JP6136647B2 - Radio correction watch and radio correction watch code determination method - Google Patents

Description

  The present invention relates to a radio-controlled timepiece that corrects time based on a standard radio wave and a code determination method for the radio-controlled timepiece.

A radio-controlled timepiece that receives a standard radio wave and corrects the internal time based on the received standard radio wave is known. The standard radio wave is transmitted by subjecting a time code of 1 Hz to amplitude modulation with a carrier wave of a predetermined frequency. The radio-controlled timepiece generates a reception signal that changes to a first level and a second level that is different from the first level based on the received standard radio wave, and determines the reception signal every second, thereby generating time information. To get. The received signal is determined based on the first level signal width (see, for example, Patent Document 1).
In the radio-controlled timepiece of Patent Document 1, the received signal changes from the first level to the second level after the second signal changes from the second level to the second level at the second synchronization timing at which the received signal is repeated at 1 second intervals. When a predetermined time has passed with the level, the timing at which the first level changes to the second level is determined as the change timing. The radio-controlled timepiece measures the elapsed time from the second synchronization timing to the change timing, and performs code determination based on the elapsed time. As a result, even if the signal level of the received signal temporarily changes from the first level to the second level due to the influence of noise, the influence of the noise can be eliminated if the signal level returns to the first level before the predetermined time elapses. , Can correctly determine the code.

JP 2011-214871 A

  However, in the radio-controlled timepiece of Patent Document 1, if the predetermined time elapses with the received signal changing from the first level to the second level due to the influence of noise or the like before the normal signal change timing, the second synchronization is performed. The elapsed time from the timing to the change timing is shorter than the original normal signal, and there is a possibility that the code determination is erroneously performed. In this case, the code cannot be correctly determined and the time information cannot be acquired correctly.

  An object of the present invention is to provide a radio correction timepiece and a code determination method for a radio correction timepiece that can reduce erroneous code determination.

  The radio-controlled timepiece according to the present invention receives a standard radio wave including time information, changes to a first level and a second level different from the first level, and from the second level to the first level at intervals of one second. A reception means for outputting a reception signal that changes to a level, and a start of setting a sampling start timing based on a second synchronization timing that is a timing of one second intervals at which the reception signal changes from the second level to the first level Timing setting means, maximum width signal detecting means for detecting a maximum width signal having the largest signal width of the first level among the received signals in a predetermined period from the sampling start timing, and the maximum width signal are transmitted. Determination timing setting means for setting a determination timing within a period, and a lapse from the sampling start timing to the determination timing Elapsed time detection means for detecting the interval, and code determination means for determining a code of a signal for 1 second from the second synchronization timing based on the elapsed time detected by the elapsed time detection means. .

Here, the standard radio wave is transmitted by subjecting a time code of 1 Hz to amplitude modulation with a carrier wave of a predetermined frequency. For this reason, the signal level of the received signal output from the receiving means changes to the first level or the second level according to the amplitude of the received standard radio wave. At this time, depending on the circuit of the receiving means, there are a case where the first level becomes a high level higher than the second level and a case where the first level becomes a low level lower than the second level.
The received signal changes from the second level to the first level (from low level to high level, or from high level to low level) at intervals of 1 second, and changes to a bit value (“0”, “1”, marker). The signal level changes from the first level to the second level (from the high level to the low level or from the low level to the high level) with a corresponding signal width.
For example, in the German standard radio wave DCF77, a time code of 60 seconds (60 bits) in one cycle (one cycle) is repeatedly transmitted. The signal width of the first level of each bit in the received signal is normally set in accordance with three types of data (bit values) of binary “1”, binary “0”, and marker “M”. . For example, in the case of DCF77, if the first level signal width is 0.1 second (100 msec), the binary number “0” is represented, and the first level signal width is 0.2 second (200 msec). For example, it represents a binary number “1”. If the signal width of the first level is 0.0 seconds, that is, if the second level continues for 1 second, the marker “M” is represented.

According to the present invention, the maximum width signal detecting means detects the maximum width signal having the largest signal width of the first level among the received signals in a predetermined period from the sampling start timing. Here, the predetermined period may be one second until the next sampling start timing, or may be set according to the type of the standard radio wave. For example, the predetermined period is set to 400 msec in DCF77 and 900 msec in JJY.
Then, the determination timing setting means sets the determination timing within a period during which the maximum width signal is transmitted. For example, the timing of the center of the signal width of the maximum width signal (1/2 of the signal width) is set as the determination timing. The elapsed time detecting means detects an elapsed time from the sampling start timing to the determination timing. The code determination unit determines the code of the signal for one second based on the elapsed time detected by the elapsed time detection unit.
Here, when there are a plurality of first level signals in the received signal in a predetermined period from the sampling start timing, the signal width of the first level signal due to the influence of noise is usually compared with the signal width of a normal signal. small. For this reason, the timing at which a normal signal is transmitted can be detected by detecting the maximum width signal. Therefore, if the determination timing is set by the determination timing setting means within the period during which the maximum width signal is transmitted, the determination timing is usually different depending on the bit value (code), that is, the first level signal width. Set to Therefore, if the elapsed time from the sampling start timing to the determination timing is detected, the code can be correctly determined based on the elapsed time, and the time information can be acquired correctly.

In the present invention, since the code is determined based on the elapsed time from the sampling start timing to the determination timing instead of the signal width of the maximum width signal, for example, the reception environment is poor and the radio wave intensity is weak. Even when the signal width changes, the code can be correctly determined.
For example, in the DCF77, when the signal width of one signal representing binary “1” in the received signal is reduced from the original 200 msec to 100 msec or less, the code is determined by the method of performing the code determination based on the signal width. A binary number “0” is erroneously determined.
However, in the present invention, the determination is not based on the signal width but based on the elapsed time from the sampling start timing to the determination timing. Since the determination timing of one signal whose signal width has decreased to 100 msec and the determination timing of 0 signal of 100 msec in which the signal width has not increased or decreased are usually different timings, the elapsed time is also different. By performing the code determination based on this elapsed time, the possibility of correctly determining the code of one signal having a reduced signal width as distinguished from the zero signal increases, and the erroneous determination of the code can be reduced.

  In the radio-controlled timepiece according to the aspect of the invention, it is preferable that the determination timing setting unit sets the timing at the center of the signal width of the maximum width signal as the determination timing.

  When the reception environment is poor and the radio wave intensity is weak, the signal width of the reception signal is on both sides (front and back), that is, the first level start portion that changes from the second level to the first level due to the characteristics of the circuit of the reception means, It may increase or decrease at the end of the first level that changes from the first level to the second level. In this case, the timing at the center of the signal width is unlikely to fluctuate even if the signal width increases or decreases. For this reason, by setting the timing at the center of the signal width of the maximum width signal as the determination timing, the elapsed time from the sampling start timing to the determination timing is less likely to fluctuate due to increase / decrease on both sides of the signal width. Thereby, even when the signal width increases or decreases, the code can be determined more correctly.

  In the radio-controlled timepiece according to the aspect of the invention, it is preferable that the determination timing setting unit sets an end timing of the maximum width signal to the determination timing.

  When the reception environment is poor and the radio field intensity is weak, the signal width of the reception signal mainly decreases at the front side, that is, at the start of the first level that changes from the second level to the first level due to the characteristics of the circuit of the receiving means. Sometimes. In this case, the signal end timing hardly changes even if the front side of the signal width increases or decreases. For this reason, by setting the end timing of the maximum width signal as the determination timing, the elapsed time from the sampling start timing to the determination timing is less likely to fluctuate due to an increase or decrease in the front side of the signal width. Thereby, even when the signal width increases or decreases, the code can be determined more correctly.

  In the radio-controlled timepiece according to the present invention, the radio-controlled timepiece includes sampling means for sampling the received signal at a predetermined sampling period to obtain a signal level at each sampling, and the maximum width signal detecting means is a signal detected by the sampling means. It is preferable to detect, as the maximum width signal, a signal having the largest number of times that the first level is continuously detected by the sampling means from the time when the level changes from the second level to the first level.

  According to the present invention, since the maximum width signal can be detected by counting the number of times the first level is detected by the sampling means, the maximum width signal can be detected with easy processing.

  In the radio-controlled timepiece according to the aspect of the invention, the start timing setting unit sets a timing that is a predetermined time before the second synchronization timing to the sampling start timing, and the reception signal is the second synchronization timing at the second synchronization timing. It is preferable that the time is set so that a change in the signal level can be detected when the level changes from the second level to the first level.

Here, the predetermined time may be set in consideration of variations in signal level change timing at intervals of 1 second. For example, the time may be set to the same time as the determination condition set in the second synchronization process for detecting the second synchronization timing. Specifically, the predetermined time may be set to about 30 to 60 msec.
According to the present invention, even if the timing at which the received signal changes from the second level to the first level is shifted with respect to the second synchronization timing at intervals of one second, the possibility that the received signal is shifted more than the predetermined time is low. Since the change of the received signal from the second level to the first level at the timing can be reliably detected, the maximum width signal can be correctly detected.

  In the radio-controlled timepiece according to the invention, the code determination unit determines that the code is a marker when the signal width of the maximum width signal is less than a signal width threshold, and the signal width of the maximum width signal is equal to or greater than the signal width threshold. In this case, it is preferable that the elapsed time detected by the elapsed time detection means is compared with an elapsed time threshold value to determine that the code is binary “0” or “1”.

  Even if the signal width decreases because the reception environment is poor and the radio field strength is weak, there is a lower limit. In the DCF 77, the signal width of the 0 signal and the 1 signal is rarely less than 40 msec, for example, and it can be determined that the signal less than 40 msec is a noise signal. For this reason, in the DCF 77, the signal width threshold is set to 40 msec, for example, and when the signal width of the maximum width signal is less than the signal width threshold, the code is determined as the marker “M”. That is, when the signal width of the maximum width signal is greater than 0 msec and less than 40 msec, the signal is determined as a noise signal. If the signal width of the maximum width signal is 0 msec, it is determined that there is no first level signal input. In these cases, the code can be determined as “M”. On the other hand, when the signal width of the maximum width signal is equal to or larger than the signal width threshold, the elapsed time detected by the elapsed time detecting means is compared with the elapsed time threshold (for example, 125 msec), and the code is determined to be “0” or “1”. To do. As a result, when the standard radio wave of DCF 77 is received, the code of “0, 1, M” can be correctly determined.

  In the radio-controlled timepiece according to the aspect of the invention, the code determination unit may be configured such that the elapsed time detected by the elapsed time detection unit is less than a first elapsed time threshold or greater than or equal to the first elapsed time threshold and the first elapsed time threshold. The code is determined to be a binary number “0”, “1” or a marker by determining whether the value is less than the second elapsed time threshold which is a larger value or greater than or equal to the second elapsed time threshold. It is preferable to do.

For example, in JJY, the signal width of a signal representing “0” is 800 msec, the signal width of a signal representing “1” is 500 msec, the signal width of a signal representing a marker is 200 msec, and usually the determination timing is Different for each signal. In other words, since the elapsed time detected by the elapsed time detection means is different for each signal, the code can be determined based on the elapsed time.
According to the present invention, the code determination means is configured such that the elapsed time is less than a first elapsed time threshold, greater than or equal to a first elapsed time threshold and less than a second elapsed time threshold, or a second elapsed time threshold. Since the code is determined by determining whether it is the above or not, “0”, “1”, and the marker code can be correctly determined based on the elapsed time.

The present invention receives a standard radio wave including time information, changes to a first level and a second level different from the first level, and changes from the second level to the first level at intervals of one second. A method for determining a code of a radio-controlled timepiece having a receiving means for outputting a received signal, wherein the received signal changes from the second level to the first level with reference to a second synchronization timing which is a one-second interval timing. A start timing setting step for setting a sampling start timing; and a maximum width signal detection step for detecting a maximum width signal having the largest signal width of the first level among the received signals in a predetermined period from the sampling start timing; A determination timing setting step for setting a determination timing within a period during which the maximum width signal is transmitted; An elapsed time detecting step for detecting an elapsed time from the timing to the determination timing; and a code determining step for determining a signal code for one second from the second synchronization timing based on the elapsed time detected in the elapsed time detecting step; It is characterized by providing.
Also in the present invention, the same operational effects as the radio wave correction timepiece can be obtained.

1 is a block diagram showing a radio wave correction watch according to a first embodiment. It is a figure which shows the receiving pulse duty and amplitude change with respect to each signal of the standard radio wave "DCF77" in Germany. It is a flowchart which shows the reception process of 1st Embodiment. It is a flowchart which shows the elapsed time detection process of 1st Embodiment. It is a wave form diagram which shows an example of the received signal of 1st Embodiment. It is a flowchart which shows the code | cord | chord determination process of 1st Embodiment. It is a figure which shows the waveform of each state when the received signal in 1st Embodiment is 1 signal. It is a figure which shows the waveform of each state when the received signal in 1st Embodiment is 0 signal. It is a figure which shows the waveform of each state when the received signal in 2nd Embodiment is 1 signal. It is a figure which shows the waveform of each state when the received signal in 2nd Embodiment is 0 signal.

[First Embodiment]
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.
[Configuration of radio-controlled clock]
FIG. 1 is a block diagram showing the internal configuration of the radio-controlled timepiece 1.
The radio-controlled timepiece 1 includes a time display means 2 for displaying time, a receiving means 5 for receiving radio waves including time information, an oscillation circuit 6 and a frequency dividing circuit 7 serving as a reference signal source for outputting a reference signal, And a control means 10 for controlling the overall operation.

The time display means 2 is composed of general pointers used in an analog timepiece, a display wheel (day wheel, day wheel) on which date and day of the week are printed, a motor driving the wheel, a train wheel, and the like. . Specifically, although not shown in the drawing, it is configured to include a dial plate, hour hand, minute hand, and second hand that are hands, and a calendar wheel such as a date indicator and a day indicator that displays date and day of the week.
Note that both the date wheel and the day wheel may be provided, only one of them may be provided, or both may not be provided. These are set in consideration of the design of each clock.
Further, a step motor is generally used as the motor, but various drive mechanisms capable of moving a pointer such as a piezoelectric actuator may be used.
The time display means 2 is not limited to the one provided with the hands and the calendar wheel, but may be one that incorporates a display device such as a liquid crystal panel and digitally displays the time information.

The receiving means 5 has the same configuration as a general standard radio wave receiving circuit, and includes an antenna 4 and a tuning circuit (not shown) constituted by a tuning capacitor and the like. The receiving means 5 is controlled by the control means 10 and is configured to cause the antenna 4 to receive a long wave standard radio wave having a frequency set by the tuning circuit.
The frequency of the standard radio wave is set according to the type of standard radio wave to be received. For example, the standard radio wave “JJY” in Japan is set to 40 Hz or 60 Hz, the standard radio wave “WWVB” in the United States is set to 60 Hz, the standard radio wave “DCF77” in Germany is set to 77.5 Hz, The standard radio wave “BPC” is set to 68.5 kHz.
The selection of the standard radio wave may be performed manually by the user, or may be set by determining whether or not the radio wave correction timepiece 1 can automatically switch the frequency and receive the radio wave.

In each standard radio wave, a signal is output by AM modulation in which the ratio of the amplitude of the high level signal and the amplitude of the low level signal is a predetermined ratio. Based on the signal width (or duty) of the high-level signal or low-level signal, the binary number “0”, the binary number “1”, and the marker “M” are recognized.
For example, in the DCF 77, as shown in FIG. 2, a signal is output by AM modulation in which the ratio of the amplitude of the high level signal and the amplitude of the low level signal is 100: 25.
In the DCF 77, as shown in FIGS. 2A to 2C, when the signal width of the low level signal is 0.1 second, that is, when the duty of the low level signal is 10%, the signal of the low level signal is It is recognized as “1” when the width is 0.2 seconds, that is, when the duty of the low level signal is 20%. Furthermore, “M” is not AM-modulated and is recognized as M when a high level signal continues for 1 second.
In each standard radio wave, time information is transmitted by using the signals “0, 1, M” in the time code format for each standard radio wave. Each standard time code format includes time information such as minutes and hours, and parity.

The receiving means 5 includes an amplifier circuit, a bandpass filter, a demodulator circuit, a decode circuit, etc. (not shown), and extracts a time code (time information) that is digital data from the received long wave standard radio wave. The extracted time code is output to the control means 10.
At this time, since the long wave standard radio wave transmits a signal modulated by amplitude modulation as described above, there are a period in which the amplitude is large and a period in which the amplitude is small. The receiving means 5 outputs the signal level of the received signal as a high level and a low level according to the change in amplitude. At this time, depending on the circuit configuration of the receiving unit 5, when the amplitude is large, the received signal may be output as a high level or may be output as a low level. For this reason, the received signal changes from the second level to the first level per second, but there are cases where the first level is the high level and the first level is the low level, and the second level is the first level. The level is different from the level.

The oscillation circuit 6 includes a reference signal source (not shown) such as a crystal resonator, and oscillates the reference signal source at a high frequency, and outputs an oscillation signal generated by the high frequency oscillation to the frequency divider circuit 7.
The frequency divider circuit 7 receives and divides the oscillation signal output from the oscillation circuit 6. The frequency dividing circuit 7 outputs a predetermined reference signal, for example, a 1 Hz pulse signal to the control means 10.

[Configuration of control means]
The control means 10 is constituted by a circuit on which, for example, an IC (Integrated Circuit) or various electric components are mounted, and performs time measurement and time correction of the radio-controlled timepiece 1.
As shown in FIG. 1, the control means 10 includes a sampling means 11, a second synchronization detection means 12, a start timing setting means 13, a maximum width signal detection means 14A, a determination timing setting means 14B, and an elapsed time detection means. 14C, a code determination unit 15, a time correction unit 16, a time measurement unit 17, and a storage unit 18.

  The sampling unit 11 samples the reception signal received by the receiving unit 5 at a predetermined sampling period. In this embodiment, since the sampling frequency is 128 Hz, the sampling period is 1000 msec / 128 = about 7.8 msec.

Second synchronization detection means 12 confirms whether second synchronization has been established by confirming whether the interval between received signals is 1 second.
Specifically, the second synchronization detection means 12 confirms the timing at which the received signal has changed from the second level to the first level by the sampling means 11, and the interval between the change timings is 5 seconds for 1 second. If ± 62.5 msec, it is determined that the second synchronization has been established. Note that 62.5 msec is 8 pulses in 128 Hz sampling. Therefore, when a signal change from the second level to the first level is detected during sampling 120 to 136 times from the previous signal change timing, the interval is 1 second ± 62.5 msec. Can be judged. The reason why ± 62.5 msec (± 8 pulses) is used is that when the 1 second interval is detected, if the error range is about 6%, it can be determined that the interval is about 1 second. The numerical value of ± 62.5 msec may be changed by increasing or decreasing in implementation.

The start timing setting means 13 is for setting the sampling start timing T0 (FIG. 5) of the received signal by the sampling means 11.
Specifically, the start timing setting unit 13 sets the sampling start timing T0 based on the second synchronization timing after the second synchronization is performed on the received signal by the second synchronization detection unit 12. Here, the sampling start timing T0 is set to a predetermined time before the second synchronization timing, specifically, a timing 50 msec before.
For example, it is assumed that signal sampling is started from the second synchronization timing without setting the sampling start timing T0 separately from the second synchronization timing. In this case, if the actual signal level change deviates before the second synchronization timing, the signal sampling starts after the received signal changes from the second level to the first level, and the signal level change timing cannot be detected. There is a fear.
Therefore, by setting the sampling start timing T0 separately from the second synchronization timing, sampling can be started from a timing a predetermined time before the second synchronization timing. For this reason, the change from the second level to the first level of the received signal at the second synchronization timing can be reliably detected.
In the present embodiment, the predetermined time is set to 50 msec. However, the predetermined time is not limited to this. When the received signal changes from the second level to the first level at the second synchronization timing, the change in the signal level is detected. What is necessary is just to set to the time which can be performed, and what is necessary is just to set normally to about 30-60 msec.

The maximum width signal detector 14A detects the maximum width signal having the largest first level signal width among the received signals for one second from the sampling start timing T0.
Specifically, the maximum width signal detection unit 14A detects the first level continuously by the sampling unit 11 from the time when the signal level detected by the sampling unit 11 changes from the second level to the first level. The first level signal having the largest number of times is detected as the maximum width signal.
The determination timing setting unit 14B sets the determination timing TA (FIG. 5) within a period during which the maximum width signal detected by the maximum width signal detection unit 14A is transmitted.
Specifically, the determination timing setting unit 14B sets the timing at the center of the signal width of the maximum width signal as the determination timing TA.
The elapsed time detection unit 14C detects the elapsed time from the sampling start timing T0 to the determination timing TA set by the determination timing setting unit 14B.

Based on the elapsed time detected by the elapsed time detection unit 14C, the code determination unit 15 determines a signal code for one second from the second synchronization timing. That is, the code determination means 15 constitutes the code determination means of the present invention.
Since each code has a different signal width of the received signal depending on the type of the standard radio wave, the determination condition may be set according to the type of the selected standard radio wave.
For example, in the DCF77, in the received signal, if the first level signal width is 100 msec, it represents a binary number “0”, if it is 200 msec, it represents a binary number “1”, otherwise it represents the marker “M”. ". That is, in this embodiment, since the sampling start timing T0 is set 50 msec before the second synchronization timing, if the time from the sampling start timing T0 to the signal center timing is 100 msec (50 msec + 100 msec / 2), “ “0”, “1” if 150 msec (50 msec + 200/2), and “M” otherwise.
For this reason, for example, the code determination unit 15 can determine that the code is “0” if the elapsed time detected by the elapsed time detection unit 14C is 125 msec or less, and can determine that the code is “1” if it is greater than 125 msec. Even if the signal width is reduced because the reception environment is poor and the radio field intensity is weak, even if the 0 signal having the shorter signal width among the 0 signal and the 1 signal is used, the signal width is less than 40 msec. Few. For this reason, if the signal width of the maximum width signal is less than 40 msec, for example, the code determination means 15 can estimate that this signal is due to the influence of noise, and therefore determines the code as “M”.
Moreover, the code determination means 15 acquires a time code (time information) from the determined code. That is, in the standard radio wave, time information is represented by a time code of one cycle and 60 seconds (60 bits), so the code determination means 15 obtains time information by determining a code for 60 bits. The time information acquired by the code determination unit 15 is output to the time correction unit 16.

The time correction means 16 determines whether the time information acquired by the code determination means 15 is the correct time according to one of the following two conditions.
The first condition is to determine whether the received time information matches the time measured by the time measuring means 17.
The second condition is that the received time information is compared with each other, and each time information differs by the reception interval. It is determined whether there are three or more pieces of information. For example, since the time information is transmitted at intervals of 60 seconds, if time information is continuously received for 7 minutes, each time information should have a time different by 1 minute in the order received. Accordingly, it is determined whether or not the reception time information matches each reception time information by adjusting the difference in reception timing.
If any one of the above two conditions is met, the time adjustment unit 16 determines that the correct time information has been acquired and outputs the time information to the time measurement unit 17.

The time measuring means 17 measures the time based on the reference clock (1 Hz) input via the oscillation circuit 6 and the frequency dividing circuit 7 and receives the reception time information from the time adjusting means 16 to receive the time measuring time (internal (Time data) is corrected to reception time information to adjust the time.
The storage unit 18 stores processing data in the control unit 10.

  The time display means 2 displays the time measured by the time measuring means 17. For example, in the case of an analog display timepiece having hands, the motor is controlled to control the hand movement of each hand, and the reception time is indicated. In the case of a digital display timepiece using a liquid crystal panel or the like, the time is displayed using the display device.

[Receiving operation of radio-controlled clock]
Next, the standard radio wave reception processing operation in the radio wave correction timepiece 1 as described above will be described with reference to the flowcharts of FIGS. 3, 4 and 6 and the waveform diagram of FIG.

  The control means 10 of the radio-controlled timepiece 1 operates the receiving means 5 when the regular reception time is reached or when a forced reception operation is performed by operating an external operation member such as a button, and the antenna 4 is turned on. Start receiving standard radio waves. In this embodiment, the DCF 77 is set to be received. However, when a receiving station is selected by operating a button or the like, the receiving station is switched using a tuning circuit or the like.

As shown in FIG. 3, the sampling unit 11 samples the reception signal output from the reception unit 5 at a frequency of 128 Hz (S1).
In the present embodiment, the receiving means 5 outputs a signal that changes from the second level (low level) to the first level (high level) in synchronization with the second signal.
In this case, the sampling means 11 samples the received signal for 1 second at 128 Hz. For this reason, when the pulse width of the first level signal is 0.1 second, the width is 12 pulses.

Next, the second synchronization detection means 12 executes second synchronization processing (S2). Here, the second synchronization process counts the number of times that the reception signal interval is 1 second ± 62.5 msec as described above.
Then, the second synchronization detection means 12 determines that the second synchronization is completed (YES in S3) when it is detected five times in succession (second synchronization condition) that is 1 second ± 62.5 msec.
For example, when the output signal (received signal) of the receiving means 5 rises every second, the rise of the pulse is detected by a change in the signal level at the time of sampling, and the change interval is 1 second ± 62.5 msec. In this case, it is determined that the second synchronization condition is met. Specifically, the sampling number from the time when the signal level is changed from the second level to the first level at the time of sampling until the time when the signal level is changed from the second level to the first level is counted. Is in the range of 120 to 136, it is determined that the second synchronization condition is satisfied.

When determining that the second synchronization has not been completed (NO in S3), the second synchronization detection unit 12 determines whether a predetermined time (specifically, 4 minutes) has elapsed from the start of reception (S4).
If the answer is No in S4, that is, if 4 minutes have not elapsed, the second synchronization detection means 12 returns to the process of S2 and executes the second synchronization process.
On the other hand, if YES in S4, that is, if the second synchronization has not been completed and 4 minutes have elapsed, it is possible that the standard radio wave has not been received or the radio wave intensity is weak even though it has been received. The means 10 turns off the receiving means 5 and ends the receiving process. The predetermined time is not limited to 4 minutes. However, if the time is too short, the probability of failure in second synchronization increases. On the other hand, if the time is too long, power is consumed wastefully, and is preferably about 4 to 6 minutes.

  When the second synchronization is completed and it is determined Yes in S3, the start timing setting means 13 sets the timing 50 msec before (predetermined time) from the second synchronization timing as the sampling start timing T0. As described above, the sampling start timing T0 is not limited to 50 msec before the second synchronization timing.

Next, the elapsed time detection process S6 is executed by the maximum width signal detection unit 14A, the determination timing setting unit 14B, and the elapsed time detection unit 14C.
The details of the elapsed time detection process S6 will be described based on the flowchart of FIG. 4 and the waveform diagram of the received signal of FIG. The waveform diagram of FIG. 5 shows a state in which the received signal includes a first level signal P2 that is a 0 signal representing “0” and first level signals P1, P3 to P5 that are noise pulses. .
The maximum width signal detection unit 14A initializes the maximum continuous count stored in the storage unit 18 to “0” (S21), and then initializes the continuous count stored in the storage unit 18 to “0”. (S22).
Further, the maximum width signal detection unit 14A determines whether the sampling of the reception signal by the sampling unit 11 has been performed for one second from the sampling start timing T0 determined in S5 (S23).

That is, when the elapsed time detection process S6 is started, NO is determined in S23. When it is determined NO in S23, the sampling unit 11 samples the received signal once (S24).
Further, the maximum width signal detection unit 14A determines whether the signal level detected in S24 is the first level (S25).

As shown in FIG. 5, since the signal level of the received signal is the second level from the sampling start timing T0 to before the signal start time T1 of the first level signal P1, NO is determined in S25. If NO is determined in S25, the maximum width signal detecting unit 14A determines whether the signal level detected in the previous sampling is the first level, that is, the second level signal detected in S24 this time. Determines whether it is the one at the time of changing from the first level to the second level (S29).
In FIG. 5, since the second level signal continues from the sampling start timing T0 to before the signal start time T1, NO is determined in S29. When it is determined NO in S29, the maximum width signal detection unit 14A returns the process to S22. For this reason, the processes of S22 to S25 and S29 are repeatedly executed until the signal start time T1.

When the signal level of the received signal changes from the second level to the first level at the signal start time T1, YES is determined in S25. When it is determined YES in S25, the maximum width signal detection unit 14A adds 1 to the continuous count stored in the storage unit 18 (S26). That is, measurement of the signal width of the first level signal P1 is started.
Further, the maximum width signal detection means 14A determines whether the signal level detected in the previous sampling is the second level, that is, the first level signal detected in S24 this time is from the second level to the second level. It is determined whether it is the one at the time when the level is changed to 1 level (S27).
In FIG. 5, the signal immediately before the signal start time T1 is the second level signal, and has changed to the first level at the time of the signal start time T1, so that the sampling immediately after the change to the first level is YES in S27. To be judged.

Immediately after the signal level of the received signal changes from the second level to the first level at the signal start time T1, YES is determined in S27. If YES is determined in S27, the maximum width signal detecting unit 14A detects the time from the sampling start timing T0 to the timing at which the received signal is sampled in S24. Then, the maximum width signal detection unit 14A updates the signal start time described in the storage unit 18 with the detected time (S28), and returns the process to S23.
After that, until the signal end time T11 of the first level signal P1, the signal level detected in S24 is the first level, so that it is determined YES in S25. Further, since the signal level detected immediately before is the first level, NO is determined in S27. When it is determined NO in S27, the maximum width signal detecting unit 14A returns the process to S23.
Therefore, the processes of S23 to S27 are repeatedly executed during the period from the signal start time T1 to the signal end time T11. As a result, the continuous count stored in the storage means 18 becomes a count corresponding to the signal width of the first level signal P1.

Next, when the signal level of the received signal changes from the first level to the second level at the signal end time T11, NO is determined in S25, and YES is further determined in S29. When it is determined YES in S29, the maximum width signal detection unit 14A determines whether the continuous count stored in the storage unit 18 is larger than the maximum continuous count stored in the storage unit 18 (S30).
Since the maximum continuous count is “0” for the first time, YES is determined in S30. If YES is determined in S30, the maximum width signal detecting unit 14A updates the maximum continuous count stored in the storage unit 18 with the continuous count stored in the storage unit 18 (S31).
Further, the maximum width signal detection unit 14A updates the maximum width signal start time stored in the storage unit 18 with the signal start time stored in the storage unit 18 (S32), and returns the process to S22.
Since the second level signal continues from the signal end time T11 to the signal start time T2, NO is determined in S25 and S29, respectively. For this reason, the maximum width signal detection unit 14A repeatedly executes the processes of S22 to S25 and S29.

When the signal level of the received signal changes from the second level to the first level at the signal start time T2 of the first level signal to be transmitted next, YES is determined in S25 and S27 immediately after that, and S23 to S28. The process is executed. Thereafter, while the first level signal continues, it is determined as YES in S25 and NO in S27, so that the processes of S23 to S27 are repeatedly executed. When the signal level of the received signal changes from the first level to the second level, NO is determined in S25, and the processes of S29 and S30 are executed.
Here, if the continuous count stored in the storage means 18 is larger than the maximum continuous count stored in the storage means 18 (YES in S30), the process returns to S22 after executing S31 and S32.
On the other hand, when the continuous count stored in the storage unit 18 is equal to or less than the maximum continuous count stored in the storage unit 18 (NO in S30), the process returns to S22.
These processes are performed each time the signal level of the received signal changes from the second level to the first level (until determined to be YES in S23) until 1 second has elapsed from the sampling start timing T0 (the signal of the first level signal). Repeated every start time).
As a result, the maximum continuous count stored in the storage means 18 is the continuous count of the maximum width signal having the largest first level signal width among the received signals for one second from the sampling start timing T0. Furthermore, the maximum width signal start time stored in the storage means 18 is the signal start time of the maximum width signal. In the example of FIG. 5, the maximum continuous count is the continuous count of the first level signal P2 having the largest signal width, and the maximum width signal start time is the signal start time T2 of the first level signal P2.
Thereby, the transmission period of the maximum width signal can be specified based on the maximum width signal start time and the maximum continuous count stored in the storage unit 18.

When one second has elapsed from the sampling start timing T0, YES is determined in S23. If YES is determined in S23, the determination timing setting unit 14B sets the timing at the center of the signal width of the maximum width signal as the determination timing TA (S33).
Furthermore, the elapsed time detection unit 14C detects the elapsed time from the sampling start timing T0 to the determination timing TA (S34), and ends the process.
Specifically, the elapsed time detection unit 14C divides the time obtained by multiplying the maximum continuous count stored in the storage unit 18 by the sampling period by two. Then, the elapsed time detection unit 14C adds the time to the maximum width signal start time stored in the storage unit 18 to detect the elapsed time.
If the received signal is an M signal and no noise pulse exists, the received signal does not include the first level signal at all. In this case, after the processes of S22 to S25 and S29 are repeatedly executed for one second and when it is determined YES in S23, the process ends without setting the determination timing TA.

Returning to FIG. 3, when the elapsed time detection process S <b> 6 is finished, the code determination unit 15 next executes the code determination process S <b> 7.
Details of the code determination processing S7 will be described based on the flowchart of FIG.
The code determination means 15 determines whether or not the longest first level signal width (maximum signal width) of received signals for one second is less than 40 msec (signal width threshold) (S41). Specifically, the code determination unit 15 determines whether the time obtained by multiplying the maximum continuous count stored in the storage unit 18 by the sampling period is less than 40 msec (signal width threshold).
Here, in the case of DCF77, the signal width of the first level of the received signal representing binary numbers “0” and “1” is usually less than 40 msec even when the radio wave intensity of the standard radio wave is weak. The nature is low.
For this reason, when the maximum signal width is less than 40 msec (YES in S41), it can be determined that the received signal is a signal representing the marker “M” instead of “0” and “1”. That is, the code determination unit 15 determines the code as “M” (S45).

  On the other hand, if it is determined NO in S41, the code determination unit 15 determines whether the elapsed time detected in S34 is equal to or less than 125 msec (elapsed time threshold) (S42). If YES in S42, the code determining means 15 determines that the code is “0” (S43). In the case of NO in S42, the code determination unit 15 determines that the code is “1” (S44).

Returning to FIG. 3, when the code determination process S7 is completed, the code determination unit 15 stores the code value (any one of “0, 1, M”) determined in the code determination process S7 in the storage unit 18 (S8). ).
Next, the code determination means 15 confirms whether codes for 60 bits, that is, one time code are stored (S9). When it is determined NO in S9, the code determination unit 15 returns the process to S6, and executes the processes of S6 to S8 on the reception signal for the next one second.
If YES is determined in S <b> 9, the code determination unit 15 decodes the acquired 60-bit time code to acquire time information, and outputs the time information to the time correction unit 16. Further, the time correction means 16 determines whether the time data match (S10).
Here, the determination as to whether the time data matches is based on whether one of the two conditions described above is met.

If YES is determined in S10, it means that the correct time information has been acquired. Therefore, the time adjusting means 16 outputs the acquired time information to the time measuring means 17, and the time measuring means 17 uses the time information to indicate the internal time. It corrects (S11). For this reason, the time displayed by the time display means 2 is also updated to the reception time. Thereafter, the control means 10 ends the reception process.
On the other hand, when it is determined NO in S10, the control means 10 confirms whether 8 minutes have elapsed since the start of reception (S12).
And when 8 minutes has not passed, the control means 10 repeats from the process of S6. On the other hand, when 8 minutes have passed, the control means 10 ends the reception process.
If the correct time information cannot be received even after 8 minutes from the start of reception, it is predicted that the radio wave intensity is weak or the radio wave cannot be received. Since only power is consumed wastefully, the processing is terminated.
Therefore, when the determination is YES in S12 and the reception is terminated, the time adjustment unit 16 does not output the reception time to the time measurement unit 17, and the time measurement unit 17 does not correct the time measurement.

Here, the state of code determination according to the present embodiment for each received signal will be described with reference to FIGS.
FIG. 7 shows waveforms in each state when the received signal is one signal.
In the case of an ideal waveform, as shown in FIG. 7 (state A), the signal width of one signal is 200 msec (denoted as ms in the figure), and the determination timing TA (the center of the signal width) of the maximum width signal from the sampling start timing T0. The elapsed time until (timing) is 150 msec. Since this is longer than the elapsed time threshold value of 125 msec, the code is correctly determined as “1”.
Next, a case where the signal width of one signal is reduced to, for example, half and becomes 100 msec will be described. In this case, since the method of simply comparing the signal width with the threshold value cannot be distinguished from the signal width of the 0 signal, the code is erroneously determined as “0”.
On the other hand, in the present embodiment, when the signal width decreases almost evenly on both sides (front and rear) due to the characteristics of the circuit of the receiving means 5, the elapsed time as shown in FIG. 7 (state B). Is 150 msec and longer than 125 msec, so the code is correctly determined as “1”. If the signal width decreases only on the front side due to the circuit characteristics of the receiving means 5, the elapsed time is 200 msec and longer than 125 msec, as shown in FIG. 7 (state C), so the code is “1”. Is correctly determined.

FIG. 8 shows waveforms in each state when the received signal is a zero signal.
In the case of an ideal waveform, as shown in FIG. 8 (state D), the signal width of the 0 signal is 100 msec, and the elapsed time from the sampling start timing T0 to the determination timing TA of the maximum width signal (timing at the center of the signal width). Is 100 msec. Since this is 125 msec or less, which is the elapsed time threshold, the code is correctly determined as “0”.
Next, a case where the signal width of the 0 signal is reduced to, for example, half and becomes 50 msec will be described. When the signal width decreases almost evenly on both sides due to the characteristics of the circuit of the receiving means 5, the elapsed time is 100 msec, which is 125 msec or less, as shown in FIG. “0” is correctly determined. If the signal width decreases only on the front side due to the circuit characteristics of the receiving means 5, the elapsed time is 125 msec, which is 125 msec or less, as shown in FIG. 8 (state F). Is correctly determined.
Next, due to the influence of noise, for example, as shown in FIG. 8 (state G), the received signal includes a first level signal P2 that is a 0 signal and first level signals P1, P3 to P5 that are noise pulses. Even if included, since the elapsed time is 100 msec and is 125 msec or less, the code is correctly determined as “0”.

According to this embodiment, there are the following effects.
In the present embodiment, the maximum width signal having the largest signal width of the first level is detected in the received signal for one second from the sampling start timing T0 by the elapsed time detection process S6. Further, the timing at the center of the signal width of the maximum width signal is set as the determination timing TA, and the elapsed time from the sampling start timing T0 to the determination timing TA is detected. Then, in the code determination process S7, the code of the signal for one second is determined based on the detected elapsed time.
Here, when there are a plurality of first level signals in the received signal for one second from the sampling start timing T0, the signal width of the first level signal due to the influence of noise is usually compared with the signal width of a normal signal. (See, for example, state G in FIG. 8). For this reason, the timing at which a normal signal is transmitted can be detected by detecting the maximum width signal. Therefore, if the timing of the center of the signal width of the maximum width signal is set to the determination timing TA, the determination timing TA is usually set to a different timing due to the difference in the bit values (codes), that is, the first level signal width. . Therefore, if the elapsed time from the sampling start timing T0 to the determination timing TA is detected, the code can be correctly determined based on the elapsed time, and the time information can be acquired correctly.

In the present embodiment, the code is determined based on the elapsed time from the sampling start timing T0 to the determination timing TA, not the signal width of the maximum width signal. For example, the reception environment is poor and the radio wave intensity is weak. Even when the signal width of the received signal changes, the code can be correctly determined.
For example, in the DCF77, when the signal width of one signal representing binary “1” in the received signal is reduced from the original 200 msec to 100 msec or less, the code is determined by the method of performing the code determination based on the signal width. A binary number “0” is erroneously determined.
However, in the present embodiment, the determination is not based on the signal width but based on the elapsed time from the sampling start timing T0 to the determination timing TA. Then, the determination timing TA of one signal at which the signal width decreases to 100 msec (for example, TA in states B and C in FIG. 7) and the determination timing TA of 0 signal at 100 msec in which the signal width does not increase or decrease (for example, FIG. In many cases, the elapsed time is different from that of TA in state D in FIG. 8, and the elapsed time is also different. By performing code determination based on the elapsed time, a 1-signal code with a reduced signal width is converted to 0 signal. The possibility of being able to make a correct determination in distinction from the code increases, and the erroneous determination of code can be reduced.

When the reception environment is poor and the radio field intensity is weak, the signal width of the received signal may increase or decrease on both sides (front and rear) due to the characteristics of the circuit of the receiving means 5. In this case, the timing at the center of the signal width is unlikely to fluctuate even if the signal width increases or decreases.
In this embodiment, since the timing of the center of the signal width of the maximum width signal is set to the determination timing TA, when the receiving unit 5 has the above characteristics, the elapsed time from the sampling start timing T0 to the determination timing TA is It becomes difficult to fluctuate by increasing or decreasing the signal width on both sides. Thereby, even when the signal width increases or decreases, the code can be determined more correctly.

By the elapsed time detection process S6, the maximum width signal detection unit 14A detects the first level continuously by the sampling unit 11 from the time when the signal level detected by the sampling unit 11 changes from the second level to the first level. The signal with the largest number of times is detected as the maximum width signal.
According to this, since the maximum width signal can be detected by counting the number of times the first level is detected by the sampling unit 11, the maximum width signal can be detected with easy processing.

By S5, the start timing setting means 13 sets the timing before the predetermined time of the second synchronization timing as the start timing, and the predetermined time is determined when the received signal changes from the second level to the first level at the second synchronization timing. It is set to a time when a change in signal level can be detected.
Here, the predetermined time may be set in consideration of variations in signal level change timing at intervals of 1 second. For example, the time may be set to the same time as the determination condition set in the second synchronization processing S2 for detecting the second synchronization timing. Specifically, the predetermined time may be set to about 30 to 60 msec.
According to the present invention, even when the timing at which the received signal changes from the second level to the first level with respect to the second synchronization timing, there is a low possibility that the received signal will shift more than the predetermined time. The change from the second level to the first level can be reliably detected. That is, the maximum width signal can be correctly detected by the elapsed time detection process S6.

By the code determination processing S7, the code determination unit 15 determines that the code is the marker “M” when the signal width of the maximum width signal is less than the signal width threshold, and the signal width of the maximum width signal is equal to or larger than the signal width threshold. Compares the elapsed time detected by the elapsed time detection means 14C with an elapsed time threshold value, and determines that the code is binary “0” or “1”.
Even if the signal width decreases because the reception environment is poor and the radio field strength is weak, there is a lower limit. In the DCF 77, the signal width of the 0 signal and the 1 signal is rarely less than 40 msec, for example, and it can be determined that the signal less than 40 msec is a noise signal. For this reason, in the DCF 77, the signal width threshold is set to 40 msec, for example, and the code is determined to be “M” when the signal width of the maximum width signal is less than the signal width threshold. That is, when the signal width of the maximum width signal is greater than 0 msec and less than 40 msec, the signal is determined as a noise signal. If the signal width of the maximum width signal is 0 msec, it is determined that there is no first level signal input. In these cases, the code can be determined as “M”. On the other hand, when the signal width of the maximum width signal is equal to or larger than the signal width threshold, the elapsed time detected by the elapsed time detection unit 14C is compared with the elapsed time threshold (for example, 125 msec), and the code is set to “0” or “1”. judge. As a result, when the standard radio wave of DCF 77 is received, the code of “0, 1, M” can be correctly determined.

[Second Embodiment]
Next, 2nd Embodiment of this invention is described based on drawing.
In the first embodiment, the determination timing setting unit 14B sets the timing at the center of the signal width of the maximum width signal as the determination timing TA. However, in the second embodiment, the determination timing setting unit 14B includes the maximum width signal. Is set to the determination timing TB (the timing at which the signal level changes from the first level to the second level).
That is, in the second embodiment, the determination timing setting unit 14B sets the end timing of the maximum width signal as the determination timing TB in S33 in the flowchart of FIG.
In the first embodiment, in order to determine “0” or “1” in the code determination unit 15, the elapsed time threshold value compared with the elapsed time detected by the elapsed time detection unit 14C is set to 125 msec. However, in the second embodiment, the elapsed time threshold is set to 180 msec.
Other processes in the second embodiment are the same as those in the first embodiment.

Here, the state of code determination according to the present embodiment for each received signal will be described with reference to FIGS.
FIG. 9 shows waveforms in each state when the received signal is one signal.
In the case of an ideal waveform, as shown in FIG. 9 (state H), the signal width of one signal is 200 msec, and the elapsed time from the sampling start timing T0 to the maximum width signal determination timing TB (signal end timing) is 250 msec. Since this is longer than the elapsed time threshold value of 180 msec, the code is correctly determined as “1”.
Next, a case where the signal width of one signal is reduced to, for example, half and becomes 100 msec will be described. In this case, since the method of simply comparing the signal width with the threshold value cannot be distinguished from the signal width of the 0 signal, the code is erroneously determined as “0”.
On the other hand, in the present embodiment, when the signal width decreases almost evenly on both sides (front and rear) due to the characteristics of the circuit of the receiving means 5, the elapsed time as shown in (state I) of FIG. Is 200 msec and longer than 180 msec, so the code is correctly determined as “1”. Further, when the signal width decreases only on the front side due to the characteristics of the circuit of the receiving means 5, the elapsed time is 250 msec and longer than 180 msec as shown in FIG. 9 (state J), so the code is “1”. Is correctly determined.

FIG. 10 shows waveforms in each state when the received signal is a zero signal.
In the case of an ideal waveform, as shown in FIG. 10 (state K), the signal width of the 0 signal is 100 msec, and the elapsed time from the sampling start timing T0 to the determination timing TB of the maximum width signal (signal end timing) is 150 msec. It becomes. Since this is 180 msec or less which is the elapsed time threshold, the code is correctly determined as “0”.
Next, a case where the signal width of the 0 signal is reduced to, for example, half and becomes 50 msec will be described. When the signal width decreases almost evenly on both sides due to the characteristics of the circuit of the receiving means 5, the elapsed time is 125 msec and 180 msec or less as shown in FIG. 10 (state L). “0” is correctly determined. If the signal width decreases only on the front side due to the characteristics of the circuit of the receiving means 5, the elapsed time is 150 msec and 180 msec or less as shown in FIG. 10 (state M). Is correctly determined.
Next, due to the influence of noise, for example, as shown in FIG. 10 (state N), the received signal includes a first level signal P2 that is a 0 signal and first level signals P1, P3 to P5 that are noise pulses. Even if included, since the elapsed time is 150 msec and 180 msec or less, the code is correctly determined as “0”.

According to such 2nd Embodiment, in addition to the effect of 1st Embodiment, the following effect can also be acquired.
When the reception environment is poor and the radio field intensity is weak, the signal width of the reception signal may decrease mainly on the front side due to the characteristics of the circuit of the reception unit 5. In this case, the signal end timing hardly changes even if the front side of the signal width increases or decreases.
In the present embodiment, since the end timing of the maximum width signal is set to the determination timing TB, when the receiving unit 5 has the above characteristics, the elapsed time from the sampling start timing T0 to the determination timing TB is the front side of the signal width. It becomes hard to fluctuate by increase / decrease. Thereby, even when the signal width increases or decreases, the code can be determined more correctly.

[Modification]
Note that the present invention is not limited to the above-described embodiments, and modifications, improvements, and the like within the scope that can achieve the object of the present invention are included in the present invention.
For example, in the first embodiment, the determination timing setting unit 14B sets the timing at the center of the signal width of the maximum width signal to the determination timing TA. In the second embodiment, the determination timing setting unit 14B The signal end timing is set to the determination timing TB. However, if the code determination unit 15 can correctly determine the codes “0” and “1” based on the set determination timing, the timing different from the above two timings is determined within the period during which the maximum width signal is transmitted. The timing may be set.
That is, the increase / decrease pattern of the signal width of the received signal due to the circuit characteristics of the receiving means 5 may be detected by a reception test or the like, and the determination timing may be assumed according to the increase / decrease pattern.

  In S23 of the elapsed time detection process S6 of the embodiment, the maximum width signal detection unit 14A determines whether the sampling of the reception signal by the sampling unit 11 has been performed for 1 second from the sampling start timing T0. However, if all transmission periods of signals representing the respective bit values are included, the one second may be set as a shorter predetermined period. For example, in DCF77, the signal width of the signal representing “0” is 100 msec, and the signal width of the signal representing “1” is 200 msec. Therefore, the signal representing “1” having the longest signal width is used in the predetermined period. For example, it may be set to 400 msec so that the end timing is included. In JJY, the signal width of the signal representing “0” is 800 msec, the signal width of the signal representing “1” is 500 msec, and the signal width of the signal representing “M” is 200 msec. For example, the period may be set to 900 msec so that the end timing of the signal representing “0” having the longest signal width is included.

The determination procedure of the code determination process S7 of the above embodiment shows an example in the DCF 77, and can be set as appropriate according to the determination condition according to the type of the standard radio wave and the circuit characteristics of the receiving means 5.
For example, in Japanese standard radio wave JJY, the signal width representing “0” is 800 msec, the signal width representing “1” is 500 msec, and signals representing markers (“M” and “P0” to “P5”) The width is 200 msec.
Therefore, each code can be determined by the following method. That is, a first elapsed time threshold value is set based on an intermediate width (350 msec) between a signal width representing a marker and a signal width representing “1”, and a pulse width representing “1” and a pulse representing “0”. The second elapsed time threshold value is set based on an intermediate width (650 msec). For example, when the sampling start timing T0 is set 50 msec before the second synchronization timing, the first elapsed time threshold is 400 msec and the second elapsed time threshold is 700 msec.
If the elapsed time detected by the elapsed time detection unit 14C is less than the first elapsed time threshold, the code is determined to be a marker. If the elapsed time is greater than or equal to the first elapsed time threshold and less than the second elapsed time threshold, the code is determined to be “1”. If the elapsed time is equal to or greater than the second elapsed time threshold, the code is determined to be “0”. Thereby, each code can be correctly determined.

  DESCRIPTION OF SYMBOLS 1 ... Radio wave correction clock, 5 ... Reception means, 11 ... Sampling means, 13 ... Start timing setting means, 14A ... Maximum width signal detection means, 14B ... Determination timing setting means, 14C ... Elapsed time detection means, 15 ... Code determination means .

Claims (8)

It receives standard radio waves including time information, receiving means for outputting a received signal that will change to a different second level to the first level and said first level,
Based on the second synchronization timing is filter timing to change to the first level said received signal from said second level, a start timing setting means for setting a sampling start timing,
A maximum width signal detecting means for detecting a maximum width signal having the largest signal width of the first level among the received signals in a predetermined period from the sampling start timing;
Determination timing setting means for setting a determination timing within a period during which the maximum width signal is transmitted;
An elapsed time detecting means for detecting an elapsed time from the sampling start timing to the determination timing;
Timepiece, characterized in that on the basis of the elapsed time during which the elapsed time detected by the detecting means comprises a determining code judging means code, a. The radio-controlled timepiece according to claim 1,
The determination timing setting means sets the timing at the center of the signal width of the maximum width signal as the determination timing. The radio-controlled timepiece according to claim 1,
The radio wave correction timepiece, wherein the determination timing setting means sets an end timing of the maximum width signal to the determination timing. The radio-controlled timepiece according to any one of claims 1 to 3,
Sampling means for sampling the received signal at a predetermined sampling period to obtain a signal level at each sampling,
The maximum width signal detecting means includes
From the time when the signal level detected by the sampling means changes from the second level to the first level, a signal having the largest number of times the first level is detected continuously by the sampling means is set to the maximum width. A radio-controlled watch that is detected as a signal. The radio-controlled timepiece according to any one of claims 1 to 4,
The start timing setting means sets a timing before a predetermined time of the second synchronization timing as the sampling start timing,
The predetermined time is set to a time during which a change in the signal level can be detected when the received signal changes from the second level to the first level at the second synchronization timing. The radio-controlled timepiece according to any one of claims 1 to 5,
The code determination means includes
If the signal width of the maximum width signal is less than the signal width threshold, determine the code as a marker,
When the signal width of the maximum width signal is equal to or greater than the signal width threshold, the elapsed time detected by the elapsed time detecting means is compared with the elapsed time threshold, and the code is expressed as a binary number “0” or “1”. A radio-controlled clock characterized by judging. The radio-controlled timepiece according to any one of claims 1 to 5,
The code determination means has a second elapsed time detected by the elapsed time detection means that is less than a first elapsed time threshold or a value greater than or equal to the first elapsed time threshold and greater than the first elapsed time threshold. A radio wave correction characterized by determining whether the code is a binary number “0”, “1” or a marker by determining whether it is less than an elapsed time threshold or greater than or equal to the second elapsed time threshold clock. It receives standard radio waves including time information, the first level and said first level to a radio-corrected code judging method of the timepiece having a reception means for outputting a received signal that will change to a different second level,
Based on the second synchronization timing is changed to filter timing from the received signal the second level to the first level, a start timing setting step of setting a sampling start timing,
A maximum width signal detecting step of detecting a maximum width signal having the largest signal width of the first level among the received signals in a predetermined period from the sampling start timing;
A determination timing setting step for setting a determination timing within a period during which the maximum width signal is transmitted;
An elapsed time detecting step for detecting an elapsed time from the sampling start timing to the determination timing;
Based on the elapsed time detected by the elapsed time detecting step, radio correction code judging method of the timepiece, characterized in that it comprises a code determining step of determining the code, the.

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