JP2014081245A - Radio wave correction clock and signal detection method of radio wave correction clock - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radio wave correction clock that can surely perform a second synchronization upon reception of a standard radio wave.SOLUTION: The radio wave correction clock comprises: a binarization circuit 37 that outputs a binarization signal having an envelope signal binarized; a determination timing setting part 411 that sets a determination timing for determining g a signal detection determination; and a signal detection determination part 412 that acquires the binarization signal for every second with reference to the determination timing, and determines whether an every second signal can be detected or not. The determination timing setting part 411 sets a timing generated at an interval of 1 sec. before a prescribed time of a start timing of a signal maximum in a signal width of a first level during a first determination period as the determination timing. The signal detection determination part 412 sequentially acquires a signal for 1 sec. from the determination timing, detects the start timing of the signal maximum in the signal width of the first level among the signals for 1 sec., detects an interval of the start timing and determines whether the every second signal can be detected or not.

Description

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

A radio-controlled timepiece that receives a standard radio wave and corrects the internal time based on the received standard radio wave is known (Patent Document 1). The standard radio wave is transmitted by subjecting a time code of 1 Hz to amplitude modulation with a carrier wave of a predetermined frequency. Therefore, when receiving a standard radio wave, in order to determine a signal per second, first, a second synchronization process for detecting a signal timing per second is performed.
For this reason, Patent Document 1 includes second synchronization detection means, which confirms the timing at which the received signal changes from the second level (for example, low level) to the first level (for example, high level). If the timing interval is 5 consecutive times for 1 second ± 62.5 msec, it is determined that the second synchronization is established.

JP 2011-214871 A

The second synchronization detection method can correctly detect when the radio wave intensity of the standard radio wave is strong. However, when the radio wave intensity is weak, a change from the second level to the first level occurs even during the change timing of the second due to the mixing of noise, and the change timing due to this noise is determined to be a normal signal change. There was a risk of it.
For this reason, a noise signal is input after the normal signal, and then the next normal signal is input. Therefore, the interval of the change timing of each signal greatly deviates from the one second interval, and the establishment of the second synchronization is established. Cannot judge. For this reason, there are problems that it takes time to establish the second synchronization, the reception time is long, and the power consumption increases.
Furthermore, there is a problem that the reception of the standard radio wave may fail because the second synchronization cannot be established.

  An object of the present invention is to provide a radio-controlled timepiece and a signal detection method for a radio-controlled timepiece that can reliably perform second synchronization when receiving a standard radio wave.

  The radio-controlled timepiece of the present invention includes a receiving unit that receives a standard radio wave including time information and outputs a reception signal, a detection unit that detects the reception signal output from the reception unit and outputs an envelope signal, A binarization unit that outputs a binarized signal obtained by binarizing the envelope signal output by the detector; a determination timing setting unit that sets a determination timing for signal detection determination based on the binarized signal; The binarization includes a signal detection determination unit that acquires the binarized signal per second based on the determination timing set by the determination timing setting unit and determines whether the signal per second can be detected. The signal changes from the first level to a second level different from the first level, and from the second level to the first level at 1 second intervals. Within one judgment period, The timing generated at a 1 second interval from a predetermined time before the start timing of the signal having the largest signal width of one level is set as the determination timing, and the signal detection determination unit sequentially acquires a signal of 1 second from the determination timing, Detecting the start timing of the signal having the largest signal width of the first level in the signal for 1 second, detecting the interval of the start timing of the signal, and determining whether or not the signal of every second has been detected. It is characterized by.

According to the present invention, the received signal of the standard radio wave is converted into an envelope signal by the detection unit, and the binarization unit outputs a binary signal obtained by binarizing the envelope signal.
Here, the standard radio wave is transmitted by subjecting a time code of 1 Hz to amplitude modulation with a carrier wave of a predetermined frequency. For this reason, the signal level of the reception signal output from the reception unit changes to the first level or the second level according to the amplitude of the received standard radio wave. At this time, depending on the circuit of the receiving unit, the first level may be a high level higher than the second level, or may be a low level lower than the second level.
The received signal changes from the second level to the first level (from high level to low level or from low level to high level) at intervals of 1 second, and the pulse width corresponding to the bit value (0, 1, M) The first level changes to the second level (from low level to high level, or from high level to low level).
For example, in JJY, which is a standard Japanese radio wave, a time code of 60 seconds (60 bits) for one cycle (one cycle) is repeatedly transmitted. The pulse width of the first level of each bit in the received signal is usually matched to three types of data (bit values) of binary “1”, binary “0”, and marker “M (P0 to P5)”. Is set. For example, in the case of JJY, if the first level pulse width is 0.5 seconds, the binary number “1” is represented. If the first level pulse width is 0.8 seconds, the binary number “1” is represented. “0”. Further, if the pulse width of the first level is 0.2 seconds, the marker (M) and the position markers (P0 to P5) are represented.

In addition, the determination timing setting unit sets a timing that occurs at intervals of 1 second from a predetermined time before the start timing of the signal having the largest signal width of the first level within the preset first determination period. And Even if the first level pulse is mixed in the binarized signal due to the influence of noise, the signal width is usually smaller than that of a normal signal representing the bit value. Therefore, even if noise is mixed, if a signal having the largest signal width is detected in the first determination period (for example, 2 seconds or 1 second), the signal can be estimated as a normal signal.
The determination timing setting unit sets the determination timing at intervals of 1 second from a predetermined time before the start timing of the signal having the largest signal width. Here, since the determination timing is set on the basis of a predetermined time before the start timing, the signal detection determination unit can reliably detect the change from the second level to the first level of the binarized signal. For this reason, the predetermined time is immediately before the change timing from the second level to the first level, such as 50 to 100 ms, and the change timing can be reliably detected by detecting the binarized signal from that timing. Set to time.
Furthermore, the signal detection determination unit sequentially acquires a signal for 1 second from the determination timing, and detects the start timing of the signal having the largest signal width of the first level in the signal for 1 second. As with the timing setting unit, a normal signal representing a bit value can be reliably detected even if noise or the like is mixed. Then, the signal detection determination unit detects an interval of the start timing of the signal and determines whether or not a signal per second can be detected. For example, the signal detection determination unit may: (1) The signal start timing interval is continuously within a predetermined range (for example, 1 second ± 62.5 ms) with 1 second as a reference for a predetermined number of times (for example, 5 times). For example, it may be determined that the signal of every second can be detected, and (2) the interval between the start timings of the signal is within a predetermined range with reference to 1 second (for example, 1 second ± 62.5 ms). If the case is a predetermined number of times (for example, 18 times) or more of the number of times of measurement (for example, 20 times), it may be determined that the signal of every second can be detected.
As a result, normal signals output at intervals of 1 second can be detected, and signals per second can be reliably detected. Therefore, it is possible to reliably perform the second synchronization when receiving the standard radio wave.

The determination timing setting unit and the signal detection determination unit initialize the maximum continuous count and continuous count to 0 at the start of processing, sample the binarized signal, and be at the first level at each sampling timing. The continuous count is counted up while it is continuous. If the continuous count is lost, the continuous count is compared with the maximum continuous count. If the continuous count is greater than the maximum continuous count, the maximum continuous count is continued. Update with the count value, record the end time of the continuous count, initialize the continuous count to 0, repeat the process until the first determination period ends, and within the first determination period Based on the maximum continuous count number, the sampling period, and the end time, the start type of the signal having the largest signal width of the first level. It is preferable to detect the ring.
According to such a configuration, the start timing of a normal signal can be detected by the same signal processing method in the determination timing setting unit and the signal detection determination unit. Therefore, the determination timing setting unit and the signal detection determination unit can also be used as a processing program.
In addition, the continuous count is incremented when it is continuously at the first level at the time of sampling, and is updated when the continuous count is larger than the maximum continuous count when the level is changed to the second level. Since the end time only needs to be updated at the time at that time, it is only necessary to store only three data of two types of count values, the continuous count and the maximum continuous count, and the end time of the maximum continuous count in the storage unit. For this reason, for example, the storage capacity of the storage unit can be reduced as compared with the case of storing the signal widths and times of all the signals of the first level in the first determination period.

  In the radio-controlled timepiece according to the aspect of the invention, the determination timing setting unit sets the first determination period to at least 2 seconds or more, and after the start of determination, the determination timing setting unit has a first level in the binarized signal in the first determination period. It is preferable that the determination timing is a timing generated at intervals of 1 second from a predetermined time before the start timing of the signal having the largest signal width.

If the first determination period is at least 2 seconds, a normal signal can be reliably detected. That is, if the first determination period is 1 second, the signal width cannot be correctly detected when the start timing of the first determination period is during the reception of a normal signal. For example, in the German standard radio wave DCF77, the binary number “0” has a first level pulse width of 0.1 second (100 ms). When the first determination period starts in the middle of this pulse, the detected signal width becomes less than 100 ms, for example, 50 ms, and becomes smaller than the signal width due to other noises, and there is a possibility that a normal signal cannot be detected.
On the other hand, if the first determination period is at least 2 seconds or more, even if the first determination period starts in the middle of a normal signal, the next normal signal can be reliably detected. For this reason, the determination timing setting unit can correctly set the determination timing. Further, the first determination period can be set to be greater than 1 second and less than 2 seconds by setting according to the type of the standard radio wave, but as long as it is 2 seconds or more as in the present invention. Can be set regardless of the standard radio wave type.

  In the radio-controlled timepiece according to the aspect of the invention, if the determination timing setting unit can confirm that the binarized signal is in the second level after the start of the determination, the binarized signal for one second from the confirmation time point. Among them, it is preferable that the determination timing is a timing generated at intervals of 1 second from a predetermined time before the start timing of the signal having the largest first level signal width.

At the start of the determination, if the binarized signal is in the first level state, if the binarized signal for 1 second is acquired and determined from the confirmation time point, the determination is made from the middle of the normal signal, and noise However, there is a possibility that the signal width becomes small and erroneous determination is made.
On the other hand, in the present invention, when the binarized signal is in the state of the first level, since the binarized signal for 1 second is acquired and determined after changing to the second level, it is normal. A normal signal can be reliably detected without determining from the middle of the signal.

  The present invention includes a receiving unit that receives a standard radio wave including time information and outputs a reception signal, a detection unit that detects a reception signal output from the reception unit and outputs an envelope signal, and an output from the detection unit And a binarization unit that outputs a binarized signal obtained by binarizing the envelope signal, and a detection timing for signal detection determination based on the binarized signal. A determination timing setting step for setting the signal, and a signal detection determination for determining whether or not the signal for every second can be detected by acquiring the binarized signal every second based on the determination timing set in the determination timing setting step The binarized signal changes from the first level to the second level different from the first level, and from the second level to the first level at 1 second intervals, and the determination timing The setting step uses, as the determination timing, a timing that occurs at intervals of 1 second from a predetermined time before the start timing of the signal having the largest signal width of the first level within a preset first determination period. The determination step sequentially acquires a signal of 1 second from the determination timing, detects a start timing of a signal having the largest signal width of the first level in the signal of 1 second, and sets an interval of the start timing of the signal It is detected and it is determined whether the signal of every second was able to be detected.

  In the signal detection method of this radio-controlled timepiece, similarly to the radio-controlled timepiece, a signal per second can be reliably detected, and second synchronization when receiving a standard radio wave can be reliably performed.

It is a block diagram which shows the structure of the electromagnetic wave correction watch which concerns on 1st Embodiment. It is a block diagram which shows the structure of the TCO decoding part which concerns on 1st Embodiment. It is a flowchart which shows the signal detection process of 1st Embodiment. It is a flowchart which shows the determination timing setting process of 1st Embodiment. It is a wave form diagram explaining the signal processing of 1st Embodiment. It is a timing chart explaining signal processing of a 1st embodiment. It is a flowchart which shows the signal detection determination process of 1st Embodiment. It is a flowchart which shows the determination timing setting process of 2nd Embodiment. It is a timing chart explaining signal processing of a 2nd embodiment.

[First Embodiment]
Hereinafter, a radio-controlled timepiece 1 according to a first embodiment of the present invention will be described with reference to the drawings.
[Configuration of radio-controlled clock]
As shown in FIG. 1, the radio-controlled timepiece 1 includes an antenna 2, a receiving circuit unit 3, a control circuit unit 4, a display unit 5, an external operation member 6, and a crystal resonator 48.

  The antenna 2 receives a long-wave standard radio wave (hereinafter referred to as “standard radio wave”), and outputs the received standard radio wave signal to the reception circuit unit 3. Standard radio waves include the Japanese standard radio wave “JJY”, the US standard radio wave “WWVB”, the German standard radio wave “DCF77”, and the Chinese standard radio wave “BPC”.

  The receiving circuit unit 3 demodulates the received signal of the standard radio wave received by the antenna 2 and outputs it to the control circuit unit 4 as a TCO (Time Code Out) signal. A detailed description of the receiving circuit unit 3 will be described later.

  The control circuit unit 4 decodes the input TCO signal to generate TC (time code, time data), and sets the time of the time counter 43 based on the generated TC. In addition, the control circuit unit 4 controls the display unit 5 to display the time of the time counter 43. The detailed description of the control circuit unit 4 will be described later.

  The display unit 5 is driven and controlled by the drive circuit unit 46 of the control circuit unit 4 and displays the time counted by the time counter 43. For example, the display unit 5 may include a liquid crystal panel and display the time on the liquid crystal panel. The display unit 5 may include a dial and a pointer, and the control circuit unit 4 may move the pointer to display the time. There may be.

  The external operation member 6 is constituted by, for example, a crown or a setting button, and outputs a predetermined operation signal to the control circuit unit 4 when operated by a user. As this operation signal, for example, a radio wave type setting signal for setting the type of standard radio wave (for example, “JJY”, “WWVB”, “DCF77”, “BPC”, etc.) received by the antenna 2 is received. Then, there is a correction request signal for correcting the time.

  The crystal oscillator 48 for the reference clock outputs a predetermined reference signal (reference clock, for example, a 32.768 kHz signal). The reference signal output from the crystal oscillator 48 is input to the control circuit unit 4. ing.

[Configuration of receiving circuit section]
As shown in FIG. 1, the receiving circuit unit 3 includes a tuning circuit 31, a first amplifier circuit 32, a band-pass filter (BPF) 33, a second amplifier circuit 34, and an envelope detector circuit. 35, an AGC (Auto Gain Control) circuit 36 as an automatic gain control circuit, a binarization circuit 37, and a decoding circuit 38.

The tuning circuit 31 includes a capacitor, and the tuning circuit 31 and the antenna 2 constitute a parallel resonance circuit. The tuning circuit 31 causes the antenna 2 to receive a radio wave having a specific frequency. The tuning circuit 31 converts the standard radio wave received by the antenna 2 into a voltage signal and outputs the voltage signal to the first amplifier circuit 32.
Note that the receiving circuit unit 3 of the present embodiment is configured to be able to receive standard radio waves such as “JJY”, “WWVB”, “DCF77”, and “BPC”. Therefore, the antenna 2 and the tuning circuit 31 constitute a receiver that can receive a plurality of types of standard radio waves.

  The first amplifying circuit 32 adjusts the gain according to a signal (AGC voltage) input from an AGC circuit 36 described later, and inputs the received signal input from the tuning circuit 31 to the band pass filter 33 as a constant amplitude. Amplify. That is, according to the signal input from the AGC circuit 36, the first amplifying circuit 32 reduces the gain when the amplitude is large, and increases the gain when the amplitude is small. Amplify so that

  The band pass filter 33 is a filter that extracts a signal in a desired frequency band. That is, by passing through the band pass filter 33, components other than the carrier wave component are removed from the received signal input from the first amplifier circuit 32.

  The second amplification circuit 34 further amplifies the reception signal input from the band pass filter 33 with a fixed gain. Therefore, in the present embodiment, the first amplification circuit 32 and the second amplification circuit 34 constitute a signal amplification unit that amplifies the reception signal.

The envelope detection circuit 35 includes a rectifier (not shown) and a low-pass filter (LPF) (not shown). The envelope signal thus obtained is output to the AGC circuit 36 and the binarization circuit 37. Therefore, in the present embodiment, the envelope detection circuit 35 constitutes a detection unit that detects a received signal and outputs an envelope signal.
The AGC circuit 36 outputs a signal for determining a gain when the first amplification circuit 32 amplifies the reception signal based on the envelope signal input from the envelope detection circuit 35.

  The binarization circuit 37 constitutes a binarization unit that compares the envelope signal input from the envelope detection circuit 35 with a reference voltage (threshold) and outputs a binarized signal, that is, a TCO signal. It is.

  The decode circuit 38 is connected to the control circuit unit 4 to be described later via a serial communication line SL. The decode circuit 38 decodes the control signal input from the control circuit unit 4 and outputs a control signal for controlling the tuning circuit 31 and the band pass filter 33 based on the code included in the control signal.

[Configuration of control circuit section]
The control circuit unit 4 controls the operation of the receiving circuit unit 3 and outputs a control signal to the receiving circuit unit 3. Specifically, the control unit 47 of the control circuit unit 4 outputs a control signal instructing switching of the tuning capacitor or switching of the bandpass filter 33 according to the received standard radio wave, and a power-on signal for starting the receiving circuit unit 3. Sent when the reception starts.
Further, the control circuit unit 4 sets the time of the time counter 43 based on the TC generated by decoding the TCO signal input from the binarization circuit 37. Furthermore, the control circuit unit 4 controls the display unit 5 to display the time of the time counter 43.

  As shown in FIG. 1, the control circuit unit 4 includes a TCO decoding unit 41, a storage unit 42, a time counter 43, a drive circuit unit 46, and a control unit 47. Note that the reference signal output from the crystal resonator 48 is input to the control unit 47.

[Configuration of TCO decoding unit]
The TCO decoding unit 41 decodes the TCO signal input from the binarization circuit 37 of the receiving circuit unit 3 and extracts a TC having date information and time information included in the TCO signal. Then, the TCO decoding unit 41 outputs the extracted TC to the control unit 47.
Specifically, as shown in FIG. 2, the TCO decoding unit 41 includes a determination timing setting unit 411, a signal detection determination unit 412, a storage unit 413, and a decoding unit 415.

The determination timing setting unit 411 sets a determination timing for signal detection determination based on the TCO signal (binarization signal) input from the binarization circuit 37. Details of the determination timing setting method will be described later.
The signal detection determination unit 412 sequentially acquires the TCO signal for 1 second based on the determination timing set by the determination timing setting unit 411, and the signal width of the first level is the largest among the signals for 1 second. The start timing of the signal is detected, the interval of the start timing of the signal is detected, and it is determined whether or not the signal of every second has been detected. Details of this signal detection determination method will also be described later.

The storage unit 413 stores processing data in the determination timing setting unit 411 and the signal detection determination unit 412.
The decoding unit 415 can detect the signal per second by the signal detection determination unit 412 and establish the second synchronization, and then the second time of the TCO signal indicates the binary number “0” using the second synchronization timing. It is determined whether the signal is one signal indicating a binary number “1” or an M signal indicating a marker.
Further, the decoding unit 415 stores the recognized 0 signal, 1 signal, and M signal for 1 minute, that is, 60 bits, and extracts the TC based on the stored signal and the time code format of the receiving station. Then, the decoding unit 415 outputs the extracted TC to the control unit 47.

In FIG. 1, the storage unit 42 is a memory that stores various information, programs, and the like necessary for the control of the receiving circuit unit 3 by the control circuit unit 4.
The time counter 43 counts time (internal time) based on the reference signal output from the crystal resonator 48. Therefore, the time counter 43 constitutes a time measuring unit.

  The drive circuit unit 46 controls the display state of the display unit 5 based on the time display control signal output from the control unit 47 and controls the display unit 5 to display the time. For example, when the display unit 5 has a liquid crystal panel and displays the time on the liquid crystal panel, the drive circuit unit 46 controls the liquid crystal panel based on the time display control signal and displays the time on the liquid crystal panel. To control. When the display unit 5 has a dial and a pointer, the drive circuit unit 46 outputs a pulse signal to the stepping motor that drives the pointer, and controls the pointer to move by the driving force of the stepping motor. .

The controller 47 is driven based on the drive frequency input from the crystal resonator 48 and performs various control processes. That is, the control unit 47 controls the correction of the count of the time counter 43 by outputting the TC input from the TCO decoding unit 41 to the time counter 43. At this time, the control unit 47 also confirms the consistency of the TC input from the TCO decoding unit 41. Therefore, the control unit 47 constitutes a time correction unit.
The control unit 47 also outputs a time display control signal for causing the display unit 5 to display the time counted by the time counter 43 to the drive circuit unit 46.

[Operation of the radio-controlled clock]
Next, the signal detection operation of the standard radio wave in the radio wave correction timepiece 1 as described above will be described.
FIG. 3 is a flowchart showing a signal detection process of the radio-controlled timepiece 1 every second.

  When the control unit 47 of the radio-controlled timepiece 1 receives an operation signal for performing time correction from the external operation member 6 or recognizes that a preset scheduled reception time has come, a power-on signal is sent to the reception circuit unit 3. Is input to activate the receiving circuit unit 3 and start receiving the standard radio wave by the antenna 2.

At this time, the control unit 47 stops moving the second hand via the drive circuit unit 46 so as not to affect reception by the antenna 2. Further, the control unit 47 sets the frequency of the tuning circuit 31 according to the standard radio wave received.
Note that the type of the standard radio wave to be received is set as the initial value of the standard radio wave received last time, but the user can also select the standard radio wave by operating the external operation member 6. For example, when “JJY” is selected, it is set to either 40 kHz (eastern Japan) or 60 kHz (western Japan). Specifically, when the user selects “JJY” (eastern Japan) and “JJY” (western Japan), the control unit 47 sets the selected frequency, and if it is not selected, Set to the previous reception frequency. The control unit 47 sets 77.5 kHz for “DCF77”, 60 kHz for “WWVB”, and 68.5 kHz for “BPC”.

When reception of standard radio waves by the antenna 2 is started, TCO signals are sequentially output from the binarization circuit 37 to the TCO decoding unit 41.
Then, the control part 47 starts the signal detection process of every second shown in FIG.

First, the control unit 47 operates the determination timing setting unit 411 of the TCO decoding unit 41 to perform a process for setting a determination timing for signal detection (step 1, hereinafter, step is abbreviated as “S”).
Specifically, the determination timing setting unit 411 performs the determination timing setting process (S1) in the process shown in FIG.
That is, the determination timing setting unit 411 initializes the maximum continuous count value to “0” (S11), and further initializes the continuous count value to “0” (S12).

Next, the determination timing setting unit 411 determines whether data for 2 seconds has been acquired from the binarization circuit 37 and sampled (S13).
If it is determined NO in S13, such as when 2 seconds have not elapsed since the start of processing, the determination timing setting unit 411 samples the waveform of the TCO signal (binarized signal) (S14). For example, the determination timing setting unit 411 samples the TCO signal at a sampling frequency of 128 Hz, and detects whether the level (voltage value) of the TCO signal at each sampling is the first level or the second level. .

Here, the TCO signal of each standard radio wave changes from the second level to the first level at intervals of 1 second, and changes from the first level to the second level before the next 1 second interval. The first level and the second level are set according to the type of standard radio wave and the circuit design of the binarization circuit 37.
In the present embodiment, in the case of JJY which is a Japanese standard radio wave, the first level is set to a value higher than the second level. That is, the first level is set to the high level and the second level is set to the low level.
For other standard radio waves (WWVB, DCF77, BCP), the first level is set to the low level and the second level is set to the high level, contrary to JJY.

The determination timing setting unit 411 detects the level of the TCO signal at the time of sampling, and determines whether the first level signal is continuous (S15).
That is, the determination timing setting unit 411 determines YES in S15 if both the current and previous sampling levels are the first level.
On the other hand, if the previous sampling level is the first level and the current sampling level is the second level, the determination timing setting unit 411 determines NO in S15. When the level at the previous sampling is the second level and the level at the current sampling is the first level, that is, immediately after switching to the first level, the first level signal is still continuous. Therefore, the determination timing setting unit 411 determines NO in S15.

If the determination timing setting unit 411 determines YES in S15, the determination timing setting unit 411 adds 1 to the continuous count (S16). The value of the continuous count is stored in the storage unit 413.
Then, the process returns to S13. Therefore, while the first level signal is being input, the processes of S13, S14, S15, and S16 are repeated, and the value of the continuous count is also incremented by +1.

If the determination timing setting unit 411 determines NO in S15, it determines whether the continuous count is greater than the maximum continuous count (S17). When the determination of S17 is performed first, since the maximum continuous count is initialized to 0, the determination timing setting unit 411 determines YES in S17.
If it is determined YES in S17, the determination timing setting unit 411 updates the maximum continuous count with the value of the continuous count and stores it in the storage unit 413. The time is recorded in the storage unit 413 (S18).

After the process of S18, the determination timing setting unit 411 returns to S13 and continues the process. For this reason, when there are a plurality of first level signals (pulses) in the TCO signal for 2 seconds, the first level signal width (continuous count value) is the largest among the signals so far. If it is larger than the length (the value of the maximum continuous count), the determination timing setting unit 411 determines YES in S17, and updates the value of the maximum continuous count and the signal end time in S18.
On the other hand, if the signal width (continuous count value) of the first level is smaller than the maximum length (maximum continuous count value) of the signals so far, the determination timing setting unit 411 determines NO in S17. And the process returns to S13 without updating the value of the maximum continuous count and the signal end time.

If the determination timing setting unit 411 determines YES in S13, the determination timing setting unit 411 determines that the signal having the largest signal width in 2 seconds is a normal signal based on the maximum continuous count and the signal end time (S19).
That is, as shown in FIG. 5A, the received signal includes a signal due to noise, and when there are a plurality of first-level (high-level) signals 51 to 58, the signal width of the signal 53 is The biggest. Therefore, in S19, the determination timing setting unit 411 determines that the signal 53 is a normal signal as shown in FIG.
The signal 53 having the largest signal width is a reception signal corresponding to the transmission signal shown as an ideal waveform in FIG. Thus, since there is almost no possibility that the signal width of a signal due to noise becomes larger than that of a normal signal in a 1-second signal, the signal having the largest signal width can be determined as a normal signal.

  Further, from the end time of the signal 53, that is, the TE timing in FIG. 5B, and the signal width of the signal 53 obtained by multiplying the value of the maximum continuous count by the period of the sampling frequency, the start time of the signal 53, that is, The signal start timing indicated by TS of 5 (B) can also be obtained.

Furthermore, the determination timing setting unit 411 of the present embodiment performs sampling for 2 seconds in S13. For this reason, even when a normal signal exists every second, a signal having a long signal width is determined as a normal signal. Therefore, as shown in FIG. 6A, when there are four signals 61 to 64 in two seconds between T1 and T3, the signal 62 having the largest signal width is determined as a normal signal.
After performing the above process, the determination timing setting unit 411 ends the determination timing setting process shown in FIG.

Next, as shown in FIG. 3, the determination timing setting unit 411 obtains a determination timing based on the signal 62 determined to be a normal signal, and stops data acquisition from the TCO signal until the determination timing (S2). Specifically, the determination timing is a timing that occurs at intervals of 1 second from a predetermined time before the start timing of a normal signal (for example, 50 ms or 100 ms).
For example, when the signal 62 is determined to be a normal signal in the state shown in FIG. 6C, that is, when sampling for 2 seconds is completed from T1 to T3, T10 which is a predetermined time before the start time of the signal 62 is used as a reference. Among the timings of 1 second intervals (T11, T12, T13, T14...), The earliest timing after the present time is the time of T12. For this reason, the determination timing setting unit 411 stops data acquisition from T3 to T12.

The reason why the reference time (T10) is a predetermined time before the start time of the signal 62 is as follows. That is, in the standard radio wave, as described above, the signal changes from the second level to the first level at intervals of 1 second. Therefore, if the timing is 1 second from the start time of the signal 62, it coincides with the signal change from the second level to the first level, or immediately after the change from the second level to the first level. There is a possibility that the change timing from the second level to the first level cannot be reliably detected.
Therefore, the timing for changing the TCO signal from the second level to the first level is reliably detected by setting the determination timing to a timing of one second with respect to a predetermined time, for example, 50 ms before the start time of the signal 62. It is set to be possible.

Next, at time T12, the signal detection determination unit 412 executes signal detection determination processing as shown in FIG. 3 (S3).
As shown in FIG. 7, the signal detection determination process S3 performs the same process as the determination timing setting process (S1) by the determination timing setting unit 411, except that it is determined whether or not sampling for 1 second is performed in S33.
That is, at the start of processing, the signal detection determination unit 412 initializes the maximum continuous count to 0 (S31), and initializes the continuous count to 0 (S32). Then, it is determined whether the TCO signal is acquired for 1 second and sampling is performed (S33).

When determining NO in S33, the signal detection determination unit 412 samples the waveform of the TCO signal (S34), and determines whether the first level signal is continuous (S35). In the case of YES in S35, the signal detection determination unit 412 adds “1” to the continuous count, stores it in the storage unit 413 (S36), and returns to S33.
If the signal detection determination unit 412 determines NO in S35, the signal detection determination unit 412 determines whether the continuous count is larger than the maximum continuous count (S37), and if so, the maximum continuous count is updated to the value of the continuous count. The signal is stored in the storage unit 413, and the signal end time, that is, the time of the sampling timing that was the first level at the end is recorded in the storage unit 413 (S38). Then, the process returns to S33.
On the other hand, if the signal detection determination unit 412 determines NO in S37, the signal detection determination unit 412 directly returns to S33.

When the signal detection determination unit 412 determines YES in S33, it determines that the signal having the largest signal width in one second is a normal signal based on the maximum continuous count and the signal end time (S39).
As described above, a normal signal in a 1-second signal can be detected. For example, in FIG. 6D, the signal 65 in one second from the determination timing T12 to T13 is determined as a normal signal.

Next, as shown in FIG. 3, the signal detection determination unit 412 stores the signal start timing T20 (second synchronization timing) of the signal 65 determined to be normal in the storage unit 413 when the signal detection determination process of S3 ends. Then, it is confirmed whether the interval between the signal start timings is a cycle of 1 second ± 62.5 ms (S4). And the signal detection determination part 412 determines whether the confirmation is OK 5 times continuously (S5).
Here, since the signal 65 in FIG. 6D is the first signal determined by the signal detection determination unit 412, the signal detection determination unit 412 has a second synchronization timing of a cycle of 1 second ± 62.5 ms. Cannot be confirmed, and NO is determined in S5.

Therefore, the signal detection determination unit 412 performs the process of S3 again in the next 1 second (determination timings T13 to T14). Therefore, as shown in FIG. 6E, the signal 66 is determined to be a normal signal in one second from T13 to T14.
Therefore, when the process of S3 ends, the signal detection determination unit 412 stores the signal start timing T21 of the signal 66 determined to be normal in the storage unit 413, and calculates the elapsed time (T21-T20) from the previous signal 65. Then, it is confirmed whether the cycle is 1 second ± 62.5 ms (S4). And the signal detection determination part 412 determines whether the confirmation is OK 5 times continuously (S5).

Accordingly, when the signal detection determination process S3 is performed 6 times (6 seconds) and the signal start timing is confirmed to be a cycle of 1 second ± 62.5 ms for 5 times continuously, the signal detection determination unit 412 It determines with YES by S5. That is, in the present embodiment, whether or not the signal start timing interval is a cycle of 1 second ± 62.5 ms for 5 consecutive times is set as a condition for determining whether or not the signal detection can be performed every second. ing.
Thereby, it is possible to detect the signal every second, to determine that the second synchronization has been established, and the processing in FIG. 3 ends.

  Thereafter, since second synchronization is established and signal detection can be performed every second, the decoding unit 415 samples the TCO signal every second, and the signal of each bit every second is the same as the conventional one. It can be determined whether the signal is a 0 signal, a 1 signal, or an M signal. Then, the decoding unit 415 extracts time data (TC) from the bit string of 60 seconds (1 minute) and outputs the time data (TC) to the control unit 47.

  The control unit 47 confirms the consistency of the TC input from the decoding unit 415. As a method for confirming consistency, for example, since the standard radio wave transmits time information at intervals of 1 minute, it is confirmed whether the TC acquired every minute is at the time of 1 minute interval, A method of checking the consistency by comparing the internal time measured by the time counter 43 and TC can be used.

  When it is determined that the TC is consistent, the control unit 47 ends the reception process. Further, the control unit 47 updates the time counter 43 with the acquired TC, and corrects the time display on the display unit 5 via the drive circuit unit 46. On the other hand, when it is determined that the TC is not consistent, the control unit 47 ends the reception process. Thereafter, the control unit 47 returns to the normal hand movement process and ends the process.

According to this embodiment, there are the following effects.
(1) In this embodiment, when the reception process is started, a determination timing setting process S1 by the determination timing setting unit 411 is first performed. In this determination timing setting process S1, the timing that occurs at intervals of 1 second from a predetermined time before the start timing of the signal having the largest signal width of the first level within 2 seconds that is the first determination period set in advance is described above. Judgment timing is used. For this reason, even if the first level pulse is mixed in the binarized signal due to noise, the signal width is small. Therefore, the normal signal is detected by detecting the signal with the largest signal width. it can.
Since the determination timing setting unit 411 sets the determination timing at intervals of 1 second from a predetermined time before the start timing of the signal having the largest signal width, the signal detection determination unit 412 has the second level of the binarized signal. The change from 1 to the first level can be reliably detected.
Further, the signal detection determination unit 412 sequentially acquires signals for 1 second from the determination timing, and detects the signal start timing of the signal having the largest signal width of the first level in the signal for 1 second. As with the determination timing setting unit 411, a normal signal representing a bit value can be reliably detected even if noise or the like is mixed. Therefore, if the interval between the signal start timings is within a predetermined range (1 second ± 62.5 ms) with a predetermined number of times (5 times) continuously (1 second ± 62.5 ms), the signal per second can be reliably detected. Therefore, it is possible to reliably perform the second synchronization when receiving the standard radio wave.

(2) Since the determination timing setting unit 411 sets the first determination period to 2 seconds, even if the first determination period starts during the reception of the normal signal, the determination timing setting unit 411 can reliably detect the normal signal. For this reason, the determination timing setting unit 411 can correctly set the determination timing.

(3) In addition, the determination timing setting unit 411 and the signal detection determination unit 412 count up the continuous count when the level is continuously at the first level during sampling, and set the maximum continuous count when the level is changed to the second level. Since it is only necessary to update when the continuous count is large in comparison and the end time of the maximum continuous count only needs to be updated at that time, two types of count values, the continuous count and the maximum continuous count, and the end of the maximum continuous count Only three pieces of time data need be stored in the storage unit 413. For this reason, for example, the storage capacity of the storage unit 413 can be reduced as compared with the case of storing the signal widths and times of all signals of the first level in the determination period.
In addition, the determination timing setting unit 411 and the signal detection determination unit 412 can detect the start timing of a normal signal by the same signal processing method. Therefore, the determination timing setting unit 411 and the signal detection determination unit 412 can also be used as a processing program, and the storage capacity of the storage unit 42 can be reduced.

[Second Embodiment]
Next, a radio-controlled timepiece according to a second embodiment of the present invention will be described with reference to the drawings.
In the determination timing setting process S1 of the first embodiment, the first determination period is 2 seconds. However, in the second embodiment, the first determination period is 1 second, and the first level signal is not output at the start of the process. I have confirmed that.
FIG. 8 is a flowchart showing the determination timing setting process S1A of the second embodiment. This flowchart corresponds to the flowchart shown in FIG. 4 in which S40 is added before S11 and S13 is replaced with S41. All other steps are the same as in FIG.

In the second embodiment, when the determination timing setting process S1A is started, the determination timing setting unit 411 determines whether the first level signal is output by sampling the TCO signal (S40).
The determination timing setting unit 411 repeats the determination process of S40 while it is determined YES in S40. On the other hand, if it is determined NO in S40, that is, if a second level signal is output at the start of processing, or if the first level changes to the second level, the initialization processing of S11 and S12 I do.

Thereafter, the determination timing setting unit 411 determines whether sampling has been performed for one second (S41). In the case of NO in S41, the processes of S14 to S18 are performed as in the first embodiment. Also in the case of YES in S41, the process of S19 is performed as in the first embodiment, and the determination timing is set.
Thereafter, as in the first embodiment, the determination timing setting unit 411 and the signal detection determination unit 412 perform the processes of S2, S3, S4, and S5 in FIG.

FIG. 9 is a waveform of the TCO signal in the second embodiment. In the example of FIG. 9, the first level is a low level and the second level is a high level.
As shown in FIG. 9A, since the TCO signal is at the second level (high level) at the timing T31 when the process of the determination timing setting process S1A is started, NO is determined in S40.
Then, as shown in FIG. 9A, when there are two first level (low level) signals 91 and 92 in one second from T31 to T32, the determination timing setting unit 411 has a signal with the largest signal width. 92 is determined as a normal signal.
After performing the above processing, the determination timing setting unit 411 ends the determination timing setting processing shown in FIG.

  Of the timings (T41, T42, T43...) At intervals of 1 second with reference to T40 which is a predetermined time before the start timing of the signal 92, the earliest timing after the present time is the time of T41. For this reason, the determination timing setting unit 411 stops data acquisition from T32 to T41 (S2).

  Next, at time T41, the signal detection determination unit 412 executes signal detection determination processing (S3). As a result, as shown in FIGS. 9D and 9E, the signal 93 for one second from the determination timings T41 to T42 and the signal 94 for one second from the determination timings T42 to T43 are determined to be normal signals.

  Then, the signal detection determination unit 412 stores the signal start timings T50 and T51 of the signals 93 and 94 determined to be normal in the storage unit 413, and determines whether the interval between the signal start timings is a cycle of 1 second ± 62.5 ms. Confirm (S4). And the signal detection determination part 412 determines whether the confirmation is OK 5 times continuously (S5).

According to such 2nd Embodiment, in addition to the effect of 1st Embodiment, the following effect can also be acquired.
At the start of the determination timing setting process S1A, the determination process of S40 is performed, and sampling for one second is started at a time point that is not the first level signal, so the first determination period starts from the middle of the normal signal. Can be surely prevented. For this reason, the determination timing can be set by sampling for one second, and the processing of the determination timing setting process S1A can be shortened compared to the first embodiment.

[Modification]
The present invention is not limited to the above-described embodiments, and modifications, improvements, and the like within the scope that can achieve the object of the present invention are included in the present invention.

  For example, in the first embodiment, the signal processing in which the first level is a high level has been described, but a signal in which the first level is a low level as in the second embodiment can be similarly processed. Similarly, in the second embodiment, a signal having a high first level can be processed in the same manner.

Furthermore, in the said 1st Embodiment, although the 1st determination period was 2 second, it should just be at least 2 second or more, for example, may be set to 3 second. If the first determination period is lengthened, the detection accuracy can be improved accordingly. On the other hand, if the first determination period is 2 seconds, the determination time can be shortened and set regardless of the type of the standard radio wave.
Further, the first determination period in the first embodiment is not limited to at least 2 seconds or more, and can be set to be greater than 1 second and less than 2 seconds. For example, when JJY is received as a standard radio wave, 0.8 seconds is the longest as the first level pulse width. Therefore, if a period of 1.8 seconds is secured as the first determination period, even if the start timing of the first determination period is in the middle of 1 second, 0.8 seconds from the signal start timing of the next 1 second is It can be included in at least the first determination period. Therefore, theoretically, the first level pulse width of the next one second signal can be detected in any of 0.2 seconds, 0.5 seconds, and 0.8 seconds. Similarly, when the DCF 77 is received as the standard radio wave, the pulse width of the first level is the largest at the pulse width of 0.2 seconds. Therefore, if a period of 1.2 seconds is ensured, it is theoretically normal. The signal can be detected.
Therefore, in consideration of an error of about ± 5 ms for each pulse width, if JJY is set to 1.9 seconds as the first determination period and DCF77 is set to 1.3 seconds as the first determination period, it is surely normal. The signal can be detected. Therefore, the first determination period may be set in a range greater than 1 second and less than 2 seconds depending on the type of standard radio wave to be received. That is, for each type of standard radio wave to be received, the first determination period may be set to a time in which 1 second and an error are taken into account for the largest first level pulse width of the standard radio wave.

  In each of the above embodiments, the determination timing setting unit 411 sets the determination timing based on a predetermined time before the start timing of the signal determined to be normal, but before the predetermined time, the determination timing is set to 50 ms or 100 ms. It is not limited and may be 10 ms.

Further, in each of the above embodiments, the signal detection determination unit 412 confirms whether the signal start timing interval is 5 consecutive times in 1 second ± 62.5 ms in S4 and S5. The number of consecutive times is not limited to five. Further, the determination of the period of S4 is not limited to the period of 1 second ± 62.5 ms, and may be 1 second ± 31.25 ms, and the range of variation may be set as appropriate.
In addition, the condition for determining whether or not the signal detection determination unit 412 has detected the signal per second is not limited to a predetermined number of times (5 times or the like) continuously, and the start timing variation of the signal is 1 A condition may be whether the number of times within a predetermined range with respect to the second (for example, 1 second ± 62.5 ms) is equal to or greater than a predetermined number (for example, 18 times) of the number of measurement times (for example, 20 times). In short, any condition may be used as long as the signal detection determination unit 412 can confirm that the interval between the start timings of the signals is approximately 1 second.

  DESCRIPTION OF SYMBOLS 1 ... Radio wave correction clock, 2 ... Antenna, 3 ... Reception circuit part, 4 ... Control circuit part, 5 ... Display part, 6 ... External operation member, 31 ... Tuning circuit, 32 ... 1st amplifier circuit, 33 ... Band pass filter , 34 ... second amplifier circuit, 35 ... envelope detection circuit, 36 ... AGC circuit, 37 ... binarization circuit, 38 ... decoding circuit, 41 ... TCO decoding unit, 42 ... storage unit, 43 ... time counter, 46 ... Drive circuit section 47... Control section 411. Determination timing setting section 412... Signal detection determination section 413. Storage section 415.

Claims (4)

A receiver that receives a standard radio wave including time information and outputs a received signal;
A detector for detecting the received signal output by the receiver and outputting an envelope signal;
A binarization unit that outputs a binarized signal obtained by binarizing the envelope signal output by the detector;
A determination timing setting unit that sets a determination timing for signal detection determination based on the binarized signal;
A signal detection determination unit that determines whether or not a signal per second can be detected by acquiring the binarized signal every second on the basis of the determination timing set by the determination timing setting unit;
The binarized signal changes to a first level and a second level different from the first level, and changes from the second level to the first level at 1 second intervals,
The determination timing setting unit sets, as the determination timing, a timing that occurs at a 1 second interval from a predetermined time before the start timing of the signal having the largest signal width of the first level within a preset first determination period,
The signal detection determination unit sequentially acquires a signal for 1 second from the determination timing, detects a start timing of the signal having the largest signal width of the first level in the signal for 1 second, and starts the signal A radio-controlled timepiece characterized by detecting whether or not a signal per second can be detected by detecting an interval of. The radio-controlled timepiece according to claim 1,
The determination timing setting unit sets the first determination period to at least 2 seconds, and after the start of determination, starts a signal having the largest first level signal width among the binarized signals in the first determination period. A radio-controlled timepiece characterized in that a timing generated at intervals of 1 second from a predetermined time before the timing is set as the determination timing. The radio-controlled timepiece according to claim 1,
When the determination timing setting unit can confirm that the binarized signal is in the second level after the start of the determination, the determination timing setting unit determines whether the first level of the binarized signal is 1 second from the confirmation point. A radio-controlled timepiece characterized in that the determination timing is a timing generated at intervals of 1 second from a predetermined time before the start timing of the signal having the largest signal width. A receiver that receives a standard radio wave including time information and outputs a received signal;
A detector for detecting the received signal output by the receiver and outputting an envelope signal;
A binarization unit that outputs a binarized signal obtained by binarizing the envelope signal output by the detection unit;
A determination timing setting step for setting a determination timing for signal detection determination based on the binarized signal;
A signal detection determination step for acquiring the binarized signal every second on the basis of the determination timing set in the determination timing setting step, and determining whether the signal per second can be detected;
The binarized signal changes to a first level and a second level different from the first level, and changes from the second level to the first level at 1 second intervals,
The determination timing setting step uses, as the determination timing, a timing that occurs at a 1 second interval from a predetermined time before the start timing of the signal having the largest signal width of the first level within a preset first determination period,
The signal detection determination step sequentially acquires a signal of 1 second from the determination timing, detects a start timing of a signal having the largest signal width of the first level in the signal of 1 second, and starts the signal A signal detection method for a radio-controlled timepiece, characterized in that it is determined whether or not a signal of every second has been detected by detecting an interval of.

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