DTV RECEIVER WITH ADAPTIVE FILTER CIRCUIT FOR REJECTING NTSC CO-CHANNEL INTERFERENCE AND SYMBOL DECODING METHOD THEREOF

摘要

In a digital receiver such as a digital TV receiver, co-channel interference involving multiple levels of symbols is suppressed by using a first comb filter to reduce the energy of the co-channel interference prior to data slicing. The first comb filter precodes the symbol decoding result value generated by the data slicing process. The second comb filter post codes the precoded symbol decoding result from the data slicing process to produce a modified symbol decoding result. The symbol precodes a first linear combination of the input sequence of symbol streams resulting from the differential delay and the differentially delayed interval. Post coding of the serial symbols recovered by the data slicing results obtained from the second linear combination of the serial symbol stream with the delayed result of the second linear combination is handled by the modular equation. One of the first and second linear combinations is subtracted and the other is added. The result of the second linear combination is equal to the modified symbol decoding result.