JP2012002769A - Second synchronization detecting device and radio clock - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a second synchronization detecting device capable of establishing a synchronization point by a relatively simple determination process even when a time code signal is finely sampled, and a radio clock including such second synchronization detecting device.SOLUTION: A second synchronization detecting device includes: sampling means (S18, S19) that detects a level of a time code signal in a predetermined sampling period; digitizing means (S21) that digitizes a change in the level detected by the sampling means; and calculating means that performs, on each of a series of values digitized by the digitizing means, an adding process (S26) for adding up each such value and multiple successive values around the value and a totalizing process (S21) for totalizing values for multiple seconds in a period of one second. Such second synchronization detecting device determines a synchronization point for every second, based on a series of values obtained by performing the adding process and the totalizing process in the calculating means.

Description

  The present invention relates to a second synchronization detection device that detects a synchronization point for each second of a time code signal, and a radio-controlled timepiece including the second synchronization detection device.

  In a conventional radio timepiece, first, a synchronization point that appears every second is detected with respect to a standard radio wave demodulated signal, and time information is generated by determining a pulse signal included in the demodulated signal based on this synchronization point. It is common to do.

  In Patent Document 1, a falling edge is detected from a demodulated signal of a standard radio wave for 10 seconds or more, and when it is determined that each time interval of a plurality of detected falling edges is close to 1 second, this falling edge is detected. A configuration for determining an edge as a second synchronization point is shown.

International Publication No. 2005/062137

  When noise is mixed in the standard radio wave, the time code signal obtained by demodulating the standard radio wave has a waveform fluctuation in which rising and falling edges are shifted in the time direction.

  Here, a case where a synchronization point is detected by sampling (sampling) a time code signal in which waveform fluctuation has occurred at two different sampling frequencies will be considered.

  First, let us consider a case where the sampling interval is increased (for example, sampling frequency 20 Hz = sampling interval 50 ms, etc.) so that the waveform blur falls within one or two consecutive sampling intervals. In this case, for example, when 10 synchronization points are detected in a 1 second cycle over 10 seconds, even if waveform blurring occurs, the same phase in the 1 second cycle is present in any of the 10 detections. The waveform change at the synchronization point is detected in one or two sampling periods. Therefore, the synchronization point can be easily determined. However, in this configuration, since the sampling interval is large, it is not possible to specify at which point in the sampling period the synchronization point is, and the accuracy of the synchronization point is lowered.

  Next, consider a case where the sampling interval is reduced (for example, sampling frequency 64 Hz = sampling interval 15.6 ms) so that the waveform blur spreads over a number of sampling periods. In this case, for example, when 10 synchronization points are detected in a 1-second period over 10 seconds, waveform changes representing the synchronization points are detected at different sampling periods every time the detection times differ due to waveform blurring, etc. The detection point of the synchronization point varies greatly. Therefore, as it is, there is a problem that it is not possible to easily determine the synchronization point as to which sampling period should be specified as a period having a synchronization point. However, in this configuration, since the sampling interval is small, if the synchronization point can be determined appropriately, the accuracy of the synchronization point is increased.

  An object of the present invention is to provide a second synchronization detection device that can determine a synchronization point by a relatively simple determination process even if a time code signal is sampled at a small sampling interval, and a radio clock including such a second synchronization detection device. Is to provide.

In order to achieve the above object, the invention according to claim 1
In a second synchronization detection apparatus for detecting the synchronization point by receiving a time code signal in which a predetermined change occurs in a signal waveform at a synchronization point every second,
Sampling means for detecting the level of the time code signal at a predetermined sampling period;
Quantification means for quantifying the level change detected by the sampling means;
For each of a series of values quantified by this quantification means, a summation process for summing the value and a plurality of consecutive values before and after the value, and a value for a plurality of seconds in a one-second cycle are overlapped. Arithmetic means for performing integration processing to be combined;
With
The synchronization point is determined based on a series of values obtained through the summing process and the summing process of the arithmetic means.

The invention according to claim 2 is the second synchronization detection device according to claim 1,
The computing means is
The summing process is performed a plurality of times such that the summing process is performed again on a series of values obtained by the summing process.

The invention according to claim 3 is the second synchronization detection device according to claim 1,
The numerical means is
If the level change is a change close to the change of the sync point, it will be a large value, if it is far from the change of the sync point, it will be a small value, and in any case, it will be a value of zero or more. It is a configuration that quantifies the change in the level,
The synchronization point is determined based on a timing at which a peak of a series of values obtained through the summation process and the summation process of the arithmetic means is present.

The invention according to claim 4 is the second synchronization detection device according to claim 1,
The present invention is characterized in that a calculation excluding means for excluding a value for a time code signal input during a period overlapping with the hand movement timing from the integrating process of the calculating means is provided.

The invention according to claim 5 is the second synchronization detection device according to claim 1,
In the case of receiving a standard radio wave that has an ideal signal waveform and does not have the predetermined change other than the synchronization point, and
If there is a peak in one of the series of values obtained by the processing of the computing means, the timing corresponding to this value is determined as the synchronization point,
When two consecutive values out of a series of values obtained by the processing of the calculating means are both peaks, the timing corresponding to any one value is determined as the synchronization point,
If the two discontinuous values in the series of values obtained by the processing of the computing means are both peaks, the synchronization point cannot be determined,
It is characterized by comprising synchronization point determination means for making it impossible to determine the synchronization point when both of three or more values in the series of values obtained by the processing of the arithmetic means are peaks. .

The invention according to claim 6 is the second synchronization detection device according to claim 1,
When receiving a standard radio wave that may cause the predetermined change even at a time point away from the synchronization point by a first period with an ideal signal waveform, and
If there is a peak in one of the series of values obtained by the processing of the computing means, the timing corresponding to this value is determined as the synchronization point,
When two consecutive values out of a series of values obtained by the processing of the calculating means are both peaks, the timing corresponding to any one value is determined as the synchronization point,
Of the series of values obtained by the processing of the computing means, if two values are both peaks in a range separated by the first period ± predetermined tolerance, the timing corresponding to the value on the front side is set. Determined as the synchronization point,
In the case where two values are both peaks in a series of values obtained by the processing of the calculation means, and are discontinuous and other than a range separated by the first period ± predetermined tolerance, the synchronization point Is undecidable,
It is characterized by comprising synchronization point determination means for making it impossible to determine the synchronization point when both of three or more values in a series of values obtained by the processing of the calculation means are peaks. .

The invention described in claim 7
A time measuring means for measuring time;
Radio wave receiving means for receiving a standard radio wave and demodulating the time code signal;
The second synchronization point detection device according to any one of claims 1 to 6, wherein the synchronization point is detected by receiving the time code signal demodulated by the radio wave reception means,
Decoding means for decoding the time code signal using the detection result of the synchronization point of the second synchronization point detection device to generate time information;
Time correcting means for correcting the time measured by the time measuring means based on the time information generated by the decoding means;
A radio-controlled timepiece characterized by comprising:

  According to the present invention, even when the sampling interval is set short with respect to the amount of blur of the time code signal, and the detection position of the waveform change representing the synchronization point varies greatly in the 1 second period, it is synchronized by the summing process by the arithmetic means. It becomes easier to narrow down to a single point as the point detection positions are averaged in the time axis direction. Therefore, even if the sampling interval is shortened, the synchronization point can be determined appropriately and easily. Further, the accuracy of the synchronization point can be increased by shortening the sampling interval.

1 is a block diagram illustrating an overall configuration of a radio timepiece that is an embodiment of the present invention. It is a data chart which shows the content of the waveform change value data stored in ROM. It is a flowchart which shows the process sequence of the time correction process performed by CPU. FIG. 4 is a first part of a flowchart showing a detailed processing procedure of a second synchronization detection process executed in step S4 of FIG. 3. 4 is a second part of a flowchart of second synchronization detection processing. FIG. 3 is a first part of an explanatory diagram showing an example of sampling processing and arithmetic processing. It is the 2nd part of explanatory drawing. It is the graph which represented a part of a series of values obtained by sampling processing and arithmetic processing in time series. FIG. 3 is a first part of an explanatory diagram showing an example of two patterns of sampling processing and arithmetic processing in which two types of sampling frequencies are applied for comparison and the summation processing is eliminated. It is the 2nd part of explanatory drawing. 8A and 8B are graphs showing a series of values obtained by sampling processing and arithmetic processing in time series, in which (a) is 20 Hz sampling without summing processing, and (b) is 64 Hz sampling without summing processing. belongs to. It is explanatory drawing showing an example of the OK determination range of FIG. It is a figure which shows the waveform of the standard radio wave of each country, (a) is Japan, (b) is the United States, (c) is the United Kingdom.

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

  FIG. 1 is a block diagram showing an overall configuration of a radio timepiece 1 according to an embodiment of the present invention.

  The radio timepiece 1 of this embodiment is an electronic timepiece having a function of receiving a standard radio wave including a time code and automatically correcting the time, and hands that rotate on a dial (second hand 2, minute hand 3, hour hand) 4) and the liquid crystal display 7 which is exposed on the dial and performs various displays, respectively, displays the time.

  As shown in FIG. 1, the radio timepiece 1 includes an antenna 11 that receives a standard radio wave, a radio wave receiving circuit (radio wave receiving means) 12 that demodulates the standard radio wave to generate a time code signal, and various timing signals. An oscillation circuit 13 and a frequency dividing circuit 14 to be generated, a time measuring circuit (time measuring means) 15 for counting the current time, a first motor 16 for rotationally driving the second hand 2, and a second motor for rotationally driving the minute hand 3 and the hour hand 4 17, a gear train mechanism 18 that transmits the rotational drive of the first motor 16 and the second motor 17 to each pointer, an operation unit 19 that has a plurality of operation buttons and inputs an operation command from the outside, and the entire device CPU (Central Processing Unit) 20 that performs various controls, RAM (Random Access Memory) 21 that provides CPU 20 with a working memory space, and various control data and control programs are stored. Further comprising the OM (Read Only Memory) 22 or the like.

  The radio wave receiving circuit 12 includes an amplifying unit that amplifies the signal received by the antenna 11, a filter unit that extracts only the frequency component corresponding to the standard radio wave from the received signal, and a time by demodulating the amplitude-modulated received signal. It includes a demodulator that extracts a code signal, a comparator that shapes the demodulated time code signal into a high level signal and a low level signal, and outputs the signal to the outside. The radio wave receiving circuit 12 is not particularly limited, and has a low active output configuration in which the output becomes low level when the standard radio wave has a large amplitude and the output becomes high level when the standard radio wave has a small amplitude. It has become.

  The frequency dividing circuit 14 can change the frequency dividing ratio to various values in response to a command from the CPU 20, and can output a plurality of types of timing signals to the CPU 20 in parallel. It has become. For example, in order to update the timing data of the timing circuit 15 with a 1-second cycle, a timing signal with a 1-second cycle is generated and supplied to the CPU 20 and a time code signal output from the radio wave receiving circuit 12 is captured. A timing signal having a sampling frequency is generated and supplied to the CPU 20.

  The first motor 16 and the second motor 17 are stepping motors. The first motor 16 steps the second hand 2 and the second motor 17 independently steps the minute hand 3 and hour hand 4, respectively. In a normal time display state, the first motor 16 is driven one step every second to rotate the second hand 2 once in one minute. The second motor 17 is driven one step every 10 seconds to rotate the minute hand 3 once in 60 minutes and rotate the hour hand 4 once in 12 hours.

The RAM 21 is provided with a waveform value memory area 21a used in the second synchronization detection process described later. The waveform value memory area 21a is a data area in which values representing changes in the waveform of the time code signal are sequentially added when the time code signal is sampled at a predetermined sampling frequency (for example, 64 Hz). A plurality of waveform value memories A _{0 to} A ₆₃ each capable of storing values of a plurality of frames (for example, 64 frames) divided at intervals are provided.

  Further, the RAM 21 is provided with a storage area 21b for city data. The city data is set and input by the user via the operation unit 19, and the type of standard radio wave received based on the city data (for example, Japanese standard radio wave JJY, US standard radio wave WWVB, UK standard radio wave MSF, etc.) ) Is distinguishable. Note that the method for determining the type of the standard radio wave is not limited to the method based on the city data, and various methods can be applied. For example, it may be configured to make a determination by receiving a plurality of types of standard radio waves and searching for actually receivable standard radio waves.

  The ROM 22 stores a time correction processing program 22b that receives a standard radio wave and automatically corrects the time as one of the control programs. Further, waveform change value data 22a used in the second synchronization detection process is stored as one of the control data.

  FIG. 2 shows a data chart showing the contents of the waveform change value data 22a. FIG. 11 is a diagram for explaining standard radio waves in each country. FIG. 11A shows the waveforms of standard radio waves in Japan, FIG. 11B shows the United States, and FIG.

  The waveform change value data 22a is data for digitizing the waveform change of the time code signal in the second synchronization detection process described later, and is a synchronization point (0.00 seconds, 1.00 seconds... 59 for each second. .0 seconds synchronization point (hereinafter also referred to as second synchronization point), a large value if the change is close to the waveform change, and a small value if the change is far from the waveform change at the second synchronization point. But it is set to be zero or more.

  Specifically, in the Japanese standard radio wave JJY, the second synchronization point changes from the high level (H) to the low level (L) in the low active time code signal. Therefore, “+2” for the waveform change of “H → L” and “± 0” for the waveform change of “L → H”, “H → H” and “L → L”. "+1" is associated with the waveform change "."

  For standard radio waves other than Japan (for example, WWVB and MSF), the second synchronization point changes from a low level (L) to a high level (H) in a low-active time code signal. Therefore, “+2” for the waveform change of “L → H” and “± 0” for the waveform change of “H → L”, “H → H” and “L → L”. "+1" is associated with the waveform change "."

  Next, a time correction process executed in the radio timepiece 1 having the above configuration will be described.

  FIG. 3 shows a flowchart of time correction processing executed by the CPU.

  The time adjustment process is started when a preset time is reached or when a predetermined operation command is input via the operation unit 19.

  During execution of the time adjustment process, the second hand 2 is controlled to be stopped every second while the minute hand 3 and the hour hand 4 are moved every 10 seconds. Therefore, when the time adjustment process is started, the CPU 20 first fast-forwards the second hand 2 to the position indicating that radio waves are being received on the dial, and sets the hand movement flag of the second hand 2 in the RAM 21 to OFF (step S1). ). Thereby, the hand movement process of the second hand 2 per second is stopped. Further, the time display process is executed in parallel with the time correction process, so that the minute hand 3 and the hour hand 4 are moved every 10 seconds.

  Next, the CPU 20 reads city data from the RAM 21 in order to specify the type of standard radio wave that can be currently received (step S2). Then, the radio wave receiving circuit 12 is operated so as to correspond to the currently receivable standard radio wave, and the reception process is started (step S3). As a result, a standard radio wave is received and a time code signal represented by a high level and a low level is supplied from the radio wave receiving circuit 12 to the CPU 20.

  When the time code signal is supplied, first, the CPU 20 executes a second synchronization detection process for detecting a second synchronization point from the time code signal (step S4). This second synchronization detection processing program and the CPU 20 executing the program constitute a second synchronization detection device. Details of this second synchronization detection process will be described later.

  When the second synchronization point is detected, the CPU 20 subsequently determines a plurality of pulse signals included in the time code signal with reference to the detected second synchronization point to generate time information (step S5: decoding). means). Then, the clock data of the clock circuit 15 is corrected based on the time information and the detected second synchronization point (step S6: time correction means). Further, if necessary, the hour hand 4 and the minute hand 3 are fast-forwarded to correct the position of the pointer (step S7). Further, the hand movement flag of the second hand 2 is turned on so that the stopped second hand 2 is driven in synchronization with the time measurement data (step S8), and this time correction processing is ended.

  Next, the second synchronization detection process executed in step S4 will be described in detail.

  4 and 5 are flowcharts of the second synchronization detection process, and FIGS. 6A and 6B are explanatory diagrams of the sampling process and the arithmetic process executed during the second synchronization detection process.

[Sampling, digitization, integration processing]
First, the sampling process, the waveform change digitization process, and the integration process executed in the second synchronization detection process will be described.

  In the second synchronization detection process, the CPU 20 samples the level of the time code signal (high level or low level in this embodiment) at a predetermined frequency (for example, 64 Hz), and digitizes the waveform change. Then, this sampling and digitization process is performed a plurality of times (for example, 10 times and 10 seconds) at a cycle of 1 second. 6A and 6B, the “first waveform data processing” to “10th waveform data processing” column shows 10 sampling waveforms and numerical results for a sampling period of 12 frames out of 64 frames per second. Each is shown.

  The digitization of the waveform change is performed according to the waveform change value data 22 a in the ROM 22. 6A and 6B show a case where a Japanese standard radio wave JJY is received. Here, waveform change value data for the Japanese standard radio wave JJY is applied. That is, when the level of the time code signal changes from “H (high level) → L (low level)”, it changes to “2”, when it changes from “L → H” to “0”, “H → H ”Or“ L → L ”, the numerical value is changed to“ 1 ”.

The waveform change values are respectively accumulated in the waveform value memories A _{0 to} A ₆₃ at a cycle of 1 second. That is, the waveform change values of 64 frames per second are added to the waveform value memories A _{0 to} A ₆₃ , respectively, and this addition is repeated for a plurality of seconds in a 1 second cycle. The value after the integration processing is shown in the row of “10 integrations” in the lowermost column of FIG. 6B.

  In addition, during the above-mentioned processing for a plurality of seconds, when one second overlapping with the hand movement timing of the minute hand 3 and the hour hand 4 is included, it is considered that a large hand movement noise is mixed in the sampling data for one second. And excluded from the above integration processing. In the example of FIG. 6A and FIG. 6B, since one second of “seventh waveform data processing” overlaps with the hand movement timing, the value in this column is excluded from the integration processing.

  The sampling, digitization, and integration processes are realized by the processes in steps S11 to S25 in the flowchart of FIG. That is, when the process proceeds to the second synchronization detection process, the CPU 20 first determines whether or not the standard radio wave being received is JJY (step S11). If the standard radio wave JJY is set, the waveform change value data for JJY among the waveform change value data 22a of the ROM 22 is set to be used (step S12). Are set so that waveform change values other than JJY are used (step S13).

Next, the CPU 20 performs initialization processing such as clearing of the waveform value memories A _{0 to} A ₆₃ (step S14), and switches the frequency dividing ratio of the frequency dividing circuit 14 to a value corresponding to the sampling frequency (64 Hz) (step S15). ). Further, the first level detection of the time code signal output from the radio wave receiving circuit 12 is performed (step S16). Then, the process proceeds to a processing loop (steps S17 to S24) for sampling for 10 seconds in a 1-second cycle.

When the processing loop is entered, first, the CPU 20 initializes a variable i representing the number of frames sampled for 64 frames per second to zero (step S17), and waits for input of a timing signal from the frequency divider circuit 14 (step S17). S18) If a timing signal is input, the level of the time code signal is detected (step S19: sampling means). Then, it is determined whether or not the hand movement timing of the minute hand 3 and the hour hand 4 is one second overlapping (step S20: calculation excluding means), and if it is not the overlapping period, the waveform change value corresponding to the i-th waveform value memory A _i is added. (Step S21: Numerical means). The waveform change value is a value representing a waveform change from the previous sampling level to the current sampling level, and the value set in step S12 or S13 is applied. On the other hand, if it is 1 second that overlaps with the hand movement timing, the adding process in step S21 is omitted.

  Thereafter, “1” is added to the variable i (step S22), and it is determined whether or not the variable i is equal to or greater than “64” (step S23). If it is not "64" or more, the process returns to step S18. On the other hand, if “64” or more, it is determined whether 64 frames have been sampled 10 times (step S24), and if not, the process returns to step S17.

  By such loop processing, the above-described sampling, digitization, and integration processing are respectively performed. Then, after sampling 64 frames 10 times, the process proceeds to “Yes” in the discrimination process of step S24 and exits the loop process. Then, the frequency dividing ratio of the frequency dividing circuit 14 switched in step S15 is reset (step S25).

[Total processing]
Next, the summing process will be described. When sampling for 10 seconds, digitization of waveform change, and integration processing are completed, the CPU 20 then sets the respective values for the values of the 64-frame waveform value memories A _{0 to} A ₆₃ after the integration processing, A summing process for summing up the values of a plurality of consecutive frames is performed twice (step S26). The calculation means is constituted by the processing of step S21 and step S26.

Specifically, as shown in the second column from the top in FIG. 6A, in the first summing process, a process of summing the values of the three successive frames to the respective values of 64 frames is performed. In the first summing process, a process of summing the values of the three consecutive frames ahead is performed for each of the series of values obtained in the first summing process. In the “Calculated values for 10 frames” column of FIG. 6B, the “Total 3 frames (first time)” row and the “3 frames total (second time)” row are added to the above first time and second time. Each processed value is shown. The series of values subjected to the summation processing is stored in, for example, the 64 frame waveform value memories A _{0 to} A ₆₃ .

  FIG. 7 shows a graph in which a part of a series of values after the summing process is represented in time series.

  A series of values as shown in FIG. 7 is obtained by the arithmetic processing as described above. FIG. 7 shows a portion of 12 frames including a second synchronization point in a series of values of 64 frames per second. As shown in this graph, even when the time code signal contains noise or waveform fluctuations, the series of values that have undergone the above integration and summation processes clearly reveals the high probability that a second sync point exists. It will be expressed as a large peak.

  In other words, random noise is integrated by multiplying the waveform change values for a plurality of times in a 1-second cycle, and the effect is reduced. For waveform blurring, the value of the second synchronization point is obtained by adding the waveform change values in the time series direction. The detection positions are narrowed down to one point as if they were averaged in the time axis direction, and as a result, a portion with a high probability that a second synchronization point exists appears as a heak.

  FIG. 8A and FIG. 8B are explanatory diagrams showing an example of processing of two patterns in which two kinds of sampling frequencies are applied for comparison and the summation processing is eliminated, and FIG. 9A shows these two patterns. FIG. 9B is a graph showing a part of a series of values obtained by 20 Hz sampling processing and arithmetic processing without summation processing in FIG. 9B. FIG. 9B shows sampling processing at 64 Hz and no summing processing. A graph showing a part of a series of values obtained by the arithmetic processing in time series is shown.

  As shown in the first row in each column of FIGS. 8A and 8B, if the sampling interval is set long, such as a sampling frequency of 20 Hz, even if there is waveform blurring, the waveform change at the second sync point is one or It will be detected in two consecutive sampling intervals. Accordingly, as shown in FIG. 9A, a large peak appears at a location including the second synchronization point, and the second synchronization point is easily determined. However, since the sampling interval is large, it is unclear at which time point in one sampling period the second synchronization point is, and the accuracy of the second synchronization point is lowered.

  On the other hand, as shown in the second row of each column in FIGS. 8A and 8B, when the sampling interval is set to be short, for example, the sampling frequency is set to 64 Hz, second synchronization is caused by the influence of waveform blurring and noise mixing. Point waveform changes are detected at different sampling periods. Therefore, as shown in FIG. 9B, simply by performing the integration processing of the waveform change values for 10 lines, the peaks are scattered in the series of integrated values, and the second synchronization point is included in any sampling period as it is. It will be difficult to determine if In the example of FIG. 9B, the peak of the maximum value appears at the same position as in the example of the present embodiment (FIG. 7). Peaks appear at multiple locations that are shifted.

In the second synchronization detection process of the present embodiment, as shown in FIG. 7, noise and waveform blur are slightly included depending on the values of the waveform value memories A _{0 to} A ₆₃ obtained by the integration process and the addition process described above. Even in the time code signal, a portion with a high probability that a second synchronization point exists appears as a clear peak.

[Second sync point confirmation process]
Next, a process for determining the second synchronization point based on the values of the waveform value memories A _{0 to} A ₆₃ will be described. After performing the summing process in step S26, the CPU 20 proceeds to a process of determining the second synchronization point based on the sampling period in which the series of peak values after the calculation exists (steps S27 to S35; FIG. 5). This process constitutes synchronization point determination means.

  The process of determining the second synchronization point is performed under different conditions depending on the type of standard radio wave. That is, in the British standard radio wave MSF, in the ideal signal waveform, the same waveform change as the waveform change at the second synchronization point may occur at times other than the second synchronization point. Specifically, as shown in FIG. 11C, the waveform of the standard radio wave MSF changes from a large amplitude to a small amplitude at the second synchronization point. In the pulse signal with the “01” code of the standard radio wave MSF, the same waveform change appears 200 ms after the second synchronization point.

  On the other hand, in the Japanese standard radio wave JJY and the US standard radio wave WWVB, in the ideal signal waveform, the same waveform change as the waveform change at the second synchronization point does not occur at other time points.

Therefore, after proceeding to the process of determining the second synchronization point, first, the CPU 20 determines whether or not the type of the standard radio wave currently being received is an MSF (step S27). If it is not an MSF, a portion having a peak is searched for from the values of the waveform value memories A _{0 to} A ₆₃ , and the number of peaks and the arrangement relation are determined (step S 28).

  As a result of this determination processing, when there is only one peak, one time point within the sampling period corresponding to the peak is determined as the second synchronization point (step S29). If there are two continuous waveform values in the waveform value memory, one time point in the sampling period corresponding to the front peak is determined as the second synchronization point (step S30). If there are peaks in two non-continuous waveform value memories, or if there are peaks at three or more locations, it is determined that an incorrect time code signal is input due to a poor reception environment. The second synchronization point cannot be determined (step S31).

In the example of FIG. 7, when a standard radio wave JJY is received, a peak clearly appears at one point of the waveform value memories A _{0 to} A ₆₃ , so that one point in time during the sampling period in which this peak is present is synchronized with the second. Confirmed as a point.

  If the time code signal of the radio wave receiving circuit 12 has a characteristic such as a predetermined delay, appropriate adjustments such as setting the second synchronization point to the time when the amount of delay is subtracted from the time when the peak is present are performed. Done.

On the other hand, if the standard radio wave is an MSF, the process proceeds to “Yes” in the determination process in step S27, and the MSF determination process is performed regarding the number of peaks and the peak arrangement relationship of the waveform value memories A _{0 to} A ₆₃ ( Step S32).

  As a result of this determination processing, when there is only one peak, one time point within the sampling period corresponding to the peak is determined as a second synchronization point (step S33). If there are two continuous waveform values in the waveform value memory, one time point in the sampling period corresponding to the front peak is determined as the second synchronization point (step S34). If two peaks are discontinuous and the interval is within an OK determination range described later, one time point within the sampling period corresponding to the front peak is determined as a second synchronization point (step S34). .

  Further, if there are two non-continuous peaks and the interval is not within the OK determination range described later, it is determined that an inaccurate time code signal is input, and the second synchronization point cannot be determined (step) S35). Even when there are peaks at three or more locations, the second synchronization point cannot be determined by the same determination (step S35).

  FIG. 10 is a diagram for explaining an OK determination range used in determination for determining the second synchronization point of the standard radio wave MSF.

  The OK determination range is, for example, a range indicated by an arrow in FIG. 10A (a range from 150 ms to 250 ms with respect to the second synchronization point). That is, in the pulse signal (a) of the “01” code of the standard radio wave MSF, it is allowed before and after the time interval (200 ms) from the change of “L → H” of the second synchronization point to the next change of “L → H”. This is a range to which an error (for example, ± 50 ms) is added.

  There are cases where a plurality of “01” codes are transmitted continuously in a time code. For this reason, when radio waves are received for detecting the second synchronization in a section where a plurality of “01” codes are arranged, an accurate time code signal is generated. Even if it is input, two peaks appear at the second synchronization point and the next “L → H” waveform change portion. Therefore, in this case, the second synchronization point is determined within the period corresponding to the front peak without disabling the determination of the second synchronization point.

  Note that the condition for determining the second synchronization point is not limited to the examples of steps S28 to S31 and S32 to S35. For example, when there are two consecutive peaks, the second synchronization point may be determined in a period corresponding to the rear peak. In addition, when three consecutive peaks occur, the second sync point can be determined during the period corresponding to one of the peaks, or the second sync point cannot be determined when the peak value is lower than the predetermined threshold. You may make it. Also, the sampling frequency, total sampling period, and summation processing can be performed, for example, by making the peak value wider so that a value slightly smaller than the maximum value is also regarded as a peak and the number of peaks and arrangement relation are determined. Various conditions can be changed according to the method.

  When the second synchronization point is determined or cannot be determined by the processes of steps S28 to S31 and S32 to S35, the second synchronization detection process is terminated and the process returns to the time correction process of FIG. When the second synchronization point is determined, as described above, the time code decoding process and the time correction process are performed using the second synchronization point.

  As described above, according to the radio timepiece 1 and its second synchronization detection process of this embodiment, a time code signal is sampled, its waveform change is quantified, and a series of values obtained by this quantification are cycled at 1 second intervals. An integration process for integrating the values for 10 seconds and an addition process for adding a plurality of values in the time axis direction are performed, and a second synchronization point is detected from a series of values obtained by these calculation processes. Yes. At this time, the influence of random noise is reduced by the above arithmetic processing, and the detection position of the second synchronization point is averaged in the time axis direction even when the waveform blur spreads over a plurality of sampling periods. It becomes easy to squeeze to one point as was done.

  Therefore, even if the sampling interval is set to be small so that the accuracy of the second synchronization point is increased, the second synchronization point can be easily determined.

  In addition, according to the radio timepiece 1 and the second synchronization detection process of the above embodiment, since the summation process of summing a plurality of values obtained by sampling in a time series direction is repeated twice, the second synchronization point Thus, it is possible to more surely obtain the effect that the detection positions are easily reduced to one point as if they were averaged in the time axis direction.

  Further, according to the radio timepiece 1 and the second synchronization detection process of the above embodiment, when the sampling waveform change is digitized, a numerical value is set so that a larger value is obtained when the waveform change at the second synchronization point is closer, and a smaller value is obtained when the distance is far. It has become. Therefore, by performing the above arithmetic processing, it is possible to easily determine a location having a high probability that a second sync point detection position exists as a numerical peak. In addition, since negative values are not used when quantifying the waveform change, when determining the peak by comparing the magnitude of a series of values, if the value is negative or negative Arithmetic processing such as switching the size comparison algorithm to that is not necessary. That is, the processing load for determining a peak from a series of values can be reduced.

  Further, according to the above-described embodiment, since a series of values obtained by sampling for 1 second in which the hand movement timings of the minute hand 3 and the hour hand 4 overlap each other are excluded from the integration process and the addition process, the second synchronization point It is possible to eliminate the influence of the large noise mixed with the movement of the hand.

In the above embodiment, the waveform value memories A _{0 to} A ₆₃ capable of storing the values for 64 frames are prepared, and the waveform change values are added to the waveform value memories A _{0 to} A ₆₃ in one second cycle. in performs multiplication processing, addition, since also performed a plurality of times of summing containing values after calculation in the waveform value memory a ₀ to a ₆₃ in the summing, required for detection processing of the second synchronization point memory The capacity can be reduced.

  Further, according to the above embodiment, by determining the second synchronization point under the conditions of steps S28 to S31 in FIG. 5, accurate second synchronization is performed with respect to a standard radio wave in which the waveform change of the second synchronization point does not appear in other places. A point determination process can be performed. Further, by determining the second synchronization point under the conditions of steps S32 to S35 in FIG. 5, the accurate second synchronization point is determined with respect to the standard radio wave MSF in which the waveform change of the second synchronization point may appear in other places. Processing can be performed.

  The present invention is not limited to the above-described embodiment, and various modifications can be made. For example, in the above-described embodiment, an example in which sampling for 10 seconds is performed for detection of the second synchronization point has been described. However, for example, it can be appropriately changed to 5 seconds, 15 seconds, or 20 seconds. In addition, the time code signal to be sampled is a binary signal. For example, the time code signal to be sampled is a signal before waveform shaping, and the level of the sampled signal is captured as multi-level data to change the waveform. You may make it detect.

  In the above embodiment, an example is shown in which a series of values obtained by sampling and quantification of waveform changes are integrated in a 1-second cycle, and thereafter, summing processing in the time-series direction is performed. The order of the summing process and the summing process is not particularly limited. For example, the processing may be performed and the series of values after the summing process may be summed in a 1-second cycle.

  Further, in the above-described embodiment, as a process of adding a time series direction to a series of values, a first addition process of adding the values of the front three frames and a second addition of adding the values of the rear three frames. Although the configuration for performing the processing is shown, the number of frames to be added, the number of times, and the calculation method of the addition can be variously changed. For example, when the sampling interval is set shorter, the values of 5 frames and 10 frames may be added together, or the number of summing processes may be increased. In addition to simply adding the values of multiple frames, the calculation method of summing can be calculated by applying the simple moving average calculation method by dividing by the number of frames, or by adding appropriate weights to each frame. A method of calculating a moving average may be applied.

  In the above embodiment, in order to quantify the waveform change, all values are set to zero or a positive value, so that a change close to the waveform change at the second synchronization point is a large value and a far change is a small value. Although an example has been shown, on the contrary, only negative values may be used, or positive and negative values may be mixed. In addition, the details shown in the embodiments can be changed as appropriate without departing from the spirit of the invention.

DESCRIPTION OF SYMBOLS 1 Radio clock 2 Second hand 3 Minute hand 4 Hour hand 7 Liquid crystal display 11 Antenna 12 Radio wave reception circuit 13 Oscillation circuit 14 Dividing circuit 15 Timekeeping circuit 16 1st motor 17 2nd motor 19 Operation part 20 CPU
21 RAM
21a Waveform value memory area 21b City data storage area 22 ROM
22a Waveform change value data 22b Time correction processing program

Claims (7)

In a second synchronization detection apparatus for detecting the synchronization point by receiving a time code signal in which a predetermined change occurs in a signal waveform at a synchronization point every second,
Sampling means for detecting the level of the time code signal at a predetermined sampling period;
Quantification means for quantifying the level change detected by the sampling means;
For each of a series of values quantified by this quantification means, a summation process for summing the value and a plurality of consecutive values before and after the value, and a value for a plurality of seconds in a one-second cycle are overlapped. Arithmetic means for performing integration processing to be combined;
With
The second synchronization detection apparatus, wherein the synchronization point is determined based on a series of values obtained through the summation process and the integration process of the arithmetic means. The computing means is
The second synchronization detection apparatus according to claim 1, wherein the summing process is performed a plurality of times such that the summing process is performed again on a series of values obtained by the summing process. The numerical means is
If the level change is a change close to the change of the sync point, it will be a large value, if it is far from the change of the sync point, it will be a small value, and in any case, it will be a value of zero or more. It is a configuration that quantifies the change in the level,
2. The second synchronization detection apparatus according to claim 1, wherein the synchronization point is determined based on a timing at which a peak of a series of values obtained through the summation process and the integration process of the arithmetic means is present.   2. The second synchronization detection apparatus according to claim 1, further comprising a calculation excluding unit that excludes a value of a time code signal input during a period overlapping with a hand movement timing from the integration process of the calculating unit. In the case of receiving a standard radio wave that has an ideal signal waveform and does not have the predetermined change other than the synchronization point, and
If there is a peak in one of the series of values obtained by the processing of the computing means, the timing corresponding to this value is determined as the synchronization point,
When two consecutive values out of a series of values obtained by the processing of the calculating means are both peaks, the timing corresponding to any one value is determined as the synchronization point,
If the two discontinuous values in the series of values obtained by the processing of the computing means are both peaks, the synchronization point cannot be determined,
A synchronization point determination unit is provided that makes it impossible to determine the synchronization point when three or more of the series of values obtained by the processing of the calculation unit are peaks. The second synchronization detection apparatus according to claim 1. When receiving a standard radio wave that may cause the predetermined change even at a time point away from the synchronization point by a first period with an ideal signal waveform, and
If there is a peak in one of the series of values obtained by the processing of the computing means, the timing corresponding to this value is determined as the synchronization point,
When two consecutive values out of a series of values obtained by the processing of the calculating means are both peaks, the timing corresponding to any one value is determined as the synchronization point,
Of the series of values obtained by the processing of the computing means, if two values are both peaks in a range separated by the first period ± predetermined tolerance, the timing corresponding to the value on the front side is set. Determined as the synchronization point,
In the case where two values are both peaks in a series of values obtained by the processing of the calculation means, and are discontinuous and other than a range separated by the first period ± predetermined tolerance, the synchronization point Is undecidable,
It comprises synchronization point determination means for making it impossible to determine the synchronization point when three or more of the series of values obtained by the processing of the calculation means are both peaks. The second synchronization detection apparatus according to claim 1. A time measuring means for measuring time;
Radio wave receiving means for receiving a standard radio wave and demodulating the time code signal;
The second synchronization point detection device according to any one of claims 1 to 6, wherein the synchronization point is detected by receiving the time code signal demodulated by the radio wave reception means,
Decoding means for decoding the time code signal using the detection result of the synchronization point of the second synchronization point detection device to generate time information;
Time correcting means for correcting the time measured by the time measuring means based on the time information generated by the decoding means;
A radio timepiece characterized by comprising.

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