Design an open DSP-based system to acquire and process the bioelectric signal in realtime

This paper introduces a design for open DSP-based system, which is applied to the bioelectric signal acquisition in real time by using the available audio port in DSP system. In order to evaluate system, sine wave signals ranged from 0 to 100Hz, corresponding to the ECG spectrum bandwidth, are used for experiment. Since the audio port only acquires the signal from 20Hz to 20 kHz, the proposed method is FM modulation-demodulation can be considered. The original signal is packed to the carrier wave whose center frequency is 1kHz by using the VCO FM modulation circuit, then the original signal is extracted out by FM mixed demodulation algorithm in DSP.