Improvements relating to television audience research systems.

摘要

System and apparatus for television audience research in relation to use of V.C.R., live T.V. or cable T.V., including a signature generator associated with an encoder related to a series of programmes or channels available to the television audience, apparatus to substitute the signature frequency for the UHF or VHF signals received by a television receiver tuner or V.C.R. tuner and apparatus already present in the T.V. or V.C.R. to accept the signature frequency to the exclusion of all others and a decoder collecting output intelligence contained in the signature to establish whether the T.V. or V.C.R. is switched to a particular program representative of the signature. The encoder may be variable to provide a sweep of frequencies and signatures representative of all channels in the viewing area and multiple decoders may be used one for each receiver feeding into a multiplexer.