| 摘要 |
PURPOSE:To attain use of an LPF with broad pass band and to eliminate spurious radiation to the circuit peripheral by giving an AND output obtained based on a signal to be frequency-modulated via a limiter and its phase inverting signal to an LPF. CONSTITUTION:An output signal S1 of the limiter 4 becomes a signal S2, becomes a signal S3 via an inverter 51 and an integration circuit 50 and the signals S2 and S3 are inputted to an AND circuit 61. An output signal S4 of the circuit 61 has a constant pulse width and a frequency twice that of the inputted frequency-modulated signal S1. The signal S4 is detected by the LPF7 and a demodulated voice signal Se is led to a terminal 8. |
