Integrated IF SAW filter in baseband digital design for analog TV (or hybrid) tuner

摘要

A filter for processing a digital TV composite signal having a video component and an audio component includes a digital video filter and a digital audio filter. The digital video filter includes a lowpass finite impulse response (FIR) filter, an up-mixer, an asymmetric filter for compensating a Nyquist slope of the video component, and a down-mixer connected in this order. The digital audio filter includes an audio down-mixer, a decimated FIR filter, an enhancing FIR filter, an interpolated FIR filter, and an audio up-mixer. These components are connected in series. Optionally, the decimating FIR filter is decimated by an integer decimation factor M, and the interpolated FIR filter is interpolated by an integer factor N. The integer M and N may have the same value.

主权项

1. A filter for processing a digital television (TV) composite signal having a video component and an audio component, the filter comprising:
an input terminal for receiving the digital TV composite signal; a first lowpass filter coupled to the input terminal, the first lowpass filter being configured to pass through the video component; a digital video filter coupled to the lowpass filter and being configured to process the video component, the digital video filter comprising:
a first mixer configured to frequency shift the video component by a first frequency offset;a digital highpass filter responsive to the first mixer and configured to compensate a Nyquist slope of the first frequency-shifted video component; anda second mixer responsive to the digital highpass filter; said first mixer, said digital highpass filter and said second mixer being coupled in series; a third mixer configured to frequency shift the digital TV composite signal by a first frequency amount; and a digital audio filter configured to receive the frequency shifted digital TV composite signal.