Electronic timepiece

Abstract

An electronic timepiece which includes a time reference base signal generator, which generates a signal which is used to count time, and is compensated in its frequency in order to have the predetermined frequency value regardless of variations in ambient temperature.

Description

BACKGROUND OF THE INVENTION

This invention relates to an electronic timepiece including a system for compensating for the variation in a frequency of a time reference base signal generator; 12, a time count unit signal generator; 13, a time counting mechanism timekeeping means for keeping a time by using a time count unit signal; 14, a mechanism display means for displaying the kept time; 15, a temperature signal generator; and 16, a temperature compensating signal generator, respectively.

The temperature signal generator 15 comprises an oscillator having a temperature sensing ability and the a predetermined temperature-frequency characteristics. The output frequency changing rate of the temperature-frequency characteristics thereof are temperature signal generator 15 is generally larger than that of the time reference base signal generator 11.

The output of the temperature signal generator 15 has a large rate of variation in its temperature-frequency characteristics so that the ambient temperature can easily be detected by measuring the frequency and, accordingly it can be considered that the output of the temperature signal generator 15 is to be the temperature signal. In FIG. 1 the signal transfer system is omitted, but it is necessary to obtain the frequency or time signal used as the standard in order to measure the frequency or periodic time. The signal from the time counting mechanism timekeeping means 13 or the temperature compensated time reference signal in the mechanism circuit 13 is useful as the basis of the frequency measurement.

For example, if the rate of frequency variation with temperature of the crystal oscillator is approximately 10-5 and that of the output of the temperature signal generator 15 is approximately 10-3, then the frequency of the output of the temperature signal generator 15 can be measured with the smaller error by using the resonance frequency as the basis. Alternatively, a signal from the separate crystal oscillator or signal transmitted with an electric wave can be used as the basis.

In FIG. 1, the output of the temperature signal generator 15 is supplied to the temperature compensating signal generator 16 as a frequency signal having the predetermined temperature characteristics.

The temperature compensating signal generator 16 acts to convert the signal from the temperature signal generator 15 into a signal in the a form of compensating which can be used to compensate for the temperature characteristics of the output frequency of the time reference base signal generator 11 in accordance with the frequency of the temperature signal and to send it to at least one of the time reference base signal generator 11, time count unit signal generator 12 and time counting mechanism timekeeping means 13.

In the embodiment of FIG. 2, a temperature compensating signal is obtained as either a frequency corresponding to the difference between the frequency of the output from at least one of the following circuits: a time reference base signal generator 21, a time counting unit signal generator 22 or time counting mechanism timekeeping means 23 and the frequency the output from a temperature signal generator 25 by mixing the signals in a temperature compensating signal generator 26, or a number given by using the last figure of the number and the figures near the last figure which are obtained by counting the number of pulses of the output from the temperature signal generator within the unit time determined by the time reference base signal.

The above method in which the difference of the frequency values is used and the method in which the end of the numbers is taken by the overflow of a counter improve analysing ability in temperature detection.

The signal prepared by one of the methods set forth above is converted into a signal which can compensate the temperature characteristics of the output frequency of the time reference base signal generator 21 and is sent to at least one the following circuits: the time reference base signal generator 21, time count unit signal generator 22 or the time counting mechanism timekeeping means 23 as in the case of FIG. 1. The reference numeral 24 denotes a time display mechanism means.

FIG. 3 shows a block diagram of a system according to this invention similar to those shown in FIGS. 1 and 2 with the exception that the temperature compensating signal generator is omitted. In the system the temperature characteristics of the output frequency of a time reference base signal generator 31 is compensated by sending the output frequency of a temperature signal generator 35 to at least one of the following circuits: a time reference base signal generator 31, a time count unit signal generator 32 and a time counting mechanism timekeeping means 33. The reference numeral 34 indicates a time display mechanism means.

FIG. 4(A) illustrates a temperature signal generating system using the combination of an amplifier having a positive amplifying rate and a temperature sensing band-pass filter and FIG. 4(D) discloses a filter including a band-pass filter, resistors and condencers.

The filter may be one of those having a coil or a mechanical resonance element, such as a ceramic filter and an electricmechanical transducer, having an electromechanical transducing function. FIG. 4(B) shows an oscillator having an oscillating frequency of about two times the shift time and includes an amplifier having a negative amplifying rate and a variable phase shifting element. FIG. 4(E) illustrates a circuit of a low-pass filter.

FIG. 4(C) shows an oscillator having a positive feed back amplifier acting as a tuning amplifier which can eliminate the components having the specified frequency and is given a negative feed back at the other frequency than the above by means of a filter, such as the filter of the circuit shown in FIG. 4(F).

Of course, with of the oscillators shown in FIGS. 4(A), 4(B) and 4(C) the oscillating condition should be satisfied.

If an oscillator having a larger variation rate in temperature-frequency characteristics is intended to be obtained, one or more elements which determine the resonance frequency of the oscillator shown in FIGS. 4(A), 4(B) or 4(C), such as a resistor, condenser or reactance inductor, may be replaced with an element which varies its characteristics with temperature. For example, when one of the resistors is replaced with a thermistor or posistor, an oscillator acting as a temperature signal generator will be constructed. Furthermore, if one of the resistors is replaced with a variable resistor the temperature characteristics may be adjusted. This is also true for the replacement of capacitance.

In the systems shown in FIGS. 4(D), 4(E) and 4(F) composite elements such as a distribution delay element shown in FIG. 4(G) or distribution band-cut filter shown in FIG. 4(H) may be used singly or in combination with an element having a temperature detecting ability. Alternatively, it is possible to use digital delay mechanism or filter mechanism including a logical circuit.

Circuits performing addition and subtraction of frequency are shown in FIGS. 5 and 6, respectively.

FIG. 5(A) shows an exclusive-OR gate or a logical not circuit which can add precisely two signals having frequencies of (f₁) and (f₂), respectively, unless the edges of the signals overlap with each other.

Error encountered upon addition would in probability be very small in the ratio to the signals to be added and is therefore negligible.

The circuit shown in FIG. 5b acts to add two signals having frequency values 2f₁ and f₂ after reforming the wave form and arrangement in connection with the phase by a logic circuit. The circuit can improve the accuracy of addition in comparison with that shown in FIG. 5(A) due to the settlement of the phase of the added signals by presence of the logic circuit.

FIG. 6 shows a frequency difference detection circuit for obtaining a difference signal f₂ -f₁ f₁ -f₂ from two signals having frequency values of f₁ and f₂, respectively. The difference signal f₂ -f₁ can also be f₁ -F₂ is obtained by counting the frequency values f₁ and f₂ in a counter separately separate counters and then taking the difference between two counted values at the a desired time. In this case the information on the frequency difference will be obtained at a constant timing certain times so that it is needed necessary to make the information continuous through by using a memory device if the difference is required continuously.

Alternatively, the an output signal from the circuit of FIG. 6 may be obtained at each time the difference in a counter reaches to the a predetermined value.

In a simpler manner, the difference value or integrated value thereof can be obtained by using an updown counter which is so operated that one signal is used to up count and the other signal to down count, with the counted value being read out by changing over or resetting the counter. A similar value can also be obtained by using an up-counter and by reading out or resetting the counter at constant intervals. For example, the frequency difference in the order of 1×10³ between two signals having frequency values of f₁ and f₂ may be obtained by reading out the counted value of the frequency f₁ every time when the counted value reaches 1,000 or 10,000. Counters having a small capacity can be used due to the fact that the difference value appears as the end of the counted number, which enables overflowing of the higher figures.

FIG. 7 shows an electronic timepiece having a temperature compensating mechanism system for a time reference base signal generator composed of a temperature signal generator and a frequency counter and a divider connecting thereto, which comprises a crystal oscillator 71 as a time reference base signal generator, a frequency counter an algebraical adding circuit such as EX-OR gate, 72, an oscillator 73 as a temperature signal generator, a time count unit signal generator 74, a time counting mechanism timekeeping means 75, a time display mechanism means 76, an operating mechanism 77 and dividers 78.

The system is composed in the form of a C/MOS-IC or a composite circuit of C/MOS-IC and other electronic parts, the ratio between the temperature coefficients of the respective oscillators 71 and 73 being larger than 1.

The outputs of the oscillators 71 and 73 are subjected to frequency division in the respective dividers 78 and to the addition of frequency the outputs of the dividers are algebraically added in the counter EX-OR gate 72 so as to count as form the minimum unit of the time count in the time count unit signal generator 74. The information in the generator 74 is displayed on the display mechanism means 76 as a kept time.

The output of the oscillator 73 acts to control the oscillation is controlled by the output of the control mechanism unit 79 corresponding to the which in turn is controlled by signals from the time counting mechanism timekeeping means 75 and the time count unit signal generator 74.

The control mechanism 74 unit 79 is provided for eliminating the increase of the consumed to reduce the electric power by the action of the oscillator 73 and for controlling the scale of which would otherwise be consumed by the temperature compensating operation or the timing, but it is in some cases unnecessary.

Referring now to FIG. 8, there is shown a system for eliminating the increase of the consumed reducing the electric power which would otherwise be consumed by the action of the oscillator 73 and for controlling the scale extent of the temperature compensating operation or for the timing of compensation, the reference numeral 81 designates a time reference signal generator; 82, a time count unit signal generator; 83, a time counting mechanism timekeeping means; 84, a time display mechanism means; 85, a timing control mechanism unit; 86, a temperature signal generator; 87, a memory; and 88, a frequency changing mechanism circuit.

In the embodiment set forth above, temperature signal generator 86 comprises an oscillator which varies the resonance frequency in the wider range with temperature.

The timing control mechanism unit 85 is to control the start and stop operation of the temperature signal generator 86 for obtaining intermittent operation. The mechanism control unit 85 also acts so as to eliminate increase consumption of electric power by the action of the oscillator 73 and to control the scale of the temperature compensation operation or timing. The control of the timing is done by using as an input the signals from the time count unit signal generator 82 and the time counting mechanism timekeeping means 83.

The temperature signal, which is obtained intermittently from the temperature signal generator 86, is supplied to the memory 87 and stored therein until the next timing signal is received from generator 86. The temperature signal stored in the memory is then supplied to the frequency changing mechanism circuit 88 and used for compensating the variation of the frequency caused by the temperature characteristics of the time reference base signal frequency.

FIG. 9 illustrates a block diagram of a system using a crystal oscillator as the temperature signal generator, in which the reference numeral 91 depicts an oscillator as a time reference base signal generator, and 92 an oscillator as a temperature signal generator wherein a crystal vibrator element 94 having a different temperature-frequency characteristics from that of a crystal vibrator element 93 in the oscillator 91 is used. The oscillators 91 and 92 intermittently generate outputs under the control of the time counting mechanism timekeeping means 912 described below.

Further to FIG. 9, the reference numeral 95 denotes a divider to divide the oscillating frequency of the oscillator, which may be omitted, and 96 temperature compensating signal generator comprising a counter 97, a memory 98 and a converter 99. The counter 97 acts to compare the output from a time counting mechanism timekeeping means 912 described below with the output of the divider 95 or the oscillator 92 when the divider 95 is omitted, in the manner, for example, that the counter 97 counts the output frequency from the divider 95 within the predetermined period of time in which the output from the time counting mechanism timekeeping means is supplied to the counter.

The result of counting resultant count is stored in the memory 98. The stored information in the memory 98 depends on is representative of the variation of temperature, that is, the information relating to temperature. The memory 98 is controlled by the output from the time counting mechanism timekeeping means 912 so as to keep an information until the following information is supplied. The converter 99 generates a temperature compensating signal using the output of the memory 98 in accordance with the predetermined characteristics corresponding to the temperature-frequency characteristics of the oscillator 91. An Exclusive-OR gate denoted by the numeral 910 adds the outputs from the oscillator 91 and the converter 99, and a time count until to form a modified signal which is supplied to the time unit signal generator 911 which prepares a time count unit signal by dividing the output frequency of the Exclusive-OR gate. Furthermore, the reference numeral 912 designates the time counting mechanism timekeeping means which prepares a signal required for display of the time using the signal from the time count unit signal generator 911, and 913 is a display mechanism means capable of displaying the time according to the output from the time counting mechanism timekeeping means 912.

When the ambient temperature varies, the resonance frequency of the oscillator 91 is a time reference signal generator which varies with the temperature, and the signal is supplied to the Exclusive-OR gate 910. On the other hand, the output frequency of the oscillator 92 as a temperature signal generator also varies with temperature, so that the output of the counter 97 is different from the time before the ambient temperature varies varies, and the output signal of the memory 98 will also vary. Accordingly, the output of the converter 99 which is varied is supplied to the Exclusive-OR gate 910 thereby to compensate the output of the oscillator 91. Namely, the output signal having a constant frequency will be obtained even when the ambient temperature varies.

FIG. 12 shows the pulse trains which exemplify the operation of the EXCLUSIVE-OR gate 910 in the circuit of FIG. 9. The gate 910 adds the outputs from converter 99, illustrated by pulse train A, to the output of oscillator 91, illustrated by pulse train B. The resultant pulse train C is applied to time counting mechanism timekeeping means 911. As is seen in FIG. 12, there is an increase in the number of pulses due to coincidence of the leading edges of the pulses A and B. The input frequency to the time count signal generator can, therefore, be kept constant in spite of temperature changes if the output signal frequency from the oscillator 91 is added in inverse proportion to the output frequency of the converter 99.

The above embodiment shown in FIG. 9, is so arranged that the variation of the frequency with temperature of the oscillator 91 is compensated for by supplying to the Exclusive-OR gate 910 the signal from the converter 99 together with the signal from the oscillator 91, but it is also possible to construct it so as to maintain the constant oscillation frequency of the oscillator 91 against variation of temperature by supplying the signal from the converter 99 to the oscillator 91.

In FIG. 10 there is illustrated an assembly in which the crystal vibrator element 93 of the oscillator 91 and the crystal vibrator element 94 of the oscillator 92 are enclosed in a casing 95. In this case, the temperature compensation will be performed more stably due to the fact that both the crystal vibrator elements 93 and 94 are laid in the equal conditions. Furthermore, the assembly can be made smaller in size and has an economical advantage, because it is necessary to use a single casing.

FIG. 11 shows a further system embodying this invention in which temperature compensation is done by taking out two output signals having different vibration modes from each other which are used in the time reference signal generator and the temperature signal generator. Two kinds of modes from a reference oscillator crystal vibrator element 111 are fed to a pair of vibrator elements oscillators 112 and 113, respectively, and the oscillator 113 is controlled so as to oscillate intermittently by a time counting mechanism timekeeping means 116. A counter 118 is controlled, similar to oscillator 113, by the time counting mechanism timekeeping means 116 and reset when the output of the oscillator 113 becomes stable, and counts the input frequency within the predetermined period time. The resultant counted value which corresponds to temperature is written in a memory 116 which may store the written information until new further information is supplied. The signal converter 120 generates a temperature compensating signal using the output of the memory 119 in accordance with the predetermined characteristics corresponding to the temperature-frequency characteristics of the time reference base signal.

A frequency changing mechanism circuit 114, in case of need, generates a signal used for obtaining a time count unit signal in the mechanism 115 by compensating the time reference signal from the time reference signal generator comprising the oscillator 112 in accordance with the signal from the time count unit signal generator 115 via the time counting mechanism 116. Furthermore, the time counting mechanism circuit 116 keeps the time counted in accordance with the time count unit signal generator 115, and a display mechanism means 117 displays the time. It is possible to form a system in which the function of the frequency changing mechanism circuit 111 is given to the time count unit signal 115 or the time counting mechanism circuit 116 itself.

The counter 118 can be constructed by connecting flip-flops in several stages if it is used in the manner of overflowing. The converter 120 may be realized with a read-only memory (so called ROM) in which codes are written for obtaining compensation of the temperature characteristics of the reference oscillator. Alternatively, a combination of gates may be used in lieu of the ROM.

According to this invention, as described above, the changes or variations of the time reference signal frequency with temperature can be compensated for stably over a long period of time and the system may be constituted as an IC without oscillators, which enables one to provide a highly accurate electronic timepiece which is small in size.

Claims

1. An electronic timepiece which is provided with a time reference signal having an output signal time count unit signal generator, a time counting mechanism and a time display mechanism, the electronic timepiece further comprising:

a temperature signal generator for generating a temperature signalsaid generator, said temperature signal generator being timed to oscillate intermittently by the output signal of said timekeeping means and including an oscillator circuit having an output different from that of said time reference signal generator, wherein the ratio of output oscillation frequencies changes with temperature variation;

means for transmitting said temperature signal intermittently in response to the output signal of said timekeeping means;

memory means for storing the temperature signal generated by said temperature signal generator until a subsequent temperature signal is generated and for delivering said stored temperature signal when the subsequent temperature signal is received by the memory, said memory means being controlled by the output signal of said timekeeping means so as to keep the temperature signal until a subsequent temperature signal is supplied;

a signal converter for generating a temperature compensating signal in response to the temperature signal stored in said memory means, wherein said compensating signal compensates for the variations of the output frequency of said time reference signal generator caused by temperature variations; and

a time reference signal frequency variable controller for synthesizing the output signal of said time reference signal generator and that of said signal converter by compensating for the changes of the output frequency of said time reference signal generator caused by the temperature variations and for delivering a resultant signal to said time unit signal generator.

2. The electronic timepiece of claim 1, wherein An electronic timepiece which is provided with a time base signal generator, having a given output signal frequency, a time unit signal generator, a timekeeping means coupled to the output of said time unit signal generator and a time display means coupled to the output of said timekeeping means; the electronic timepiece further comprising:

a temperature signal generator for generating a temperature signal, said temperature signal generator is being timed to oscillate intermittently by the output signal of said time count unit signal generator and including an oscillator circuit having an output signal of a frequency different in frequency from that of said time base signal generator, wherein the output oscillation frequency of said temperature signal generator changes with temperature variation;

means for transmitting said temperature signal intermittently in response to the output signal of said time unit signal generator;

memory means for storing the temperature signal generated by said temperature signal generator until a subsequent temperature signal is generated and for delivering said stored temperature signal when the subsequent temperature signal is received by the memory;

a signal converter for generating a temperature compensating signal in response to the temperature signal stored in said memory means, wherein said compensating signal compensates for variations of the output frequency of said time base signal generator caused by temperature variations; and

a time base signal frequency variable controller for synthesizing the output signal of said time base signal generator and that of said signal converter by compensating for changes of the output frequency of said time base signal generator caused by temperature variations and for delivering a resultant signal to said time unit signal generator.

3. The electronic timepiece of claim 1, wherein An electronic timepiece which is provided with a time base signal generator, having a given output signal frequency, a time unit signal generator, a timekeeping means coupled to the output of said time unit signal generator and a time display means coupled to the output of said timekeeping means; the electronic timepiece further comprising:

a temperature signal generator for generating a temperature signal, said generator including an oscillator circuit having an output signal of a frequency different in frequency from that of said time base signal generator, wherein the output oscillation frequency of said temperature signal generator changes with temperature variation;

means for transmitting said temperature signal intermittently;

memory means for storing the temperature signal generated by said temperature signal generator until a subsequent temperature signal is generated and for delivering said stored temperature signal when the subsequent temperature signal is received by the memory;

a signal converter for generating a temperature compensating signal in response to the temperature signal stored in said memory means, wherein said compensating signal compensates for variations of the output frequency of said time base signal generator caused by temperature variations; and

a time base signal frequency variable controller for synthesizing the output signal of said time base signal generator and that of said signal converter by compensating for changes of the output frequency of said time base signal generator caused by temperature variations and for delivering a resultant signal to said time unit signal generator;

said temperature signal generator is being timed to oscillate intermittently by the output signal from a timing control mechanism, which is driven by inputs from the time count unit signal generator and the time counting mechanism;

said means for transmitting said temperature signal intermittently in response to the output signal from said timing control circuit.

4. The electronic timepiece of claim 1 3, wherein said time reference base signal generator and said temperature signal generator are crystal oscillators including crystal vibrator elements, which differ from each other in frequency output caused by the temperature variations, which results in changing frequency ratios.

5. The electronic timepiece of claim 4, wherein the vibrator elements of said crystal oscillator used as the time reference base signal generator and of said crystal oscillator used as said temperature signal generator are enclosed in a common casing.

6. The electronic timepiece of claim 1 3, wherein frequencies of two modes of oscillation are derived from a single reference vibrator element; one of the frequencies being used as a reference vibrator element of said time reference base signal generator and the other as the reference vibrator of said temperature signal generator.

7. The electronic timepiece of claim 1 3, wherein said temperature compensating signal generator includes EXCLUSIVE-OR gate which intermittently enables said time count unit signal generator.

8. An electronic timepiece having a time base signal generator to provide a time base signal of given frequency and having a given temperature-frequency characteristic, means for generating an output signal in response to said time base signal, a time unit signal generator, a timekeeping means coupled to the output of said time unit signal generator and time display means coupled to the output of said timekeeping means; the electronic timepiece further comprising:

a temperature signal generator for generating a temperature signal, said temperature signal generator including an oscillator circuit having a predetermined temperature-frequency characteristic different from that of said time base signal generator and providing said temperature signal different in frequency from said time base signal, wherein an output oscillation frequency of said temperature signal generator changes with temperature variation;

compensating signal generating means for generating a compensating signal in response to said temperature signal; and

algebraical adding circuit means comprising logical circuit means for algebraically adding a frequency of said compensating signal to a frequency of said output signal to compensate for changes in a frequency of said time base signal caused by the temperature variations.

9. An electronic timepiece according to claim 8, in which said temperature signal generator comprises a temperature sensing oscillator.

10. An electronic timepiece according to claim 9, in which said temperature sensing oscillator comprises a temperature sensing filter circuit and an amplifier connected thereto.

11. An electronic timepiece according to claim 10, in which temperature sensing filter circuit comprises a band-pass filter. 12. An electronic timepiece according to claim 10, in which said temperature sensing filter circuit comprises a phase shifting element.

13. An electronic timepiece according to claim 9, in which said temperature sensing oscillator comprises a band-cut filter and an amplifier connected thereto.

14. An electronic timepiece according to claim 9, in which said temperature sensing oscillator comprises a resistor and a condenser connected thereto.

15. An electronic timepiece according to claim 9, in which said temperature sensing oscillator comprises a mechanical resonance element having an electro-mechanical transducing function, and an amplifier connected to said mechanical resonance element.

16. An electronic timepiece according to claim 15, in which said mechanical resonance element comprises a ceramic resonator.

17. An electronic timepiece according to claim 15, in which said mechanical resonance element comprises a quartz crystal resonator.

18. An electronic timepiece according to claim 8, in which said compensating means comprises an algebraical frequency adding circuit for algebraically adding the frequency of said oscillator circuit to the frequency of said time base signal.

19. An electronic timepiece according to claim 18, in which said frequency adding circuit comprises an EX-OR gate.

20. An electronic timepiece according to claim 17, in which said time base signal generator comprises a quartz crystal controlled oscillator.

21. An electronic timepiece according to claim 9, further comprising a timing control unit for providing a timing control signal to control an oscillating operation of said temperature sensing oscillator so as to cause said temperature sensing oscillator to intermittently operate.

22. An electronic timepiece according to claim 21, in which said temperature sensing oscillator comprises a gate circuit to control starting and stopping operations of said temperature sensing oscillator in response to said timing control signal.

23. An electronic timepiece according to claim 22, further comprising a memory circuit for storing said temperature signal until a next temperature signal is stored.

24. An electronic timepiece according to claim 9, in which said time base signal generator and said temperature sensing oscillator comprise a common reference vibrator element, and first and second oscillator circuits connected to said common reference vibrator element.

25. An electronic timepiece according to claim 9, in which said time base signal generator and said temperature sensing oscillator comprise vibrator elements, respectively, which are enclosed in a common casing.

26. An electronic timepiece according to claim 8, in which said compensating signal generating means comprises a frequency difference detection circuit for detecting a frequency difference between said time base signal and said temperature signal and providing a frequency difference signal as said compensating signal.