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Publication numberUS3916612 A
Publication typeGrant
Publication dateNov 4, 1975
Filing dateSep 26, 1973
Priority dateOct 2, 1972
Also published asDE2349508A1, DE2349508B2, DE2349508C3, DE2366320C2
Publication numberUS 3916612 A, US 3916612A, US-A-3916612, US3916612 A, US3916612A
InventorsHashimoto Yukio, Morokawa Shigeru
Original AssigneeCitizen Watch Co Ltd
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Electronic timepiece
US 3916612 A
Abstract
To facilitate acceleration or deceleration of the stepping rate of a clockwork motor responding to pulses from a frequency divider connected to a crystal-controlled oscillator, an Exclusive-OR gate is inserted between the oscillator and the divider and has another input connected to several stage outputs of the divider by way of a branched feedback circuit. The divider and its feedback circuit form a time-delay loop whose delay time corresponds to a small fraction of a cycle of the oscillator frequency whereby the pulse rates from the oscillator and from the feedback circuit are invariably added in the input of the divider. Logic gates in the several branches of the feedback circuit have inputs connected to selectively energizable terminals for enabling optional blocking and unblocking of certain branches to vary the pulse rate in the divider output.
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[75] Inventors: Shigeru Morokawa, Tokorozawa; Yukio Hashimoto, Niiza, both of United States Patent 1191 1111 3, Morokawa et a]. h 1 [45] Nov. 4, 1975 ELECTRONiC TIMEPIECE 3,789,599 2/1974 Dome 58/23 R 3,798,428 3/1974 lzawa 58/23 R Japan Primary Examiner-Stephen J. Tomsky Assistant ExaminerU. Weldon lgn C t zen Watch C0., Ltd., Tokyo, Attorney, Agent, or FirmEmest G. Montague; Karl Japan F. Ross; Herbert Dubno [22] Filed: Sept. 26, 1973 [2]] Appl. No.: 401,118 [57] CT To facilitate acceleration or deceleration of the stepping rate of a clockwork motor responding to pulses [3O] Forelgn Apphcatmn Pnomy Data from a frequency divider connected to a crystal- Oct. 2, 1972 Japan 47-098766 controlled oscillator, an Exclusive-OR gate is inserted May 21, 1973 Japan 48-056444 between the oscillator and the divider and has another input connected to several stage outputs of the divider [52] US. Cl. 58/23 R; 58/85.5 by way of a branched feedback circuit. The divider [51] Int. Cl. G04C 3/00; G04B 27/00 and its feedback circuit form a time-delay loop whose -[58] Field of Search 58/23 R, 85.5, 28 R, 4 A, delay time corresponds to a small fraction of a cycle 58/50 R of the oscillator frequency whereby the pulse rates from the oscillator and from the feedback circuit are [56] References Cited invariably added in the input of the divider. Logic UNITED STATES PATENTS gates in the several branches of the feedback circuit have inputs connected to selectively energizable ter- ,53(), 3 l 5 3,540,287 311333 $5.12. 535535 mmals for enablmg 01110191 blockmg and unblockmg 3,668,859 6/1972 Polin et al 58/85.5 of Certain branches to y the pulse rate in the 3,756,014 9 1973 Zatsky et al. 58/28 R vider Output. 3,777,471 12/1973 Koehler et al. 58/85.5 X 3,786,625 1/1974 Sauthier 58/85.5 x 7 Clams 10 Draw'ng Flgures l I 1 nc s1 n RR R 910 X-tal 93 PULSE PER 962 f 98 u T 3 8 -t 4 a 96m .R TIIIE r I DISPLAY 6 i 9 i" I2 -u---4 6 at 9B U.S. Patent Nov. 4, 1975 Sheet 1 of5 3,916,612

I W R R Four TIME DISPLAY 12 9 L3 s as U.S. Patent Nov. 4, 1975 Sheet4 0f5 3,916,612

US. Patent Nov. 4, 1975 Sheet 5 of5 3,916,612

FIG-.9

ELECTRONIC TIMEPIECE FIELD OF THE INVENTION Our present invention relates to an electronic timepiece wherein a time-indicating display unit is driven by a clockwork including a stepping motor, or equivalent means, responsive to a train of electrical pulses derived with the aid of a binary frequency divider from a primary pulse source, such as a crystal-controlled oscillator, serving as a high-frequency standard.

BACKGROUND OF THE INVENTION In order to increase or reduce the stepping rate of such a timepiece, it has heretofore been the practice to change a parameter in the oscillator circuit which determines its resonance frequency, e.g. by adjusting a variable capacitor. This expedient, however, does not assure a stable long-term correction since the capacitances of variable condensers are subject to drift.

OBJECT OF THE INVENTION The object of our invention is to provide an improved electronic timepiece enabling precise and lasting adjustment of its stepping rate.

SUMMARY OF THE INVENTION This object is realized, in accordance with our invention, by the insertion of an anticoincidence gate, such as an Exclusive-OR (hereinafter referred to as EX-OR) gate or its logical negation, between a source of standard high-frequency pulses and an associated binary frequency divider, this gate having a first input connected to the source and a second input connected to certain stage outputs of the divider through branched feedback circuitry whereby the lower-frequency pulse trains issuing from the respective divider stages are logically combined with the standard pulse train so as to modify the mean pulse rate in the divider input. Selected branches of the feedback circuitry are optionally open-circuitable and short-circuitable to vary that mean pulse rate and thereby the stepping rate of a pulse-responsive device connected to one or more stage outputs of the divider.

We have found that an anticoincidence gate, in contradistinction to AND and OR gates, invariably produces a sequence of output pulses whose mean rate or cadence is the sum of the cadences of two harmonically related pulse trains received at its inputs, provided that a certain relative phase shift exists between overlapping pulses of the two harmonically related trains so that their leading edges and their trailing edges do not exactly coincide. This phase shift, resulting in a narrow gap in what would otherwise be a broader pulse or in a narrow spike where otherwise no pulse would be generated, is achieved in accordance with a further feature of our invention by such a dimensioning of the elements of the divider and its feedback circuitry that the same form a timedelay loop with a delay time equal to a fraction of a pulse cycle of the standard source. If necessary, special delay units may be included in the feedback circuitry for this purpose.

BRIEF DESCRIPTION OF THE DRAWING The above and other features of our invention will be described in greater detail hereinafter with reference to the accompanying drawing in which:

FIG. 1 is a circuit diagram of a pulse-train synthesizer for the adjustable stepping of a clockwork in accordance with our invention;

FIG. 2 is a set of graphs showing waveforms of pulse trains appearing at several points in the system of FIG.

FIG. 3 is a circuit diagram similar to FIG. 1, showing a modified pulse-train synthesizer according to our invention;

FIGS. 4A, 4B and 5 are sets of graphs relating to the operation in the system of FIG. 3;

FIG. 6 is a perspective view of a physical realization of a terminal assembly serving to control the pulse rate in the system of FIG. 3; and

FIGS. 7, 8 and 9 are plan views of modified terminal assemblies of the type shown in FIG. 6.

SPECIFIC DESCRIPTION In FIG. 1 we show a pulse-train synthesizer for an electronic timepiece according to our invention. FIG. 2 shows waveforms of pulse trains appearing at various points of the circuit shown in FIG. 1 where reference numeral 91 designates a crystal-controlled oscillator circuit whose operating frequency is 2 Hz. A frequency divider 95 receives the oscillator output f and a feedback wave f from a circuit 93, controlling the step-down ratio of this frequency divider, through an EX-OR gate 911. A combination of stage outputs Q -Q of divider 95 work into a clockwork 96 of the electronic timepiece which includes a NAND gate 961 connected to these outputs, an electromechanical converter 97 stepped by the output of gate 961 via a pulse shaper 962, and a display 98 driven by motor 97 for indicating the time in the conventional manner. Circuit 93 has a control input 94 with selectively energizable terminals .l -J connected to respective NAND gates 92 which derive low-frequency pulse trains from stages Q -Q of frequency divider 95 in response to the selected pattern of energization of the terminals I 4 The output has a frequency of about 1 Hz. If the terminals J J J,, are de-energized, the frequencies of the stage outputs Q21, Q20, Q1 are combined by means of cascaded EX-OR gates 931 and added to the signal f from the crystal oscillator 91 in gate 911. The signal f, thus obtained is supplied to an input terminal 912 of the frequency divider 95.

The pulse frequency fi at the output 913 of the last stage of the frequency divider 95 is given by If the frequency of the output signal f of crystal oscillator 91 be f then The circuit shown in FIG. 1 is simple in construction but requires a series of fairly stable delay elements 910 in order to produce a phase shift At around the feedback loop which, as shown in FIG. 2, is a small fraction of a cycle of pulse sequence f This delay is essential in order that the mean pulse rate of train f, be the exact sum of the pulse rates f and f The phase shift At results in a narrow gap in the region of the leading edge and a narrow spike in the region of the trailing edge of a pulse of train f which, as shown, is harmonically related to train f In FIG. 3 we have shown another circuit for changing the step-down ratio of a frequency divider which is simple in construction and may be used for adjusting a pulse cadence in a manner not subject to any change over a length of time. The output from an oscillator circuit 112, controlled by a crystal 111, is supplied through an EX-OR gate 113 to a frequency divider 114 constituted by a binary counter with n stages formed by flip-flops FFl-FF10.

The output terminal of the frequency divider 114 is connected to a mechanical converter such as a motor stepped by the oncoming pulses and may be operated by means of a gear mechanism or electronically to drive a display 116 for indicating the time as in the preceding embodiment. A feedback circuit for adjusting the step-down ratio has input leads 117a to 117d for selectively blocking or unblocking a group of AND gates 71 to 74 whose other inputs are connected to various stage outputs of the frequency divider 114 in the order indicated in FIGS. 3 and 5. The AND gates 71 to 74 work through an OR gate 75 into the EX-OR gate 113. According to which of the leads 117a to 117d are selectively short-circuited or open-circuited, corrective pulses are fed back to the EX-OR gate 113 at different rates to change the mean pulse cadence in the input of divider 114.

FIGS. 4A and 4B illustrate how, in gate 113, the output signal f of the oscillator is combined with a feedback signal f of either one-fourth or one-half the oscillator frequency to provide an input signal f of increased mean cadence, the two pulse trains being relatively phase-shifted by a delay introduced in the feedback loop.

In FIG. 5 we have shown the phase position of the output signals from the AND gates 71 to 74 when the corresponding leads 117a to 117d are short-circuited. The AND gate 71 is connected to stage outputs Q Q U and emits spaced-apart groups of four pulses.

The AND gate 72 is connected to stage outputs Q 61 ,6 and emits similarly spaced pulse pairs.

The AND g a tes 73 an d74, respectiy ely con rlected to Stage outputs 14 12 13 and 15 14 13 12 emit single pulses with-different recurrence periods.

In FIG. 6 we show a physical realization of the severable connections formed by leads 117a-117d in FIG. 3. A metallic holder 141 for a crystal oscillator 140 is provided at one edge with comb-shaped (ctenoid) projections or tongues forming the leads 117a to 117d extending to an integrated module 149 incorporating a frequency divider and its rate-adjusting feedback circuit, the assembly being mounted on a base plate 148 for the electronic timepiece. In the present embodiment, the lead l17b is cut while the other leads are intact.

FIG. 7 shows ctenoid leads 142 made of metal and incorporated into the electronic timepiece. The leads overlie a printed portion 143 of base plate 148.

FIG. 8 shows modified leads 144, two of them sev-, ered and two made continuous by means of solder 145.

FIG. 9 shows another embodiment with three concentric leads 151 which are selectively engageable by a sliding contact arm rotatable about a center shaft. The sliding arm 150 is fixed to the shaft in its correct position by means of a screw 152.

For a more precise adjustment of the rate of the electronic timepiece, the number of leads may be increased and additional circuitry may be included to provide properly phased signal feedback.

If practice, it is preferable to effect a coarse adjustment of the electronic timepiece by means of the terminal portions shown in FIGS. 6 to 8 and a precise adjustment by means of the contact assembly shown in FIG. 9.

What is claimed is:

1. An electronic timepiece comprising:

a source of electrical pulses having a constant elevated frequency;

a multistage binary frequency divider for producing lower-frequency pulse trains at a plurality of stage outputs thereof;

pulse-responsive means connected to at least one of said stage outputs for stepping by the pulse train thereof;

an anticoincidence gate inserted between said source and said frequency divider having a first and a second input, said first input being connected to said source;

time-indicating means connected to said pulseresponsive means;

feedback means having branches coupling said second input to certain of said stage outputs for logically combining said lower-frequency pulse trains thereof with said electrical pulses; and

circuit-breaking means in said feedback means for optionally open-circuiting and short-circuiting selected branches of said feedback means to vary the stepping rate of said pulse-responsive means.

2. A timepiece as defined in claim 1 wherein said frequency divider and said feedback means form a timedelay loop with a delay time equal to a fraction of a pulse cycle of said source.

3. A timepiece as defined in claim 1 wherein said anticoincidence gate is an Exclusive-OR gate.

4. A timepiece as defined in claim 1 wherein said circuit-breaking means comprises a mechanical switch.

5. A timepiece as defined in claim 1 wherein said circuit-breaking means comprises a set of logic gates in said branches having first inputs connected to selectively energizable terminals, second inputs connected to said certain stage outputs, and outputs coupled to 'said second input of said anticoincidence gate.

6. A timepiece as defined in claim 5 wherein the connections between said terminals and the said first inputs of said logic gates include a multiplicity of individually severable leads.

7. A timepiece as defined in claim 6 wherein said leads are a set of ctenoid metallic tongues.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US3530663 *May 16, 1968Sep 29, 1970Patek Philippe SaAutomatic and continuous time adjusting device for a clock
US3540207 *Sep 20, 1968Nov 17, 1970Timex CorpElectronic watch counting circuit
US3668859 *Jun 5, 1970Jun 13, 1972Vogel PaulTime setting device for an electronic clock
US3756014 *May 18, 1971Sep 4, 1973Timex CorpSynchronized quartz crystal watch
US3777471 *Aug 27, 1971Dec 11, 1973Bulova Watch Co IncPresettable frequency divider for electronic timepiece
US3786625 *Dec 5, 1972Jan 22, 1974Suisse Pour Ind Horlogere ManaArrangement for correcting of seconds indication of a timepiece
US3789599 *Oct 20, 1972Feb 5, 1974Suisse Pour L Ind Horlogere SaCorrection of errors occurring in electronic timepieces
US3798428 *Mar 20, 1972Mar 19, 1974Seikosha KkElectronic time-keeping apparatus
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US4028879 *Jul 24, 1975Jun 14, 1977Eurosil G.M.B.H.Switching arrangement for setting time-measuring apparatus
US4051663 *Dec 5, 1974Oct 4, 1977Kabushiki Kaisha Suwa SeikoshaElectronic timepiece
US4055945 *Dec 15, 1975Nov 1, 1977Timex CorporationFrequency adjustment means for an electronic timepiece
US4133169 *Apr 19, 1977Jan 9, 1979Ebauches S.A.Electronic circuit for a quartz crystal watch
US4141208 *Jan 19, 1976Feb 27, 1979Hughes Aircraft CompanyDigitally tuned timepiece
US4162608 *Sep 19, 1977Jul 31, 1979Kabushiki Kaisha Suwa SeikoshaElectronic timepiece frequency regulating circuit
US4176517 *Jul 22, 1977Dec 4, 1979Citizen Watch Co. Ltd.Integrated circuit for timepiece
US4232510 *Feb 28, 1977Nov 11, 1980Citizen Watch Co., Ltd.Timepiece
US4282594 *Dec 3, 1979Aug 4, 1981Citizen Watch Company LimitedElectronic timepiece
US4345320 *Mar 31, 1980Aug 17, 1982Jean-Claude Berney SaIntegrated circuit for a time-piece
US4378167 *Mar 28, 1980Mar 29, 1983Kabushiki Kaisha Suwa SeikoshaElectronic timepiece with frequency correction
US4407019 *Feb 19, 1981Sep 27, 1983Kabushiki Kaisha Suwa SeikoshaElectronic wristwatch
US4492905 *Mar 4, 1983Jan 8, 1985Pfister Jean FrancoisIntermittent drive arrangement
US4615625 *Apr 24, 1984Oct 7, 1986Seiko Epson Kabushiki KaishaAnalog electronic timepiece
Classifications
U.S. Classification368/201, 968/823, 368/159, 368/80, 968/903
International ClassificationG04F5/00, G04G3/00, G04G3/02, H03K23/66, H03K23/00, G04F5/06
Cooperative ClassificationG04G3/022, H03K23/662, G04F5/06
European ClassificationG04G3/02B, H03K23/66A, G04F5/06