A reused chopper/AM mixing amplifier for bio-signals acquisition

Bio-signal audio-transmission schemes require the design of a dedicated audio-modulation circuit to modulate the signal to audio band. In the conventional system, amplification and audio-modulation of the bio-signals are separated. A chopper/AM mixing amplifier is proposed in this paper according to the characteristics of the audio-transmission. The proposed amplifier could implement chopper-modulation and audio-modulation functions simultaneously as input signal passes through only one multiplier. This scheme reduces the three modulations into one modulation, and combines the two low-pass filtering into a band-pass filtering, which substantially simplifies the system structure and effectively reduces the power consumption.