JP6910933B2 - Electronic clock - Google Patents

Description

The present invention relates to an electronic clock.

Patent Document 1 describes a clock that receives a signal from a GPS (Global Positioning System) satellite or the like and adjusts the time based on the received signal, and changes the processing speed of the reception operation according to the reception mode. The technology to make it is disclosed. In Patent Document 1, a high-speed clock is used in the manual reception mode, and a low-speed clock is used in the automatic reception mode. Processing based on the clock signal such as reception operation is performed by supplying power from the built-in battery built in the clock, and in processing with a high clock frequency, reception is performed as compared with processing with a low clock frequency. While the probability of success can be improved, the amount of battery voltage drop will increase. In an electronic watch, if the battery voltage of the built-in battery drops excessively, the built-in processor that holds the current time and other important operations cannot operate, and there is a risk of system down.

Japanese Patent No. 4488066

Here, the amount of voltage drop of the built-in battery largely depends on the internal temperature of the timepiece. If the processing with a high clock frequency is performed when the internal temperature is low, the battery voltage may drop excessively.

The present invention has been made in view of the above problems, and an object of the present invention is to provide an electronic clock capable of appropriately limiting operation according to an internal temperature.

(1) A built-in battery, a clock generation circuit that generates a clock signal, a processing circuit that receives power from the built-in battery and executes processing based on the clock signal, and a control circuit that controls the processing circuit. An electronic clock comprising, comprising a temperature sensor for detecting the internal temperature of the electronic clock, the control circuit sets the frequency of the clock signal based on the internal temperature.

(2) In (1), the control circuit sets the frequency to the first frequency when the internal temperature is higher than the first threshold value, and sets the frequency to the first frequency when the internal temperature is equal to or lower than the first threshold value. An electronic clock set to a second frequency lower than the first frequency.

(3) In (2), the control circuit sets the frequency to a third frequency lower than the first frequency when the internal temperature is higher than the second threshold value higher than the first threshold value. ..

(4) In (3), the control circuit prohibits execution of the process when it is higher than the third threshold value higher than the second threshold value or when the internal temperature is lower than the fourth threshold value lower than the first threshold value. Electronic clock.

(5) In any of (2) to (4), the voltage sensor for detecting the battery voltage of the built-in battery is further provided, and the control circuit sets the first threshold value according to the battery voltage. Electronic clock.

(6) In (5), an electronic clock including a memory for storing a candidate for the frequency in relation to a combination of the internal temperature range and the battery voltage range, respectively.

(7) In (6), the width of the range of the internal temperature associated with each of the candidate frequencies is so narrow that the range relates to a low temperature.

(8) In (5), an electronic clock including a memory for storing the first threshold value, which becomes smaller as the battery voltage becomes higher.

(9) In (8), the memory is an electronic clock that stores the second threshold value that increases as the battery voltage increases.

(10) In (9), the first threshold value and the second threshold value are represented by a linear expression, and the absolute value of the slope of the linear expression representing the first threshold value is the slope of the linear expression representing the second threshold value. An electronic clock that is larger than the absolute value.

(11) In any one of (2) to (10), the processing circuit is a circuit that performs a receiving operation for receiving a signal from the outside, and the processing is the receiving operation. An electronic clock.

(12) In (11), the reception operation includes a capture operation for capturing the signal and a tracking operation performed after the capture is successful, and the control circuit has the capture operation based on the internal temperature. And an electronic clock that sets the frequency for each of the tracking operations.

(13) In (12), the electronic clock in which the first threshold value in the case where the capture fails and the capture operation is performed again is higher than the first threshold value before the capture failure.

(14) In any of (1) to (10), an electronic clock having an operation unit that accepts an operation from the outside, and the processing circuit executes the process according to the operation received by the operation unit. ..

(15) In any one of (1) to (10), the processing circuit has a receiving circuit for receiving a signal from the outside, and the processing circuit is said to respond to time information included in the signal received by the receiving circuit. An electronic clock that executes a process, and the process is an operation of correcting the internal time of the electronic clock.

(16) In any one of (1) to (15), the temperature sensor and the built-in battery are both arranged in a region on one side of a dichotomy line passing through the center of the electronic timepiece.

(17) In any of (1) to (16), the control circuit sets the frequency based on the internal temperature detected by the temperature sensor at the start of the process.

(18) In any of (1) to (16), the control circuit sets the frequency based on the internal temperature detected by the temperature sensor before a predetermined time at the start of the process. clock.

(19) In (17) or (18), the control circuit switches the frequency based on the internal temperature detected by the temperature sensor during the process.

It is a top view which shows an example of the appearance of the satellite radio-wave wristwatch which concerns on 1st Embodiment of this invention. It is a block diagram which shows the internal structure of the satellite radio-wave wristwatch which concerns on 1st Embodiment of this invention. It is a figure which shows the outline of the voltage transition of a secondary battery when the receiving circuit continuously executes a receiving operation, for each temperature of a secondary battery. It is a figure which shows an example of the frequency table in 1st Embodiment. It is a flowchart explaining the operation of the reception control circuit in 1st Embodiment. It is a figure which shows the frequency table in 2nd Embodiment. It is a flowchart explaining the operation of the reception control circuit in 2nd Embodiment. It is a figure explaining the 1st threshold value and 2nd threshold value in the modification of 2nd Embodiment. It is a figure which shows the frequency table in 3rd Embodiment. It is a flowchart explaining the operation of the reception control circuit in 3rd Embodiment. It is a figure which shows the frequency table in the reception operation for acquiring the position information.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

The satellite radio wristwatch 1 according to the first embodiment receives a satellite signal including time information, and corrects the internal time measured by itself using the time information included in the received satellite signal. In the first embodiment, a satellite radio-controlled wristwatch will be described as an example, but the present invention is not limited to this, and any electronic clock having a receiving circuit capable of receiving a signal from the outside may be used.

FIG. 1 is a plan view showing an example of the appearance of the satellite radio-controlled wristwatch according to the first embodiment, and FIG. 2 is a block diagram showing an internal configuration of the satellite radio-controlled wristwatch. As shown in these figures, the satellite radio wristwatch 1 includes an antenna 10, a receiving circuit 20, a DCDC converter 23, a clock circuit 30, a vibrator 38, a power supply unit 40, a drive mechanism 50, and the like. It includes a time display unit 51, a pointer 52, a dial 53, and an operation unit 60.

The antenna 10 receives a satellite signal transmitted from the satellite as a radio wave including time information. In particular, in the first embodiment, the antenna 10 is a patch antenna that receives radio waves having a frequency of about 1.6 GHz transmitted from GPS satellites. GPS is a kind of satellite positioning system, and is realized by a plurality of GPS satellites orbiting the earth. Each of these GPS satellites is equipped with a high-precision atomic clock, and periodically transmits satellite signals including time information measured by the atomic clock.

The reception circuit 20 includes a high frequency circuit (RF circuit) 21, a decoding circuit 22, a reception control circuit 24, and a clock generation circuit 25. The satellite signal received by the antenna 10 is decoded, and the result of the decoding is obtained. A bit string (received data) indicating the content of the obtained satellite signal is output. The output voltage of the secondary battery 42 converted to a predetermined voltage by the DCDC converter 23 is supplied to the receiving circuit 20 as the power supply voltage.

The high-frequency circuit 21 is an integrated circuit that operates based on a signal corresponding to the oscillation of the TCXO (temperature-compensated crystal oscillator) 26. The analog signal received by the antenna 10 is amplified and detected, and is used as a base. Convert to a band signal. The decoding circuit 22 decodes the baseband signal output by the high-frequency circuit 21 to generate a bit string indicating the content of the data received from the GPS satellite. The generated bit string (received data) is transmitted from the reception control circuit 24 and is sequentially written to the buffer area in the RAM 33 included in the clock circuit 30.

The decoding circuit 22 includes a correlator 22a that correlates with the satellite signal when capturing the satellite, and a tracking circuit 22b for tracking the satellite. After the correlator 22a correlates with the satellite number of the satellite signal, the correlation data regarding the satellite number and the timing is sent to the tracking circuit 22b. When the acquisition of the target satellite is completed, the operation of the correlator 22a is stopped. Then, the tracking circuit 22b tracks the satellite based on the satellite number and timing sent from the correlator 22a.

Here, the acquisition operation is to take out one of the signals multiplexed by CDMA (Code Division Multiple Access), and specifically, a C / A (Coarse / Acquisition) code corresponding to one signal. Is an operation of extracting a correlated signal by multiplying the received signal. Further, in the tracking operation, the phase of the carrier wave of the received signal and the phase of the C / A code included in the received signal are matched with the phase of the carrier wave of the selected C / A code and the phase of the code for decoding. This is an operation of continuously fetching data.

The clock generation circuit 25 is configured to be capable of generating a plurality of types of clock signals having different frequencies based on the signal corresponding to the oscillation of the TCXO26. In the first embodiment, the clock generation circuit 25 generates a clock signal of 64 MHz (high frequency) and a clock signal of 16 MHz (low frequency). Then, the decoding circuit 22 described above executes a reception operation including a capture operation and a tracking operation based on the clock frequency generated by the clock generation circuit 25.

The dial 53 of the satellite radio watch 1 is provided with a reception status display 61 indicating the status of the reception circuit 20 by, for example, the characters "OK", "NG", and "RX", and the satellite signal by the reception circuit 20 is provided. The second hand 52c indicates the character "RX" during reception, and then if the reception circuit 20 succeeds in receiving the satellite signal, the second hand 52c indicates the character "OK" and then the normal hand movement is resumed. .. If the reception of the satellite signal fails, the second hand 52c indicates the character "NG" and then the normal hand movement is restarted.

The clock circuit 30 includes a clock control circuit 31, a motor drive circuit 35, a clock generation circuit 36, and a temperature sensor 37, and is composed of one integrated circuit. The clock control circuit 31 is a circuit that controls various circuits and mechanisms included in the satellite radio wristwatch 1, and includes a calculation unit 32, a RAM (Random Access Memory) 33, and a ROM (Read Only Memory) 34.

The calculation unit 32 performs various types of information processing according to the program stored in the ROM 34. The RAM 33 functions as a work memory of the calculation unit 32, and data to be processed by the calculation unit 32 is written. In particular, in the first embodiment, bit strings (received data) representing the contents of the satellite signal received by the receiving circuit 20 are sequentially written in the buffer area in the RAM 33, and the values of various variables for control are held.

The clock generation circuit 36 generates a clock signal used for timekeeping inside the satellite radio-controlled wristwatch 1 and supplies it to the arithmetic unit 32. The calculation unit 32 acquires the internal time based on the clock signal supplied from the clock generation circuit 36, and determines the time (display time) to be displayed on the time display unit 51. The clock generation circuit 36 is electrically connected to an external oscillator 38. In the first embodiment, the oscillator 38 is a crystal oscillator, and oscillates at a frequency that serves as a reference for the internal time of the satellite radio-controlled wristwatch 1 using the secondary battery 42 as a power source. For example, the oscillation frequency of the crystal oscillator is 32.768 kHz, and 1 second is counted by reading the timing at which the 16-bit counter included in the clock circuit 30 overflows. Then, the clock control circuit 31 outputs a drive signal to the motor drive circuit 35 according to the number of counts counted by the counter. The motor drive circuit 35 drives a drive mechanism 50 including a stepping motor and the like based on a drive signal. As a result, the time display unit 51 displays the time with the hour hand 52a, the minute hand 52b, and the second hand 52c described above.

Since the oscillation frequency of the vibrator 38 is temperature-dependent, the clock generation circuit 36 performs a temperature compensation operation so as to keep the frequency of the clock signal generated by itself constant. Specifically, when the clock control circuit 31 acquires temperature data related to the internal temperature of the satellite radio watch 1 detected by the temperature sensor 37, the clock control circuit 31 provides a compensation signal so as to keep the frequency of the clock signal constant. It is transmitted to the clock generation circuit 36. The clock generation circuit 36 changes the oscillation frequency of the vibrator 38 according to the compensation signal, thereby making the oscillation frequency of the vibrator 38 and the frequency of the clock signal output from the clock generation circuit 36 constant regardless of the temperature. There is.

The temperature sensor 37 acquires temperature data by measuring the state of the temperature sensitive device. For example, the temperature sensor 37 may be configured to include a CR oscillator, and the oscillation frequency of the CR oscillator can be measured, and temperature data can be acquired from the oscillation frequency thus obtained.

Here, as shown in FIG. 1, the temperature sensor 37 is built in the corner of the clock circuit 30, which is an integrated circuit. In the case of the satellite radio watch 1, the vibrator 38 is arranged next to the circular secondary battery 42 in a plan view, and the temperature sensor 37 is located in the corner formed by the secondary battery 42 and the vibrator 38. The corners of the provided clock circuit 30 are arranged so that the temperature sensor 37 is close to not only the vibrator 38 but also the secondary battery 42. The secondary battery 42, the vibrator 38, and the temperature sensor 37 are all arranged in a region (upper side in FIG. 1) of the dichotomy line α passing through the center of the clock (the position of the rotation axis of the pointer 52). In FIG. 1, the dichotomy line α passes through the positions of 3 o'clock and 9 o'clock, but the dichotomy line α may be an arbitrary straight line that passes through the center of the clock and divides the dial 53 in two in a plan view. When the secondary battery 42 is large, the center 42a of the secondary battery 42 may be located in the region on one side of the dichotomy α, and a part of the peripheral edge thereof is on the other side. May be good. Other elements, such as parts of the clock circuit 30 other than the temperature sensor 37, the antenna 10, the receiving circuit 20, the DCDC converter 23, and the like may be arranged on either side of the dichotomy α, and FIG. 1 shows the clock circuit 30. This is an example of the arrangement of the antenna 10, the receiving circuit 20, and the DCDC converter 23. Due to the arrangement of the secondary battery 42, the vibrator 38 and the temperature sensor 37 as described above, the temperature data output by the temperature sensor 37 not only indicates the temperature of the vibrator 38 but also the temperature of the secondary battery 42. It can also be used as. The temperature sensor 37 does not have to be built in the clock circuit 30, and may be an independent device. Alternatively, the temperature sensor 37 may be built into another device. In either case, the temperature sensor 37 may be arranged in the vicinity of the secondary battery 42 and the vibrator 38. The temperature of the vibrator 38 and the temperature of the secondary battery 42 may be detected by separate sensors.

The motor drive circuit 35 outputs a drive signal for driving the motor included in the drive mechanism 50 according to the display time determined by the calculation unit 32. As a result, the display time generated by the clock control circuit 31 is displayed on the time display unit 51.

Further, in the satellite radio wristwatch 1 according to the first embodiment, the arithmetic unit 32 includes the internal time measured based on the clock signal supplied from the clock generation circuit 36 in the satellite signal received by the reception circuit 20. Correct based on the time information.

The power supply unit 40 supplies electric power necessary for its operation to each part in the satellite radio-controlled wristwatch 1, such as the reception circuit 20, the clock circuit 30, and the drive mechanism 50. The power supply unit 40 includes a solar cell 41, a secondary battery 42, and a switch Sw1.

The solar cell 41 is arranged under, for example, a dial 53 which is a translucent thin plate, generates electricity by external light such as sunlight emitted to the satellite radio watch 1, and secondarily generates the generated electric power. It is supplied to the battery 42.

The secondary battery 42 includes a rechargeable battery such as a lithium ion battery and a battery management circuit that manages charging and discharging of the battery such as the lithium ion battery, and stores the power generated by the solar cell 41. Then, the stored electric power is supplied to each part that requires electric power, such as the receiving circuit 20, the clock circuit 30, and the driving mechanism 50. Further, the above battery management circuit includes a voltage sensor that detects the voltage of the secondary battery 42 main body, and the voltage detected by the voltage sensor is notified to the clock control circuit 31.

The secondary battery 42 is connected in parallel with the solar cell 41 via a switch Sw1 connected in series. Specifically, the positive electrode of the solar cell 41 and the positive electrode of the secondary battery 42 are connected via the switch Sw1. The solar cell 41 supplies power to the secondary battery 42 while the switch Sw1 is on.

Here, since the reception of the satellite signal by the receiving circuit 20 consumes a relatively large amount of power, the power supply from the DCDC converter 23 to the receiving circuit 20 is controlled by the switch Sw2 output from the clock circuit 30. The clock control circuit 31 is trying to save electric power by supplying power to the receiving circuit 20 with the switch Sw2 turned on only when necessary. For example, the clock control circuit 31 supplies power to the receiving circuit 20 at a predetermined time every day, or supplies power to the receiving circuit 20 when a receiving operation is performed by the operation unit 60. Further, the clock control circuit 31 is used in the receiving circuit 20 when it is presumed that the amount of power generated by the solar cell 41 is large and the antenna 10 arranged under the dial 53 is likely to face the satellite direction. Power may be supplied.

Here, even when the reception circuit 20 executes the reception operation, the reception may not succeed within the predetermined upper limit time depending on the reception environment or the like. In such a case, the reception operation is repeatedly executed. .. When the reception operation is repeatedly executed a plurality of times, the voltage of the secondary battery 42 may drop excessively, and the voltage supplied to the clock circuit 30 may drop excessively. As a result, there is a risk that the system will go down, making it impossible to perform important operations such as holding the current time.

Further, the voltage drop amount (drop speed) of the secondary battery 42 largely depends on the temperature of the secondary battery 42. Here, the relationship between the voltage of the secondary battery 42 and the temperature of the secondary battery 42 will be described with reference to FIG. FIG. 3 is a diagram showing an outline of the voltage transition of the secondary battery when the receiving circuit continuously executes the capture operation for each temperature of the secondary battery. Specifically, the case where the temperature of the secondary battery is high (about 60 ° C) is shown by a solid line, the case where the temperature of the secondary battery is normal temperature (about 24 ° C) is shown by a broken line, and the case where the temperature is low (about -10 ° C) is a two-dot chain line. Indicated by. As shown in the figure, the lower the temperature, the larger the amount of voltage drop of the secondary battery 42. Note that FIG. 3 shows an outline of the transition of the voltage, and the actual waveform has a shape in which the voltage drops significantly as a whole while repeating the drop and recovery according to the reception operation.

As described above, the reception operation in the reception circuit 20 is performed based on the clock signal generated by the clock generation circuit 25. When the reception operation is executed based on the high-frequency clock signal, the processing speed in the reception circuit 20 is increased, so that the acquisition sensitivity and the tracking sensitivity are improved, so that the probability of successful reception of the satellite signal is improved, but the secondary The load on the battery 42 is large. On the other hand, when the reception operation is executed based on the low-frequency clock signal, the load on the secondary battery 42 is small, but the probability of successful reception of the satellite signal is low.

Therefore, in the first embodiment, the reception control circuit 24 sets the frequency of the clock signal in the reception operation based on the internal temperature of the satellite radio-controlled wristwatch 1. Specifically, when the internal temperature of the satellite radio watch 1 detected by the temperature sensor 37 is higher than the first threshold Tth1 set in advance according to the battery voltage of the secondary battery 42 detected by the voltage sensor, a high frequency is generated. The reception operation is executed based on the clock signal of the above, and when the first threshold value is Tth1 or less, the reception operation is executed based on the low frequency clock signal.

Here, the internal temperature means the internal temperature of the satellite radio watch 1, and in the first embodiment, the internal temperature is detected by the temperature sensor 37 to obtain the battery temperature of the secondary battery 42 and the clock circuit 30. The temperature is indirectly detected.

FIG. 4 is a diagram showing an example of a frequency table according to the first embodiment. The frequency table shown in FIG. 4 is held in the ROM 27, and stores clock frequency candidates in association with each combination of voltage data and temperature data acquired by the reception control circuit 24. Hereinafter, the temperature data detected by the temperature sensor 37 and notified to the reception control circuit 24 is also simply referred to as an internal temperature, and the voltage data detected by the voltage sensor and notified to the reception control circuit 24 is also simply referred to as a battery voltage. ..

In FIG. 4, "high" indicates that the clock frequency of the clock signal in the reception operation is high frequency, "low" indicates that the clock frequency of the clock signal in the reception operation is low frequency, and "prohibited" indicates that the clock frequency is low. Indicates that the reception operation is not executed. Further, in the first embodiment, the clock frequency is set to 64 MHz in "high" and the clock frequency is set to 16 MHz in "low". The frequency value here is an example, and is not limited to this. Further, in the first embodiment, an example of setting to one of two types of frequencies, high frequency and low frequency, will be described, but the present invention is not limited to this, and the configuration is set to any of three or more types of frequencies. It doesn't matter. For example, the ROM 27 may hold a frequency table in which the clock frequency is set to any of 64 MHz, 32 MHz, 16 MHz, 8 MHz, and 4 MHz according to the battery voltage and the internal temperature.

In the first embodiment, in the battery management circuit of the secondary battery 42, the battery voltage of the secondary battery 42 at the start of the reception operation is 2.4 V or less (voltage range 1), higher than 2.4 V and 2.65 V or less. (Voltage range 2) Higher than 2.65V and less than 2.7V (Voltage range 3) Higher than 2.7V and less than 2.8V (Voltage range 4) Higher than 2.8V and less than 2.9V (Voltage range 5) It is either higher than 2.9V and 3.1V or less (voltage range 6), higher than 3.1V and 3.2V or less (voltage range 7), higher than 3.2V and 3.3V or less (voltage range 8). Is detected. Then, the reception control circuit 24 acquires the voltage data detected by the voltage sensor. Hereinafter, 3.3V is referred to as a full charge voltage, and 2.4V is referred to as a charge warning voltage. The full charge voltage is the voltage at which the secondary battery 42 is in the maximum charge state. The charge warning voltage is a voltage at which execution of the reception operation is prohibited when the voltage of the secondary battery 42 drops further.

Further, the temperature sensor 37 has an internal temperature at the start of the reception operation of −10 ° C. or lower (temperature range 1), higher than −10 ° C. and lower than −5 ° C. (temperature range 2), higher than −5 ° C. and 0 ° C. or lower. (Temperature range 3), higher than 0 ° C and 5 ° C or lower (Temperature range 4), higher than 5 ° C and 10 ° C or lower (Temperature range 5), higher than 10 ° C and 25 ° C or lower (Temperature range 6), higher than 25 ° C 40 It detects whether the temperature is below ° C. (temperature range 7), above 40 ° C. and below 70 ° C. (temperature range 8), or above 70 ° C. (temperature range 9). Then, the reception control circuit 24 acquires the temperature data detected by the temperature sensor 37. The temperature range is set so that the lower the temperature, the narrower the range. As a result, the lower the temperature, the finer the frequency control can be performed.

In the first embodiment, an example in which the temperature data and the voltage data are directly notified from each sensor to the reception control circuit 24 will be described, but the temperature data and the voltage data are notified to the calculation unit 32 and are notified from the calculation unit 32. The configuration may be such that the reception control circuit 24 is notified.

In the first embodiment, when the internal temperature is higher than the first threshold value Tth1 determined by the battery voltage, the clock frequency is set to a high frequency, and when the internal temperature is equal to or lower than the first threshold value Tth1, the clock frequency is set to a low frequency. Specifically, as shown in FIG. 4, when the battery voltage is higher than 2.9 V and 3.3 V or lower, and the internal temperature is higher than 0 ° C. (first threshold Tth1), the clock frequency is set to high frequency and 0. When the temperature was below ° C, the clock frequency was set to a low frequency. Similarly, when the battery voltage is higher than 2.65 V and 2.9 V or less, the clock frequency is set to a high frequency when the internal temperature is higher than 5 ° C (first threshold Tth1), and the clock is set when the internal temperature is 5 ° C or lower. The frequency was set to low frequency. Similarly, when the battery voltage is higher than 2.4 V and 2.65 V or lower, the clock frequency is set to a high frequency when the internal temperature is higher than 10 ° C., and the clock frequency is set to a low frequency when the internal temperature is 10 ° C. or lower.

Further, when the battery voltage is 2.4 V (charge warning voltage Vth) or less, the reception operation is prohibited regardless of the internal temperature. This is because if the receiving operation with high power consumption is performed while the battery voltage of the secondary battery 42 is low, the system may go down.

Further, when the internal temperature is −5 ° C. (fourth threshold value Tth4) or less, the reception operation is prohibited regardless of the battery voltage. This is because if the reception operation is performed in a state where the internal temperature is low, the amount of voltage drop of the secondary battery 42 becomes excessively large, which may cause a system down. Further, when the internal temperature is higher than 70 ° C. (third threshold value Tth3), the reception operation is prohibited regardless of the battery voltage. This is because if the reception operation is performed in a state where the internal temperature is excessively high, problems such as failure may occur in various circuits and the like included in the satellite radio-controlled wristwatch 1. The third threshold value Tth3 and the fourth threshold value Tth4 may be preset regardless of the battery voltage. It is preferable that a flag indicating "prohibited" is stored in the frequency table for the combination of the temperature data and the voltage data in which the receiving operation by the receiving circuit 20 is prohibited.

Further, the clock control circuit 31 may display the voltage detected by the voltage sensor. For example, the letter "L0" indicating the low voltage level, the letter "L1" indicating the medium voltage level, and the letter "L2" indicating the high voltage level are displayed on the dial 53, and the operation unit 60 is displayed. When a predetermined operation is performed, the pointer 52 such as the second hand 52c may be used to point to the character corresponding to the voltage data sent from the voltage sensor. Here, for example, in the case of the voltage range 1, "L0" is instructed, in the case of the voltage range 2 to 5, "L1" is instructed, and in the case of the voltage range 6 to 8, "L2" is instructed. ..

Further, the clock control circuit 31 may display the temperature detected by the temperature sensor 37. Here, especially when a wristwatch is worn, the temperature inside the watch and the temperature of the outside air may be different values, but the temperature to be displayed should be the temperature inside the watch.

As described above, the dial 53 of the satellite radio-controlled wristwatch 1 is provided with a reception status display 61. For example, when the reception operation is prohibited, the character "NG" may be indicated by the guideline 52. Further, the configuration may be such that the user is notified so that the cause of the prohibition of the reception operation is the battery voltage or the internal temperature. Specifically, for example, in a state where the reception operation is prohibited due to the battery voltage being 2.4 V or less, the second hand 52c indicates the above-mentioned character "L0", and the minute hand 52b indicates "NG". It is good to indicate the character of. In addition, when the reception operation is prohibited due to the internal temperature of -5 ° C or lower, the second hand 52c indicates a character indicating that the temperature is -5 ° C or lower, and the minute hand 52b indicates "NG". It is good to indicate the character of. Further, for example, in a state where the reception operation is prohibited due to the battery voltage of 2.4 V or less, the second hand 52c indicates "NG", and the reception operation is prohibited because the internal temperature is −5 ° C. or less. In this state, the minute hand 52b may indicate "NG". The pointer shown here is an example, and the pointer indicating "NG" may be the hour hand 52a or the functional hand provided on the sub dial. With the configuration as described above, the user can generate electricity in an environment in which the secondary battery 42 is charged (for example, the solar cell 41 is generated by external light such as sunlight) in order to enable reception operation. It is possible to determine whether the satellite radio-controlled wristwatch 1 should be moved outdoors) or in a hot environment (for example, indoors where the temperature is high).

In the first embodiment, an example in which the clock frequency is set to a low frequency (16 MHz) when the internal temperature is equal to or lower than the first threshold value Tth1 and higher than the fourth threshold value Tth4 has been described. It may be further subdivided and set. For example, when a fifth threshold value lower than the first threshold value Tth1 is set and the internal temperature is equal to or lower than the first threshold value Tth1 and higher than the fifth threshold value, the clock frequency is set to the first low frequency (for example, 16 MHz) and is equal to or lower than the fifth threshold value. If it is higher than the fourth threshold value Tth4, the clock frequency may be set to the second low frequency (for example, 8 MHz). Further, the high frequency may be set by setting a separate threshold value in the same manner.

Next, the operation of the reception control circuit 24 will be described with reference to FIG. FIG. 5 is a flowchart illustrating the operation of the reception control circuit according to the first embodiment.

First, the reception control circuit 24 acquires the battery voltage V notified from the voltage sensor (step S101). When the battery voltage V is equal to or less than the charge warning voltage Vth (NO in step S102), the reception operation is prohibited. When the battery voltage V is higher than the charge warning voltage Vth, the first threshold value Tth1 is acquired based on the frequency table (step S103), and the internal temperature T notified from the temperature sensor 37 is acquired (step S104).

When the internal temperature T is higher than the preset third threshold value Tth3 or equal to or lower than the preset fourth threshold value Tth4, the execution of the reception operation is prohibited (YES in step S105). When the internal temperature T is within the range in which the execution of the reception operation is not prohibited and is higher than the first threshold value Tth1 (YES in step S106), the clock frequency is set to a high frequency (step S107). On the other hand, when the internal temperature T is within the range in which the execution of the reception operation is not prohibited and is equal to or less than the first threshold value Tth1 (NO in step S106), the clock frequency is set to a low frequency (step S8). Then, before the elapse of the upper limit time of the reception operation (step S110), when the reception circuit 20 succeeds in receiving the satellite signal (YES in step S109), the clock circuit displays information about the time obtained from the received satellite signal. It is transmitted to 30 (step S111). After that, the clock circuit 30 corrects the internal time of the satellite radio-controlled wristwatch 1 based on the information regarding the time transmitted from the reception control circuit 24.

Within the upper limit of the reception operation, the reception operation may be executed a plurality of times until the reception is successful. In that case, the reception control circuit 24 may acquire the battery voltage and the internal temperature at the time when the reception operation is started again, and set the clock frequency again based on the battery voltage and the internal temperature at that time.

In the first embodiment, an example in which the first threshold value Tth1 is set according to the battery voltage of the secondary battery 42 has been described, but the first threshold value Tth1 is set regardless of the battery voltage of the secondary battery 42. It doesn't matter. For example, regardless of the battery voltage of the secondary battery 42, if the internal temperature of the satellite radio watch 1 is higher than 5 ° C, the clock frequency is set to a high frequency, and if it is 5 ° C or lower, the clock frequency is set to a low frequency. The table may be held in the ROM 27.

In the first embodiment, an example of setting the clock frequency based on the internal temperature at the start of the reception operation has been described, but the present invention is not limited to this, and the time constant of the specific heat inside the watch is taken into consideration. Therefore, the clock frequency may be set based on the internal temperature detected before a predetermined time at the start of the reception operation. Further, if the temperature detection is continued during the reception operation and the internal temperature becomes higher than the first threshold value Tth1 or becomes lower than the first threshold value Tth1 during the reception operation, the clock frequency may be switched at that time.

Further, the reception control circuit 24 may acquire the transition of the change in the battery voltage of the secondary battery 42 and set the clock frequency based on the transition of the acquired change. For example, if the secondary battery 42 is being discharged, the battery voltage tends to decrease, and there is a high possibility that the battery voltage will be lower than the battery voltage at the start of the reception operation during the reception operation. Therefore, if the secondary battery 42 is being discharged, the clock frequency may be set to a low frequency even when the internal temperature T at the start of the reception operation is about several ° C. higher than the first threshold value Tth1. Further, when the secondary battery 42 is being charged, the battery voltage tends to increase, and it is highly possible that the battery voltage becomes higher than the battery voltage at the start of the reception operation during the reception operation. Therefore, when the secondary battery 42 is being charged, the clock frequency may be set to a high frequency even when the internal temperature T at the start of the reception operation is about several ° C. lower than the first threshold value Tth1.

Similarly, the clock frequency may be set based on the transition of the power generation amount of the solar cell 41. When the transition of the power generation amount of the solar cell 41 is on an upward trend, it is highly possible that the voltage becomes higher than the battery voltage at the start of the reception operation during the reception operation. Therefore, even when the transition of the power generation amount of the solar cell 41 is such that the internal temperature T at the start of the reception operation is several degrees lower than the first threshold value Tth1 (for example, 2 to 3 degrees lower), the clock frequency is set to a high frequency. It is good to set to. Further, the amount of power generated by the solar cell 41 is significantly different between the case where power is generated by external light such as sunlight and the case where power is generated by light from indoor lighting. When it is determined that the transition of the power generation amount of the solar cell 41 tends to generate power by external light such as sunlight, the internal temperature T at the start of the reception operation is much lower than the first threshold Tth1 (for example,). Even if it is 5 ° C lower), the clock frequency may be set to a high frequency.

The first threshold value Tth1 is set by estimating in advance the amount of voltage drop when the reception operation is executed. The reception operation is performed, the battery voltage before and after the execution of the reception operation is acquired, and if the actual voltage drop amount is larger or smaller than the pre-estimated voltage drop amount, the first threshold value is set accordingly. The frequency table may be updated so as to be changed, and the updated frequency table may be retained in the ROM 27.

Further, the reception control circuit 24 may acquire the transition of the change in the internal temperature of the satellite radio-controlled wristwatch 1 and set the clock frequency based on the transition of the acquired change. For example, when the internal temperature tends to decrease, it is highly possible that the internal temperature becomes lower than the internal temperature at the start of the receiving operation during the receiving operation. Therefore, when the internal temperature tends to decrease, the clock frequency may be set to a low frequency even when the internal temperature at the start of the reception operation is about several ° C. higher than the first threshold value Tth1. Further, when the internal temperature tends to rise, it is highly possible that the internal temperature becomes higher than the internal temperature at the start of the receiving operation during the receiving operation. Therefore, when the internal temperature tends to rise, the clock frequency may be set to a high frequency even when the internal temperature at the start of the reception operation is about several ° C. lower than the first threshold value Tth1.

Further, in the first embodiment, an example in which the second hand 52c points to the character “RX” while receiving the satellite signal by the receiving circuit 20 has been described, but the present invention is not limited to this, and is based on a high-frequency clock signal. The guideline 52 may be configured to point to a predetermined character so that the user can visually distinguish and recognize either the state of reception or the state of reception based on a low-frequency clock signal. Further, when the reception operation is started, the pointer 52 may be configured to point to a predetermined character so that the user can recognize whether or not the reception operation can be executed by the high-frequency clock signal.

In the configuration of the first embodiment described above, it is possible to improve the accuracy of reception success by the reception operation while suppressing the occurrence of system down. The configuration of the first embodiment is particularly effective when a small secondary battery 42 having a small battery capacity is adopted.

Next, the second embodiment will be described with reference to FIGS. 6 and 7. FIG. 6 is a diagram showing a frequency table according to the second embodiment. In the second embodiment, the same reference numerals are used for the same configurations as those in the first embodiment, and the description thereof will be omitted.

In the first embodiment, an example of setting whether to set the clock frequency to a high frequency or a low frequency depending on whether the internal temperature is higher than the first threshold value Tth1 has been described. In the second embodiment, an example of setting whether to set the clock frequency to a high frequency or a low frequency will be described depending on whether or not the internal temperature is higher than the second threshold Tth2, which is higher than the first threshold Tth1.

In the second embodiment, as shown in the frequency table of FIG. 6, as in the first embodiment, whether the clock frequency is set to a high frequency or a low frequency depending on whether the internal temperature is higher than the first threshold value Tth1. To set. Here, when the battery voltage is higher than 2.9 V and 3.3 V or less, the first threshold value Tth1 is set to 0 ° C., and when the battery voltage is higher than 2.65 V and 2.9 V or less, the first threshold value Tth1 is set to 5 ° C. When the battery voltage is higher than 2.4V and 2.65V or less, the first threshold value Tth1 is set to 10 ° C. Further, as in the first embodiment, when the battery voltage is 2.4 V or less, the reception operation is prohibited regardless of the internal temperature, and when the internal temperature is −5 ° C. or less, the reception operation is prohibited regardless of the battery voltage. do.

Further, in the second embodiment, when the internal temperature is higher than the second threshold value Tth2 determined by the battery voltage, the clock frequency is set to a low frequency, and when the internal temperature is equal to or lower than the second threshold value Tth2, the clock frequency is set to a high frequency. Specifically, as shown in FIG. 6, when the battery voltage is higher than 2.4V and 2.7V or less, and the internal temperature is higher than 45 ° C. (second threshold value Tth2), the clock frequency is set to a low frequency. When the temperature was 45 ° C. or lower, the frequency was set to high frequency.

As described above, when the internal temperature is higher than the second threshold value Tth2, the reason why the clock frequency is set to a low frequency is that various circuits and the like included in the satellite radio wave watch 1 are loaded with heat and the secondary battery 42 has a load. This is because if the reception operation that consumes a large amount of power is performed in a state where the battery voltage is low, various circuits included in the satellite radio wave watch 1 may not operate normally.

In the frequency table of FIG. 6, the low temperature side "low" frequency (second frequency) which is equal to or lower than the first threshold value Tth1 and the high temperature side "low" frequency (third frequency) higher than the second threshold value Tth2. May be different frequencies. That is, for example, the "low" frequency on the low temperature side may be 8 MHz, and the "low" frequency on the high temperature side may be 16 MHz.

Further, the operation of the reception control circuit 24 in the second embodiment will be described with reference to FIG. 7. FIG. 7 is a flowchart illustrating the operation of the reception control circuit according to the second embodiment.

First, the reception control circuit 24 acquires the battery voltage V notified from the voltage sensor (step S201). When the battery voltage V is equal to or less than the charge warning voltage Vth (NO in step S202), the reception operation is prohibited. When the battery voltage V is higher than the charge warning voltage Vth, the first threshold value Tth1 and the second threshold value Tth2 are acquired (step S203), and further, the internal temperature T notified from the temperature sensor 37 is acquired (step S204).

When the internal temperature T is higher than the preset third threshold value Tth3 or equal to or lower than the preset fourth threshold value Tth4, the execution of the reception operation is prohibited (YES in step S205). When the internal temperature T is within the range in which the execution of the reception operation is not prohibited, is higher than the first threshold value Tth1 and is equal to or lower than the second threshold value Tth2 (YES in step S206), the clock frequency is set to a high frequency (step S207). .. When the internal temperature T is within the range in which the execution of the reception operation is not prohibited and is equal to or less than the first threshold value Tth1 or higher than the second threshold value Tth2 (NO in step S206), the clock frequency is set to a low frequency (step). S208). When the battery voltage V is in the range in which the second threshold value Tth2 is not set (when the battery voltage is higher than 2.7 V and 3.3 V or less (see FIG. 6)), the internal temperature is set to the second threshold value in step S206. Since the condition that it is higher than Tth2 does not apply, it is preferable to set the clock frequency to a high frequency (step S207).

Then, when the receiving circuit 20 succeeds in receiving the satellite signal (YES in step S209) before the elapse of the upper limit time of the receiving operation (step S210), the clock circuit displays information about the time obtained from the received satellite signal. It is transmitted to 30 (step S211). After that, the clock circuit 30 corrects the internal time of the satellite radio-controlled wristwatch 1 based on the information regarding the time transmitted from the reception control circuit 24.

Next, a modified example of the second embodiment will be described with reference to FIG. In the second embodiment, as shown in FIG. 6, an example in which the first threshold value Tth1 and the second threshold value Tth2 are set based on the table held in the ROM 27 has been described. In this modification, as shown in FIG. 8, an example in which the first threshold value Tth1 and the second threshold value Tth2 are held in the ROM 27 as linear expressions of the battery voltage (V) and the internal temperature (° C.), respectively, will be described. “Prohibited” shown in FIG. 8 represents a region where reception operation is prohibited (hereinafter, also referred to as a prohibited region), and “high frequency” is a region where reception operation by a high frequency clock signal is executed (hereinafter, also referred to as high frequency region). And "low frequency" represents a region (hereinafter, also referred to as a low frequency region) in which a reception operation by a low frequency clock signal is executed. As shown in FIG. 8, in the modified example of the second embodiment, the first threshold value Tth1 and the second threshold value Tth2 are each represented by a linear expression. More specifically, the first threshold Tth1 is a point (-5, 3.3) which is the lower limit of the internal temperature T and the upper limit of the battery voltage V, and the upper limit of the internal temperature T and the lower limit of the battery voltage V. It is represented by a straight line connecting the points (0, 2.4) that are the values. The second threshold value Tth2 is a point (45, 2.4) which is a lower limit value of the internal temperature T and a lower limit value of the battery voltage V, and a point (70) which is an upper limit value of the internal temperature T and an upper limit value of the battery voltage. , 3.3) are represented by a straight line connecting them. Further, the boundary between the low frequency region and the prohibited region based on the internal temperature T is represented by a constant (T = -5 or 70), and the boundary between the high frequency region or the low frequency region based on the battery voltage V and the prohibited region is a constant (T = -5 or 70). It is represented by V = 2.4).

In FIG. 8, when the internal temperature is −5 ° C. (fourth threshold value Tth4) or less, or higher than 70 ° C. (third threshold value Tth3), or when the battery voltage is 2.4 V (charge warning voltage Vth) or less. Indicates that the reception operation is prohibited.

Further, in FIG. 8, a sloping broken line in a range where the internal temperature is higher than −5 ° C. and 0 ° C. or lower is a linear expression indicating the first threshold value Tth1. That is, if the internal temperature is lower than the sloping broken line, the clock frequency is set to a low frequency, and if the internal temperature is higher than the sloping broken line, the clock frequency is set to a high frequency. As shown by this linear equation, the first threshold value Tth1 becomes linearly smaller as the battery voltage increases.

Further, in FIG. 8, a sloping broken line in the range where the internal temperature is higher than 45 ° C. and 70 ° C. or lower is a linear expression indicating the second threshold value Tth2. That is, if the internal temperature is higher than the sloping broken line, the clock frequency is set to a low frequency, and if the internal temperature is lower than the sloping broken line, the clock frequency is set to a high frequency. As shown by this linear equation, the second threshold value Tth2 becomes a linearly large value as the battery voltage increases.

In this modification, the absolute value of the slope of the linear expression indicating the first threshold value Tth1 is made larger than the absolute value of the slope of the linear expression indicating the second threshold value Tth2. That is, the amount of change in the first threshold value Tth1 that changes according to the battery voltage is made larger than the amount of change in the second threshold value Tth2 that changes according to the battery voltage. This is more precise when the clock frequency is set depending on whether the internal temperature is higher than the first threshold Tth1 than when the clock frequency is set depending on whether the internal temperature is higher than the second threshold Tth2. This is because various frequency control is required.

Note that FIG. 8 shows an example in which the first threshold value Tth1 and the second threshold value Tth2 are represented by a linear equation, that is, an example in which the second threshold value Tth2 changes linearly according to the battery voltage, but the present invention is not limited to this. It may change stepwise according to the voltage. Further, the first threshold value Tth1 and the second threshold value Tth2 are not limited to the straight line represented by the linear equation, and may be a curve represented by a quadratic or higher function. Further, the boundary between the high frequency region or the low frequency region and the prohibited region is not limited to a constant, and may be represented by a function of a first order or a second order or higher. Further, the first threshold value Tth1 and the second threshold value Tth2 are not limited to those represented by functions, and may change irregularly according to the battery voltage.

Next, the third embodiment will be described with reference to FIGS. 9 and 10. In the first embodiment, an example of setting the clock frequency in the reception operation based on the internal temperature has been described, but in the third embodiment, the clock frequency is set in each of the capture operation and the tracking operation in the reception operation. An example of setting will be described. In the third embodiment, the same reference numerals are used for the same configurations as those in the first embodiment, and the description thereof will be omitted.

Here, the capture operation consumes more power than the tracking operation. That is, the voltage drop amount of the secondary battery 42 when the capture operation is executed is larger than the voltage drop amount of the secondary battery 42 when the tracking operation is executed. Therefore, if the capture operation is executed with a high-frequency clock signal while the internal temperature of the satellite radio-controlled wristwatch 1 is low, there is a high possibility that the system will go down. On the other hand, regarding the tracking operation, it is unlikely that such a problem will occur even if the tracking operation is performed with a high-frequency clock signal. Therefore, in the third embodiment, the frequency table for the capture operation and the frequency table for the tracking operation are held in the ROM 27, respectively. FIG. 9 is a diagram showing an example of a frequency table according to the third embodiment. In FIG. 9, the upper row shows the frequency table for the capture operation, and the lower row shows the frequency table for the tracking operation.

Here, when the battery voltage of the secondary battery 42 is the same, the first threshold value of the internal temperature in the frequency table for the acquisition operation is Tth1a, and the first threshold value of the internal temperature in the frequency table for the tracking operation is Tth1b (<Tth1a). ). Specifically, as shown in FIG. 9, for example, when the battery voltage of the secondary battery 42 is higher than 2.9 V and 3.3 V or less, the first threshold value Tth1a is set to 5 ° C. and the first threshold value Tth1b is set to 0. The temperature was set to ° C. Further, as in the first embodiment, when the internal temperature is higher than the third threshold value Tth3 (70 ° C.), the capture operation and the tracking operation are not executed regardless of the battery voltage of the secondary battery 42. Further, when the internal temperature is the fourth threshold value Tth4 (-5 ° C.) or less, the capture operation and the tracking operation are not executed regardless of the battery voltage of the secondary battery 42. Further, when the battery voltage of the secondary battery 42 is 2.4 V or less, the capture operation and the tracking operation are not executed regardless of the internal temperature.

Further, with reference to FIG. 9, the clock frequency at the time of executing the capture operation and the tracking operation set when the battery voltage of the secondary battery 42 is higher than 2.9 V and 3.3 V or less will be specifically described. .. If the internal temperature of the satellite radio-controlled wristwatch 1 is higher than the first threshold value Tth1a (5 ° C.) and equal to or lower than the third threshold value Tth3 (70 ° C.), the acquisition operation and the tracking operation are executed by a high-frequency clock signal. If the internal temperature of the satellite radio-controlled wristwatch 1 is equal to or lower than the first threshold value Tth1a (5 ° C.) and higher than the first threshold value Tth1b (0 ° C.), the acquisition operation is executed with a low-frequency clock signal, and after successful acquisition, tracking is performed. The operation is performed with a high-frequency clock signal. When the internal temperature of the satellite radio-controlled wristwatch 1 is equal to or lower than the first threshold value Tth1b (0 ° C.) and higher than the fourth threshold value Tth4 (−5 ° C.), the acquisition operation and the tracking operation are executed by a low-frequency clock signal.

The high-frequency clock frequency and the low-frequency clock frequency may be different between the capture operation and the tracking operation. For example, in the acquisition operation, the high frequency clock frequency may be 64 MHz, the low frequency clock frequency may be 16 MHz, and in the tracking operation, the high frequency clock frequency may be 16 MHz and the low frequency clock frequency may be 4 MHz. The clock frequency of the tracking operation is lower than that of the acquisition operation because it is sufficient to perform the reception operation with a sensitivity that does not lose sight of the satellite after the correlation with the satellite signal is obtained, that is, after the acquisition is successful. Is. Further, the clock frequency is not limited to two types, and for example, in the tracking operation, the clock frequency may be set to any of 16 MHz, 8 MHz, and 4 MHz based on the internal temperature.

Further, the frequency table may be updated so that the first threshold value Tth1 in the case where the capture fails and the capture operation is performed again is higher than the first threshold value Tth1 before the failure. As a result, it is possible to prevent the battery voltage from dropping excessively and causing the system to go down by continuously executing the capture operation based on the high-frequency clock signal.

FIG. 10 is a flowchart showing the operation of the reception control circuit according to the third embodiment.

First, the reception control circuit 24 acquires the battery voltage V notified from the voltage sensor (step S301). When the battery voltage V is equal to or less than the predetermined charge warning voltage Vth, the execution of the reception operation is prohibited (NO in step S302). When the battery voltage V is higher than the predetermined charge warning voltage Vth (YES in step S302), the first threshold value Tth1a and the first threshold value Tth1b are acquired based on the battery voltage V (step S303). Further, the internal temperature T notified from the temperature sensor 37 is acquired (step S304).

When the internal temperature T is higher than the preset third threshold value Tth3 or equal to or lower than the preset fourth threshold value Tth4, the execution of the reception operation is prohibited (YES in step S305). When the internal temperature T is within the range in which the execution of the reception operation is not prohibited and is higher than the first threshold value Tth1a (YES in step S306), the clock frequency is set to a high frequency (step S307). On the other hand, when the internal temperature T is within the range in which the execution of the reception operation is not prohibited and is equal to or less than the first threshold value Tth1a (NO in step S306), the clock frequency is set to a low frequency (step S308). Then, before the upper limit time of the capture operation elapses (step S310), if the reception circuit 20 succeeds in capture (YES in step S309), the correlation data regarding the satellite number and the timing is transmitted to the tracking circuit 22b (step S311). ..

Further, when the internal temperature T is higher than the first threshold value Tth1b (YES in step S312), the clock frequency is set to a high frequency (step S313). On the other hand, when the internal temperature T is equal to or less than the first threshold value Tth1b (NO in step S312), the clock frequency is set to a low frequency (step S314). Then, if the receiving circuit 20 succeeds in demodulating the data (YES in step S315) before the elapse of the upper limit time of the tracking operation (step S316), the information regarding the demodulated time is transmitted to the clock circuit 30 (step). S317). After that, the clock circuit 30 corrects the internal time of the satellite radio-controlled wristwatch 1 based on the information regarding the time transmitted from the reception control circuit 24.

In the third embodiment, an example of setting the clock frequency based on the internal temperature T and the battery voltage V at the start of the reception operation has been described, but the present invention is not limited to this. For example, the internal temperature T and the battery voltage V are acquired for each of the capture operation and the start of the tracking operation, and the clock frequency in the capture operation is set based on the internal temperature T and the battery voltage V at the start of the capture operation to perform tracking. The clock frequency in the tracking operation may be set based on the internal temperature T and the battery voltage V at the start of the operation. Further, in consideration of the time constant of the specific heat inside the watch, the internal temperature T and the battery voltage V detected before the predetermined time at the start of the acquisition operation, or the internal temperature T detected before the predetermined time at the start of the tracking operation. And the clock frequency may be set based on the battery voltage V. Further, the internal temperature T and the battery voltage V are continuously acquired during the capture operation and the tracking operation, and the capture operation or the tracking operation is being executed based on the acquired internal temperature T and the battery voltage V. The clock frequency may be switched.

In the first to third embodiments, an example of performing a reception operation for acquiring time information has been described, but the present invention is not limited to this, and the reception operation for acquiring position information is not limited to this. The clock frequency may be set based on the internal temperature. FIG. 11 is a diagram showing a frequency table in a reception operation for acquiring position information. The ROM 27 holds, for example, the frequency table shown in FIG. 6 and the frequency table shown in FIG. 11, and the reception control circuit 24 may select which table to use depending on the type of reception operation. It should be noted that the reception operation for acquiring the position information consumes a large amount of power as compared with the reception operation for acquiring the time information. That is, the amount of voltage drop of the secondary battery 42 is large. Therefore, in the frequency table shown in FIG. 11, the range of the battery voltage and the internal temperature at which the reception operation is performed based on the high-frequency clock signal is made smaller than that in the frequency table shown in FIG.

Further, the ROM 27 may separately hold a frequency table for setting the clock frequency in the reception operation for acquiring the leap second information included in the satellite signal based on the internal temperature. The leap second corrects the internal time and adjusts the deviation between the time output by the atomic clock of the GPS satellite and UTC (Universal Time, Coordinated). Information about leap seconds is included only once out of 25 transmissions of subframe 4 of the satellite signal (pages 1-25). Specifically, information about leap seconds is contained only in the subframe SF4 on page 18. Since each of the subframes 1 to 5 is transmitted over 6 seconds, the information regarding the leap second is transmitted once every 12.5 minutes. In order to acquire the leap second information transmitted only once every 12.5 minutes with higher accuracy, it is necessary to perform the operation time longer than the reception operation for receiving the time information. Therefore, when the reception operation for acquiring the information regarding the leap second is performed, the battery voltage of the secondary battery 42 drops significantly. Therefore, in the frequency table used when performing the reception operation for acquiring information on leap seconds, it is preferable to set the first threshold value Tth1 higher than the examples shown in FIGS. 4 and 6. Further, it is preferable to set the second threshold value Tth2 lower than the example shown in FIG. As a result, when the internal temperature is high or low, a reception operation for acquiring information on leap seconds is performed based on a low-frequency clock signal, and the battery voltage of the secondary battery 42 drops excessively. It is possible to suppress the occurrence of system down due to.

The clock frequency may be set in each of the capture operation and the tracking operation for each of the reception operation for acquiring the time information, the position information, and the leap second information. That is, a frequency table for capturing operation and a frequency table for tracking operation regarding reception operation for acquiring time information, a frequency table for capturing operation and a frequency table for tracking operation regarding receiving operation for acquiring position information, And the frequency table for the acquisition operation and the frequency table for the tracking operation regarding the reception operation for acquiring the information regarding the leap second may be held in the ROM 27, respectively.

In the above embodiment, an example of receiving a satellite signal from GPS has been described, but the present invention is not limited to this, and for example, from QZSS (Quasi-Zenith Satellite System) or GLONASS (Global Navigation Satellite System). The satellite signal may be received. As a result, even when the GPS is located behind the building, the reception success rate of the satellite signal is improved by enabling reception of other satellites. Further, when the acquisition fails, the type of satellite may be switched in order to improve the reception success rate when reacquiring.

Further, the fourth embodiment will be described with reference to FIG. In each of the above embodiments, an example of setting the clock frequency in the reception operation by the receiving circuit 20 based on the internal temperature of the satellite radio-controlled wristwatch 1 has been described. However, in the fourth embodiment, the internal temperature of the satellite radio-controlled wristwatch 1 has been described. An example of setting the clock frequency in the processing by the clock circuit 30 will be described based on the above.

In the clock circuit 30, the clock control circuit 31 including the arithmetic unit 32 controls various circuits and mechanisms included in the satellite radio-controlled wristwatch 1. Various processes in the clock circuit 30 are executed based on the clock signal of the frequency set by the clock control circuit 31. The clock signal used when executing the process controlled by the clock control circuit 31 may be generated by the clock generation circuit 36 shown in FIG. 2 or may be generated by the clock generation circuit 25. In this case, for example, the clock generation circuit 25 or the clock generation circuit 36 is configured to include a multiplication circuit so that clock signals having different frequencies (for example, a 32 kHz clock signal and a 64 kHz clock signal) can be generated. It is good. Alternatively, a circuit that generates a clock signal used when executing the process controlled by the clock control circuit 31 may be separately provided.

In the fourth embodiment, it is preferable to hold a frequency table similar to the frequency table shown in FIG. 4 or the like in the ROM 34. However, since the processing in the clock circuit 30 consumes less power of the secondary battery 42 than the reception operation described in the first embodiment and the like, the first threshold value is set lower than in the example shown in FIG. 4 and the like. However, unless the battery voltage or internal temperature is excessively low, it is basically preferable to enable processing at a high frequency clock frequency.

The clock circuit 30 receives, for example, information about the time acquired by the receiving circuit 20, and performs a process of correcting the internal time based on the information. In the internal time correction process, when the clock frequency is high frequency, the processing speed from the transmission of information on the time from the receiving circuit 20 to the reflection of the information in the internal time is improved. On the other hand, in the internal time correction process, when the clock frequency is low, the power consumption in the clock circuit 30 is reduced, and it is possible to prevent the battery voltage of the secondary battery 42 from being excessively lowered.

Further, the clock circuit 30 performs various processes according to an external operation received by, for example, the crown or the button of the operation unit 60. For example, when the user presses and holds the button for a predetermined second, the clock circuit 30 switches to various modes such as a mode for normal hand movement, a mode for setting an alarm, and a mode for using a chronograph. Perform processing. In this case, if the clock frequency at the time of performing the processing is high, the switching speed between the modes becomes high, and the convenience for the user is improved. On the other hand, if the clock frequency is low, the switching speed between the modes becomes slow, but it is possible to prevent the battery voltage of the secondary battery 42 from dropping excessively.

In each of the above embodiments, an example in which the frequency table is stored in the ROM provided in the satellite radio-controlled wristwatch 1 in advance has been described, but the amount of information that can be stored in the satellite radio-controlled wristwatch 1 is limited. Therefore, an external electronic terminal such as a PC (personal computer) or a smartphone may hold the frequency table. As a result, the amount of information stored in the satellite radio-controlled wristwatch 1 can be reduced. In this case, it is preferable that the electronic terminal and the satellite radio-controlled wristwatch 1 can be connected by short-range wireless communication. As a standard for short-range wireless communication, for example, BLE (Bluetooth (registered trademark) Low Energy) may be used. The external electronic terminal receives information on the internal temperature and battery voltage from the satellite radio watch 1 by short-range wireless communication, and based on the information and the frequency table held by itself, the clock frequency in the reception operation of the satellite radio watch 1. Should be decided. Then, the external electronic terminal may transmit a command signal regarding which clock frequency the reception operation is to be executed to the satellite radio-controlled wristwatch 1 by short-range wireless communication. Then, the satellite radio-controlled wristwatch 1 may receive a command signal from an external electronic terminal, and set the clock frequency in the reception operation based on the command signal. The receiving circuit 20 may be kept idling while the external electronic terminal is performing the above processing. As a result, it is possible to prevent an extra load from being applied to the secondary battery 42 or the like while the external electronic terminal is performing the process.

The external electronic terminal receives information on the tendency of the battery voltage of the secondary battery 42 and the tendency of the internal temperature of the satellite radio-controlled wristwatch 1 from the satellite radio-controlled wristwatch 1, and based on the information, the satellite radio-controlled wristwatch 1 of the satellite radio-controlled wristwatch 1. You may create or update a frequency table suitable for your environment. For example, when the satellite radio-controlled wristwatch 1 is in a low temperature environment and the low frequency or reception operation is always prohibited, the first threshold value Tth1 is set to be lower than the value shown in FIG. Update to the frequency table. As a result, there is room for executing the reception operation based on the high-frequency clock signal even in a low temperature environment. It should be noted that the present invention is not limited to the electronic terminal as described above, and a configuration may be configured in which the satellite radio-controlled wristwatch 1 and the cloud server can be connected by communication, and the frequency table is created or updated in the cloud server.

Although the embodiment according to the present invention has been described above, the specific configuration shown in this embodiment is shown as an example, and it is not intended to limit the technical scope of the present invention to this. Those skilled in the art may appropriately modify these disclosed embodiments, and it should be understood that the technical scope of the invention disclosed herein also includes such modifications.

1 satellite radio watch, 10 antennas, 20 receiving circuit, 21 high frequency circuit, 22 decoding circuit, 22a correlator, 22b tracking circuit, 23 DCDC converter, 24 receiving control circuit, 25 clock generation circuit, 26 TCXO, 27 ROM, 30 clock Circuit, 31 clock control circuit, 32 arithmetic unit, 33 RAM, 34 ROM, 35 motor drive circuit, 36 clock generation circuit, 37 temperature sensor, 38 oscillator, 40 power supply unit, 41 solar cell, 42 secondary battery, 50 Drive mechanism, 51 time display unit, 52 pointer, 52a hour hand, 52b minute hand, 52c second hand, 53 dial, 60 operation unit, 61 reception status display.

Claims (19)

With built-in battery
A clock generation circuit that generates a clock signal and
A processing circuit that receives power from the built-in battery and executes processing based on the clock signal.
A control circuit that controls the processing circuit and
An electronic clock that includes
It has a temperature sensor that detects the internal temperature of the electronic clock.
The control circuit sets the frequency of the clock signal based on the internal temperature.
Electronic clock. When the internal temperature is higher than the first threshold value, the control circuit sets the frequency to the first frequency, and when the internal temperature is equal to or lower than the first threshold value, the frequency is set to a second frequency lower than the first frequency. Set to,
The electronic clock according to claim 1. When the internal temperature is higher than the second threshold value higher than the first threshold value, the control circuit sets the frequency to a third frequency lower than the first frequency.
The electronic clock according to claim 2. It said control circuit, said case internal temperature is higher than the third threshold higher than the second threshold value, or if the internal temperature is below the lower than the first threshold fourth threshold, prohibits execution of the processing,
The electronic clock according to claim 3. Further having a voltage sensor for detecting the battery voltage of the built-in battery,
The control circuit sets the first threshold value according to the battery voltage.
The electronic clock according to any one of claims 2 to 4. A memory that stores the frequency candidates in association with the combination of the internal temperature range and the battery voltage range, respectively.
The electronic clock according to claim 5. The width of the internal temperature range associated with each of the frequency candidates is narrower as the range relates to lower temperatures.
The electronic clock according to claim 6. A memory for storing the first threshold value, which becomes smaller as the battery voltage becomes higher, is included.
The electronic clock according to claim 5. It further has a voltage sensor for detecting the battery voltage of the built-in battery and a memory.
The memory stores the second threshold value, which increases as the battery voltage increases.
The electronic clock according to claim 3 or 4. The first threshold value and the second threshold value are represented by a linear expression.
The absolute value of the slope of the linear expression representing the first threshold value is larger than the absolute value of the slope of the linear expression representing the second threshold value.
The electronic clock according to claim 9. The processing circuit is a circuit that performs a reception operation for receiving a signal from the outside.
The process is the reception operation.
The electronic clock according to any one of claims 2 to 10. The reception operation includes a capture operation for capturing the signal and a tracking operation performed after the capture is successful.
The control circuit sets the frequency for each of the capture operation and the tracking operation based on the internal temperature.
The electronic clock according to claim 11. The first threshold value in the case where the capture fails and the capture operation is performed again is higher than the first threshold value before the capture failure.
The electronic clock according to claim 12. It has an operation unit that accepts operations from the outside.
The processing circuit executes the processing according to the operation received by the operation unit.
The electronic clock according to any one of claims 1 to 10. It has a receiving circuit that receives signals from the outside,
The processing circuit executes the processing according to the time information included in the signal received by the receiving circuit.
The process is an operation of correcting the internal time of the electronic clock.
The electronic clock according to any one of claims 1 to 10. The temperature sensor and the built-in battery are both arranged in a region on one side of a dichotomy that passes through the center of the electronic timepiece.
The electronic clock according to any one of claims 1 to 15. The control circuit sets the frequency based on the internal temperature detected by the temperature sensor at the start of the process.
The electronic clock according to any one of claims 1 to 16. The control circuit sets the frequency based on the internal temperature detected by the temperature sensor before a predetermined time at the start of the process.
The electronic clock according to any one of claims 1 to 16. The control circuit switches the frequency based on the internal temperature detected by the temperature sensor during the process.
The electronic clock according to claim 17 or 18.

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