DTV receiver with baseband equalization filters for QAM signal and for VSB signal which employ common elements

摘要

During the reception of VSB DTV signal, the channel equalizer for a QAM/VSB DTV signal receiver the equalizer is operated to equalize only the real sample stream of VSB symbol code, rather than being operated as a complex equalizer. During the reception of QAM DTV signal, the real sample stream of QAM symbol code and the imaginary sample stream of QAM symbol code are time-division-multiplexed together on an alternate sample basis to generate input signal for the channel equalizer, which is operated as a dual-phase filter. After equalization, the time-division-multiplexed real and imaginary samples of QAM symbol code are de-multiplexed to recover parallel real and imaginary sample streams of QAM symbol code that are independent of each other, but have been subjected to similar equalization. Supposing that the QAM DTV symbol code rate is half the VSB DTV symbol code rate, the minimum sampling rate for operation of the channel equalizer is the same for both types of symbol code.