| 摘要 |
PROBLEM TO BE SOLVED: To provide an FM detection method by a pulse count method in which an S/N ratio of an FM demodulating signal is increased by 6 dB and an intermediate frequency component of an FM intermediate frequency signal does not affect the FM demodulating signal. SOLUTION: An FM detection method is composed of a limiter portion 1, a rectangular wave delay portion 2, a rectangular wave forming portion 3, a monostable multi-vibrator 4, and a low pass filter 5, wherein the limiter portion 1 converts an FM intermediate frequency signal into a rectangular wave, the rectangular wave delay portion 2 prepares the first rectangular wave which is not delayed and the second rectangular wave to which a predetermined delay is performed based on the rectangular wave, the rectangular wave forming portion 3 forms the third and fourth rectangular waves from the first and second rectangular waves, the monostable multi vibrator 4 generates a pulse signal with a twice intermediate frequency of an FM intermediate frequency signal from the third and fourth rectangular waves, and the low pass filter 5 passes the pulse signal to output the FM demodulating signal. COPYRIGHT: (C)2007,JPO&INPIT
|
