RECEIVING APPARATUS AND DEMODULATION METHOD

摘要

A receiver simultaneously receives a plurality of signals on a plurality of channels, which have been modulated using frequency shift keying (FSK). A calculation range controller detects a Mark frequency and a Space frequency for each channel, determines for each channel a frequency range for Fourier transform calculation of the plurality of receiving signals, based on the detected Mark frequency and the detected Space frequency and indicates the frequency range to a frequency component detector. The frequency component detector performs Fourier transformation on the determined frequency range for each channel and detects, for each channel, frequency components (FFT signals) of the plurality of receiving signals respectively. The channel shifter allocates the FFT signals output from the frequency component detector to data of channel 1 to channel N and outputs the signals to respective demodulators.

主权项

1. A receiving apparatus comprising:
a receiver that simultaneously receives a plurality of signals on a plurality of channels, which have been modulated using frequency shift keying (FSK); a calculation range controller that detects a Mark frequency and a Space frequency for each channel, controls and determines for each channel a frequency range for Fourier transformation calculation of the plurality of receiving signals, based on the detected Mark frequency and the detected Space frequency; a frequency component detector that performs the Fourier transformation calculation on the determined frequency range for each channel and detects, for each channel, frequency components of the plurality of receiving signals respectively; a channel shifter that shifts for each channel a central frequency of the detected frequency components to a predetermined reference frequency; and a demodulator that demodulates the shifted frequency components of each channel and extracts demodulation data for each channel.