INFINITE IMPULSE RESPONSE FILTER FOR FREQUENCY SHIFTING KEYING(FSK) DEMODULATION AND FREQUENCY SHIFTING KEYING DEMODULATION SYSTEM USING THE INFINITE IMPULSE RESPONSE FILTER

摘要

PURPOSE: Infinite impulse response filter for FSK demodulation has a magnitude characteristic which has a band pass characteristic about both a mark frequency and a space frequency, and its phase characteristic follows a predetermined requirement derived from the demodulation signal characteristic. CONSTITUTION: A magnitude characteristic of infinite frequency response filter(500) for FSK demodulation has a band pass characteristic about a mark frequency and a space frequency, A phase characteristic of the infinite frequency response filter(500) has a phase gain opposite to a predetermined mark frequency and space frequency. A determining part(520) calculates an original data value from an output signal of an infinite frequency response filter. Thereby, a demodulation system having a low power-consumption is made.