Societe Suisse Pour L'industrie Horlogere Management Services S.a.

Laboratoire Suisse De Recherches Horlogeres

Alphonse E Zumsteg

Hans E Hintermann

Jean Engdahl

Raymond Huguenin

Pavel Suda

Jorg Sekler

A piezoelectric detector for determination of the mass or film thickness of gaseous, liquid or solid substances being adsorbed or condensed on the surface of a piezoelectric resonator, having at least one measuring resonator with at least one integrated thin-film sensor, one discrete or integrated on the resonator re-evaporation heating element, and a reference resonator separated from the measuring resonator with a contamination shield, and protected from contamination, but not from heat radiation, with an optical window, which all allow correction by electronic or numerical means of influences of temperature changes on the resonant frequency and of cut-angle deviations and the temperature differences between the resonators.

Piezoelectric contamination detector

The oscillator circuit comprises a digital temperature compensation circuit connected to a low and a high frequency quartz oscillator. The two quartz oscillators have the same inversion temperature points and a different temperature behaviour. In the temperature compensation circuit a beat frequency is produced between the divided signal of the high frequency oscillator and the frequency of the low frequency oscillator and then fed to a correction circuit and multiplied therein with a correction factor which has been stored in a PROM. The obtained correction signal is fed into the frequency divider chain for obtaining a temperature compensated outgoing signal for use in a timer circuit. The temperature compensation circuit is simply designed and allows high accuracy, which is particularly well suited for a wristwatch or a photo camera.

Oscillator circuit with digital temperature compensation

An oscillator circuit having a digital temperature compensation circuit which contains two low frequency quartz oscillators, a beat frequency generator and a correction circuit and a logic circuit selectively controlling an addition circuit. The beat frequency generator receives the frequencies generated by the low frequency oscillators. The difference between the low frequencies is fed into the correction circuit which in turn cooperates with the logic circuit. The beat frequency generator is controlled by a high frequency oscillator having an integrated RC circuit and the correction circuit has a PROM in which the correction functions are stored. The selectively controlled addition circuit acts on the output signal of the first oscillator and corrects the frequency thereof. An oscillator circuit connected in such a manner requires no pre-selection of the quartz crystals in pairs and the correction may be effected by influencing the high frequency oscillator, whereby a high degree of accuracy may be obtained.

A signal generator having a digital temperature compensation circuit contains high and low frequency quartz oscillators (HF and NF), the low frequency oscillator being used for temperature compensation. Both oscillators are manufactured such that the descending portion of the temperature dependent parabolic frequency curve of the low frequency oscillator passes through the temperature inversion point of the parabola of the high frequency oscillator. The frequencies of both oscillators are first adjusted such that the ratio thereof is inversely proportional to the ratio of the parabolic temperature coefficient, i.e., f.sub.1 :f.sub.2 =.beta..sub.2 :.beta..sub.1. Subsequently two substantially identical reference frequencies are adjusted and, by feeding back the output frequency, combined in such a manner that an output frequency independent of temperature is produced which is determined substantially by the high frequency oscillator. The signal generator is thus temperature compensated and, due to the use of a high frequency oscillator, has much better properties with regard to aging and frequency stability than a low frequency oscillator.

Temperature compensated signal generator including two crystal

A signal generator includes a high frequency oscillator such as a quartz crystal oscillator at a frequency of 4.19 MHz, a low frequency quartz oscillator with a frequency of 32 kHz, a beat frequency generator for producing a correction signal which is transmitted to a programmable frequency divider, and an electronic switch for periodic switching of the high frequency quartz oscillator. By periodically switching-on the high frequency quartz oscillator, comparing its frequency curve with that of the low frequency quartz oscillator and and appropriately adjusting the programmable frequency divider, the advantages of long term stability, temperature of behavior and aging of a high frequency oscillator are combined with the low current consumption characteristics associated with the low frequency quartz oscillator, whereby the life of a battery powering the signal generator can be substantially extended.

Signal generator including high and low frequency oscillators

A yzw 35.degree.0' thickness shear crystal bar is provided with bevels cut n its longest narrow surfaces (b, c) proximate the ends in order to obtain energy trapping of the coupled mode vibrations which may arrive at said ends and thus permit shortening of the bar for a given quality factor.

Beveled, coupled mode piezo-electric resonator

A multiple resonator or filter is described in the form of a rectangular of piezoelectric material having dimensional ratios selected so as to assure vibration in a thickness shear mode strongly coupled with a flexural mode. At least two energy trapping zones are provided extending over the entire width of the bar. The arrangement enables achievement of a high quality factor combined with extremely small dimensions.

Multiple resonator or filter vibrating in a coupled mode

This specification describes a rectangular quartz crystal which has been igned with specific length-width-thickness ratios whereby vibration takes place in the thickness shear mode strongly coupled with flexural vibrations. The choice of the specific ratios permits an improved performance insofar as dynamic capacitance range, temperature dependent variations of frequency and finally quality factor are concerned. The dimensions and proportions make the crystal suitable for use as a high frequency time piece resonator.

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Solothurn, Switzerland

Alphonse E Zumsteg