US3566601A - Crystal oscillator watch - Google Patents

Crystal oscillator watch Download PDF

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Publication number
US3566601A
US3566601A US795242*A US3566601DA US3566601A US 3566601 A US3566601 A US 3566601A US 3566601D A US3566601D A US 3566601DA US 3566601 A US3566601 A US 3566601A
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US
United States
Prior art keywords
crystal
watch
transistor
resistor
frequency
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US795242*A
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English (en)
Inventor
Lewis B Shrady
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Timex Group USA Inc
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Timex Corp
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Publication date
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Publication of US3566601A publication Critical patent/US3566601A/en
Assigned to CHASE MANHATTAN BANK, N.A., THE reassignment CHASE MANHATTAN BANK, N.A., THE SECURITY INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: FREDERIKSPLEIN HOLDING 1970 B.V., TIMEX CLOCK COMPANY, A DE CORP., TIMEX COMPUTERS LTD., A DE CORP., TIMEX CORPORATION, A DE CORP., TIMEX ENTERPRISES, INC., A BERMUDA CORP., TIMEX GROUP LTD., A BERMUDA CORP., TIMEX MEDICAL PRODUCTS LTD., A BERMUDA CORP., TIMEX N.V.
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • G—PHYSICS
    • G04—HOROLOGY
    • G04F—TIME-INTERVAL MEASURING
    • G04F5/00—Apparatus for producing preselected time intervals for use as timing standards
    • G04F5/04—Apparatus for producing preselected time intervals for use as timing standards using oscillators with electromechanical resonators producing electric oscillations or timing pulses
    • G04F5/06—Apparatus for producing preselected time intervals for use as timing standards using oscillators with electromechanical resonators producing electric oscillations or timing pulses using piezoelectric resonators

Definitions

  • An electronic watch includes a power source, a time base, a drive circuit and time indicating means.
  • the time base is a piezoelectric crystal oscillator, specifically an astable multivibrator having a low duty cycle which pulses the crystal at the fundamental or a subharmonic of its natural frequency.
  • the present invention relates to horology and more particularly to a watch utilizing an electronic crystal oscillator.
  • a watch particularly a wrist watch, is limited in its physical size. Too large or heavy a wrist watch, regardless of the accuracy of its timekeeping, is not acceptable.
  • the limited size of the watch means that it can only contain a relatively small battery. i.e., a button cell. The watch should run at least one year without changing the battery cell, so that there is only a small amount of power available to operate the watch.
  • the size of the watch also presents a problem as to the piezoelectric crystal.
  • the lower the frequency of the crystal the larger is its size. It is difficult to fit a crystal having a frequency of 500 Hz. into a watch case, as it is too large.
  • the obvious solution is to increase the frequency and use a smaller crystal.
  • the use of a smaller higher frequency crystal implies: (1) a requirement for more power, as the pulse rate to impulse the crystal rises to match the frequency of the crystal; and (2) a more complex count-down circuit, which is required to reduce the high frequency of the crystal oscillator to the much lower freqeuncy needed to operate the watch, the complex count-down circuit itself using relatively more power.
  • a watch is provided utilizing a crystal oscillator as its time base.
  • the crystal oscillator is selected to fit within the watch case and preferably is no larger than one of the other components, for example, the battery cell.
  • the crystal may be a piezoelectric quartz crystal having a resonant (natural) frequency of 60,000 Hz. which can be /2-inch in length.
  • the crystal is connected at one of the low impedance points of a regenerative freedback astable multivibrator.
  • the astable multivihrator is preferably a 3,566,601 Patented Mar. 2, 1971 relaxation oscillator having a very short duty cycle and utilizing a complementary pair of transistors.
  • the crystal is pulsed at a selected subharmonic rate of its resonant frequency, for example, of its natural frequency. This provides an output frequency of the multivibrator above a minimum threshold level, which is at the selected subharmonic of the resonant frequency of the crystal.
  • the astable multivibrator is adjustable, for example, by changing the time constant of its resistor-capacitor network, so that the crystal may be compensated for manufacturing tolerances and aging. Such compensation may occur at the initial manufacture of the watch or in its subsequent testing or repair.
  • FIG. 1 is a top plan partially cut-away view of the watch of the present invention.
  • FIG. 2 is a schematic diagram of the preferred crystal oscillator.
  • FIG. 1 the horological device of the present invention is shown as a wrist watch or other timepiece.
  • the wrist watch includes a case 1 having a bezel 2.
  • the crystal 3 covers a dial 4 having numbers 5 or other indicia of time.
  • the time is indicated, as in conventional watches, by a seconds hand 6, a minutes hand 7, and an hours hand 8, which rotate from a common center 9.
  • the power to operate the watch is derived from the small battery cell which is internal to the watch case 1. Alternatively, a solar cell or other electrical power source may be used.
  • the battery cell 10 is connected to a time base 11 by means of line 12.
  • the time base is a high-frequency piezoelectric oscillator.
  • the high output frequency of the time base, by means of line 13, is provided to the dividing circuit 14, which counts down the high frequency of the time base.
  • the output of the dividing circuit 14, by line 15, is connected to a drive circuit 16.
  • the output of the drive circuit, by line 17, is connected to a coil 19 of fine wire.
  • the battery 10 is used, as shown by line 26, to power the dividing circuit and, by line 27, to power the drive circuit.
  • the coil when pulsed by the drive circuit, attracts the magnetic piece 20 fastened to the pivotable arm 21, which arm is returned to its normal position by the spring 22.
  • the train of the watch rotates the previously mentioned hands 6, 7 and 8.
  • time display includes rotatable hands as shown in FIG. 1, electro-optical display means such as a series of bulbs arranged on the dial of the watch, and other types of time indicating mechanisms.
  • the circuit of FIG. 2 is a regenerative feedback astable multivibrator. Specifically, it is a relaxation oscillator utilizing a complementary pair of transistors. Preferably the circuit is formed by integrated circuit techniques.
  • the cir cuit includes a first transistor which is the output transistor of the circuit and is an NPN transistor.
  • the second transistor 31 of the circuit is a PNP transistor. These transistor types may be interchanged by changing the polarity of the power source.
  • the collector of transistor 30 is connected to the positive terminal of the power source 10,
  • resistor 36 the power source being, for example, the same small button type of battery cell 10 which is within the watch case.
  • the base of transistor 30- is connected, through resistor 32, to the collector of transistor 31.
  • the emitter of transistor 31 is connected, through resistor 33, to the collector of transistor 30.
  • a resistor 36, representing the load, is positioned between the positive terminal of source 10 and junction 37.
  • the junction 37 is connected to one side of a capacitor 39', the other end of which is connected to the base of the transistor 31.
  • a piezoelectric crystal 40 for example, a quartz crystal, is connected in parallel with the resistor 33 and between the terminals 41 and 42.
  • the crystal 40 of quartz or other piezoelectric material, exhibits a low impedance at its resonant frequency and a higher impedance at other frequencies.
  • a capacitor 43, connected to junction 41, is connected through the resistance 44 to the negative terminal of source 10.
  • a capacitor 39a is connected in parallel with resistance 32 between the collector of transistor 31 and the base of the transistor 30.
  • a resistor 38 is connected to the base of transistor 30 and has its other terminal connected to the negative terminal of source 10.
  • the quartz crystal has a resonant frequency of 60 kilo Hz., asuitable cut being NT.
  • Resistor 32 (R3) of tolOK ohms. Resistor 34(R4) of 1.5 megohms. Resistor 44(R5) of K ohms. Capacitor 39(C1) of 100 picofarad. Capacitor 43(C2)of 600 picofarad. Capacitor 39(C3) of 0 to 100 picofarad.
  • transistor 31 In operation, when power is applied, transistor 31 conducts from base current applied through resistor 34. Transistor 31 supplies base current to transistor 30, which also conducts. As the collector of transistor goes to ground, capacitor 39 attempts to drive the base of transistor 31 more negative, thus increasing regenerative action. As capacitor 39 attempts to drive the base of transistor 31 goes slightly more positive, causing a regenerative action which cuts transistor 30 and transistor 31 off. The base ofi transistor 31 now goes toward ground at a rate determined by resistor 34, capacitor 39 and resistor 36. When the base of transistor 31 reaches the conductive state once more, the cycle repeats.
  • the short spikes at the collector of transistor 30 cause crystal 40 to emit a decaying train of oscillations. These appear across resistor 33 and cause the circuit to synchronize at the fundamental or a submultiple of the crystal frequency. A wide range of subharmonics can be utilized by proper choice of resistor 34 and capacitor 39.
  • the circuit operates at very low power.
  • the output frequency may be adjusted over a narrow range by choice of capacitor 43 and resistor 44, either one, or both, of which may be made adjustable.
  • Crystal 40 operates into a fairly low impedance, thus improving stability with voltage and temperature.
  • the crystal may be used in any low impedance portion of the circuit, such as across the resistor 36 if desired.
  • a timepiece comprising a power source; a high frequency crystal oscillator connected to said power source a count-down circuit connected to said power source and dividing the frequency output of said oscillator; a drive circuit connected to said power source and to said countdown; and time indicating means coupled to and driven by said drive circuit; wherein the crystal oscillator comprises an astable relaxation oscillator and a crystal which is impulsed by the astable relaxation oscillator at the fundamental of a subharmonic of its resonant frequency and wherein said astable oscillator includes a pair of complementary transistors as active elements thereof and a resistor and said crystal is connected in parallel and across said resistor to provide a low impedance input to said crystal.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Electric Clocks (AREA)
  • Oscillators With Electromechanical Resonators (AREA)
  • Electromechanical Clocks (AREA)
US795242*A 1969-01-30 1969-01-30 Crystal oscillator watch Expired - Lifetime US3566601A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US79524269A 1969-01-30 1969-01-30

Publications (1)

Publication Number Publication Date
US3566601A true US3566601A (en) 1971-03-02

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Family Applications (1)

Application Number Title Priority Date Filing Date
US795242*A Expired - Lifetime US3566601A (en) 1969-01-30 1969-01-30 Crystal oscillator watch

Country Status (5)

Country Link
US (1) US3566601A (ja)
JP (1) JPS4819276B1 (ja)
DE (1) DE2001569A1 (ja)
FR (1) FR2029664B1 (ja)
GB (1) GB1268613A (ja)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3861142A (en) * 1973-02-05 1975-01-21 Ranendra K Bose Anti-pollution systems for automobiles
DE2166739A1 (de) * 1971-06-24 1975-10-09 Suwa Seikosha Kk Quarzkristall-armbanduhr
DE2131476C3 (de) 1970-07-27 1976-03-04 K.K. Suwa Seikosha, Tokio Quarzkristall-Armbanduhr

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2131272B1 (de) * 1971-06-24 1972-05-25 Kienzle Apparate Gmbh Vorrichtung an elektronischen Taxametern
US4137463A (en) * 1977-06-16 1979-01-30 P.R. Mallory & Co. Inc. Control system utilizing momentary switching devices
JPS5982562U (ja) * 1982-11-25 1984-06-04 三菱重工業株式会社 マルチサイクロン

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2131476C3 (de) 1970-07-27 1976-03-04 K.K. Suwa Seikosha, Tokio Quarzkristall-Armbanduhr
DE2166739A1 (de) * 1971-06-24 1975-10-09 Suwa Seikosha Kk Quarzkristall-armbanduhr
US3861142A (en) * 1973-02-05 1975-01-21 Ranendra K Bose Anti-pollution systems for automobiles

Also Published As

Publication number Publication date
DE2001569A1 (de) 1970-08-13
FR2029664B1 (ja) 1974-05-03
JPS4819276B1 (ja) 1973-06-12
FR2029664A1 (ja) 1970-10-23
GB1268613A (en) 1972-03-29

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Legal Events

Date Code Title Description
AS Assignment

Owner name: CHASE MANHATTAN BANK, N.A., THE

Free format text: SECURITY INTEREST;ASSIGNORS:TIMEX CORPORATION, A DE CORP.;TIMEX COMPUTERS LTD., A DE CORP.;TIMEX CLOCK COMPANY, A DE CORP.;AND OTHERS;REEL/FRAME:004181/0596

Effective date: 19830331