TRANSMITTER-RECEIVER FOR CORDLESS TELEPHONE SET

摘要

PURPOSE:To make the transmitter-receiver small in size and to reduce the power consumption by providing an incoming call detection section and a digital code modulation section to a transmitter of a master set and providing a digital code demodulation section and a ringer section to a receiver of a slave set. CONSTITUTION:A transmitter 21 of a master set 11 has at least an incoming call detection section 22 and a digital code modulation section 23 and a receiver 24 of a slave set 12 has at least a digital code demodulation section 25 and a ringer section 26. When the incoming call detection section 22 detects the arrival of an incoming call signal SC, a carrier is modulated by using a digital code displaying the detection of the incoming call signal SC synchronously with the ringer tone. The digital code demodulation section 25 demodulates the original digital code at the period of the ringer tone and drives the ringer section 26 directly based on the demodulation digital code to reproduce the ringer tone R. Thus, the device size is made small and the power consumption is reduced.