JP2011214871A - Time receiver, radio controlled timepiece and method for controlling time receiver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a time receiver which reduces incorrect determination of code data even when a demodulation waveform is disturbed by noise or the like.SOLUTION: A radio controlled timepiece 1 is equipped with: a receiving means 5; a signal level change determining means 13 which determines a change in a signal level of a received signal; a code determining means which determines transmitted code data, based on the result of determination of the signal level change determining means 13; and a time information acquiring means which acquires time information, based on the code data determined by the code determining means. The signal level change determining means 13 determines that the signal level changes when a prescribed time elapses from the point of time when the received signal changes from a first level to a second level after the second synchronization timing. The code determining means measures an elapsed time from the second synchronization timing to the point of time when the signal level is determined to have changed by the signal level change determining means 13, and determines the code data of the signal for one second of the elapsed time, according to the length of this time.

Description

  The present invention relates to a time receiving device, a radio-controlled timepiece, and a control method for the time receiving device.

  In recent years, radio-controlled timepieces that receive radio waves (long wave standard radio waves) including time information and automatically correct and display the time based on the time information have been used. In particular, conventional radio-controlled timepieces have mainly been clocks (table clocks and wall clocks), but in recent years, they have also been incorporated into portable watches (watches and the like).

As such a radio-controlled timepiece, there is disclosed a time receiving device that generates a time code signal by sampling a received signal at a predetermined sampling period (Patent Document 1).
The time receiving apparatus of Patent Document 1 detects a change point that changes last in a period divided every second of a time code signal, and changes the time code signal according to the time from the start of the period to the change point. The code of “P, 1, 0” is determined to reduce the influence of noise. For example, as shown in the second period T2 (t2 to t3) of FIG. 5 of Patent Document 1, when the time code signal falls at two points of time t21 and t23, the falling of the time t21 is ignored, and finally Based on the falling time t23, the code code indicated by the time code signal in the second period T2 is determined.

JP 2007-139705 A

However, even with the coding determination method described in Patent Document 1, there are cases where the influence of noise cannot be completely removed when the reception environment is poor. For example, when the last signal level change in the second period occurs due to the influence of noise, in the determination method of Patent Document 1, what is originally determined as “1” can be determined as “0”. There is also sex.
For this reason, there has been a problem that time information may not be received correctly. In particular, the German standard radio wave “DCF77” represents a binary number “0” if the carrier wave amplitude is reduced by 25% for 0.1 seconds, and a binary number “1” for 0.2 seconds. Represents. Thus, when the difference in pulse duty of each code data (bit data) is small, there is a problem that erroneous determination is likely to occur in the determination method of Patent Document 1.
In addition, when the code data is erroneously determined, the reception process must be performed again, and the time until the reception process is completed becomes long, and there is a problem that a large amount of power is consumed.

  An object of the present invention is to provide a time receiving device, a radio-controlled timepiece, and a time receiving device control method capable of reducing erroneous determination of code data even when a demodulated waveform is disturbed by noise or the like.

  The time receiving apparatus of the present invention includes a receiving unit that receives a standard radio wave including time information and outputs a received signal, a signal level change determining unit that determines a change in the signal level of the received signal, and the signal level change determination Code receiving means for determining transmitted code data based on the determination result of the means; and time information acquiring means for acquiring time information based on the code data determined by the code determining means, and The signal changes from the first level to the second level different from the first level, and from the second level to the first level at the second synchronization timing repeated at intervals of one second, before the next second synchronization timing. The signal level change determining means is configured to change the received signal from the first level to the second level after the second synchronization timing. The code determination means determines that the signal level has changed when a predetermined time has elapsed from the time of change to the bell, and does not determine the signal level change until the next second synchronization timing after this determination. Measures the elapsed time from the second synchronization timing to the time when the signal level change determining means determines that the signal level has changed, and determines the code data of the signal for that second by the length of this elapsed time. It is characterized by doing.

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, the first level may be the Hi level or the Low level.
The received signal changes from the second level to the first level (from Hi level to Low level, or from Low level to Hi level) at the second synchronization timing repeated at intervals of one second, and before the next second synchronization timing. The first level is changed to the second level (Low level to Hi level, or Hi level to Low level).
For example, in JJY, a time code in which one period (one cycle) is 60 seconds (60 bits) is repeatedly transmitted. The pulse width of the first level of each bit in the received signal is usually set according to three types of data “1”, “0”, and “M (P0 to P5)”. For example, in the case of JJY, if the first level pulse width is 0.5 seconds, the binary number “1” is represented. If the first level pulse width is 0.8 seconds, the binary number “1” is represented. “0”. Further, if the pulse width of the first level is 0.2 seconds, the marker (M) and the position markers (P0 to P5) are represented.

The signal level change determining means determines that the signal level has changed when a predetermined time has elapsed from the time when the received signal has changed from the first level to the second level after the second synchronization timing. The signal level change is not determined until the next second synchronization timing.
For this reason, even if the received signal changes from the first level to the second level, if the signal returns to the first level before the predetermined time elapses, the signal level temporarily changes due to the influence of noise. Judgment does not determine that the signal level has changed. Also, after determining that the signal level has changed, the signal level change determination is not performed until the next second synchronization timing. Therefore, even if the signal level change occurs due to noise after the signal level change determination, Does not affect the level change judgment.
On the other hand, when the reception signal changes from the first level to the second level and the predetermined time has elapsed, it is determined that the signal level is changed due to the signal level change of the transmission signal itself.
Therefore, the change from the first level to the second level in the received signal can be accurately detected without being affected by noise.

  Since the code determination means measures the elapsed time from the second synchronization timing to the time when the signal level change determination means determines that the signal level has changed, the received signal is changed from the first level to the second level. When it is confirmed that the level has been changed reliably, the length of the first level can be detected, and the code data can be correctly determined. Therefore, correct time information can be calculated based on the code data.

The predetermined time may be set according to the type of standard radio wave to be received. That is, in order not to detect a temporary signal change due to noise, the predetermined time should be as long as possible.
On the other hand, the code determination means determines the code data based on the time until the predetermined time elapses. Here, when the predetermined time becomes longer, the difference between the time during which the first level is actually continued and the time during which the first level is determined to be continued by the signal level change determination means increases.
For example, in the German standard radio wave DCF77, if the first level pulse width is 0.1 second, it represents binary “0”, and if it is 0.2 second, it represents binary “1”. Further, when the second level signal is output for one second without changing to the first level at the second synchronization timing, the marker “M” is indicated. As described above, when the difference between the pulse widths of the code data “0” and “1” (the width of the first level in the received signal) is as small as 0.1 seconds, the possibility of erroneous recognition of the code data increases. .
On the other hand, in JJY, which is the Japanese standard radio wave, the pulse width of each code data of “0”, “1”, “M” is 0.8 seconds, 0.5 seconds, 0.2 seconds as described above. Since the difference between the pulse widths is relatively large at 0.3 seconds, the code data can be correctly determined even if the predetermined time is somewhat longer.
Therefore, the predetermined time may be set according to the type of standard radio wave to be received. In one example, the predetermined time may be set to about 20 to 30 msec. This is because if it is less than 20 msec, the possibility of detecting a change due to noise increases, and if it is greater than 30 msec, the possibility of erroneous determination of code data by the DCF 77 or the like increases.

  The time receiving apparatus of the present invention comprises sampling means for sampling the received signal at a predetermined sampling period to obtain a signal level at each sampling, and the signal level change determining means is the signal acquired by the sampling means. When the level is changed from the first level to the second level, when the signal of the second level is continuously detected for a predetermined sampling number or more, it is determined that the signal level has changed, and the code determination means The number of samplings from the second synchronization timing to the time when the signal level change determining means determines that the signal level has changed is counted, and from the time when the signal level is determined to change to the next second synchronization timing During that time, the count of the sampling number is stopped, and depending on the count number of the sampling, for 1 second It is preferred to determine the signal code data.

The present invention includes sampling means for sampling the received signal. The sampling period may be set to, for example, a sampling period of about 128 Hz so that the change in the signal level of the received signal can be detected without much delay.
Then, the signal level change determination means continuously measures the predetermined time from the time point when the first level is changed to the second level, continuously from the time point of the change by a predetermined number of times of sampling, for example, three times of sampling. Is detected, it can be determined that the second level has continued for the predetermined time. For example, if one second is sampled at 128 Hz, the time for three samplings is 1000 × 3/128 = about 23.4 msec. Therefore, it is included in the range of 20 to 30 msec.
The code determination means determines the code data based on the number of samplings from the second synchronization timing to the time when the signal level change is determined.
As described above, since each measurement time is measured by counting the number of times of sampling, the process of measuring the time can be easily performed.

  The radio-controlled timepiece of the present invention includes the time receiving device, time correcting means for correcting internal time data based on the time information acquired by the time receiving device, and a time display for indicating the time based on the internal time data. Means.

  According to such a radio-controlled timepiece, since the time receiving device is provided, the probability of successful reception can be increased even in a reception environment including noise. Accordingly, correct time data can be received, the instruction of the time display means can be corrected to the correct time based on the received time data, and a highly accurate time instruction can be performed.

The present invention relates to a method for controlling a time receiving device including receiving means for receiving a standard radio wave including time information and outputting a received signal, wherein the received signal is a second level different from the first level and the first level. Change from the second level to the first level at the second synchronization timing repeated at intervals of one second, and change from the first level to the second level before the next second synchronization timing, After the second synchronization timing, it is determined that the signal level has changed when a predetermined time has elapsed from the time when the received signal has changed from the first level to the second level, and after this determination, until the next second synchronization timing. A signal level change determination step in which no signal level change determination is performed, and a time point when it is determined that the signal level has changed in the signal level change determination step from the second synchronization timing The elapsed time is measured, and the time information is acquired based on the code determination step for determining the code data of the signal for one second according to the length of the elapsed time, and the code data determined in the code determination step. And a time information acquisition step.
Also in the present invention, the same effect as the time receiving device can be obtained.

It is a block diagram which shows the structure of the radio wave correction timepiece which concerns on one Embodiment of this invention. It is a block diagram which shows the structure of the counting means of the said embodiment. It is a block diagram which shows the structure of the decoding means of the said embodiment. It is a flowchart which shows the reception process of the said embodiment. It is a flowchart which shows the code | cord | chord determination process of the said embodiment. It is a flowchart which shows the code | cord | chord determination process of the said embodiment. It is a figure which shows the example of a waveform of the received signal of the said embodiment, and is a wave form diagram when there is no influence of noise. It is a figure which shows the example of a waveform of the received signal of the said embodiment, and is a waveform figure when there exists an influence of noise. It is a figure which shows the example of a waveform of the received signal of the said embodiment, and is a waveform figure when there exists an influence of noise.

Hereinafter, embodiments 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 receive a long-wave standard radio wave having a frequency set by the tuning circuit with an antenna.
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, the standard radio wave “MSF” in the United Kingdom is set to 60 Hz, and the standard radio wave “DCF77” in Germany is Set to 77.5 Hz.
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.

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, 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 Hi 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 Hi level or may be output as a Low level. For this reason, the received signal changes from the first level to the second level per second, but there are cases where the first level is the Hi level and the Low level, and the second level is a level different from the first level. It becomes.

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 signal level change determination means 13, a counting means 14, a decoding means 15, a time correction means 16, and a time measuring means. 17.

  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 signal level change determination unit 13 is executed after the second synchronization is established by the second synchronization detection unit 12 and determines a change in the signal level of the received signal sampled by the sampling unit 11. In particular, when the signal changes from the first level to the second level, the signal level change judging means 13 changes from the first level to the second level when the second level continues for three pulses from the actual change point. It is determined that the signal has changed to the level.

As shown in FIG. 2, the counting unit 14 includes a sampling counter 141, a first signal level counter 142, and a signal level change determination counter 143.
The sampling counter 141 counts the number of samplings of the sampling means 11 and is used for measuring a 1 second period.
The first signal level counter 142 counts a period during which the received signal is at the first signal level, and is used to measure the pulse width of the first signal level and determine the code.
The signal level change determination counter 143 is used to measure whether the second level continues for a predetermined period after the signal level change determination means 13 detects that the first level has changed to the second level.

As shown in FIG. 3, the decoding unit 15 includes a code determination unit 151 and a time information acquisition unit 152.
The code determination unit 151 determines a code for one second (bit) based on the count number counted by the first signal level counter 142 of the count unit 14.
Since each code differs according to the type of standard radio wave, the determination condition may be set according to the type of standard radio wave selected.

For example, in the DCF 77, if the first level is 0.1 second in the received signal, it represents a binary number “0”, and if it is 0.2 seconds, it represents a binary number “1”. In other cases, the marker “M” is represented.
For this reason, the code determination means 151 determines the code under the conditions shown in Table 1.

That is, the code determination unit 151 determines that the code is “0” when the count value counted by the first signal level counter 142 is in the range of 0-21. Since the sampling is performed at 128 Hz, the count value 0 to 21 corresponds to the signal width 0 to 164 msec.
The code determination unit 151 determines the code as “1” if the count value counted by the first signal level counter 142 is in the range of 22 to 41. The count values 22 to 41 correspond to a signal width of 165 to 320 msec.
Furthermore, if the count value counted by the first signal level counter 142 is in the range of 42 to 127 (in the case other than the determination conditions of the codes 0 and 1), the code determination unit 151 determines the code as “M”. To do. The count values 42 to 127 correspond to signal widths 321 to 1000 msec.

  The time information acquisition unit 152 acquires a time code (time information) from the code decoded by the decoding unit 15. 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 time information acquisition unit 152 acquires time information by acquiring a code of 60 bits. The time information acquired by the time information acquisition unit 152 is output to the time correction unit 16.

The time adjustment unit 16 determines whether the time information acquired by the time information acquisition unit 152 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 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.

Therefore, in this embodiment, the time receiving apparatus includes the antenna 4, the receiving means 5, the sampling means 11, the second synchronization detecting means 12, the signal level change determining means 13, the counting means 14, and the decoding means 15 (code determining means 151, time The information acquisition means 152) is provided.
The radio-controlled timepiece 1 includes the time receiving device, the time correcting means 16, the time measuring means 17, and the time display means 2.

[Receiving operation of the radio-controlled watch]
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.

  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. The standard radio wave is started to be received (S1). 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.

The sampling unit 11 samples the reception signal output from the reception unit 5 at a frequency of 128 Hz, that is, 1 second at 128 Hz (S2).
In this embodiment, as shown in FIG. 7, the transmission signal changes from the second level (Hi level) to the first level (Low level) in synchronization with the standard second signal. The receiving means 5 that has received the standard radio wave whose amplitude is modulated with the signal level change of the transmission signal outputs a signal that changes from the second level (Hi level) to the first level (Low level) in synchronization with the second signal. To do.
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 a second synchronization process (S3). 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 detecting means 12 determines that the second synchronization is completed when it is detected 5 times in succession (second synchronization condition) (S4).
For example, as shown in FIG. 7, when the pulse of the output signal (received signal) of the receiving means 5 falls every second, the fall of the pulse is detected by the change in the signal level at the time of sampling, and the change When the interval is 1 second ± 62.5 msec, it is determined that the second synchronization condition is satisfied. Specifically, the sampling counter 141 counts the number of samplings from the time when the signal level changes from the second level to the first level during sampling until the time when the signal level changes from the second level to the first level. If the count number is in the range of 120 to 136, it is determined that the second synchronization condition is met.

When determining that the second synchronization is not completed in S4 (S4: No), the second synchronization detection unit 12 determines whether a predetermined time (specifically, 3 minutes) has elapsed since the start of reception (S5).
If the answer is No in S5, that is, if 3 minutes have not elapsed, the second synchronization detection means 12 returns to the process of S4 and determines whether the second synchronization is completed.
On the other hand, if Yes in S5, that is, if the second synchronization has not been completed and 3 minutes have elapsed, the standard radio wave may not be received or the radio wave intensity may be weak even though it is received. The means 10 turns off the receiving means 5 and ends the receiving process (S6).

When the second synchronization is completed and “Yes” is determined in S4, the code determination process (S7) is executed by the code determination unit 151 of the signal level change determination unit 13, the count unit 14, and the decoding unit 15.
Details of the code determination processing S7 will be described based on the flowcharts of FIGS.

  When the code determination process S7 is started, the control means 10 confirms whether the A flag is 1 (S21). Here, the A flag is a flag for determining whether to initialize the counting means 14 and the like every second. At the start of the code determination process S7, the A flag is set to “0”, and the B flag described later is also set to “0”. Further, the counters 141, 142, and 143 provided in the counting means 14 are also initialized and cleared.

Therefore, when the code determination process S7 is executed first after the reception operation is started, it is determined No in S21. On the other hand, as described later, when the code determination for 1 second is performed and the code determination process S7 is executed again to determine the next 1 second code, the A flag is set to “1” at the previous code determination. In step S21, the determination is Yes.
When it is determined Yes in S21, the control unit 10 clears and initializes the sampling counter 141, the first signal level counter 142, and the signal level change determination counter 143 provided in the counting unit 14 (S22). ).

After the initialization in S22, the control means 10 initializes the A flag and the B flag to “0” (S23).
The B flag is a flag that is set to “1” when it is determined that the signal level has changed from the first level to the second level.

  Next, the control means 10 determines whether or not the B flag is “1” (S24). As described above, when the first code determination process S7 after the start of the reception operation or the second code determination process S7 is executed, since the B flag = 0, it is determined as “No” in S24.

When it is determined “No” in S24, the control unit 10 adds +1 to the count value of the first signal level counter 142 (S25).
Subsequently, the control means 10 confirms whether or not the sampled received signal has reached the second level (Hi level in the present embodiment) (S26). In S26, the determination is made on the assumption that the second level is changed to the first level (low level in the present embodiment) at the second synchronization timing. For this reason, in the case of the code “M” in which the second level is output without changing to the first level, it is determined as “No” in S26 although it is the second level.

When it is determined “No” in S26, the control means 10 clears the signal level change determination counter 143 (S27). That is, when the sampled signal is at the first level and when the bit data is the code “M” and is maintained at the second level, it is determined as “No” in S26, so that the control is performed. The means 10 clears the signal level change determination counter 143.
On the other hand, if “Yes” is determined in S26, that is, if the sampled received signal is at the second level (Hi level in the present embodiment), the control means 10 counts the counter value (count value) of the signal level change determination counter 143. ) Is incremented by 1 (S28).

Then, the signal level change determination unit 13 determines whether the counter value of the signal level change determination counter 143 is 3 or more (S29).
When it is determined “Yes” in S29, the signal level change determination unit 13 determines that the level of the received signal has changed from the first level to the second level, and sets the B flag to “1” (S30). .
On the other hand, when it is determined “No” in S29, the signal level change determination unit 13 continues the process without setting the B flag.

Here, each process after S21 of S7 is performed every time the received signal is sampled, as will be described later. Accordingly, even if the second level (Yes) is determined in S26 at the previous sampling and the counter value of the signal level change determination counter 143 is incremented by +1, the first level (No) in S26 at the next sampling. If it is determined, the signal level change determination counter 143 is cleared in S27.
For this reason, in order to determine “Yes” in S29, it is once changed to the first level at the second synchronization timing, and it is determined in S26 that the second level is determined continuously three times. Limited.
Then, after the B flag is set to “1” in S30, since “Yes” is determined in S24 at each sampling, the addition processing (S25) of the first signal level counter 142 is not executed, and the first The signal level counter 142 is stopped.
Therefore, the signal level change determination step for determining that the signal level has changed from the first level to the second level is performed by the processing of S26 to S30. If the code “M” is output, it is determined “No” in S26, and the B flag is maintained at “0”, so that the addition process of the first signal level counter 142 is repeated for each sampling. . For this reason, when the code “M” is output, the counter value of the first signal level counter 142 is also a large value, and is usually in the range of 42 to 127 (maximum value).

When the processing of S26 to S30 is performed, as shown in FIG. 6, the control means 10 determines whether 1 second has elapsed from the time of second synchronization, based on the count value of the sampling counter 141 (S31).
If it is determined as “No” in S31, the control means 10 determines whether or not the next sampling timing has come (S32). If the next sampling timing is not reached, the determination process of S32 is repeated until that timing is reached.
When it is determined “Yes” in S32 and the next sampling timing is reached, the control unit 10 returns to S21 and continues the process. Accordingly, the processing from S21 to S32 is repeatedly performed for each sampling (1000/128 = approximately 7.8 msec interval).

  If it is determined as “Yes” in S31, the control means 10 sets the A flag to “1” (S33). As described above, the A flag is also set to “1” in order to initialize each counter and flag at the time of second synchronization, that is, every second.

Next, the code determination unit 151 of the decoding unit 15 performs a code (bit) determination process. Specifically, whether the counter value (count value) of the first signal level counter 142 is “0 to 21” (Yes in S34), 22 to 41 (Yes in S35), or otherwise. (No in S34 and S35) is confirmed.
When it is determined “Yes” in S34, the code determination unit 151 determines that the code is “0” as shown in Table 1 (S36).
If it is determined “No” in S34 and “Yes” in S35, the code determination unit 151 determines the code as “1” (S37).
Furthermore, when it is determined “No” in S35, the code determination unit 151 determines the code as “M” (S38).
Therefore, the code determination process for determining the code data for 1 second (each bit) is performed by the processes of S24, S25, S31, and S34 to S38.

When the code determination process S7 is completed as described above, as shown in FIG. 4, the code determination unit 151 stores the code value (0, 1, M) determined in the code determination process S7 in a storage unit (not shown). Store (S8).
Next, the time information acquisition means 152 of the decoding means 15 confirms whether or not codes for 60 bits, that is, one time code have been stored (S9). When it is determined “No” in S9, the control unit 10 returns to the code determination process S7 and performs the next 1-bit code determination process S7.

On the other hand, if “Yes” is determined in S 9, the time information acquisition unit 152 acquires the time information by decoding the acquired 60-bit time code, 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, the reception process is terminated (S6). In this case, since the correct time information has been acquired, the time correction means 16 outputs the acquired time information to the time measurement means 17, and the time measurement means 17 corrects the internal time with the time information. For this reason, the time displayed by the time display means 2 is also updated to the reception time.

On the other hand, when it is determined as “No” in S10, the control means 10 confirms whether or not 7 minutes have elapsed since the start of reception (S11).
And when 7 minutes has not passed, the control means 10 repeats from the process of S7. On the other hand, when 7 minutes have passed, the control means 10 ends the reception process (S6).
If the correct time information cannot be received even after 7 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 it is determined “Yes” in S11 and the reception is completed, 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.

  7 and 8 are timing charts showing examples of received signal waveforms when a signal having a pulse width of 0.1 second (code “0”) is received from the DCF 77. FIG. It is a timing chart which shows the example of a waveform of the received signal at the time of receiving the signal of a second (code | symbol "1"). FIG. 7 shows a case where there is no noise in the received signal, and FIG. 8 shows an example in which the signal level changes due to noise after changing to the second level (after 0.1 seconds from the second synchronization timing). FIG. 9 shows an example in which the signal level is changed by noise during the first level (within 0.2 seconds from the second synchronization timing).

As shown in these drawings, the second synchronization detection means 12 receives the reception signal at the time of sampling immediately after the second synchronization timing when the transmission signal and the reception signal have changed from the second level (Hi level) to the first level (Low level). Is changed from the second level to the first level, and it is confirmed whether or not the second synchronization is performed based on whether or not this timing is repeated every 1 second ± 62.5 msec.
Further, the signal level change determination means 13 determines that the signal level has changed when the detection level at the time of sampling is the second level for three consecutive times after the received signal has changed from the first level to the second level. To do. Therefore, the signal level change determination signal in which the period in which the signal level change determining means 13 determines the first level is the Hi level and the period in which the signal level change determining means 13 determines the second level is the Low level is shown in FIG. As shown in FIG. 9, the received signal is changed from the first level to the first level from the second synchronization timing (at the start time of 1 second, specifically at the time of sampling immediately after the received signal changes from the second level to the first level). At the time of the third sampling after changing to 2 level, that is, until the counter value of the signal level change judging counter 143 becomes 3 or more, it is judged as the Hi level (first level).

The first signal level counter 142 counts the number of samplings during the period when the signal level change determination signal is at the Hi level.
Here, in the case of a pulse width of 0.1 seconds, the length is about 12 samples, so at the 13th sampling from the second synchronization timing, the received signal changes from the first level to the second level. Change. Then, when the second level is detected three times consecutively from the time of the change, the first level count is ended, and the counter value of the first signal level counter 142 becomes “15”. Accordingly, the code is correctly determined as “0” in S36.

In addition, after the received signal changes from the second level to the first level, if the counter value of the signal level change determination counter 143 becomes 3 or more, the B flag becomes 1 (S30), and the determination process of S24 thereafter The counter value of the first signal level counter 142 is not added.
Therefore, as shown in FIG. 8, even if the received signal changes to the second level and then changes to the first level again due to the influence of noise, the counter value of the first signal level counter 142 does not change. For this reason, the counter value of the first signal level counter 142 is increased and the code is not erroneously determined to be “1” or the like, and it is possible to prevent the code from being erroneously determined due to the influence of noise.

Further, even if the received signal changes to the second level while the received signal is at the first level, if it does not continue three times continuously, the signal level change determination counter 143 is cleared (S27). The count of the 1 signal level counter 142 is continued (S25).
Therefore, as shown in FIG. 9, even if the received signal temporarily changes to the second level due to the influence of noise during the first level, the signal level change determining means 13 determines that the signal level has changed. Without adding, the addition of the counter value of the first signal level counter 142 is also continued. For this reason, the counter value of the first signal level counter 142 increases until the signal level change determining means 13 determines that the signal level has actually changed, that is, until the counter value reaches “28” in FIG. For this reason, it is possible to correctly determine the code as “1”, and to prevent erroneous determination of the code due to the influence of noise.
That is, if it is determined in FIG. 9 that the signal level has changed when the first level is changed to the second level without applying the present invention, the time when noise is input, that is, the first signal level. When the counter value of the counter 142 is “21”, it is determined that the signal level has changed, and the code is erroneously determined to be “0”.
On the other hand, in the present invention, as described above, even if the signal level temporarily changes due to noise, the counter value of the first signal level counter 142 becomes “28” and the code can be correctly determined as “1”. .

According to this embodiment, the following operational effects can be achieved.
(1) After the second synchronization timing, the signal level change determination means 13 continues for a predetermined number of times when a predetermined time has elapsed from the time when the received signal changes from the first level to the second level. When the second level is detected, it is determined that the signal level has changed.
For this reason, even if the received signal temporarily changes from the first level to the second level due to the influence of noise, if the signal level returns to the first level before the predetermined time has elapsed, the signal level has changed. Do not judge. If the signal level change determining means 13 determines that the first level has changed to the second level, the B flag is set to “1” and the count of the first signal level counter 142 is stopped. Thus, even if the signal level changes, the determination of the signal level change is not affected.
Therefore, the change from the first level to the second level in the received signal can be accurately detected without being affected by noise. For this reason, the code determination means 151 can correctly determine the code and acquire the correct time information by counting the signal width of the first level by the sampling number.
In particular, even when DCF 77 is received, which has a small pulse width difference for each code and is susceptible to noise, the influence of noise can be reduced and correct time information can be acquired.

(2) Since the sampling means 11, the sampling counter 141 of the counting means 14, the first signal level counter 142, and the signal level change determination counter 143 are provided and the length of each time is measured by counting the number of sampling times, Measurement can be performed easily.

(3) Since the reception stop determination is performed in S5 and S7, when the reception is difficult, it is possible to end the reception process at an early stage and prevent the useless reception process from continuing.

Note that the present invention is not limited to the above-described embodiments, and modifications, improvements, and the like within a scope in which the object of the present invention can be achieved are included in the present invention.
For example, in the above-described embodiment, the case of receiving the German standard radio wave DCF77 has been described. However, the same process can be performed when the standard radio wave of another country is received. For example, in the Japanese standard radio wave JJY, the pulse width representing “1” is 0.5 seconds, the pulse width representing “0” is 0.8 seconds, the marker “M” and the position markers “P0 to P5”. Is set to 0.2 seconds, and can be dealt with by setting the determination conditions for each code shown in Table 1 based on these pulse width conditions.
Similarly, the standard radio waves of other countries may be set in consideration of the determination conditions of each code.

  Moreover, in the said embodiment, although each time was measured using the sampling means 11, you may measure time using a timer etc.

Further, the circuits and means of the control means 10 shown in FIG. 1 are not limited to those constituted by hardware such as various logic elements, but a computer having a CPU (central processing unit), a memory (storage device), etc. It may be provided in the radio-controlled timepiece 1 and may be configured to implement each circuit and means by incorporating a predetermined program and data (data stored in each storage unit) into this computer.
For example, a CPU and memory (ROM, RAM, etc.) are arranged in the radio-controlled timepiece 1 so as to function as a computer, and a predetermined control program and data are stored in this memory as communication means such as the Internet, CD-ROM Alternatively, the program may be installed via a recording medium such as a memory card, and the CPU or the like may be operated by the installed program.

  In addition, in order to install a predetermined program or the like in the radio-controlled timepiece 1, it can be implemented by directly inserting a memory card, CD-ROM or the like into the radio-controlled timepiece 1, or by externally attaching a device that reads these storage media. It may be connected to the modified watch 1. Furthermore, a LAN cable, a telephone line or the like may be connected to the radio-controlled watch 1 to supply and install a program or the like by communication, or since an antenna is provided, the program is supplied and installed by radio. Also good.

  In addition, the specific structure and procedure for carrying out the present invention can be appropriately changed to other structures and the like within a range in which the object of the present invention can be achieved.

  DESCRIPTION OF SYMBOLS 1 ... Radio wave correction clock, 2 ... Time display member, 4 ... Antenna, 5 ... Receiving means, 6 ... Oscillation circuit, 7 ... Frequency dividing circuit, 10 ... Control means, 11 ... Sampling means, 12 ... Second synchronization detection means, ... Signal level change judging means, 14 ... counting means, 15 ... decoding means, 16 ... time adjusting means, 17 ... time measuring means, 141 ... sampling counter, 142 ... first signal level counter, 143 ... signal level change judging counter, 151 ... code determination means, 152 ... time information acquisition means.

Claims (4)

Receiving means for receiving a standard radio wave including time information and outputting a received signal;
Signal level change determining means for determining a change in signal level of the received signal;
Code determination means for determining transmitted code data based on the determination result of the signal level change determination means;
Time information acquisition means for acquiring time information based on the code data determined by the code determination means,
The received signal changes from the first level to the second level different from the first level, and from the second level to the first level at the second synchronization timing repeated at one second intervals, and becomes the next second synchronization timing. Change from the first level to the second level before,
The signal level change determination means determines that the signal level has changed when a predetermined time has elapsed from the time when the received signal has changed from the first level to the second level after the second synchronization timing, and after this determination The signal level change is not judged until the next second synchronization timing,
The code determination unit measures an elapsed time from the second synchronization timing to a time point when the signal level change determination unit determines that the signal level has changed, and according to the length of the elapsed time, the signal of the one second is measured. A time receiving device characterized by determining code data. The time receiver according to claim 1,
Sampling means for sampling the received signal at a predetermined sampling period to obtain a signal level at each sampling,
The signal level change determination unit is configured to detect a second level signal continuously more than a predetermined number of times from the time when the signal level acquired by the sampling unit is changed from the first level to the second level. To determine that the signal level has changed,
The code determination means counts the number of samplings from the second synchronization timing to the time when the signal level change determination means determines that the signal level has changed, and from the time when it is determined that the signal level has changed, The time receiving apparatus, wherein the count of the sampling number is stopped until the second synchronization timing, and the code data of the signal for one second is determined based on the count number of the sampling. The time receiving device according to claim 1 or 2,
Time correction means for correcting internal time data according to the time information acquired by the time receiver;
A radio-controlled timepiece comprising time display means for indicating a time based on the internal time data. A method for controlling a time receiving device comprising a receiving means for receiving a standard radio wave including time information and outputting a received signal,
The received signal changes from the first level to the second level different from the first level, and from the second level to the first level at the second synchronization timing repeated at one second intervals, and becomes the next second synchronization timing. Change from the first level to the second level before,
After the second synchronization timing, it is determined that the signal level has changed when a predetermined time has elapsed from the time when the received signal has changed from the first level to the second level, and after this determination, until the next second synchronization timing. A signal level change determination step in which no signal level change determination is performed between,
A code that measures the elapsed time from the second synchronization timing to the time when it is determined that the signal level has changed in the signal level change determination step, and determines the code data of the signal for that second by the length of this elapsed time A determination process;
A time information acquisition step of acquiring time information based on the code data determined in the code determination step.

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