The key challenges in designing a multi-channel biosignal acquisition system for an ambulatory or invasive medical application with a high channel count are reducing the power consumption, area consumption and the outgoing wire count. This paper proposes a spread-spectrum modulated biosignal acquisition system using a shared amplifier and an analog-to-digital converter (ADC). We propose a design method to optimize a recording system for a given application based on the required SNR performance, number of inputs, and area. The proposed method is tested and validated on real pre-recorded atrial electrograms and achieves an average percentage root- mean-square difference (PRD) performance of 2.65% and 3.02% for sinus rhythm (SR) and atrial fibrillation (AF), respectively by using pseudo-random binary-sequence (PRBS) codes with a code-length of 511, for 16 inputs. We implement a 4-input spread-spectrum analog front-end in a 0.18μm CMOS process to demonstrate the proposed approach. The analog front-end consists of a shared amplifier, a 2nd order ΣΔ ADC sampled at 7.8MHz , used for digitization, and an on-chip 7-bit PRBS generator. It achieves a number-of-inputs to outgoing-wire ratio of 4:1 while consuming 23μA /input including biasing from a 1.8V power supply and 0.067mm2 in area.
|Original language||English (US)|
|Number of pages||13|
|Journal||IEEE Transactions on Biomedical Circuits and Systems|
|State||Published - Sep 19 2023|
ASJC Scopus subject areas
- Biomedical Engineering
- Electrical and Electronic Engineering