Using intercarrier signals for detecting NTSC interference in digital TV receivers

摘要

During a period of transition from broadcasting analog TV signals to broadcasting digital TV signals, digital TV reception is susceptible to disruption owing to co-channel interference by analog TV signals. During this same transition period usually a digital TV receiver will incorporate an auxiliary analog TV receiver. This auxiliary analog TV receiver is advantageously used during digital TV signal reception for determining the amount of co-channel interference by analog TV signals, so that comb filtering can be selectively applied to symbol coding recovered from the digital TV signal, for suppressing artifacts of co-channel interfering analog TV signal when they are large enough to have substantial adverse on symbol decoding. The amount of NTSC co-channel interference is estimated by detecting the level of intercarrier generated by mixing the audio and video signals of the analog TV signal.