Audience measurement system employing local time coincidence coding

This invention relates to a system for monitoring and collecting data on the viewing habits of television viewers. More specifically this invention relates to an apparatus and method for monitoring and collecting data on the viewing habits of television viewers employing local time coincidence coding. The present invention provides a system for recording a viewer's television viewership habits. Sensors monitor the audio signal, synchronization signal, and video signal emanating from the television. A time coincidence channel tag is mixed with the transmitted television audio or video signal at a dwelling by a master unit. Then by matching the channel tag of the viewed channel with the channel tag, an accurate identification of the viewed channel can be made.