| 摘要 |
PURPOSE:To simplify the transmission circuit of a slave station and to improve the error detection capability by modulating a pilot signal transmitted from a slave station to a master station with a transmission code of a frame architecture added with an error detection code so as to form the said pilot signal. CONSTITUTION:An operation control circuit 20 of a slave station operates arithmetically dial information in terms of a binary signal and adds a transmission code of frame architecture with the error detection code corresponding to the dial information to a pilot modulation circuit 22. Then the pilot signal from a pilot generating circuit 21 is modulated by using an output of the circuit 20, its output is added (24) with a voice input signal of a microphone 8 and the result is transmitted to a modulation circuit 25. The circuit 25 modulates the output of the adder circuit 24 with a carrier of a prescribed frequency and its output is transmitted to a master station via a transmission circuit 26 and an antenna 3. On the other hand, this radio signal is received and decoded at the master station side. Then the dial information at the slave station is dialed through a telephone line. |
