System and method for digital tracking and compensation of frequency offset error in a satellite receiver

Abstract

A DBS receiver front end which converts the received signal directly to the baseband representation and maintains a high performance with a new techniques for tracking and counteracting frequency drift and I/Q angular error. The DBS receiver front end comprises a tuner and a demodulator/decoder. The tuner receives a high frequency signal and converts it to a baseband signal having a frequency offset error. In one embodiment, the DBS receiver front end includes a demodulator/decoder which receives the baseband signal and produces a compensation signal for canceling the frequency offset error. The demodulator/decoder performs the frequency-offset error compensation digitally. The demodulator/decoder includes an A/D converter which over-samples (samples at a rate of more than two samples per symbol period) the baseband signal and converts it to digital form. The demodulator/decoder also includes a complex multiplier which multiplies the over-sampled digital baseband signal by the compensation signal to produce an offset-error-canceled signal. The complex multiplier is followed by a decimation block which reduces the sample rate of the offset-error-canceled signal to two samples per symbol period. This embodiment has a substantially increased frequency offset tracking range, which allows for the use of relaxed tolerances in the tuner and/or LNB.

Dependencies are inferred from the claim text.