In a receiver for processing a vestigial sideband modulated signal containing
terrestrial broadcast high definition television information and a pilot component,
and for which multipath interference can lead to significant attenuation within
narrow bands of the received signal spectrum containing the pilot tone of an Advanced
Television Systems Committee high definition television broadcast signal, it has
been found desirable to amplify the input signal in order to achieve synchronization
of the receiver's phase-locked loop to the received pilot tone. Once this initial
acquisition has been established, the amplification applied to the received signal
can be reduced to a level appropriate for remaining blocks in the demodulation
chain without upsetting the pilot tone synchronization. Thus, according to the
present invention, the gain applied to the received ATSC VSB signal is set higher
during pilot tone acquisition than it is during the remaining stages of demodulation.