| 摘要 |
Disclosed is a data modulation/demodulation device comprising a comparison portion(10), a level test portion(20), a band filtering portion(30), a mixing portion(60), a demodulation portion(80), and a first through third amplification portions(40, 70, 90). The comparison portion(10) receives a frequency shift keying modulation signal in the non-inverting port and receives a reference voltage in the inverting port and then outputs the compared signal. The level test portion(20) tests the level of the compared signal output from the comparison portion(10). The band filtering portion(30) makes a frequency within a predetermined scope among the outputs of the comparison portion(10) pass. The mixing portion(60) mixes the frequency generated in the oscillation portion(50) with the signal passed through the amplification portion(40) from the band filtering portion(30). The demodulation portion(80) demodulates the FSK signal passed through the second amplification portion(70) from the mixing portion(60). The first through third amplification portions(40, 70, 90) amplify the signal transmitted from an output ports of the band filtering portion(30), the mixing portion(60) and the demodulation portion(80) connected each other.
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