JP5159829B2 - Time correction device - Google Patents

Description

  The present invention relates to a time adjustment device, and more particularly to a time adjustment device that adjusts time based on time signals from a plurality of time sources such as radio broadcasts and standard radio waves.

  2. Description of the Related Art Conventionally, there are watches equipped with a time adjustment device that adjusts the time using radio broadcast time signals. NHK (Nippon Broadcasting Corporation, hereinafter NHK) time signal is transmitted 440Hz forecast sound that lasts 0.1 seconds 3 times at 1 second intervals, and 880Hz correct sound that decays 1 second after 1 second. It is configured to transmit.

  In this type of time adjustment device, there is a problem that the correction is not performed due to an erroneous correction due to noise or the like or a failure of the radio receiver, and some countermeasures are provided with two radio receivers. For example, in the time adjustment device disclosed in Patent Document 1, two radio receivers are used, and the time of a clock in the device is corrected by the logical product output of the time signal from each radio receiver, so that noise etc. It is trying to suppress miscorrection due to the influence. In addition, this time adjustment device advances the count contents of the counting circuit by the logical sum output of the detection output of the time signal from each radio receiver, and resets the counting circuit when the time is corrected. A notification signal is generated when the counting circuit counts a predetermined value, and a failure such as a failure of the radio receiver can be notified.

  In the system disclosed in Patent Document 2, the first and second radio clock means are used, and the time information of the first and second radio clock means is measured in the normal time, and the second is based on the deviation amount. The time information of the first radio clock is corrected, the time information of the first radio clock is used as the system time information, and when the time information of the first radio clock is abnormal, the time information of the second radio clock is Used as system information.

JP-A-63-42493 JP 2007-322199 A

  In the technique disclosed in Patent Document 1, a time signal is detected as a time signal by two radio receivers, and the time of the time signal is detected at the same time to correct the time of the clock. There was a problem in that the radio receiver could not correct the time just because it could not detect the time signal, and the frequency of time adjustment was reduced.

  The one disclosed in Patent Document 2 is a complicated configuration that requires a configuration for correcting the time information of the second radio clock device to the time information of the first radio clock device based on a deviation amount measured in advance. There was a problem. In addition, since the time information of the second radio clock is corrected to the time information of the first radio clock until an abnormality is detected in the time information of the first radio clock, the time information of the first radio clock It is necessary to detect abnormalities as frequently as possible, and there is a problem of increasing the processing load.

  The time correction device according to the present invention is based on a time measuring means for measuring time, a plurality of receiving means for receiving a signal synchronized with time information of each time source and outputting a reference signal, and a reception state of the receiving means. Discriminating means for discriminating the validity of each of the reference signals, and the plurality of reference signals are inputted, and the predetermined receiving means among the plurality of reference signals received based on the discrimination result of the discriminating means When it is determined that the reference signal is valid, the reference signal from the predetermined receiving unit is preferentially selected, and when the reference signal from the predetermined receiving unit is not valid, it is input earliest in a predetermined period. And selecting the reference signal determined to be valid, generating a synchronization signal synchronized with the selected reference signal, and correcting the time of the time measuring means in synchronization with the synchronization signal. Characterized in that it comprises a correction means, a.

  It is preferable that at least one of the receiving means receives the time information from a time source, and the correcting means corrects the time based on the time information received by the receiving means.

  The synchronization signal generating means generates a composite signal by taking a logical sum of a pulse width adjusting means that uses a plurality of reference signals from the receiving means as a common pulse width signal and a signal from the pulse width adjusting means. It is preferable that a logical sum means is provided to generate the synchronization signal in synchronization with the generation of the synthesized signal.

  The common pulse width is preferably larger than a predetermined error allowing correction in time correction.

  Preferably, the predetermined receiving means is a GPS receiver, and the other receivers are receivers that receive radio waves on which time signals are superimposed or receivers that receive standard radio waves.

  In the present invention, in a time adjustment device having a redundant configuration, a predetermined one of a plurality of reference signals respectively received by the receiving means is preferentially used as a synchronization signal for time adjustment, and the predetermined reference signal is effective. If not, the reference signal that is input earliest in a predetermined period among the other reference signals and determined to be valid is used as a synchronization signal for time adjustment. This eliminates the complicated configuration of correcting the time by taking into account the deviation between the reference signals, and selecting the earliest reference signal as the synchronization signal minimizes the time deviation from the time source due to transmission delay. Thus, the time correction accuracy can be improved as much as possible with a simple configuration.

FIG. 1 is a block diagram showing a configuration of a time correction apparatus according to an embodiment of the present invention. FIG. 2 is a block diagram showing the configuration of the main part of FIG. FIG. 3 is a timing chart for explaining the operation of the time adjustment apparatus according to the embodiment of the present invention.

  FIG. 1 is a block diagram of a time adjustment apparatus according to an embodiment of the present invention. A time adjustment apparatus 10 includes a time measuring means 11, a time adjustment means 12, a GPS (Global Positioning System) receiver 13, and a time signal receiver. 14a, a time signal receiver 14b, a standard radio wave receiver 14c, an effective signal selection means 15, a correct time signal timing adjustment means 16, a timing correction means 17, and a synchronization signal generation means 18. The time measuring means 11, the time correcting means 12, the valid signal selecting means 15, the hour signal timing adjusting means 16, the timing correcting means 17, and the synchronization signal generating means 18 are computer hardware not shown and its control. It is realized by a computer program for Further, this computer is connected to a network, executes a computer program called an NTP (Network Time Protocol) daemon, and provides an NTP server that provides high-precision time information to clients and servers on the network by NTP. In other words, it operates as a time server.

  The time measuring means 11 measures the time of the time adjusting device 10 and is realized by a time measuring process executed on the computer, for example, a time measuring process by an NTP daemon. The computer includes a crystal oscillator or an OCXO (Oven Controlled Crystal Oscillator) that provides a highly accurate oscillation signal as an oscillation signal source for timing.

  The time correction means 12 sets the time information obtained by the time measuring means 11 with the GPS receiver 13 or the time information obtained with the standard radio wave receiver 14c to the time measured by the time measuring means 11, for example, NTP The date, time, minute, and second are set in the daemon, and a synchronization signal, which will be described later, is input as a 1-second pulse signal, and time is synchronized with this synchronization signal to correct the time of the time measuring means 11.

  The GPS receiver 13 receives a signal from a GPS satellite having a highly accurate timing device, and extracts time information and a 1-second pulse signal, a so-called 1 PPS (Pulse Per Second) signal. The GPS receiver 13 outputs a signal indicating whether the GPS satellite is captured and in a state where positioning is possible, in other words, whether the receiving state is capable of outputting a highly accurate and effective 1-second pulse signal. Configured as follows. The rising edge of the 1-second pulse signal is synchronized with high precision at the timing of advancing the second of the GPS satellite time measuring device. As shown in FIG. 3, the 1-second pulse signal is a signal that rises to “H” in a 1-second cycle with the “L” state as a reference, but is not limited to this, and the “H” state is the reference. The signal may fall to “L”. In this case, the rising edge may be read as the falling edge, and the same applies to other signals such as a normal time signal and a synchronization signal described later.

  Each of the time signal receivers 14a and 14b receives a predetermined radio broadcast radio wave, demodulates a sound signal carried by the radio wave, and detects a time signal composed of three forecast sounds and a subsequent correct sound. The hour signals A and B are output in synchronism with the generation of the correct alarm sound. Each tuner (not shown) of each of the time signal receivers 14a and 14b is set to receive radio waves from different broadcasting stations. For example, when the time adjustment device 10 is installed in the suburbs of Funabashi City, Chiba Prefecture, one of the time signal receivers 14a and 14b receives an FM broadcast (82.5 MHz) of NHK in Tokyo and the other is an FM broadcast of NHK in Chiba. Set to receive (80.7 MHz). The time signal receivers 14a and 14b are configured to determine whether the reception state of radio waves is good or not, for example, a means for measuring the electric field strength in the frequency band of the received radio waves. A signal indicating that the reception state is not output. Otherwise, a signal indicating that the reception state is bad is output. In addition, as a structure which discriminate | determines the quality of a receiving state, a noise component is measured in the silence area (for example, silence area immediately after generation | occurrence | production of a forecast sound) of a speech signal, or the frequency component more than the predetermined frequency of a speech signal A configuration may be adopted in which measurement is performed as a noise component, and when the noise component is equal to or less than a predetermined value, the reception state is good, and otherwise, the reception state is bad.

  The standard radio wave receiver 14c receives the long wave standard radio wave (40KHz of the Otakado and Yama standard radio wave transmission stations or 60KHz of the mountain peak standard radio wave transmission station) of the National Institute of Information and Communications Technology, and the source time source The time code synchronized with the second is demodulated to extract time information. The standard radio wave receiver 14c is configured to output a time signal C in synchronization with the time code of the time of the standard time of the standard radio wave in a time zone in which the time signal is transmitted by the above-described radio broadcast. . Further, the standard radio wave receiver 14c includes a configuration for determining whether the radio wave reception state is good, for example, means for measuring the electric field strength in the frequency band to be received, and the reception state is good when it is equal to or higher than a predetermined strength. If not, a signal indicating that the reception state is bad is output. As a configuration for determining whether the reception state is good or not, a noise component, that is, a frequency component higher than the frequency band of the time code is measured. If the noise component is equal to or less than a predetermined value, the reception state is good. May be configured such that the reception state is bad.

  The effective signal selection means 15 receives signals indicating the reception states of the GPS receiver 13, time signal receivers 14a and 14b, and standard radio wave receiver 14c, and receives the GPS receiver 13, time signal receivers 14a and 14b, and standard radio wave reception. A selection signal for selecting a signal from the machine 14c that functions effectively is output. The effective signal selection means 15 sets the selection signal d to “H” when receiving a signal indicating that the reception state is good from the GPS receiver 13, that is, the 1-second pulse signal is effective, and otherwise. The selection signal d is set to “L”. Further, when the valid signal selection means 15 receives a signal indicating that the reception state is good from each of the time signal receivers 14a and 14b, that is, the hourly signals A and B are valid, the selection signal corresponding to each is received. a and b are set to “H”, and otherwise, the selection signals a and b are set to “L”. The effective signal selection means 15 sets the corresponding selection signal c to “H” when receiving a signal indicating that the reception state is good from the standard radio wave receiver 14c, that is, the hourly signal C is valid. Otherwise, the selection signal c is set to “L”.

  The hour signal timing adjustment means 16 receives the hour signals A, B, C and the selection signals a, b, c, and is a composite signal that is synchronized with an effective and earliest signal among the hour signals A, B, C. Is configured to output. Here, the hourly signal timing adjusting means 16 is configured as shown in FIG. This configuration may be realized by hardware or may be realized by software processing. The one-shot triggers 161a, 161b, 161c generate signals having a predetermined pulse width in synchronization with the generation of the hour signals A, B, C, respectively. The logical product means 162a, 162b, 162c receives the signals from the one-shot triggers 161a, 161b, 161c at one input, and receives the selection signals a, b, c at the other input, and adjusts the pulse width. Of the hourly signals after being set, only those that are validated by the selection signal that has become “H” are passed. The logical sum means 163 receives the outputs of the logical product means 162a, 162b, and 162c, calculates the logical sum of these, and outputs a composite signal. Here, the time correction device 10 has an error that is allowed in a predetermined time correction interval (for example, one day), that is, a time interval between the timing of advancing the second of the time measuring means 11 and the rising timing of the synchronization signal is predetermined. When the error (for example, 50 milliseconds) is exceeded, the time is not adjusted. When the error is exceeded, the time adjustment is not performed on the assumption that the synchronization signal generating unit 18 has a problem because the time accuracy of the time measuring unit 11 cannot be maintained or the time signal cannot be acquired. The pulse widths of signals from the one-shot triggers 161a, 161b, 161c are set to be larger than the above error. As a result, for the hourly signals A, B, and C within the error range that is allowed to be used for time correction, the pulse-like signals from the one-shot triggers 161a, 161b, and 161c that move back and forth within the error range described above. Are combined by the logical sum means 163 to obtain a one-pulse signal. As a result, it is possible to output a synthesized signal synchronized with the earliest one of the hour signals A, B, and C with a simple configuration.

  The timing correction means 17 receives the 1-second pulse signal from the GPS receiver 13, the combined signal from the hour signal timing adjustment means 16, and the selection signal d. When the selection signal d is "H", the timing correction means 17 A pulse signal is selected, and when the selection signal d is “L”, a composite signal is selected and output to the synchronization signal generating means 18.

  The synchronization signal generation means 18 repeats a count process for one second on a computer that operates with a clock based on a crystal oscillator or OCXO oscillation signal, or a counter that counts such an oscillation signal causes a synchronization signal with a period of one second. Is generated. The synchronization signal generation means 18 starts counting with the rising edge of the signal selected by the timing correction means 17 as a trigger, and synchronizes the rising edge of the synchronization signal generated by the synchronization signal generation means 18 with the rising edge of the signal selected by the timing correction means 17. Let Thus, the synchronization signal matches the 1-second pulse signal when the reception state of the GPS receiver 13 is valid, and is synchronized with the composite signal when the reception state of the GPS receiver 13 is not valid. It becomes a 1 second pulse signal.

  Next, the operation of the time adjustment device 10 will be described with reference to the timing chart of FIG. The time adjustment device 10 confirms that the time of the time measuring means 11 is before the hour and is in a predetermined time zone in which the time signal is broadcast, and operates the time signal receivers 14a and 14b and the standard radio wave receiver 14c. . The time adjustment device 10 assumes that the time adjustment is performed in a predetermined period for time adjustment, for example, a period before and after a predetermined time every day, and the time measured by the time measuring means 11 is set to 50 milliseconds before and after the current time. In a certain period, the time adjustment process of the time adjustment means 12 is permitted. The hourly signal receivers 14a and 14b and the standard radio wave receiver 14c output hourly signals A, B and C, respectively. FIG. 3 shows a state after adjusting the pulse width of the hour signals A, B, and C by the respective one-shot triggers 161a, 161b, and 161c. The hour signals are temporarily arranged in the order shown in FIG. As generated. The hour signal timing adjustment means 16 outputs a synthesized signal obtained by synthesizing those which are valid. FIG. 3 shows a combined signal in a state where all of the hourly signals A, B, and C are valid in a predetermined period for time correction. This combined signal is synchronized with the earliest hourly signal A. Thus, the signal rises and falls in synchronization with the fall of the signal after the pulse width adjustment of the latest hourly signal C. The timing correction unit 17 selects one of the 1-second pulse signal from the GPS receiver 13 and the combined signal from the hour signal timing adjustment unit 16 according to the selection signal d from the valid signal selection unit 15. When the reception state of the GPS receiver 13 cannot be validated, the timing correction unit 17 selects the composite signal and outputs it to the synchronization signal generation unit 18. At this time, the synchronization signal generator 18 outputs a synchronization signal shown as the synchronization signal (when the GPS receiver is disabled) in FIG. The timing correction means 17 selects the composite signal and outputs it to the synchronization signal generation means 18 when the reception state of the GPS receiver 13 is not valid. At this time, the synchronization signal generator 18 outputs a synchronization signal shown as the synchronization signal (when the GPS receiver is valid) in FIG. This synchronization signal coincides with the 1 second pulse signal.

  The synchronization signal is used for the time adjustment means 12, and the NTP daemon performs time adjustment processing using the synchronization signal as a 1-second pulse signal. In this time adjustment process, when the reception state of the GPS receiver 13 is not valid, the time information measured by the time measuring unit 11 is kept as it is, and the timing of advance of the second is synchronized with the synchronization signal. Further, when the reception state of the GPS receiver 13 is invalid and the reception state of the standard radio wave receiver 14c is valid, a process of updating the time information of the time measuring means 11 based on the time information acquired by the standard radio wave receiver 14c is added. Also good.

  As described above, the time correction device 10 receives signals synchronized with the respective times from a plurality of time sources, and preferentially uses the 1-second pulse signal of the GPS receiver 13 with the highest accuracy as a synchronization signal. When the reception status of the GPS receiver 13 is invalid, the time adjustment is performed with the synchronization signal based on the most accurate time signal by adjusting the time signal of FM broadcasting and the time signal based on the standard radio wave. For example, the synchronization signal is supplied to the NTP daemon as a 1-second pulse signal to adjust the time. For multiple hourly signals, the hourly signal with the shortest delay time from the transmission source should be used for time adjustment, so the hourly signal timing adjustment means synchronizes with the earliest rise of the hourly signal in a predetermined period. Thus, a synchronization signal is generated. There is a method to set and correct the delay time in advance when using the time signal for time correction, but if the delay time is not constant, there is an advantage in correcting the time with the earliest time signal. . Further, the effective signal selection means 15 can select a valid hour signal based on the reception state of each hour signal receiver, thereby reducing the possibility of erroneous correction due to noise or the like in advance. .

DESCRIPTION OF SYMBOLS 10 Time adjustment apparatus 11 Time measuring means 12 Time correction means (correction means)
13 GPS receiver (reception means)
14a Time signal receiver (reception means)
14b Time signal receiver (reception means)
14c Standard radio wave receiver (reception means)
15 Effective signal selection means (discrimination means)
16 Correct signal timing adjustment means (synchronization signal generation means)
17 Timing correction means (synchronization signal generation means)
18 Synchronization signal generating means

Claims (5)

A time measuring means for measuring time;
A plurality of receiving means for receiving a signal synchronized with time information of each time source and outputting a reference signal;
Discriminating means for discriminating the validity of each of the reference signals based on the reception state of the receiving means;
The plurality of reference signals are input, and when the reference signal received by the predetermined receiving unit among the plurality of reference signals is determined to be valid based on the determination result of the determining unit, the predetermined Select the reference signal from the receiving means preferentially, and when the reference signal from the predetermined receiving means is not valid, select and select the reference signal that is input earliest in a predetermined period and determined to be valid Synchronization signal generating means for generating a synchronization signal synchronized with the reference signal,
Correction means for correcting the time of the time measuring means in synchronization with the synchronization signal;
A time correction apparatus comprising:   The at least one of the receiving means receives the time information from a time source, and the correcting means corrects the time based on the time information received by the receiving means. The time correction device described in 1.   The synchronization signal generating means generates a composite signal by taking a logical sum of a pulse width adjusting means that uses a plurality of reference signals from the receiving means as a common pulse width signal and a signal from the pulse width adjusting means. The time correction apparatus according to claim 1, further comprising: a logical sum unit, wherein the synchronization signal is generated in synchronization with the generation of the combined signal.   4. The time adjustment apparatus according to claim 3, wherein the common pulse width is larger than a predetermined error that allows correction in time adjustment.   The predetermined receiving means is a GPS receiver, and the other receivers are receivers that receive radio waves superimposed with time signals or receivers that receive standard radio waves. A time correction device according to any one of the above.