| 摘要 |
PROBLEM TO BE SOLVED: To provide an FM multiplex demodulator that can keep a stereophonic sense and reduce an offensive sound noise to ears. SOLUTION: The FM multiplex demodulator is provided with a filter that separates a signal multiplexed by using a 38 kHz sub carrier from an FM detected signal, a ratio change section that changes a synthesis ratio between an output signal from the filter and the FM-detected signal and provides an output of the result, a noise detection section that detects a noise from the FM-detected signal and changes the synthesis ratio of the ratio change section corresponding to the detected noise, a demodulation section that multiplies the subcarrier with the output signal from the ratio change section to demodulate a multiplexed signal, an adder section that sums the FM-detected signal and an output signal from the demodulation section, and a subtractor section that subtracts the output signal of the demodulation section from the FM-detected signal. |
