VHF radio receiver with automatic tuning suppression - is operative only when decoded received regional code equals stored regional transmitter code

摘要

TheThe VHF radio receiver has an extra memory storing the regional codes of transmitters. A regional-code decoder has its output compared with the code stored in the extra memory. This second comparator's output controls a gate between a first comparator and the automatic tuning circuit. The gate only passes a 'stop tuning' signal to the tuning circuit when the stored code is the same as the decoded code. Another memory stores the transmission frequencies of transmitters with regional codings, transmitters with no regional coding but the same broadcasting authority, and transmitters with the same or adjacent geographical locations. This memory is served by a third comparator.