Richard E Webster

US Patent:

47120789, Dec 8, 1987

Filed:

Mar 27, 1985

Appl. No.:

6/716729

Inventors:

Andrew J. Slobodnik - Londonderry NH
Martin R. Stiglitz - Lexington MA
George A. Roberts - Weston MA
Richard T. Webster - Bedford MA

Assignee:

The United States of America as represented by the Secretary of the Air
Force - Washington DC

International Classification:

H03B 518
H03L 102

US Classification:

331 99

Abstract:

A digital compensation circuit for improving the temperature stability of dielectric resonator oscillators is disclosed. A temperature sensor indicates a measure of ambient temperature which is correlated with an amount of phase shift necessary to compensate for frequency drift in a dielectric resonator oscillator. The correlation is made using a correction table or correction function which is determined empirically in a calibration process. The necessary phase shift is then supplied via a voltage controlled phase shifter. This phase shifter is part of the RF oscillation loop which also includes an amplifier, directional coupler and dielectric resonator filter (including microstrip).

US Patent:

46021825, Jul 22, 1986

Filed:

May 25, 1984

Appl. No.:

6/614190

Inventors:

Richard T. Webster - Bedford MA

Assignee:

The United States of America as represented by the Secretary of the Air
Force - Washington DC

International Classification:

H01L 4108

US Classification:

310313A

Abstract:

An X-cut, 33. 44 degree quartz crystal for propagating surface acoustic waves with a temperature stability in the order of -0. 0209 ppm/C. sup. 2. The crystal orientation requires only a single rotation (33. 44. degree. ) from the crystal axes. This orientation is substantially simpler than previously reported cuts with comparable temperature stability which typically require three rotations. The X cut orientation has a surface acoustic wave (SAW) velocity of 3175 m/sec, an electromechanical coupling (. DELTA. v/v) of 4. times. 10. sup. -4, and a power flow angle of 2. 7 degrees.