Apparatus and method of controlling driving selection of NTSC rejection filter

摘要

When both an NTSC signal and an ATV signal are concurrently broadcast in a co-channel, it is desirable to remove the NTSC signal at the receiver when reproducing the broadcast ATV signal, since the NTSC signal would interfere with the ATV signal. An NTSC rejection filter is used to remove most of the signal power of an NTSC broadcast signal. To more effectively handle multipath interference signals, the present invention adaptively controls the driving selection of an NTSC rejection filter. The mean power levels are calculated for an input signal which has not been NTSC rejection filtered and for a second input signal which has been NTSC rejection filtered. Error differences are then calculated for each of these mean power levels and a driving selection is determined for the NTSC rejection filter based upon the calculated error differences. The present invention includes a driving selection determination circuit which compares the error difference signals over a predetermined period of time to produce a selection signal.