DTV receiver with filter in I-F circuitry to suppress FM sound carrier of NTSC Co-channel interfering signal

摘要

The frequency-modulated sound carrier of any co-channel interfering NTSC television signal that accompanies multiple-level symbols in a digital receiver, such as a digital television receiver, is suppressed using a surface-acoustic-wave (SAW) filter in the intermediate-frequency (I-F) amplifier circuitry. This reduces data-slicing errors during symbol decoding and improves bit error rate (BER) during subsequent trellis decoding. When a comb filter is used before data slicing to reduce the energy of co-channel interfering NTSC television signal, the SAW filter in the I-F amplifier circuitry eases the filtering requirements on the comb filter such that only video components of co-channel interfering NTSC television signal need be suppressed.