FSK DEMODULATION CIRCUIT AND RECEIVING CIRCUIT

摘要

PROBLEM TO BE SOLVED: To provide an FSK modulation circuit which can securely remove noise without being affected by the frequency of a signal showing transmission data. SOLUTION: The FSK modulation circuit samples a received data signal in an orthogonal relation with a reference signal at every prescribed change timing of the reference signal obtained from a received modulation signal, and outputs a demodulation digital signal. The FSK modulation circuit is provided with: a first noise removing circuit (110) for removing a noise component from the demodulated digital signal in accordance the first value of transmission binary data with an operation synchronized with the reference signal; and a second noise removing circuit (120) for removing the noise component from the demodulated digital signal in accordance with the second value of transmission binary data with the operation synchronized with the reference signal. COPYRIGHT: (C)2005,JPO&NCIPI