JPS63108292A - Method for controlling reference timepiece - Google Patents

Abstract

PURPOSE:To prevent the error of the real time to be applied from exceeding a permissible value even if a timepiece of relatively low accuracy is used as a reference timepiece by determining a time adjusting period from the error rate of the reference timepiece and the permissible error permitted to the reference timepiece and making time adjustment of the reference timepiece in accordance with the error rate and the time adjusting period. CONSTITUTION:Exact time t0 is first read in, then the time t0 is set in the reference timepiece to be controlled. The time t0 is stored and the monitoring of the time is started. The exact time t1 is read in upon lapse of the prescribed time T0 and the time t1 is reset. A difference d0 between the indicated value of the reference timepiece when the time t1 is reset and the exact time t1 is determined and the error rate is calculated. The time adjusting period T is determined in accordance with the error rate and the permissible error permitted to the reference timepiece. The monitoring of the time is started from the time t1 and the time adjustment of the reference timepiece is made by as much as the difference d of the time in accordance with the error rate and the time adjusting period T upon lapse of the period T at the time t2.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a reference clock control method for providing real time in electronic equipment and the like.

[Conventional technology]

In electronic devices and the like that perform signal processing using micro combinators, accurate real time information such as month, day, hour, minute, and second may be required.

Conventionally, the clock built into the microcomputer itself has generally been used as the ninth reference clock for giving the real time in such electronic devices, etc., and the real time is estimated based on this clock. It was to execute a predetermined process. Therefore, in order to always provide accurate real time, it was necessary to use high-precision parts for the clock part and to make precise adjustments to ensure its accuracy was sufficiently high. .

[Problem that the invention seeks to solve]

The real time in conventional electronic devices is given as described above, and the high precision parts and precise adjustments directly lead to increased costs. Accuracy is constrained by economics, and not only is it difficult to obtain a sufficiently accurate one, but due to the nature of watches, errors will accumulate over a long period of time and the tolerance will drop, no matter how high the precision is used. The problem was that it exceeded the limit.

This invention was made in order to solve the above-mentioned problems, and provides a reference clock control method in which the error in real time given does not exceed a permissible value even when a clock with relatively low accuracy is used as the reference clock. The purpose is to obtain.

[Means for solving problems]

The reference clock control method according to the present invention first determines the error rate of the reference clock, determines a time adjustment cycle from the obtained error rate and the allowable error allowed for the reference clock, and adjusts the error rate for each time adjustment cycle. The time of the reference clock is adjusted based on the rate and time adjustment cycle.

[Effect]

The reference clock control method according to the present invention determines a time adjustment period based on the actual expected error rate and the allowable tolerance of the reference clock, and determines the error of the reference clock based on the time adjustment period and the error rate. Automatically adjust the time before it exceeds the tolerance.

[Example] Hereinafter, an example of the present invention will be described with reference to the drawings. 1st
The figure is a flowchart showing a reference clock control method according to an embodiment of the present invention, and FIG. 2 is a time chart for explaining the method. In Figure 2, 1 is the time scale of the standard accurate time, for example, obtained from a telephone time signal service, radio time signal, or standard radio wave (JJY), and 2 is the time scale of the reference clock to be controlled. It shows.

First, in step ST1, the accurate time t is determined from the time signal service of the telephone. The time t is read into the controlled reference clock. Set. Next, in step ST2, the time t0 is stored and time monitoring is started. A predetermined time T predetermined in step ST3. When it is detected that, for example, three days have passed, in step ST4, the accurate time t1 is read again from a telephone time signal service, etc., and the time t1 is reset to the controlled reference clock.

Next, in step ST5, the difference d between the instruction value of the reference clock at the time of resetting the time t1 and the accurate time t is determined. Find this difference d. From this, the error per unit time, such as the advance of 30 seconds/day, that is, the error rate is calculated. Next, in step ST6, the time adjustment period shown by T in FIG. 2 is determined based on the obtained error rate and the allowable error allowed for the reference clock. That is, if the error allowed for this reference clock is one minute, the time adjustment period T is determined to be within two days, for example, two days. The processing up to this point is performed, for example, by an adjustment operator as an initial adjustment before shipping the product.

Next, in step STγ, time monitoring starts from the reset time t1, and the reference clock continues normal timekeeping operation until time t2 is reached and the passage of the time adjustment cycle T is detected in step ST8. I am doing it. This time monitoring is performed based on the timekeeping of the controlled reference clock itself, and when the passage of the time adjustment period T is detected in step ST8, the error rate calculated in step ST5 is determined in step ST9. and this time adjustment period T.
The time of the reference clock is adjusted by the difference in time indicated by d in the figure. For example, if the error rate advances by 30 seconds/day as described above and the time adjustment period T is 2 days, step ST9
In this case, the reference clock is delayed by 60 seconds. When the time adjustment in step ST9 is completed, the process returns to step ST7, time monitoring starts from time t2, and the same process as described above is repeated.

FIG. 3 is a flowchart showing a reference clock control method according to another embodiment of the present invention, which enables processing when readjustment becomes necessary due to long-term use or the like. In FIG. 3, from step ST1 to step ST
9 are the same as those shown in FIG. 1, so their explanation will be omitted.

In this embodiment, if it is determined in step ST8 that the time adjustment period T has not elapsed, the process is directly performed in step S.
The process is not returned to T7, but is returned via step ST10. This step STIO
The determination is made as to whether there is a need for readjustment. For example, this is done by detecting the state of a switch that the user operates when he or she feels the need for readjustment during use. Therefore, when the user who feels the need for readjustment performs a switch operation, step ST10 that detects this moves the process to step ST11 without returning to step ST7. In step ST11, the accurate time tn at that time is read from a telephone time signal service, etc., and the time tn is reset to the reference clock to be controlled. Next, in step ST12, the difference between the indicated value of the reference clock at the time of resetting the time tn and the accurate time t is calculated, and this difference is combined with the number of times the time adjustment has been performed by step ST9 up to now, and the last time. The error rate is recalculated based on the time from when the time adjustment is performed until the reference clock is reset at step ST11, and this is corrected, and the process returns to step ST7. Thereafter, the process proceeds in the same manner as in the embodiment shown in FIG. 1, and in step ST7, the time of the reference clock is adjusted every time adjustment period T based on this time adjustment period T and the corrected error rate. It will be done.

〔Effect of the invention〕

As described above, according to the present invention, the error rate of the reference clock to be controlled is measured, and each time adjustment cycle is determined based on the obtained error rate and the tolerance allowed for the reference clock. Since the time of the reference clock is automatically adjusted based on this time adjustment cycle and the error rate, the time of the reference clock is adjusted to an accurate value before the error exceeds the tolerance. Even if a clock with relatively low accuracy is used as the reference clock, the real time given by the reference clock will not exceed the allowable error value.

[Brief explanation of the drawing]

FIG. 1 is a flowchart showing a reference clock control method according to an embodiment of the present invention, FIG. 2 is a time chart for explaining the method, and FIG. 3 is a flowchart showing another embodiment of the invention. 1 is the time scale of the standard accurate time, 2 is the time scale of the reference clock, the predetermined time for determining the ToFi error rate, T is the time adjustment period, t0 to t are the times, do,
d is the time difference.

Claims (1)

[Claims] Set a reference clock to an accurate time, read the accurate time after a predetermined time has elapsed from the set time, detect the error rate of the reference clock, and calculate the detected error rate and the tolerance given to the reference clock. A reference clock control method characterized in that a time adjustment cycle is determined based on the error, and the time of the reference clock is automatically adjusted for each time adjustment cycle based on the time adjustment cycle and the detected error rate.