In Receiver Side,Carrier Signal what Happen?And Now-a-days What is frequency Range Of Carrier Signal?

Question

With Statistics

Answer 1

Your circuit has a stage that extracts the signal off the receiver side of circuit. If the  transmitter stops or is cut off the alarm will sound until signal circuit is reset. You can by-pass the circuit and put into check. Each circuit will have different frequency that it operates. Some are preset by manufacture and some are set at panel. I know our fire alarm is set at a high frequency range. set  875 to 925 khz. There are many on-line examples and I copy and paste to files.