Carrier frequency compensation system and method

摘要

Systems and methods automatically compensate for long-term drift of frequency standards or references used by transmitting and receiver terminals to avoid manual adjustment of the terminals to bring them back within operating tolerances and minimize communications outages caused by inability of the system to otherwise accommodate for such drift. The present invention may provide automatic band selection to maintain a modulated carrier within an operating range of an automatic frequency control or tracking capability of a communication device. This may be accomplished by selecting an appropriate reference signal used to control a center frequency of an automatic frequency control circuit (such as a PLL) or used to convert the carrier frequency of the modulated carrier to fall within the operating range of the automatic frequency control circuit and/or by causing the transmitting station to at least partially correct the frequency discrepancy.