  This paper presents a dynamic predictive sampling (DPS) based
analog-to-digital converter (ADC) that provides a non-uniform sampling of input
analog continuous-time signals. The processing unit generates a dynamic
prediction of the input signal using two prior-quantized samplings to compute
digital values of an upper threshold and a lower threshold. The digital
threshold values are converted to analog thresholds to form a tracking window.
A comparator compares the input analog signal with the tracking window to
determine if the prediction is successful. A counter records timestamps between
the unsuccessful predictions, which are the selected sampling points for
quantization. No quantization is performed for successfully predicted sampling
points so that the data throughput and power can be saved. The proposed
circuits were designed as a 10-bit ADC using 0.18 micro CMOS process sampling
at 1 kHz. The results show that the proposed system can achieve a data
compression factor of 6.17 and a power saving factor of 31% compared to a
Nyquist rate SAR ADC for ECG monitoring.
