Fairchild Camera and Instrument Corp.

Donald R Duff

Donald E Pezzolo

Larry D Wickwar

James V Barnett, Ii

James O Lamb

A network of impedance elements comprising combinations of resistors and capacitors in which the impedance of the network is modified by the selective destruction of the individual elements of the network by electrical impulses. The selective destruction of the individual elements may be planned so as to result in any combination of shorting or opening thereof. In a specific application the frequency of the oscillator used in a digital watch is adjusted by the inclusion of a network of impedance elements, wherein the elements are then selectively destroyed in accordance with measurements of the oscillator frequency to improve the precision of oscillation. This selective destruction of elements may be done automatically by electrical means, resulting in less labor, greater speed and smaller size of the oscillator, all of which are extremely important in the manufacture of digital watches. The method also simplifies the production of digital watches.

Crystal controlled oscillator and method of tuning same

A circuit for adjusting the frequency of operation of an electronic time keeping device, which device includes a source of clock pulses. The circuit of this invention is preferably located between the source of clock pulses and the time keeping device counting circuitry, so that the clock pulses can be periodically interrupted for a programmed amount of time. Accordingly, the variable adjustment capacitor, typically employed in prior art time keeping devices, can be eliminated.

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Mountain View, CA, United States of America

Donald R Duff