JP2016148537A - Standard radio wave receiving device, radio wave correction timekeeper, and standard radio wave receiving method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a standard radio wave receiving device having high reception sensitivity, a radio wave correction timekeeper, and a standard radio wave receiving method.SOLUTION: A standard radio wave receiving device comprises: an antenna 4 and a receiving circuit 5 for receiving a standard radio wave and outputting a received signal; filter processing means 13 for applying each of multiple kinds of filter outputting an output value for determining a high-level signal width to the received signal; intermediate signal count detection means 14 for detecting the number of intermediate signals included in an intermediate signal range among the output values outputted from the filters; filter selection means 15 for selecting a filter on the basis of the number of intermediate signals; and code determination means 16 for determining a time code corresponding to a received signal for a one-second period from seconds-synchronization timing on the basis of the output value outputted from the selected filter.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a standard radio wave receiver that receives standard radio waves, a radio wave correction watch, and a standard radio wave reception method.

A radio-controlled timepiece that receives a standard radio wave and corrects the internal time based on the received standard radio wave is known (for example, see Patent Document 1).
The radio-controlled timepiece of Patent Literature 1 generates a demodulated signal from a received standard radio wave, performs a binarization determination (high level / low level determination) of the demodulated signal using a threshold value, and outputs a digital signal (received signal). Output. Then, code determination is performed using the output received signal, and time information is extracted from the code determination result. In this radio-controlled timepiece, the ratio RH of the high-level count number in the received signal sampled for a predetermined period (20 seconds) is calculated, and binarization determination is performed based on the average value or the assumed range in the theoretical value of the ratio RH. The threshold of the time (at the time of reception signal generation) is set.

Japanese Patent No. 5037397

  By the way, a 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 (for example, a high level) and a second level (for example, a low level) different from the first level based on the received standard radio wave. Time information is acquired by determining every second. At this time, the reception signal is determined based on the signal width of the first level. Therefore, in order to extract time information from the standard radio wave, the type of signal may be determined from the first level signal width.

On the other hand, in the standard radio wave receiving apparatus described in Patent Document 1, the threshold value at the time of binarization determination is set so that the calculated ratio RH becomes a reference based on the theoretical value. It is determined whether or not the length of the received signal is within the reference (within the allowable error range).
However, since the threshold is only set so that the ratio RH calculated based on the received signal for 20 seconds is used as a reference, it is determined whether or not the code for each second is accurately determined. I can't. For example, the reception signal with the bit value “0”, “1”, “0”, “1” and the reception signal with the bit value “1” “0” “0” “1” have the same ratio RH. Here, in the watch of Patent Document 1, a received signal whose bit value is originally “0”, “1”, “0”, “1” is received, and a received signal whose bit value is “1”, “0”, “0”, “1” is received. Even when the code is determined as a signal, since the ratio RH is the same, it cannot be determined with a code determination error.
That is, when the first level signal width included in the received signal for one second is detected, the signal width varies, and in the timepiece of Patent Document 1, the detected first level signal width is in which code. It may not be possible to accurately determine whether or not the signal is a corresponding signal. For example, the DCF 77 determines whether the signal width of the first level is 100 msec corresponding to the bit value “0” or 200 msec corresponding to the bit value “1”. However, the detected signal width of the first level is not necessarily 100 msec or 200 msec, and may be an intermediate value between 100 msec and 200 msec, such as 150 msec. In this case, it is unknown whether the signal width of 150 msec is the signal width corresponding to the bit value “0” or the signal width corresponding to the bit value “1”. Gets worse. In particular, when the first level signal widths corresponding to two codes are close to each other as in the case of DCF77, the above problem becomes significant.

  An object of the present invention is to provide a standard radio wave receiving apparatus, a radio wave correction watch, and a standard radio wave receiving method that can reduce the probability of erroneous code determination and improve reception sensitivity.

  The standard radio wave receiver of the present invention receives a standard radio wave on which a time code is superimposed, and receives a first level and a reception signal that changes to a second level different from the first level, and the reception The signal width of the first level included in the received signal for one second from the second synchronization timing is determined with reference to the second synchronization timing at intervals of one second at which the signal changes from the second level to the first level. Filter processing means for outputting an output value for each of the filters, and applying a plurality of types of filters with different output value calculation algorithms to the received signal to output the output value from each filter, A first set value that is the output value corresponding to the first code in the time code, and a second code different from the first code in the time code. An intermediate signal range between the second set values that are the output values corresponding to the output value is set for each filter, and the output value output when the filter is applied to the received signal for a predetermined period. Of these, based on the number of intermediate signals detected for each filter, the number of intermediate signals detected for each filter, the number of intermediate signals based on the number of output values included in the intermediate signal range, Based on the filter selection means for selecting one filter from each of the filters and the output value output by the filter selected by the filter selection means, the code of the signal for one second from the second synchronization timing is determined. And a code determination unit.

According to the present invention, the filter processing means applies each of a plurality of types of filters to the received signal for a predetermined period, and each filter is included in 1 second (between successive second synchronization timings) from the second synchronization timing. It is output as an output value for determining the signal width of one level. This output value has a different calculation algorithm for determining the first-level signal width depending on each filter. For example, a determination timing is set for a filter whose output value is the total time of the first level signal width in one second from the second synchronization timing, or for the maximum width signal having the largest first level signal width in the one second. And a filter that uses the time from the second synchronization timing to the determination timing as an output value.
Since these filters have different output value calculation algorithms, the setting values (first setting value and second setting value) corresponding to the first code and the second code are different for each filter. For example, in the case of DCF77, a filter that uses the total time of the first level signal width in one second from the second synchronization timing described above as an output value has a good reception environment, and the received signal does not include noise pulses, etc. When sufficient signal strength is obtained, the output value corresponding to the bit value “0” as the first code is 100 msec, and this value is the first set value. Similarly, the output value corresponding to the bit value “1” as the second code is 200 msec, and this value is the second set value. On the other hand, with a filter that uses the elapsed time from the second synchronization timing to the center timing of the maximum width signal set as the determination timing as the output value, the reception environment is good, the received signal does not contain noise pulses, etc. When a high signal strength is obtained, the output value corresponding to the bit value “0” as the first code is 50 msec, and this value is the first set value. The output value corresponding to the bit value “1” as the second code is 100 msec, and this value is the second set value.
In the present invention, the first code and the second code may be set as codes that are easily misidentified due to the proximity of the first level signal width according to the type of the standard radio wave. For example, the marker “M” is easy to determine because the transmission timing is determined. Therefore, as in the DCF 77 described above, the bit values “0” and “1” are normally set as the first code and the second code. For this reason, in JJY, which is a Japanese standard radio wave, the signal width of the first level corresponding to the code having the bit value “0” is 800 msec, and the signal width corresponding to the code having the bit value “1” is 500 msec. The output value corresponding to a signal width of 800 msec may be set as the first set value, and the output value corresponding to the signal width of 500 msec may be set as the second set value.
In JJY, if it is easy to misjudge the marker “M” and the bit value “1”, the output value corresponding to the signal width of 200 msec corresponding to the code of the marker “M” is set as the first set value. The number of intermediate signals may be detected using the output value corresponding to 500 msec as the second set value.

In the present invention, the intermediate signal number detection means detects the number of intermediate signals based on the number of output values included in a predetermined intermediate signal range between the first set value and the second set value. The number of intermediate signals may be, for example, the number of output values included in the intermediate signal range, or the ratio of the number of output values included in the intermediate signal range to the total number of output values. Good.
Further, the filter selection means selects a filter that outputs an output value for performing code determination based on the number of intermediate signals, and the code determination means, based on the output value output from the selected filter, Perform code determination.
Here, the predetermined period in the present invention may be set to a period in which a plurality of output values can be output by the filter. That is, since the output value is output for each received signal for 1 second, 20 output values can be output if the predetermined period is set to 20 seconds, and 60 output values are output if the predetermined period is set to 60 seconds. it can.

By the way, each filter is a filter for outputting an output value for determining the signal width of the first level included in one second from the second synchronization timing, and different calculation algorithms are set as described above. Yes. Therefore, variations in output values output by the filters may be different depending on the reception environment. For this reason, for example, there may be a difference between the number of intermediate signals when the first filter is applied to a reception signal of a predetermined period and the number of intermediate signals when the second filter is applied to a reception signal of the same predetermined period. is there.
For standard radio waves, as described above, an ideal value of the first level signal width corresponding to the first code when the reception environment is good and there is no influence of noise pulses or the like (for example, 100 msec in DCF77), and An ideal value (for example, 200 msec in DCF77) of the first level signal width corresponding to the second code is defined, and output values corresponding to these codes are also output values output from the filters. As the ideal value, a first set value and a second set value are defined for each filter. Therefore, in order to perform the code determination based on the output value, the code determination accuracy is improved when the variation of the output value output from the filter with respect to the first set value and the second set value is small. On the other hand, when the variation of the output value with respect to the first set value and the second set value increases, the number of output values near the intermediate value (intermediate signal range) between the first set value and the second set value increases. In this case, it is unclear whether the output value corresponds to the first set value or the second set value, and a code determination error is likely to occur.

On the other hand, in the present invention, a filter is selected based on the number of intermediate signals based on the number of output values included in the intermediate signal range, and code determination is performed based on the output value output by the filter. In other words, the smaller the number of intermediate signals, the smaller the variation in the output value of the filter. Therefore, if this filter is selected, the code can be determined with higher accuracy than when other filters are used. This makes it possible to select an optimum filter according to the reception environment, improve the reception sensitivity of standard radio waves, reduce the occurrence of code determination errors, and determine time codes from standard radio waves with high accuracy.
It is also possible to calculate the appearance rate of each of the first set value and the second set value from the obtained distribution of output values (standard deviation σ). For example, in a power-saving CPU for a wristwatch Since the processing capability is limited, it is difficult to calculate the standard deviation σ in real time. On the other hand, in the present invention, since the optimum filter can be selected simply by obtaining and comparing the number of output values included in the intermediate signal range and the ratio to the total output values for each filter, complicated calculation processing is performed. This is unnecessary, can save power, and can be processed by a wristwatch CPU.

In the standard radio wave receiver of the present invention, the number of intermediate signals is the number of output values included in the intermediate signal range or the number of output values included in the intermediate signal range with respect to the total number of output values. Preferably, the filter selecting means selects a filter that minimizes the number of intermediate signals.
In the present invention, the filter selection means selects a filter that minimizes the number of intermediate signals, and the code determination means performs code determination based on the output value output from the selected filter. In this case, the probability that the output value output from the selected filter belongs to the intermediate signal range is the lowest, and the occurrence rate of the code determination error can be effectively suppressed.

In the standard radio wave receiver of the present invention, the plurality of types of filters include a first filter that outputs, as the output value, a sum of times that are the first level in the received signal for one second from the second synchronization timing. Is preferred.
In the present invention, the filter processing means uses the first filter to detect the time of the first level included in the received signal for 1 second from the second synchronization timing, and sets the sum as the output value. In such a filter process using the first filter, it is only necessary to sample the received signal and add the number of samplings at the first level, thereby simplifying the filter process. In particular, in a small device such as a wristwatch, the amount of power supply is limited, and power saving can be achieved by performing the filter process using the first filter with a small power consumption.

In the standard radio wave receiver of the present invention, the plurality of types of filters detect a maximum width signal having the largest signal width of the first level among the received signals in a predetermined determination period from the second synchronization timing. It is preferable to include a second filter that outputs an elapsed time from the second synchronization timing to a determination timing of a period during which the maximum width signal is transmitted as the output value.
Here, the determination period may be 1 second, which is a period until the next second synchronization timing, or may be set according to the type of the standard radio wave. For example, it may be set to 400 msec in DCF77, and may be set to 900 msec in JJY which is a standard Japanese radio wave.

In the present invention, the filter processing means uses the second filter to detect the maximum width signal having the largest first level signal width among the received signals in the predetermined determination period from the second synchronization timing. Then, a determination timing is set within a period during which the maximum width signal is transmitted, an elapsed time from the second synchronization timing to the determination timing is detected, and the elapsed time is output as an output value. Examples of the determination timing include the timing of the center of the signal width of the maximum width signal (1/2 of the signal width).
Here, when the reception signal in the determination period from the second synchronization timing includes a plurality of periods that become the first level, the signal width of the first level due to the influence of the noise pulse is usually a signal of a normal signal. Small compared to the width. 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 within the period during which the maximum width signal is transmitted, the determination timing is usually set to a different timing due to the difference in the bit width (code), that is, the first level signal width. Therefore, if the elapsed time from the second synchronization timing to the determination timing is output as an output value, highly accurate code determination with reduced influence of noise pulses or the like can be performed.

In the standard radio wave receiving apparatus of the present invention, a signal reception process for determining the code based on the reception signal of the predetermined period is continuously performed a plurality of times, and the filter selection unit performs the signal reception process for each signal reception process. Preferably, the filter is selected based on the number of intermediate signals for each filter.
In the present invention, signal reception processing for determining a code based on a reception signal for a predetermined period is continuously performed a plurality of times. That is, when the time is corrected based on the standard radio wave, the standard radio wave for a predetermined period (for example, 1 minute) is received and the time information is extracted from the code superimposed on the standard radio wave. At this time, when the time adjustment is performed using only one time information, since it is unclear whether or not the correct time has been acquired, the received signal is usually processed a plurality of times in succession to obtain a plurality of time information. It is acquired and it is determined whether correct time information has been acquired. In the present invention, filter selection based on the number of intermediate signals is performed by the filter selection means for each signal reception process for receiving time information based on a reception signal for a predetermined period. As a result, even when the standard radio wave reception environment changes, such as when a user with a standard radio wave receiver is moving, the optimum filter corresponding to the reception environment can be selected. Standard radio waves can be received and processed with the best reception sensitivity.

In the standard radio wave receiver of the present invention, the signal reception process for determining the code based on the received signal of the predetermined period is continuously performed a plurality of times, and the filter selection unit performs the signal reception process for the first time in the signal reception process. The filter is selected based on the number of intermediate signals, and the code determination unit is configured to set the output value from the filter selected by the filter selection unit in the signal reception process for the first time to the output value from the filter. Preferably, the code is determined based on the code.
In the present invention, when a filter is selected by the filter selection unit in the first signal reception process, the code determination unit does not change the filter used in the subsequent signal reception process, and outputs the output value output by the selected filter. Based on the code determination. In this case, the processing related to the selection of the filter can be omitted, so that power saving can be achieved.

The radio-controlled timepiece according to the present invention acquires time information based on the standard radio wave receiver described above, a time measuring unit that counts internal time information, and the code determined by the code determination means of the standard radio wave receiver. And a time information correcting unit that corrects the internal time information, and a time display unit that displays the internal time information.
In the present invention, since the standard radio wave receiver as described above is provided, the reception sensitivity can be increased, and the code determination error can be suppressed. Therefore, accurate time information can be grasped based on the acquired code, and the accurate time can be displayed on the time display unit.

The standard radio wave reception method of the present invention receives a standard radio wave on which a time code is superimposed, outputs a first level and a received signal that changes to a second level different from the first level, and the received signal is Output for determining the signal width of the first level included in the received signal for one second from the second synchronization timing with reference to the second synchronization timing at intervals of one second changing from the second level to the first level A first code in the time code that outputs a value and outputs the output value from each filter by applying a plurality of types of filters having different output value calculation algorithms to the received signal. And a second set value that corresponds to a second code different from the first code in the time code. An intermediate signal range between fixed values is set for each filter, and among the output values output when the filter is applied to the received signal for a predetermined period, the output values included in the intermediate signal range The number of intermediate signals based on the number of signals is detected for each filter, one filter is selected from each filter based on the number of intermediate signals detected for each filter, and output by the selected filter Based on the output value thus determined, a code of a signal for one second is determined from the second synchronization timing.
In this invention, there can exist the same effect as the standard radio wave receiver mentioned above.

1 is a block diagram showing an internal configuration of a radio-controlled timepiece according to a first embodiment of the present invention. The figure which shows the receiving pulse duty with respect to each signal of DCF77 which is a standard radio wave in Germany, and an amplitude change. The figure explaining the calculation algorithm of the 1st filter in a 1st embodiment. The figure explaining the calculation algorithm of the 2nd filter in a 1st embodiment. It is a figure which shows distribution of the output value output from the filter process means, (A) shows distribution of the 1st output value from a 1st filter, (B) shows distribution of the 2nd output value from a 2nd filter. Figure. The flowchart which shows the processing operation of the standard radio wave reception method in the radio wave correction timepiece of the first embodiment. 7 is a flowchart showing filter processing in FIG. 6. The flowchart which shows the 2nd filter process in FIG. The figure which shows an example of the waveform diagram of a received signal. The flowchart which shows the processing operation of the standard radio wave reception method in the radio correction timepiece of 2nd Embodiment. The wave form diagram for demonstrating the calculation algorithm of the output value of a 3rd filter.

[First Embodiment]
DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, a first embodiment of the 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 (time display unit) for displaying time, an antenna 4, a receiving circuit 5 for receiving and processing a standard radio wave on which a time code received by the antenna 4 is superimposed, and a reference signal Are provided with an oscillation circuit 6 and a frequency dividing circuit 7 serving as a reference signal source for outputting the signal, and a control means 10 for controlling the operation of the entire apparatus. Here, the antenna 4 and the receiving circuit 5 constitute the receiving means of the present invention, and the receiving means and the control means 10 constitute the standard radio wave receiving apparatus of the present invention.

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.

Although not shown, the receiving circuit 5 receives a general standard radio wave including a tuning circuit, an amplifier circuit, a band pass filter, an envelope detection circuit, an AGC (Auto Gain Control) circuit, a binarization circuit, and the like. Circuit. The receiving circuit 5 is controlled by the control means 10 and is configured to receive the long wave standard radio wave having the frequency set by the receiving circuit by the antenna 4.
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 “DCF77” in Germany is set to 77.5 Hz, the standard radio wave “JJY” in Japan is set to 40 Hz or 60 Hz, and the standard radio wave “WWVB” in the United States is set to 60 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.

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 FIG. 2A, 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%, as shown in FIG. When the signal width of the low level signal is 0.2 seconds, that is, when the duty of the low level signal is 20%, it is recognized as “1”. Further, as shown in FIG. 2C, “M” is recognized as M when AM modulation is not performed and 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 circuit 5 outputs a received signal that is digital data from the received long wave standard radio wave to the control means 10.
Here, since the long wave standard radio wave is transmitted as 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 reception circuit 5 outputs a reception signal including a high level signal level and a low level signal level in accordance with the change in amplitude. At this time, depending on the circuit configuration of the receiving circuit 5, when the amplitude is large, the signal level of 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 present embodiment shows an example in which a high level signal is output as the first level when the amplitude is small, and a low level signal is output as the second level when the amplitude is large.

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 filter processing means 13, an intermediate signal number detection means 14, a filter selection means 15, a code determination means 16, The time correction means 17 (time information correction part), the time measurement means 18 (time measurement part), and the memory | storage means 19 are provided.

  The sampling unit 11 samples the reception signal input from the reception circuit 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.

The second synchronization detection means 12 confirms whether the interval between the received signals is 1 second, detects that the second synchronization is established, and sets the detected second synchronization timing as the second synchronization timing.
Specifically, the second synchronization detection means 12 confirms the timing at which the received signal has changed from the low level to the high level by the sampling means 11, and the interval of this change timing is 1 second ± 62. If it is 5 msec, it is determined that the second synchronization is established. Note that 62.5 msec is 8 pulses in 128 Hz sampling. Therefore, when a signal change from the low level to the high level is detected during sampling 120 to 136 times from the previous signal change timing, it can be determined that the interval is 1 second ± 62.5 msec. . 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 filter processing unit 13 applies a plurality of types of filters to the received signal, and outputs an output value for determining a high level signal width in the received signal for 1 second from the second synchronization timing.
In the present embodiment, the first filter 13A and the second filter 13B, each having a different output value calculation algorithm, are used as the plurality of types of filters. Hereinafter, the filters 13A and 13B will be described in detail.

FIG. 3 is a diagram showing an output value calculation algorithm by the first filter 13A.
The first filter 13A outputs, as an output value (first output value), the total time that is at a high level in the received signal for one second from the second synchronization timing T0. Specifically, the first filter 13A outputs (sampling period) × (high level count number detected by the sampling unit 11) as an output value.
Therefore, as shown in FIG. 3, when there is a high level interval a and interval b between 1 second from the second synchronization timing T0, the first filter 13A has the sum (a + b) of the intervals a and b. Are output as the first output value.

FIG. 4 is a diagram for explaining an output value calculation algorithm by the second filter 13B.
The second filter 13B determines the elapsed time from the second synchronization timing T0 to the predetermined determination timing in the high level interval where the signal width is maximum in the received signal from the second synchronization timing to a predetermined determination period (for example, 1 second). And the output value (second output value) is detected.
Specifically, as shown in FIG. 1, the second filter 13B includes a maximum width signal detection unit 13B1, a determination timing setting unit 13B2, and an elapsed time detection unit 13B3.

  The maximum width signal detector 13B1 detects the maximum width signal having the largest high-level signal width among the received signals for one second from the second synchronization timing T0. Specifically, the maximum width signal detection unit 13B1 has a count number in which the high level is continuously detected by the sampling unit 11 from the time when the signal level detected by the sampling unit 11 changes from the low level to the high level. The largest section (high level signal) is detected as the maximum width signal.

  As shown in FIG. 4, the determination timing setting unit 13B2 sets the determination timing TA within a period during which the maximum width signal detected by the maximum width signal detection unit 13B1 is transmitted. Specifically, the determination timing setting unit 13B2 sets the center timing of the signal width of the maximum width signal as the determination timing TA.

  The elapsed time detection means 13B3 detects the elapsed time from the second synchronization timing T0 to the determination timing TA set by the determination timing setting means 13B2, and outputs it as the output value (second output value) of the second filter 13B.

The intermediate signal number detection means 14 uses the filter processing means 13 to output each output value (first output value, second output value) when the filters 13A and 13B are applied to the received signals for a predetermined period from the second synchronization timing T0. Among them, the number of output values belonging to the intermediate signal range set for each of the filters 13A and 13B is detected as the number of intermediate signals.
Here, the intermediate signal range includes an ideal value of the first signal width corresponding to the first code of the time code (bit value “0”) (100 msec in DCF77) and the second code of the time code (bit value “0”). 1 ”), and is set for each of the filters 13A and 13B based on the ideal value of the second signal width corresponding to 1”) (200 msec in the case of DCF77). The ideal value described here refers to the signal width of the high level signal when the reception environment is good, there is no influence of noise pulses or the like, and a reception signal with sufficient signal strength is acquired.
Specifically, since the first output value output from the first filter 13A is the high-level time sum included in one second from the second synchronization timing T0, if the first output value is 100 msec, An ideal signal width corresponding to one code is obtained. If the first output value is 200 msec, an ideal signal width corresponding to the second code is obtained. In this case, 100 msec which is the same value as the first signal width with respect to the first output value from the first filter 13A is set as the first setting value for the first code, and 200 msec which is the same value as the second signal width is the second value. It is set as the second set value corresponding to the code. The intermediate value between the first setting value and the second setting value is 150 msec, and an intermediate signal range having a predetermined width is set around the intermediate value. In the present embodiment, as the width, ± 20% of the difference value (100 msec) between the first setting value (100 msec) and the second setting value (200 msec) is set. That is, for the first filter 13A, the intermediate signal range is set to 130 msec or more and 170 msec or less.

On the other hand, the second output value output from the second filter 13B is an elapsed time from the second synchronization timing T0 to the center of the maximum width signal (determination timing TA) in the determination period of 1 second. For this reason, when the high level of the ideal signal width (100 msec) corresponding to the first code is output from the second synchronization timing T0, the second output value is 50 msec. That is, the first setting value corresponding to the first code is 50 msec. Similarly, when the high level of the ideal signal width (200 msec) corresponding to the second code is output from the second synchronization timing T0, the second output value is 100 msec, and therefore the second setting corresponding to the second code. The value is 100 msec.
In this case, an intermediate value between the first set value and the second set value is 75 msec, and an intermediate signal range having a predetermined width is set around the intermediate value. In this embodiment, the width is set in the same manner as the width for the first filter 13A, and is set to ± 20% of the difference value (50 msec) between the first setting value (50 msec) and the second setting value (100 msec). ing. That is, for the second filter 13B, the intermediate signal range is set to 65 msec or more and 85 msec or less.

Hereinafter, the process of the intermediate signal number detection unit 14 will be described using the DCF 77 as an example.
5A and 5B are diagrams showing the output distribution of the output values output from the filter processing means 13, wherein FIG. 5A is an example of the output distribution of the first output values, and FIG. 5B is an example of the output distribution of the second output values. Indicates.
When the output value is output by the filters 13A and 13B for the reception signal, the reception environment is good, the reception signal does not include noise pulses and the like, and sufficient signal strength is obtained. Is output as the first set value or the second set value. However, in practice, the output values from the filters 13A and 13B may be shifted from the first set value and the second set value due to the influence of noise pulses and the like. Therefore, as shown in FIGS. 5A and 5B, the output values from the filters 13A and 13B are output in a distribution substantially following the normal distribution with the first set value and the second set value as peaks. Is done.
However, whether the output value in the intermediate signal range centered on the intermediate value between the first set value and the second set value is an output value corresponding to the first code or an output value corresponding to the second code. Is unknown and it is difficult to accurately determine the code. For example, in FIG. 5A, there are a plurality of first output values output as the intermediate signal range (130 msec to 170 msec), but these first output values are originally noise signals of the first set value (100 msec). It is unclear whether the signal is within the intermediate signal range due to a pulse or the like, or whether the signal of the second set value (200 msec) is within the intermediate signal range without obtaining sufficient signal strength. On the other hand, in FIG. 5B, the second output value output as the intermediate signal range (65 msec to 85 msec) is small, and the second output value output by the filter processing is an output corresponding to the first code. It is possible to easily determine whether it is a value or an output value corresponding to the second code.
The intermediate signal number detection means 14 detects the number of output values included in the intermediate signal range as the intermediate signal number for each of the filters 13A and 13B. In the present embodiment, the number of output values included in the intermediate signal range is exemplified as the number of intermediate signals, but is not limited thereto. For example, the ratio of the number of output values included in the intermediate signal range with respect to all output values may be detected as the number of intermediate signals.

The filter selection unit 15 selects a filter having the smallest number of intermediate signals detected by the intermediate signal number detection unit 14 as a use filter.
For example, in the example shown in FIG. 5, the number of intermediate signals in the second filter 13B is smaller than the number of intermediate signals in the first filter 13A. In this case, the filter selection unit 15 selects the second filter 13B as the use filter.

Based on the output value output from the used filter selected by the filter selection unit 15, the code determination unit 16 determines a code corresponding to the received signal for one second from the second synchronization timing T0.
Moreover, the code determination means 16 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 unit 16 obtains time information by determining a code for 60 bits. The time information acquired by the code determination unit 16 is output to the time correction unit 17.

The time correction means 17 determines whether the time information acquired by the code determination means 16 is the correct time, according to one of the following two conditions.
The first condition is to determine whether or not the received time information matches the time measured by the time measuring means 18.
The second condition is that the received time information is compared with each other, and each time information is different by the reception interval. If the reception interval is adjusted, the time information is the same as the received seven times. 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 either one of the above two conditions is met, the time adjustment unit 17 determines that the correct time information has been acquired, and outputs the time information to the time measurement unit 18.

The time measuring means 18 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 17 to receive the time measuring time (internal). (Time information) is corrected to reception time information to adjust the time.
The storage unit 19 stores processing data in the control unit 10.

  The time display means 2 displays the time measured by the time measuring means 18. 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 will be described. FIG. 6 is a flowchart showing the processing operation of the standard radio wave receiving method of this embodiment.

  The control means 10 of the radio-controlled timepiece 1 activates the reception circuit 5 to activate the antenna 4 when a regular reception time is reached or when a forced reception operation is performed by operating an external operation member such as a button. 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. 6, the sampling unit 11 samples the reception signal output from the reception circuit 5 at a frequency of 128 Hz (S1).
In the present embodiment, the receiving circuit 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 high-level signal width 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 detecting means 12 determines whether or not the received signal is detected five times continuously at the interval of 1 second ± 62.5 msec (whether the second synchronization processing is completed) (S3).
When it is determined Yes in S3, the detected timing of the interval of 1 second ± 62.5 msec is set as the second synchronization timing T0.
For example, when the output signal (received signal) of the receiving circuit 5 rises every second, the rising edge 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 number of samplings from the time when the signal level changes from the low level to the high level at the time of sampling until the next time when the signal level changes from the low level to the high level is counted. If the range is 136, it is determined that the second synchronization condition is met.

When determining that the second synchronization has not been completed (S3; No), 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, 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 circuit 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, filter processing and intermediate signal number detection processing are performed (S5).
FIG. 7 is a flowchart showing detailed processing of the filter processing and the intermediate signal number detection processing.
Specifically, the intermediate signal number detection means 14 first initializes the intermediate signal numbers (first intermediate signal number and second intermediate signal number) for each of the filters 13A and 13B stored in the storage means 19 (" 0 ”) (S21).
Thereafter, the filter processing means 13 acquires a reception signal for one second from the second synchronization timing T0 (S22).
Next, the filter processing means 13 applies a first filter to the received signal acquired in S22 and outputs a first output value (S23; first filter processing). That is, the filter processing unit 13 counts the number of high levels sampled by the sampling unit 11 in one second from the second synchronization timing T0. Then, a value obtained by multiplying the counted number of high levels by the sampling period (1000 msec / 128 Hz) is output as the first output value. The output first output value is stored in the storage unit 19 as appropriate.

  Further, the intermediate signal number detection unit 14 determines whether or not the first output value output in S23 is a value included in the intermediate signal range (130 msec to 170 msec) for the first filter 13A (S24). When it is determined Yes in S24, “1” is added to the first intermediate signal number for the first filter 13A (S25).

On the other hand, if it is determined No in S24, and after S25, the second output value is output by applying the second filter 13B to the received signal for 1 second acquired in S22 (S26; second filter). processing).
FIG. 8 is a flowchart showing the second filter processing. FIG. 9 is an example of a waveform diagram of a received signal. The received signal includes a high level signal P2 that is a 0 signal representing “0” and high level signals P1, P3 to P5 that are noise pulses. It shows the state.
In the output of the second output value using the second filter 13B, first, the maximum width signal detection unit 13B1 initializes a variable n indicating the signal sampled from the second synchronization timing T0 and stored in the storage unit 19. (N = 0) (S31). The total number N of signals sampled in one second is N = 128 (= 1000 / 7.8) because the sampling period is about 7.8 msec.
Further, the maximum width signal detection unit 13B1 initializes the maximum continuous count stored in the storage unit 19 to “0” (S32), and then sets the continuous count stored in the storage unit 19 to “0”. Initialization is performed (S33).
Thereafter, the maximum width signal detection means 13B1 adds “1” to the variable n (S34), and determines whether or not the variable n = N (S35).

  When it is determined No in S35, the signal level of the nth signal sampled by the sampling unit 11 is acquired (S36). Further, the maximum width signal detector 13B1 determines whether or not the signal level detected in S34 is a high level (S37).

As shown in FIG. 9, since the signal level of the received signal is low from the second synchronization timing T0 to before the signal start time T1 of the high level signal P1, it is determined No in S37. In this case, the maximum width signal detection means 13B1 determines whether the signal level detected in the previous sampling is high, that is, the low level signal detected in S36 this time is changed from the high level to the low level. It is determined whether the current time is changed (S38).
In FIG. 9, since the low level signal continues from the second synchronization timing T0 to before the signal start time T1, it is determined No in S38. When it is determined No in S38, the maximum width signal detection unit 13B1 returns the process to S33. For this reason, the processing of S33 to S38 is repeatedly executed until the signal start time T1.

When the signal level of the received signal changes from the low level to the high level at the signal start time T1, it is determined Yes in S37. When it is determined Yes in S37, the maximum width signal detection unit 13B1 adds 1 to the continuous count stored in the storage unit 19 (S39). That is, measurement of the signal width of the high level signal P1 is started.
Further, the maximum width signal detection means 13B1 determines whether the signal level detected in the previous sampling is low level, that is, the high level signal detected in S36 this time changes from low level to high level. It is determined whether it is the one at the time (S40).

In FIG. 9, the signal immediately before the signal start time T1 is a low level signal and has changed to a high level at the time of the signal start time T1, so that sampling immediately after the change to the high level is judged Yes in S40. .
When it is determined Yes in S40, the maximum width signal detector 13B1 detects the time from the second synchronization timing T0 to the timing when the received signal is sampled in S36. Then, the maximum width signal detection unit 13B1 updates the signal start time recorded in the storage unit 19 with the detected time (S41), and returns the process to S34.
After that, until the signal end time T11 of the high level signal P1, the signal level detected in S36 is at a high level, so it is determined Yes in S37. Further, since the signal level detected immediately before is high, it is determined No in S40. When it is determined No in S40, the maximum width signal detection unit 13B1 returns the process to S34.
Accordingly, during the period from the signal start time T1 to the signal end time T11, the processes of S34 to S37 and S39 to S40 are repeatedly executed. Thus, the continuous count stored in the storage unit 19 becomes a count corresponding to the signal width of the high level signal P1.

Next, when the signal level of the received signal changes from the high level to the low level at the signal end time T11, it is determined No in S37, and further, Yes is determined in S38. When it is determined Yes in S38, the maximum width signal detection unit 13B1 determines whether the continuous count stored in the storage unit 19 is larger than the maximum continuous count stored in the storage unit 19 (S42).
Since the maximum continuous count is “0” for the first time, it is determined Yes in S42. When it is determined Yes in S42, the maximum width signal detection unit 13B1 updates the maximum continuous count stored in the storage unit 19 with the continuous count stored in the storage unit 19 (S43).
Further, the maximum width signal detection unit 13B1 updates the maximum width signal start time stored in the storage unit 19 with the signal start time stored in the storage unit 19 (S44), and returns the process to S33.
Since the low level signal continues from the signal end time T21 to the signal start time T3, it is determined No in S37 and S38, respectively. Therefore, the maximum width signal detection unit 13B1 repeatedly executes the processes of S33 to S38.

Then, when the signal level of the received signal changes from the low level to the high level at the signal start time T2 of the next high-level signal to be transmitted, immediately after that, it is determined Yes in S37 and S40, and S34-S37, S39- The process of S41 is executed. Thereafter, while the high-level signal continues, it is determined Yes in S37 and No in S40, so that the processes of S34 to S37 and S39 to S40 are repeatedly executed. When the signal level of the received signal changes from the high level to the low level, it is determined No in S37, and the processes of S38 and S42 are executed.
Here, when the continuous count stored in the storage means 19 is larger than the maximum continuous count stored in the storage means 19 (Yes in S42), the process returns to S33 after executing S43 and S44.
On the other hand, when the continuous count stored in the storage unit 19 is equal to or less than the maximum continuous count stored in the storage unit 19 (No in S42), the process returns to S33.

If it is determined Yes in S35, the maximum continuous count stored in the storage means 19 is the continuous count of the maximum width signal having the largest high-level signal width among the received signals for one second from the second synchronization timing T0. It becomes. Further, the maximum width signal start time stored in the storage unit 19 is the signal start time of the maximum width signal. In the example of FIG. 9, the maximum continuous count is the continuous count of the high level signal P2 having the largest signal width, and the maximum width signal start time is the signal start time T2 of the high 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 19.

If one second has elapsed from the second synchronization timing T0 and it is determined Yes in S35, the determination timing setting unit 13B2 sets the timing at the center of the signal width of the maximum width signal as the determination timing TA (S45).
Further, the elapsed time detection means 13B3 detects the elapsed time from the second synchronization timing T0 to the determination timing TA (S46). Specifically, the elapsed time detection unit 13B3 divides the time obtained by multiplying the maximum continuous count stored in the storage unit 19 by the sampling period by two. The elapsed time detecting means 13B3 adds the time to the maximum width signal start time stored in the storage means 19, thereby outputting the elapsed time as the second output value. When the received signal is an M signal and no noise pulse exists, the received signal does not include a high level signal at all. In this case, after the processes of S37 to S38 are repeatedly executed for 1 second (for all the sampled signals), it is determined Yes in S35, and the process ends without setting the determination timing TA.
Further, the filter processing unit 13 appropriately stores the second output value output in S46 in the storage unit 19.

  Returning to FIG. 7, after the second filter processing S26, the intermediate signal number detection means 14 is a value in which the second output value output in S46 is included in the intermediate signal range (65 msec to 85 msec) for the second filter 13B. It is determined whether or not there is (S27). When it is determined Yes in S27, “1” is added to the second intermediate signal number for the second filter 13B (S28).

On the other hand, when it is determined No in S27 and after S28, the filter selection unit 15 determines whether or not the number of intermediate signals for 60 seconds has been recorded (S29). When it determines with No in S29, it returns to S22, receives the received signal for the next 1 second, and repeats the process of S23-S29.
In this embodiment, the predetermined time of the present invention is exemplified as 60 seconds, but is not limited to this, and if a distribution of output values substantially following the normal distribution as shown in FIG. 5 is obtained, Any time may be set. However, if the number of outputs of each output value is small, an accurate distribution cannot be obtained, causing a code determination error. Preferably, the output time is set to 60 seconds or more so that more than 60 output values are output. It is preferable that it is set.

When it is determined Yes in S29 and the filter process and the intermediate signal number detection process S5 are completed, as shown in FIG. 6, the filter selection unit 15 selects a filter to be used based on the intermediate signal number for each of the filters 13A and 13B. (Set) (S6).
Table 1 below shows an example of the detection result of the number of intermediate signals detected in S5.

In S6, the filter selection unit 15 selects one of the first filter 13A and the second filter 13B having a smaller number of intermediate signals as a use filter used for code determination. For example, in the example shown in Table 1 and FIG. 5, since the number of second intermediate signals for the second filter 13B is small, the second filter 13B is selected as the use filter.
Then, the code determination unit 16 determines the time code based on the output value output from the use filter (S7). Here, the code determination means 16 determines as the marker “M” when the output value is less than the predetermined value. As the predetermined value, for example, 40 msec is set for the first output value output from the first filter 13A, and for example, 20 msec is set for the second output value output from the second filter. The code determination means 16 determines an output value from the predetermined value to the intermediate value as a signal for the first code (bit value “0”), and outputs an output value equal to or higher than the intermediate value to the second code (bit value “1”). )).

After this, when the code determination process S7 ends, the code determination unit 16 stores the determined code value (any one of “0, 1, M”) in the storage unit 19 (S8).
Then, the code determination unit 16 decodes the acquired 60-bit time code to acquire time information, and outputs the time information to the time correction unit 17. Moreover, the time correction means 17 determines whether time information corresponds (S9).
Here, whether or not the time information matches is determined based on one of the two conditions described above.

If it is determined Yes in S9, it means that the correct time information has been acquired. Therefore, the time correcting means 17 outputs the acquired time information to the time measuring means 18, and the time measuring means 18 uses the time information as the internal time information. Is corrected (S10). 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 S9, the control means 10 confirms whether 8 minutes have elapsed since the start of reception (S11).
If 8 minutes have not elapsed in S11, the control means 10 repeats the process from S5. That is, in the present embodiment, as described above, the time information received as the second condition is compared with each other, the time information differs by the reception interval, and the time information is adjusted by adjusting the reception interval. It is determined whether there are three or more pieces of matching information among the received seven pieces of time information. For this reason, the signal reception process (S5 to S9) is repeatedly performed a plurality of times (minimum 3 times, maximum 8 times) continuously.
On the other hand, when 8 minutes have passed, it is determined No in S11, and the control unit 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, if the reception is terminated due to the determination of Yes in S11, the time adjustment means 17 does not output the reception time to the time measurement means 18, and the time measurement means 18 does not correct the time measurement.
In addition, although it is determined whether 8 minutes have passed since the start of reception, it is not limited to this, and may be 9 minutes or more, or 7 minutes or less. That is, the maximum number of times that the signal reception process is performed is not particularly limited.

[Operational effects of this embodiment]
In the present embodiment, the filter processing unit 13 applies the first filter 13A and the second filter 13B to the received signal, and outputs an output value from each filter. Further, the intermediate signal number detection means 14 determines between the first set value and the second set value from the output value output when each filter 13A, 13B is applied to the received signal for a predetermined period (60 seconds). The number of output values (number of intermediate signals) included in the intermediate signal range (130 to 170 msec for the first filter 13A and 65 to 85 msec for the second filter 13B) is detected. Then, the filter selection unit 15 selects the filter having the smallest number of intermediate signals as the use filter, and the code determination unit 16 determines the bit value (0, 1) in the time code based on the output value output from the use filter. , M).
The output value included in the intermediate signal range has a value because the received signal is mixed with noise pulses, etc., and the value is large, and the radio wave intensity is weak, and a received signal with sufficient signal strength cannot be obtained. A pattern that becomes smaller is conceivable, and it is unclear whether the output value corresponds to the first code or the output value corresponds to the second code. Therefore, if there are many output values included in the intermediate signal range, the rate of occurrence of code determination errors increases. In contrast, in the present embodiment, as described above, the output value is output from the received signal using the filter that minimizes the output value included in the intermediate signal range. For this reason, the occurrence of code determination errors can be reduced. As a result, regardless of the reception position and the reception time for receiving the standard radio wave, and when using the wristwatch type radio wave correction watch 1, whether or not the radio wave correction watch 1 is hidden by the user's sleeve is further increased. Can improve reception sensitivity regardless of whether or not the vehicle is moving.
In addition, since the reception sensitivity can be improved by the filter processing (program processing) by the control means 10, for example, a metal part (titanium or the like) that is unsuitable for receiving standard radio waves is used as the exterior case of the radio-controlled timepiece 1. Is also possible. That is, the freedom degree of the material used for each component of the radio-controlled timepiece 1 can be improved, and the design is improved.
Furthermore, for example, compared to a case where an output value is output using one type of filter and the appearance rate of each of the first set value and the second set value is calculated in real time from the distribution of the output value output by arithmetic processing. Thus, the processing load can be reduced. In other words, the wristwatch type radio-controlled timepiece 1 with a small amount of power supply and a limited space for placing an IC chip or the like does not require complicated arithmetic processing and can save power.

  In the present embodiment, the first filter 13A, which is one of the filters applied to the received signal by the filter processing means 13, outputs the sum total of the time that is high in the received signal for 1 second from the second synchronization timing T0 as the first output. Output as a value. That is, the first output value can be easily calculated by multiplying the high-level count included in one second from the second synchronization timing T0 detected by the sampling unit 11 by the sampling period. Therefore, the load of the first filter process using the first filter 13A can be reduced, and power saving can be achieved.

Further, the second filter 13B detects the maximum width signal having the largest high level signal width among the received signals for one second from the second synchronization timing T0, and determines the timing at the center of the signal width of the maximum width signal. As TA, an elapsed time from the second synchronization timing T0 to the determination timing TA is output as a second output value.
When a plurality of high level signals are present in the received signal for one second from the second synchronization timing T0, the signal width of the high level signal due to the influence of the noise pulse is usually smaller than the signal width of the normal signal. For this reason, the timing at which a normal signal is transmitted can be detected by detecting the maximum width signal. Accordingly, if the timing at 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 code width, that is, the high level signal width. As a result, if the elapsed time from the second synchronization timing T0 to the determination timing TA is output as the second output value, the time code can be accurately determined based on the second output value.

In the present embodiment, time correction is performed when time information of at least 3 minutes within 8 minutes is acquired and the second condition is satisfied. At this time, every time the signal reception process is performed for one minute, the filter process and the intermediate signal number detection process S5 are performed, and the used filter selection process S6 is performed.
For this reason, for example, even when the standard radio wave reception environment changes, such as when the user using the radio wave correction watch 1 is moving, it is possible to select a filter that can obtain the optimum reception sensitivity for the changed reception environment. it can. As a result, for example, after a used filter is selected once, the occurrence of a code determination error can be reduced compared to a case where the used filter is not changed for a predetermined time, and time correction based on the standard radio wave can be performed accurately.

[Second Embodiment]
Next, 2nd Embodiment of this invention is described based on drawing.
In 1st Embodiment mentioned above, when it determines with No in S11, the process of S5 and S6 was implemented again in the signal reception process with respect to the reception signal of the following 1 minute. That is, for each one-minute signal reception process, the number of intermediate signals for each of the filters 13A and 13B was detected, and the used filter was selected.
On the other hand, in the second embodiment, when S5 and S6 are performed and the filter to be used is selected in the signal reception process for the first one-minute reception signal, in each subsequent signal reception process for seven minutes, This is different from the first embodiment in that the previously used filter is used.

FIG. 10 is a flowchart illustrating time correction processing according to the second embodiment. In the following description, the same configurations and processes as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted or simplified.
As shown in FIG. 10, in the second embodiment, in the first one-minute signal reception process, the processes of S1 to S9 and S11 are performed as in the first embodiment. For this reason, in S6, the filter selection means 15 selects the used filter based on the number of intermediate signals.
And if it determines with No in S11, in this embodiment, it will return to the process of S7. That is, in the second and subsequent signal reception processes, the code determination process in S7 is performed using the use filter set in S6 in the first signal reception process.

[Operational effects of this embodiment]
In the present embodiment, in the first signal reception process, the process of S5 and S6 is performed to select the use filter. In the remaining 7 minutes of signal reception processing, code determination processing S7 is performed using the used filter selected in the initial signal reception processing.
For example, when the time is adjusted at a preset time (for example, midnight), the reception environment of the standard radio wave does not change. In such a case, the filters 13A and 13B are set for each signal reception process for 1 minute. Even if the filter processing using both or the detection processing of the number of intermediate signals is performed, there is a high possibility that the same use filter is selected, which is not suitable for power saving.
On the other hand, in this embodiment, since the filtering process and the number of intermediate signals detection process are not performed in the second and subsequent signal reception processes, the time correction process when the reception environment does not change as described above can be further saved. The generation of code determination errors can also be reduced by the process of selecting a filter to be used, which is performed in the initial signal reception process.

[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.

In the said 1st and 2nd embodiment, although the 1st filter 13A and the 2nd filter 13B were illustrated as a some filter in this invention, it is not limited to this.
For example, a third filter as shown in FIG. 11 may be used instead of the first filter 13A and the second filter 13B.
FIG. 11 is an example of a waveform diagram for explaining an output value calculation algorithm by the third filter.
The third filter detects the sum of the high-level signal widths included in the received signal for one second from the second synchronization timing T0, sets the half-value timing as the determination timing TB, and from the second synchronization timing T0 to the determination timing TB. The elapsed time is output as an output value.

For example, in the example of FIG. 11, the signal width (200 msec) of one signal is divided into five high level signals P <b> 1 to 5 due to the influence of noise pulses. In this example, the high level signal P1 has a signal start time T1 (elapsed time from the second synchronization timing T0) of 50 msec and a signal width of 15 msec. The high level signal P2 has a signal start time T2 of 75 msec and a signal width of 25 msec. The high level signal P3 has a signal start time T3 of 110 msec and a signal width of 70 msec. The high level signal P4 has a signal start time T4 of 195 msec and a signal width of 15 msec. The high level signal P5 has a signal start time T5 of 235 msec and a signal width of 15 msec.
In this case, the filter processing unit 13 calculates 70 msec, which is half of 140 msec obtained by adding all the signal widths of the high level signals P1 to P5.
Then, the filter processing means 13 sequentially subtracts the signal width of the high level signal from the high level signal P1 from this 70 msec. At this time, when subtraction is performed up to the high level signal P3, the subtraction result is “−40 msec” (= 70 msec−15 msec−25 msec−70 msec), that is, 0 or less, and the filter processing means 13 uses the high level signal P3 as a determination signal. . The filter processing means 13 adds 40 msec, which is the added value of the signal widths of the high level signals P1, P2, and 30 msec, which is the difference between the 70 msec, to the signal start time T3 (110 msec) of the high level signal P3. The determined timing is set to the determination timing TB (140 msec). Then, the filter processing means 13 detects the elapsed time from the second synchronization timing T0 to the determination timing TB and outputs it as an output value.
Even if such a filter is used, the same effect as each said embodiment can be acquired.

  In each of the above embodiments, the filter processing unit 13 applies two types of filters to the received signal and outputs the respective output values. However, three or more types of filters are applied to the received signal, respectively. Then, each output value may be output. For example, each output value may be output by applying each of the first filter 13A, the second filter 13B, and the third filter shown in FIG. 11 to the received signal. In this case, the code determination unit 16 selects a filter that minimizes the number of intermediate signals among these output values as a use filter.

In each of the above embodiments, the DCF 77 is exemplified as the standard radio wave. However, the present invention is not limited to this. For example, the standard radio wave “JJY” and the standard radio wave “WWVB” in the United States can be applied.
Here, in the Japanese standard radio wave “JJY”, the first level signal width (for example, high level signal width) corresponding to the code of the bit value “0” is 800 msec, and corresponds to the code of the bit value “1”. The signal width to be performed is 500 msec, and the signal width corresponding to the code of the marker “M” is 200 msec. Thus, when there are a plurality of codes corresponding to the time codes, the number of intermediate signals is detected based on the output values corresponding to the signal widths close to each other among the signal widths corresponding to each code.
Here, since the marker “M” is easily transmitted because the transmission timing is determined, the first set value is set to 800 msec corresponding to the code of the bit value “0” for the first filter 13A. Then, the second set value is set to 500 msec corresponding to the bit value “1”, and the intermediate signal range is 590 msec to 710 msec centering on the intermediate value (650 msec) between the first set value and the second set value. Detect the number of signals. For the second filter 13B, the first setting value is set to 400 msec corresponding to the code of the bit value “0”, the second setting value is set to 250 msec corresponding to the bit value “1”, The number of intermediate signals is detected with an intermediate signal range of 295 msec to 355 msec centered on an intermediate value (325 msec) between the first set value and the second set value.
In a state where the marker “M” and the bit value “1” are easily erroneously determined, the first set value is set to 500 msec corresponding to the code of the bit value “0” for the first filter 13A. Corresponding to the marker “M”, the second set value is set to 200 msec, the intermediate signal range is set to 290 msec to 410 msec centered on the intermediate value (350 msec) of the first set value and the second set value, and the number of intermediate signals is set. It may be detected. Similarly, for the second filter 13B, the first set value is set to 250 msec corresponding to the code of the bit value “0”, the second set value is set to 100 msec corresponding to the marker “M”, The number of intermediate signals may be detected using an intermediate signal range of 145 msec to 205 msec centered on an intermediate value (175 msec) between the first set value and the second set value.

Furthermore, for the first filter 13A, the first set value is set to 800 msec corresponding to the code of the bit value “0”, the second set value is set to 500 msec corresponding to the bit value “1”, Corresponding to the marker “M”, the third set value is set to 200 msec, 590 msec to 710 msec centered on the intermediate value between the first set value and the second set value is set to the first intermediate signal range, the second set value, and You may set 290 msec-410 msec centering on the intermediate value of a 3rd setting value as a 2nd intermediate signal range. Similarly, for the second filter 13B, the first set value is set to 400 msec corresponding to the code of the bit value “0”, the second set value is set to 250 msec corresponding to the bit value “1”, Corresponding to the marker “M”, the third set value is set to 100 msec, 295 msec to 355 msec centering on the intermediate value between the first set value and the second set value is set to the first intermediate signal range, the second set value, and You may set 145 msec-205 msec centering on the intermediate value of a 3rd setting value as a 2nd intermediate signal range.
In this case, for example, the intermediate signal number detection means 14 has, for each filter 13A, 13B, the number of output values included in the first intermediate signal range and the number of output values included in the second intermediate signal range. Or the ratio of the total value to the total number of output values may be detected as the number of intermediate signals.
Further, the intermediate signal number detection means 14 includes, for each of the filters 13A and 13B, the number of output values included in the first intermediate signal range and the number of output values included in the second intermediate signal range. One with a larger number may be detected as the number of intermediate signals. Alternatively, the larger of the ratio of the number of output values included in the first intermediate signal range to the total number of output values and the ratio of the number of output values included in the second intermediate signal range to the total number of output values May be detected as the number of intermediate signals.

  Further, the radio-controlled timepiece 1 may receive the standard radio wave preliminarily and perform main reception for time correction after the preliminary reception. In this case, for example, in preliminary reception, the processing of S1 to S6 in the first embodiment is performed to select a use filter. Thereafter, in this reception, time correction using the selected use filter is performed. In this case, the optimum use filter can be selected for the surrounding environment of the current radio-controlled timepiece 1 in the preliminary reception, and the standard radio wave reception process can be performed with good reception sensitivity in the main reception.

In the first embodiment, each filter 13A, 13B is applied to a received signal of 60 seconds from which time information can be acquired, and the number of intermediate signals is detected based on the output value from each filter 13A, 13B. , Used filter selected.
On the other hand, as described below, the time (60 seconds) in which the time information can be acquired may be divided into two, and the processing method may be changed in each.
That is, the filter processing means 13 performs the filtering process and intermediate signal of S5 and S6 on the received signal of the first first time (for example, the first 30 seconds) of the time (60 seconds) in which time information can be acquired. The number detection process and the used filter selection process are performed, the used filter is selected, and the code determination unit 16 performs code determination. Thereafter, the filter processing means 13 outputs the received signal of the remaining second time (for example, the second half 30 seconds) out of the time (60 seconds) in which the time information can be acquired, using the previously used filter. Output the value. The code determination means 16 performs code determination based on the output value that is output. Even with the above processing, the same operational effects as those of the above embodiments can be obtained, and it is not necessary to apply a plurality of types of filters to the received signal in the second time, so that the processing load can be reduced and saved. Electricity can be promoted.

In the second embodiment, the filter processing and the intermediate signal number detection processing are performed only for the first signal reception processing, the used filter is selected, and the subsequent used signal reception processing selects the previously used used filter. However, the use filter may not be changed for a predetermined period thereafter.
For example, the use filter selected in S6 may be used for a predetermined period (for example, one week) after performing the time adjustment process by receiving the standard radio wave.
Also, only when the time correction process is performed at a fixed time such as midnight, as shown in the second embodiment, the code determination is performed using the use filter selected for the first time, and the time correction process is performed manually. In this case, as shown in the first embodiment, the filter to be used may be selected for each signal reception process for one minute.

  In each of the above embodiments, the intermediate signal range is centered on the intermediate value between the first set value and the second set value, and ± 20% of the difference value between the first set value and the second set value is increased or decreased from the intermediate value. Although it was set as a range, it is not limited to this. The intermediate signal range may be set to any range as long as the intermediate value is included. For example, the intermediate signal range may be narrowed or widened according to the reception sensitivity. The lower limit value or the upper limit value of the intermediate signal range may be increased or decreased.

Furthermore, in the above-described embodiment, an example in which a filter having the minimum number of intermediate signals is selected as the use filter has been described, but the present invention is not limited to this.
For example, when the number of intermediate signals for the first filter 13A and the number of intermediate signals for the second filter 13B are the same value, or when the difference is less than a predetermined value and can be determined to be extremely small, more power saving can be achieved. The first filter 13A that can be used may be selected as the use filter.
In addition, when both the number of intermediate signals for the first filter 13A and the number of intermediate signals for the second filter 13B are equal to or greater than a predetermined threshold, a code determination error occurs regardless of which filter 13A, 13B is used. The time correction process may be canceled assuming that the rate is high.

  In addition, the specific structure 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 means (time display part), 4 ... Antenna (reception means), 5 ... Reception circuit (reception means), 10 ... Control means, 11 ... Sampling means, 12 ... Second synchronization detection means , 13 ... Filter processing means, 13A ... First filter, 13B ... Second filter, 13B1 ... Maximum width signal detection means, 13B2 ... Determination timing setting means, 13B3 ... Elapsed time detection means, 14 ... Intermediate signal number detection means, 15 ... Filter selection means, 16 ... Code determination means, 17 ... Time correction means (time information correction section), 18 ... Timekeeping means (timekeeping section), 19 ... Storage means.

Claims (8)

Receiving means for receiving a standard radio wave superimposed with a time code and outputting a received signal that changes to a first level and a second level different from the first level;
The signal width of the first level included in the received signal for one second from the second synchronization timing is defined with reference to the second synchronization timing at one second intervals at which the received signal changes from the second level to the first level. Filter processing means for outputting an output value for determination, and applying a plurality of types of filters having different output value calculation algorithms to the received signal to output the output value from each filter When,
Between the first set value that is the output value corresponding to the first code in the time code and the second set value that is the output value corresponding to a second code different from the first code in the time code. An intermediate signal range is set for each filter, and based on the number of output values included in the intermediate signal range among the output values output when the filter is applied to the received signal for a predetermined period Intermediate signal number detecting means for detecting the number of intermediate signals for each filter;
Filter selecting means for selecting one filter from each filter based on the number of intermediate signals detected for each filter;
Code determination means for determining a code of a signal for one second from the second synchronization timing based on the output value output by the filter selected by the filter selection means;
A standard radio wave receiver characterized by comprising: In the standard radio wave receiver according to claim 1,
The number of intermediate signals is the number of output values included in the intermediate signal range, or the ratio of the number of output values included in the intermediate signal range to the total number of output values,
The standard radio wave receiver according to claim 1, wherein the filter selection unit selects a filter that minimizes the number of intermediate signals. In the standard radio wave receiver according to claim 1 or 2,
The standard radio wave receiver according to claim 1, wherein the plurality of types of filters include a first filter that outputs, as the output value, a sum of times that become the first level in the received signal for one second from the second synchronization timing. The standard radio wave receiver according to any one of claims 1 to 3,
The plurality of types of filters detect a maximum width signal having the largest signal width of the first level in the received signal in a predetermined determination period from the second synchronization timing, and detect the maximum width from the second synchronization timing. A standard radio wave receiving apparatus comprising: a second filter that outputs an elapsed time until a predetermined determination timing of a period during which a signal is transmitted as the output value. In the standard radio wave receiver according to any one of claims 1 to 4,
A signal reception process for determining the code based on the reception signal of the predetermined period is performed continuously several times,
The standard radio wave receiving apparatus, wherein the filter selection means selects the filter based on the number of intermediate signals for each filter for each signal reception process. In the standard radio wave receiver according to any one of claims 1 to 4,
A signal reception process for determining the code based on the reception signal of the predetermined period is performed continuously several times,
The filter selection means selects the filter based on the number of intermediate signals in the first signal reception process,
The code determination unit determines the code based on the output value from the filter selected by the filter selection unit in the first signal reception process in the signal reception process a plurality of times. Standard radio wave receiver. A standard radio wave receiver according to any one of claims 1 to 6,
A timekeeping section that keeps internal time information,
A time information correction unit that acquires time information based on the code determined by the code determination unit of the standard radio wave receiver and corrects the internal time information;
A time display unit for displaying the internal time information;
A radio-controlled timepiece characterized by comprising: Receiving a standard radio wave on which a time code is superimposed, and outputting a received signal that changes to a first level and a second level different from the first level;
The signal width of the first level included in the received signal for one second from the second synchronization timing is defined with reference to the second synchronization timing at one second intervals at which the received signal changes from the second level to the first level. An output value for determination is output, and a plurality of types of filters having different output value calculation algorithms are applied to the received signal to output the output value from each filter,
Between the first set value that is the output value corresponding to the first code in the time code and the second set value that is the output value corresponding to a second code different from the first code in the time code. An intermediate signal range is set for each filter, and based on the number of output values included in the intermediate signal range among the output values output when the filter is applied to the received signal for a predetermined period Detect the number of intermediate signals for each filter,
Based on the number of intermediate signals detected for each filter, one filter is selected from each filter,
A standard radio wave receiving method, comprising: determining a code of a signal for one second from the second synchronization timing based on the output value output by the selected filter.

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