The Effects of Vestigial Sideband Passband Characteristics upon Television Transient Response

The task of ensuring acceptable detected transient response in consumer television receivers is complicated by the large variety of different transmitter vestigial sideband and receiver IF filter characteristics in use. In this paper, the effects of different typical transmitter and receiver passband characteristics in the vestigial sideband region upon detected transient response are analytically examined. Both envelope and synchronous demodulation systems are investigated, and various levels of carrier modulation are assumed. In addition, the effects on transient response of alternate methods for transmitter vestigial sideband filter (VSBF) phase correction are described. In general, it is found that even with the substantial response of many receiver IF filters in the 1-MHz region of the vestigial sideband, acceptable transient response can be obtained provided that appropriate phase correction of the transmitter VSBF is used. Experimental verification of the analytical results is also presented.