A cable television distribution system in which the head end substitutes different
channels for a plurality of separated geographic zones. The head end creates a
plurality of channel spectrums and transmits the spectrums on distribution trunks
such that a different spectrum may be present on each distribution trunk. The spectrums
on the distribution trunks are connected to zones of the viewer community which
have been selected for market research purposes on the basis of demographics. Product
sales collection units are provided at stores throughout the community served by
the cable television distribution to collect consumer purchase data for market
research purposes.