| 摘要 |
PURPOSE: A bio-signal modem is provided to stably embody multiple channels, and to achieve a great amount of low frequency band signals from a limited frequency band of a sound card. CONSTITUTION: For embodying a signal modem(9) for utilizing a sound card basically contained in the computer as an analog-digital converter, a signal modulation part(26) consists of a reference waveform generator for producing a low frequency band signal and a frequency belonging to an audio band; a signal multiplier for performing the modulation of amplitude by multiplying a reference signal; a band-pass filter part for setting the waveform; and a signal level controller. After the modulation of the attained signal being performed, a modulated signal is applied to one signal line of sound card line-in stereo input lines, and a reference frequency signal is applied to another signal line. Also, for restoring an original signal, a signal demodulation part(6) consists of a low threshold pass filter part.
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