscillator.

[0095] Although the present disclosure has been described above using embodiments, the technical scope of the present disclosure is not limited to the scope described in the embodiments above, and various modifications and changes are possible within the scope of its gist. For example, all or part of the apparatus can be configured by functionally or physically distributing and integrating in any unit. Furthermore, new embodiments resulting from any combination of multiple embodiments are also included in the embodiments of the present disclosure. The effects of the new embodiments resulting from the combinations will also have the effects of the original embodiments. [Explanation of Symbols]

[0096] 1. Electronic devices 2 Oscillators 3 Upstream Devices 4. Oscillator 11 Receiving circuit 12. Data acquisition circuit 13 memory 14. Temperature sensor 15 AD converters 16 Oscillator Circuit 17 Measurement Circuit 18 Correction Circuit 20 CPU 31 Frequency divider 32 frequency divider 33 Phase comparator 100 Electronic equipment 161 Reference Clock Generation Circuit 162 Trimming Circuit 163 Phase-locked circuit 200 Electronic equipment 300 Electronic equipment 400 Electronic equipment 500 indoor unit 600 outdoor unit 610 Compressor Devices 620 Fan Device 630 Oscillator 640 Oscillator 650 Oscillator

Claims

1. An oscillator circuit that generates an operating clock, A receiving circuit that receives a communication signal synchronized with the high-precision clock from an upstream device operating with a high-precision clock having a frequency accuracy higher than the frequency accuracy of the aforementioned operating clock, A measurement circuit that measures the pulse width, which is the width of the pulses included in the communication signal, based on the aforementioned operating clock, A memory for storing the reference value of the pulse width, A correction circuit that corrects the frequency of the operating clock based on the result of comparing the measured value of the pulse width measured by the measurement circuit with the reference value, It has, The oscillator circuit is A reference clock generation circuit that generates a reference clock with a different frequency from the aforementioned operating clock, A phase-locking circuit that generates the operating clock by dividing or multiplying the reference clock, A trimming circuit that adjusts the frequency of the reference clock based on the input voltage, It has, The range of operating clock frequencies that the trimming circuit can change is greater than the range of operating clock frequencies that can be changed by changing the internal parameters of the phase synchronization circuit. The correction circuit corrects the frequency of the operating clock by inputting a voltage based on the difference between the measured value and the reference value to the trimming circuit. Electronic devices.

2. An oscillator circuit that generates an operating clock, A receiving circuit that receives a communication signal synchronized with the high-precision clock from an upstream device operating with a high-precision clock having a frequency accuracy higher than the frequency accuracy of the aforementioned operating clock, A measurement circuit that measures the pulse width, which is the width of the pulses included in the communication signal, based on the aforementioned operating clock, A memory for storing the reference value of the pulse width, A correction circuit that corrects the frequency of the operating clock based on the result of comparing the measured value of the pulse width measured by the measurement circuit with the reference value, It has, The oscillator circuit is A trimming circuit that changes the frequency of the operating clock based on the input voltage, A reference clock generation circuit that generates a reference clock with a different frequency from the aforementioned operating clock, A phase-locking circuit that generates the operating clock by dividing or multiplying the reference clock, It has, The trimming circuit changes the frequency of the operating clock by changing the capacitance of the oscillation loop for generating the reference clock based on the input voltage. The correction circuit corrects the frequency of the operating clock by inputting a differential voltage based on the difference between the measured value and the reference value to the trimming circuit, and then corrects the frequency of the operating clock by changing the internal parameters of the phase synchronization circuit based on the result of comparing the measured value obtained by the measurement circuit measuring the pulse width of the new communication signal with the reference value. Electronic devices.

3. The correction circuit corrects the frequency of the operating clock with a first resolution by inputting the differential voltage to the trimming circuit, and then corrects the frequency of the operating clock with a second resolution higher than the first resolution by changing the internal parameters of the phase synchronization circuit. The electronic device according to claim 2.

4. An oscillator circuit that generates an operating clock, A receiving circuit that receives a communication signal synchronized with the high-precision clock from an upstream device operating with a high-precision clock having a frequency accuracy higher than the frequency accuracy of the aforementioned operating clock, A measurement circuit that measures the pulse width, which is the width of the pulses included in the communication signal, based on the aforementioned operating clock, A memory for storing the reference value of the pulse width, A correction circuit that corrects the frequency of the operating clock based on the result of comparing the measured value of the pulse width measured by the measurement circuit with the reference value, It has, The memory stores multiple candidate reference values, The correction circuit selects from among the plurality of reference value candidates the reference value candidate that is closest to the pulse width measured by the measurement circuit, and compares the selected reference value with the measured value. Electronic devices.

5. The system further includes a data acquisition circuit that acquires the setting data for the aforementioned reference value and stores the aforementioned reference value included in the acquired setting data in the memory. The electronic device according to any one of claims 1 to 3.

6. The system further includes a data acquisition circuit that acquires instruction data including an instruction to correct the frequency of the operating clock, The correction circuit corrects the frequency of the operating clock in accordance with the fact that the data acquisition circuit has acquired the instruction data. The electronic device according to any one of claims 1 to 4.

7. The electronic device further includes a temperature sensor for measuring the internal temperature of the electronic device, The correction circuit corrects the frequency of the operating clock when the deviation of the internal temperature measured by the temperature sensor from the reference temperature exceeds a threshold. The electronic device according to any one of claims 1 to 4.

8. The memory further stores the cumulative period while the electronic device is operating. The correction circuit corrects the frequency of the operating clock when the cumulative period reaches a predetermined period. The electronic device according to any one of claims 1 to 4.

9. A first electronic device operating with a first frequency accuracy high-precision clock, A second electronic device that generates an operating clock with a second frequency accuracy lower than the first frequency accuracy, It has, The second electronic device described above is An oscillator circuit that generates an operating clock, A receiving circuit that receives a communication signal synchronized with the high-precision clock from the first electronic device, A measurement circuit that measures the pulse width, which is the width of the pulses included in the communication signal, based on the aforementioned operating clock, A memory for storing the reference value of the pulse width, A correction circuit that corrects the frequency of the operating clock based on the result of comparing the measured value of the pulse width measured by the measurement circuit with the reference value, It has, The oscillator circuit is A reference clock generation circuit that generates a reference clock with a different frequency from the aforementioned operating clock, A phase-locking circuit that generates the operating clock by dividing or multiplying the reference clock, A trimming circuit that adjusts the frequency of the reference clock based on the input voltage, It has, The range of operating clock frequencies that the trimming circuit can change is greater than the range of operating clock frequencies that can be changed by changing the internal parameters of the phase synchronization circuit. The correction circuit corrects the frequency of the operating clock by inputting a voltage based on the difference between the measured value and the reference value to the trimming circuit. electronic equipment.

10. The system comprises a first electronic device and a second electronic device capable of communicating with the first electronic device. The first electronic device has a first electronic device that operates with a first frequency accuracy high-precision clock, The second electronic device has a second electronic device that generates an operating clock with a second frequency accuracy lower than the first frequency accuracy, The second electronic device described above is An oscillator circuit that generates an operating clock, A receiving circuit that receives a communication signal synchronized with the high-precision clock from the first electronic device, A measurement circuit that measures the pulse width, which is the width of the pulses included in the communication signal, based on the aforementioned operating clock, A memory for storing the reference value of the pulse width, A correction circuit that corrects the frequency of the operating clock based on the result of comparing the measured value of the pulse width measured by the measurement circuit with the reference value, It has, The oscillator circuit is A reference clock generation circuit that generates a reference clock with a different frequency from the aforementioned operating clock, A phase-locking circuit that generates the operating clock by dividing or multiplying the reference clock, A trimming circuit that adjusts the frequency of the reference clock based on the input voltage, It has, The range of operating clock frequencies that the trimming circuit can change is greater than the range of operating clock frequencies that can be changed by changing the internal parameters of the phase synchronization circuit. The correction circuit corrects the frequency of the operating clock by inputting a voltage based on the difference between the measured value and the reference value to the trimming circuit. Electronic equipment systems.

11. An air conditioning system comprising an indoor unit and an outdoor unit, One of the indoor unit and the outdoor unit has a first electronic device that operates with a first frequency accuracy high-precision clock, The other of the indoor and outdoor units has a second electronic device that generates an operating clock with a second frequency accuracy lower than the first frequency accuracy. The second electronic device described above is An oscillator circuit that generates an operating clock, A receiving circuit that receives a communication signal synchronized with the high-precision clock from a device having the first electronic device, A measurement circuit that measures the pulse width, which is the width of the pulses included in the communication signal, based on the aforementioned operating clock, A memory for storing the reference value of the pulse width, A correction circuit that corrects the frequency of the operating clock based on the result of comparing the measured value of the pulse width measured by the measurement circuit with the reference value, It has, The oscillator circuit is A reference clock generation circuit that generates a reference clock with a different frequency from the aforementioned operating clock, A phase-locking circuit that generates the operating clock by dividing or multiplying the reference clock, A trimming circuit that adjusts the frequency of the reference clock based on the input voltage, It has, The range of operating clock frequencies that the trimming circuit can change is greater than the range of operating clock frequencies that can be changed by changing the internal parameters of the phase synchronization circuit. The correction circuit corrects the frequency of the operating clock by inputting a voltage based on the difference between the measured value and the reference value to the trimming circuit. Air conditioning system.

12. An air conditioning system capable of communicating with a communication device equipped with a first electronic device operating with a first frequency accuracy high-precision clock, The air conditioning device has a second electronic device that generates an operating clock with a second frequency accuracy lower than the first frequency accuracy, The second electronic device described above is An oscillator circuit that generates an operating clock, A receiving circuit that receives a communication signal synchronized with the high-precision clock from the aforementioned communication device, A measurement circuit that measures the pulse width, which is the width of the pulses included in the communication signal, based on the aforementioned operating clock, A memory for storing the reference value of the pulse width, A correction circuit that corrects the frequency of the operating clock based on the result of comparing the measured value of the pulse width measured by the measurement circuit with the reference value, It has, The oscillator circuit is A reference clock generation circuit that generates a reference clock with a different frequency from the aforementioned operating clock, A phase-locking circuit that generates the operating clock by dividing or multiplying the reference clock, A trimming circuit that adjusts the frequency of the reference clock based on the input voltage, It has, The range of operating clock frequencies that the trimming circuit can change is greater than the range of operating clock frequencies that can be changed by changing the internal parameters of the phase synchronization circuit. The correction circuit corrects the frequency of the operating clock by inputting a voltage based on the difference between the measured value and the reference value to the trimming circuit. Air conditioner.

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