Accession Number : ADD011537

Title :   SAW Oscillator with Digital Compensation for the Temperature Related Frequency Changes.

Descriptive Note : Patent,

Corporate Author : DEPARTMENT OF THE AIR FORCE WASHINGTON DC

Personal Author(s) : Slobodnik,A J ; Colvin,R D

Report Date : 18 Dec 1984

Pagination or Media Count : 14

Abstract : The inherent temperature instability of surface acoustic wave (SAW) clock oscillators is improved by the use of a thermometer oscillator circuit that senses temperature changes in the SAW substrate. The thermometer oscillator is used in combination with a calibrated programmable read only memory and a logic circuit and provides frequency corrections to the clock oscillator. The basic device is an oscillator clock circuit using a SAW substrate having a dealy path orientation with good temperature stability. A second oscillator, the thermometer oscillator circuit, and the electronic compensation scheme are added in order to produce minimum temperature coefficient of delay over all temperatures in the range of interest. The thermometer oscillator delay path utilizes a high temperature coefficient of delay orientation of the same SAW substrate and at an appropriate angle to the clock oscillator delay path orientation. Its frequency of oscillation; is used as a highly accurate thermometer in order to control a correction signal applied to a variable phase shifter in the clock oscillator loop.

Descriptors :   *Patents, *Surface acoustic wave devices, *Crystal oscillators, *Digital systems, Thermal stability, Control systems, Temperature coefficients, Transducers, Crystals, Precision, Frequency, Thermometers, Compensation

Subject Categories : Line, Surface and Bulk Acoustic Wave Devices

Distribution Statement : APPROVED FOR PUBLIC RELEASE