Receiver having a search tuning circuit

Claim 1

A receiver having a search tuning circuit for tuning the receiver from a present tuning datum to a next tuning datum from a group of tuning data stored in a memory circuit, said search tuning circuit having means for starting a search action under the influence of a starting signal which depends on the field strength of a received transmitter signal, said starting signal being generated when the field strength of the received transmitter signal becomes too weak, the receiver comprising a start-signal delay circuit having an adjustable time delay for delaying the occurrence of the starting signal in dependence on the behavior of the field strength signal, and further comprising a field strength responsive control circuit for controlling the time delay of the start-signal delay circuit such that the time delay increases to a value above a first existing time delay each time the field strength, within a first fixed time interval after a preceding search action, decreases below a preset level for a period of time greater than the first existing time delay, and such that the time delay decreases to a value below a second existing time delay each time after a second subsequent fixed time interval in which the field strength does not decrease below said preset level for a period of time greater than the second existing time delay.