AN APPARATUS, METHOD AND ARTICLE OF MANUFACTURE FOR CARRIER FREQUENCY COMPENSATION IN AN FM RADIO

摘要

A method, apparatus and article of manufacture for compensating for carrier frequency error is disclosed. An FM signal is received from an antenna and the received FM signal is provided to a receiver. The receiver takes the FM signal at the carrier frequency and outputs a baseband signal. This baseband signal is then processed by a DSP which provides carrier frequency compensation and decoding to produce a data stream that a microprocessor provides to a host device. Frequency differences between the FM carrier frequency and the frequency used to demodulate the FM signal can shift the DC bias level of the baseband signal. The DSP compensates for such frequency difference by using a receive compensation value and applying it to each received signal sample. When transmitting, data to be transmitted is provided from the host device to the DSP via a microprocessor. The DSP provides encoding and carrier frequency compensation of the data to provide a baseband signal to a transmitter that modulates the baseband signal to produce anFM signal at a desired carrier frequency. Frequency differences between the desired FM carrier frequency and the frequency used to modulate the baseband signal can produce errors in receiver systems. The DSP compensates for such a frequency difference by using a transmit compensation value and applying it to each encoded signal sample.