Level-Crossing ADC Modeling for Wireless Electrocardiogram Signal Acquisition System
Résumé
The wireless biomedical acquisition and transmission (Wibio’ACT) is a contributive project for real-time electrocardiogram (ECG) monitoring based on a special level-crossing analog-to-digital converter (LC-ADC). The authors present, as the first step in their design flow, modeling and simulation results of the converter in the presence of noise in ECG and comparator errors. Compared to pulse coding modulation (PCM) and differential pulse code modulation (DPCM) it is shown that LC-ADC is more suitable for the digitization of the biomedical signal with the possibility to achieve a PRD less than 2% which is the criteria for a good reconstructed signal quality. As far as it concerns the performances in presence of comparators errors, a delay higher than 0.21 % of TC, may imply a PRD higher than 2 %. However, the comparator offset voltage impact varies with the design considerations.