| 摘要 |
PURPOSE: A data demodulating apparatus is provided to achieve a noiseless data demodulation by a correct level detection from a multi level frequency shift keying(FSK) demodulation signal. CONSTITUTION: A data demodulating apparatus comprises a limiter(400) for amplitude-limiting a multi level FSK signal into a predetermined level and outputting the result, a band-pass filter(410) for performing band-pass filtering for the FSK signal output from the limiter(400), a sampling unit(420) for sampling the FSK signal passed the band-pass filter(410) during an inputted clock period, an analog to digital converting unit(430) for converting the sampled FSK signal output from the sampling unit(420) into a digital signal, and a control unit(440). The control unit(440) generates a clock corresponding to a demodulation level, restores the digital data output from the analog to digital converting unit(430) during a clock period inputted to the sampling unit(420), compares the restored data with a configuration of data frame, and outputs a binary data if the restored data matches with the configuration of data frame.
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