JPH04151592A - Clock device - Google Patents

Abstract

PURPOSE:To enable indication of correct time without controlling fine oscillation frequency of an oscillator by measuring the frequency error of each oscillator, storing the time error factors based on the frequency error in a memory, and correcting the time. CONSTITUTION:The oscillation output from a quartz oscillator 1 is supplied to a frequency divider 6 to count with a date and time counter 8, and second, minute, hour, day of the week, date, month and year are calculated to send to a calculator 10. On the other hand, the error factors of each component are stored in advance, in an nonvolatile memory 12. That is, by measuring the oscillation frequency from a terminal 7 in advance to get the error DELTAf of the oscillation frequency f from the reference frequency f0, i.e. DELTAf=¦f-f0¦, the time error factor is obtained with the DELTAf to store. When the power is turned on, a time register 16 sends the time data used previously by the components to the calculator 10. The calculator 10 calculates the remaining period from the registered 16 data and the initiation of using time, and then calculates the time error to be produced in the remaining period from the time error factor in the memory 12. It then corrects a counter 8 by way of a control register 11.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention particularly relates to a timepiece device suitable for use when built into a battery-powered electronic device.

[Summary of the invention]

In a clock device suitable for use when built into a battery-powered electronic device, the present invention measures the frequency error of an oscillator for each device, stores a time error coefficient based on this frequency error in a memory, and stores a time error coefficient based on this frequency error in a memory. By correcting the time using a time error coefficient, it is possible to display the correct time without making fine adjustments to the oscillation frequency of the oscillator.

[Conventional technology]

Many electronic devices have a built-in clock in order to set a timer, display the time, or insert and edit the recording time. BACKGROUND ART Electronic devices that operate using a commercial AC power source use a built-in clock that counts waveform-shaped commercial AC power pulses. In the case of a clock that counts commercial AC power pulses as described above, time errors do not occur as long as the frequency of the commercial AC t'a is well controlled.

On the other hand, in the case of a battery-driven electronic device such as a camera-integrated VTR, a clock configured with a crystal oscillator is used because a clock that counts commercial AC power pulses cannot be constructed. In the case of a clock with a crystal oscillator configuration, time errors will occur if the crystal oscillator is not well managed.

That is, for example, if a crystal resonator has an error of ±10 ppm, an error of approximately ±5 minutes will occur in one year.

In a watch using a crystal oscillator as described above, a trimmer capacitor is provided to compensate for variations in the crystal oscillator, and the oscillation frequency is finely adjusted by this trimmer capacitor.

That is, FIG. 3 shows the configuration of a crystal oscillator used in constructing a conventional timepiece. In FIG. 3, 51 is an oscillation cell, 52 is a crystal resonator, 53 is a capacitor, and 54
is a trimmer capacitor for adjustment. The trimmer capacitor 54 finely adjusts the oscillation frequency of this crystal oscillator. This compensates for time errors due to variations in the crystal oscillator 52.

[Problem to be solved by the invention]

Conventionally, the oscillation frequency of the crystal oscillator must be fine-tuned for each individual device because the variations in crystal oscillators are different for each device.

However, it is not easy to finely adjust the oscillation frequency of a crystal oscillator in this way. Further, even if the oscillation frequency of such a crystal oscillator is finely adjusted, an oscillation frequency error remains due to measurement errors and adjustment errors. Therefore, after a long period of time, a large time error occurs.

Therefore, it is an object of the present invention to eliminate the need for adjustment work;
However, the object of the present invention is to provide a clock device that can eliminate time errors.

[Means to solve the problem]

This invention measures the frequency error of an oscillator for each device, stores a time error coefficient based on this frequency error in a memory,
This is a clock device that corrects the time using a time error coefficient in a memory.

[Effect]

The time error can be determined by measuring the variation in the oscillation frequency, determining the error coefficient in advance, measuring the elapsed time T, and multiplying the error coefficient by this elapsed time. By using the time error obtained in this way, the time can be corrected correctly even if there are variations in the oscillation frequency.

[Example] Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 shows an embodiment of the present invention. 1st
In the figure, 1 is a crystal oscillator. The crystal oscillator 1 is
It is composed of an oscillation cell 2, a crystal resonator 3, and capacitors 4 and 5. This crystal oscillator does not require a trimmer capacitor for adjustment. The oscillation frequency of the crystal oscillator 1 is set to 32.768, for example.

The oscillation output of the crystal oscillator is supplied to the frequency divider 6.

The frequency divider 6 divides the oscillation output of the crystal oscillator 1 by, for example, 32. Therefore, from the frequency divider 6, for example, the frequency 1
A signal of 0.024 Hz is output. A terminal 7 is led out from the frequency divider 6 so that the oscillation frequency of the output of the frequency divider 6 can be measured.

The output of the frequency divider 6 is supplied to a date and time counter 8.

A date and time counter 8 counts the output of the frequency divider 6 and records the date and time, that is, seconds, minutes, hours, day of the week, date,
The month and year are each required. The determined date and time are sent to the calculation unit 10 via the control bus 9.

This time counter 8 is controlled by a control signal sent from an arithmetic unit 10 via a control register 11.

12 is a nonvolatile memory in which the error coefficient K is stored.

This nonvolatile memory 12 stores coefficients for each device in advance. That is, the frequency of the signal from the terminal 7 is measured in advance for each device. Error Δf between this frequency and the reference frequency Δf=:f−f.

From this, the error coefficient K K=k·Δf is obtained. This error coefficient K is given to the nonvolatile memory 12 from the terminal 17, and this error coefficient K is stored in the volatile memory 12.

13 is a power switch. When using the device, the power switch 13 is switched to the a side.

When the power switch 13 is switched to the a side, power from the power terminal 14 is supplied to the arithmetic unit 1 via the power switch 13.
0, and power is also supplied to other parts.

When the device is not in use, the power switch 13 is set to the b side. As a result, power from the backup power supply 15 is supplied to the calculation unit 10.

Thereby, the arithmetic unit 10 can be operated even when the power is turned off.

16 is a time register. This time register 16 is
It is connected to the control bus 9. This time register 16 is supplied with power from the backup power supply 13 when the device is not in use so that its data is retained even when the device is not in use.

In the case of a clock using a crystal oscillator, oscillation frequency errors accumulate and become time errors. Therefore, the time error increases in proportion to the elapsed time. The coefficient at this time is a predetermined value for each device depending on the oscillation frequency error. From this, if we measure the variation in the oscillation frequency and find the coefficient in advance, measure the elapsed time, and multiply this elapsed time by the coefficient, we get:
Time error can be determined.

In one embodiment of the present invention, based on such a principle,
I am trying to correct the time.

The operation of one embodiment of the present invention will be described with reference to the flowchart shown in FIG.

As mentioned above, the oscillation frequency from the terminal 7 is measured in advance, and this oscillation frequency f and the reference frequency f.

Error Δf, Δf=　ff−f.

is measured, and an error coefficient K is determined based on this error Δf. Then, this error coefficient K is stored in the volatile memory 12 in advance.

Further, as shown in FIG. 3, the time register 16 stores the time T at the end of the previous period of use. In addition, in FIG. 3, the horizontal axis shows the period, and the vertical axis shows the time error.

In FIG. 2, in order to use the device, it is determined whether t'a is turned on (step 21). Whether or not the power has been turned on can be determined from whether or not the power switch 13 has been turned on.

When the power is turned on, the time T when the device was previously used is stored in the time register 16.

The data shown in FIG. 3 is read out at time T.

is sent to the calculation unit 10 (step 22).

Then, from the time T stored in the time register 16 and the time T2 at the start of use, the arithmetic unit 10 calculates the unused period T0 To=Tz T . (Step 23).

Error coefficient K is read from nonvolatile memory 12 (step 24).

From this error coefficient and the unused period TD, as shown in FIG. 3, the time error ΔT occurring within the unused period ΔT = K-T.

is determined (step 25).

According to this time error ΔT, the control register 11
The time counter 8 is corrected via (step 26)
.

The time register 16 is rewritten to the second corrected time (step 27).

It is determined whether the power has been turned off (step 28).
, when the power is turned off, the time at this time is stored in time register 1.
It is stored in 6. This time will be used to correct the time the next time it is used.

Thus, in one embodiment of the present invention, when the device is used, time errors are corrected from the error coefficients from the non-volatile memory 12 and from the unused period.

Therefore, the correct time is always displayed when using the device.

Note that the time is corrected when the device starts to be used, so the period of use is T. A time error of -T6, minutes remains, but this time error can be ignored.

In this embodiment, the time error is corrected when the device is used, but the time error is corrected in the same way at every predetermined period
The time may be corrected.

Alternatively, the temperature characteristics of each device may be measured, and the time may be corrected in accordance with the temperature characteristics as well as the oscillation frequency error.

〔Effect of the invention〕

According to this invention, the time error is corrected by measuring the variation in the oscillation frequency, determining the error coefficient in advance, measuring the elapsed time, and multiplying the error coefficient by the elapsed time. Therefore, even if there are variations in the oscillation frequency, the time can be corrected correctly, and fine adjustment of the oscillation frequency is not necessary.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention, FIG. 2 is a flowchart used to explain the embodiment of the invention, and FIG.
The figure is a graph used to explain one embodiment of the present invention. Explanation of main symbols in the drawings 1: Crystal oscillator, 8: Time counter. 10: Summer section, 12: Non-volatile memory 16: Time register. Fig. 1 Fig. 2 Period □ 8 days ahead Fig. 4 This is the next case Fig. 4 Procedural amendment (engraved on December 20, 1991 Wataru Fukazawa, Commissioner of the Patent Office 1, Case display clock device 3, Amendment Relationship with the case of a person who does
8) Sony Corporation Representative Director Norio Ohga 4, Agent 170 Address: 1-48-10-6 Higashiikebukuro, Toshima-ku, Tokyo Column 7 for a brief explanation of the drawings in the specification subject to amendment, Details of the amendment This is the graph used in the book, page 11, line 12. '' has been corrected to read ``The graph used in FIG. 4 is a connection diagram used to explain the conventional timepiece device.''that's all

Claims (1)

[Claims] A clock device that measures the frequency error of an oscillator for each device, stores a time error coefficient based on this frequency error in a memory, and corrects the time using the time error coefficient in the memory.