Multirate digital filter design for a PAL TV modulator

摘要

This paper develops a multirate digital filter design for the vestigial sideband (VSB) modulator required in the analog TV transmission systems, like PAL. The modulator takes as the input the composite video signal digitized at 13.5 MHz sample rate and the output is a VSB signal modulated to the usual 38.9 MHz IF picture carrier frequency and sampled at 121.5 MHz rate. The design is based on a complex baseband VSB filter running at the input sampling rate, digital multirate techniques for increasing the sampling rate by a factor of nine, and a combination of multirate techniques and digital mixing to translate the signal to the 38.9 MHz picture carrier frequency.