The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Dec. 01, 1998
Filed:
Feb. 10, 1997
Nadav Ben-Efraim, Cupertino, CA (US);
Christopher R Keate, Santa Clara, CA (US);
LSI Logic Corporation, Milpitas, CA (US);
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.