PURPOSE: To reduce noise, to detect a response delay generated in a loop at the time of reducing noise and to correct the delay time by narrowing loop band width by PLL demodulation. ;CONSTITUTION: In a carrier detecting part A, a phase comparator 5 compares the phase of an FM signal with that of a carrier outputted from a VCO 14 and extracts only an FM change. In an error voltage detecting part B, a phase comparator 18 compares an output from a VCO 17 with the FM signal and extracts a phase difference change due to the delay time of an LPF 16. The change is detected by a PLL loop consisting of a phase comparator 19, an LPF 20 and a VCO 21 and a DC change corresponding to the delay time is extracted. An FM demodulation part C corrects the delay time of an FM modulation signal by the DC change.;COPYRIGHT: (C)1995,JPO
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