Tuning circuit for car radio with automatic search - stores all transmitters providing required programme and selects that providing strongest signal

摘要

The circuit allows automatic search for the required transmitter over the full tuning range. Each detected transmitter with a given characteristic modulation is entered in a corresp. location of a store with that which gives the best reception quality according to predetermined criteria being fed from the store to the receiver LF stage. The quality of the signal to which the receiver is tuned is continuously monitored with the receiver switched to a different transmitter held in the store when this provides a better signal. The search procedure may be carried out continuously with the detected transmitters for the required station being stored. The circuit prevents the radio from having to be manually returned when travelling through zones covered by different transmitters, without programme interruption.