Synchronous acquisition of multi-channel signals by single-channel ADC based on square wave modulation

Synchronous acquisition of multi-channel biopotential signals, such as electrocardiograph ( ECG) and electroencephalograph, has vital significance in health care and clinical diagnosis. In this paper, we proposed a new method which is using single channel ADC to acquire multi-channel biopotential signals modulated by squarewaves synchronously. In this method, a specific modulate and demodulate method has been investigated without complex signal processing schemes. For each channel, the sampling rate would not decline with the increase of the number of signal channels. More specifically, the signal-tonoise ratio of each channel is n times of the time-division method or an improvement of 3.01 x log(2)n dB, where n represents the number of the signal channels. Anumerical simulation shows the feasibility and validity of this method. Besides, a newly developed 8-lead ECG based on the new method has been introduced. These experiments illustrate that the method is practicable and thus is potential for low-cost medical monitors. Published by AIP Publishing.