Derivative Level-Crossing Sampling

Abstract

A new continuous-time level-crossing sampling LCS technique, which is called derivative LCS (DLCS), and associated reconstruction are proposed for bandpass signals. The derivative of the input is level-crossing sampled, and the result is transmitted; at the receiver, these samples are zero-order held and integrated, automatically resulting in piecewise-linear reconstruction, which has much lower quantization error than zero-order-hold (ZOH) reconstruction. Two refinements are presented, namely companded DLCS and adaptive-resolution DLCS. For some signals, the schemes proposed can significantly reduce the number of samples generated per unit of time, compared to schemes based on ZOH reconstruction, for a given signal-to-error ratio (SER), without the need for elaborate reconstruction techniques, such as linear prediction. Contrary to Nyquist-rate-clocked systems, DLCS and its variants exploit the varying spectral context and sparse structure of bursty signals by generating samples only when the signal rate of change requires it, thus promising to lead to low dynamic power dissipation in the associated hardware. Simulation results are presented.