AUTOMATICALLY CORRECTING DATA DETECTION CIRCUIT FOR FREQUENCY SHIFT KEYING MODULATED SIGNAL AND ITS OPERATION

摘要

PROBLEM TO BE SOLVED: To exactly process a frequency shift keying modulated signal irrespective of frequency fluctuation due to the ambient temperature or other conditions. ;SOLUTION: In an automatic correction data detecting circuit 30 for the frequency shift keying modulated signal, the modulated signal is received in an input, the modulated signal is converted into a voltage level corresponding to frequency of the modulated signal and the voltage level is supplied to an output by the demodulator 32. The input of a voltage clamp circuit 42 is connected to the output of the demodulator 32, the voltage level of the output of the demodulator 32 is sampled and stored in the voltage clamp circuit 42 and a trip point voltage level representing the sum of the voltage level stored in the output and a fixed voltage offset is supplied by the voltage clamp circuit 42. A first input of a comparator 50 is connected with the output of the voltage clamp circuit 42, a second input is connected to the output of the demodulator 32, the output of the voltage clamp circuit 42 is compared with the output of the demodulator 32 and a logical output signal is supplied to the output of the comparator 50 by responding to the comparison.;COPYRIGHT: (C)1996,JPO