Browse Prior Art Database

REFERENCE OSCILLATOR DESIGN FOR IMPROVED RECEIVER FREQUENCY STABILITY

IP.com Disclosure Number: IPCOM000006059D
Original Publication Date: 1991-Apr-01
Included in the Prior Art Database: 2001-Nov-29
Document File: 2 page(s) / 79K

Publishing Venue

Motorola

Related People

Authors:
Ed Callaway

Abstract

Frequency drift of narrowband receivers is a major design concern. Frequency drift over temperature, of superheterodyne receivers is largely caused by two factors: local oscillator drift and i.f. filter drift. These drifts must be compensated by widening the i.f. filters, which in turn degrades receiver selectivity. With the introduction of digitally stabilized reference oscillators, local oscillators controlled by the phase locked loop method can be stabilized to 1 ppm or less quite economically, eliminating the local oscillator drift as a concern. This leaves the i.f. filter as the major source of receiver drift. This invention uses the local oscillator to counteract the filter drift, to produce a receiver with significantly greater frequency stability.