| 摘要 |
PURPOSE:To simplify the circuit constitution by providing a storage device storing an output of a counter measuring a period or a half period of an FM signal and a ROM using an output of the storage device as an address. CONSTITUTION:An output signal of a zero cross detector is given to a counter 2 to clear it and a DFF 3 stores a count value just before the counter 2 is cleared. Since the stored value represents the half period of the FM signal counted by a clock (f), it is given as an address of the ROM table 4. Since a data corresponding to the address is written in advance to the ROM table 4, a normalized value as the demodulated output is outputted when the address is given and a filter connected to the ROM output can be a simple filter.
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