Broadcast receiver with time switch - has relay which switches on alarm if received signal is below a certain level

摘要

The broadcast receiver is provided with a time switch and also a relay which switches on an alarm. The alarm is switched on if the received signal is below a certain level. A certain level of a demodulated low frequency signal is used in the AM-FM receiver as a criterion for operation of the relay (19). A control voltage for this relay is delivered by a capacitor (8), connected at time specified by the timer (17) through a resistor (6) to a supply voltage. Means (4, 5, 7) are provided which prevent the capacitor (8) charging to a voltage sufficient for the relay (19) operation when the low frequency signal is above the limit.