PLL-FM DEMODULATOR

摘要

PURPOSE: To obtain high sensitivity by making a loop band width of a PLL broad in the PLL-FM demodulator. ;CONSTITUTION: An FM signal e₁(t) and a signal e₄(t) from a VCO (voltage controlled oscillator) 7 are synchronizingly detected by a synchronization detector 9 in the state of in-phase, then outputs e₆(t) and e₄(t) are mixed by a mixer circuit 11, a signal e₁(t) and the obtained signal e₇(t) are calculated by a computing element 13 to obtain a noise component e₈(t). The signal e₈(t) is fed back to the computing element 3 at a pre-stage of the PLL loop and subtracted by the e₁(t) and the difference is fed to a phase comparator 4.;COPYRIGHT: (C)1994,JPO&Japio