Digital frequency multiplex signal generation for TV signal transmission - using digital filter after A=D converter operating at same sampling rate as following filters for frequency division

摘要

The television channels are sampled at a frequency fA, digitised (A/D) and filtered by similar filters (CHBF) having complex coefficients and producing complex outputs. The signals for each channel are then shifted in frequency so that neighbouring channel signals do not overlap. A polyphase filter network with complex coefficients effects a sampling rate conversion by interpolation using a factor L. A multiplexer is driven at a sampling rate of fA.L to produce a frequency-multiplexed signal (FMUX). After the A/D converters further filters are provided (RBF) which use the same sampling rate as the following filter (CHBF) and the A/D converter. USE/ADVANTAGE - For TV distribution via optical cable. Requires less complex analogue pre-filtering of channel signals.