Integration of Zero Crossing Method in a Nonuniform Sampling System Using Optical Feedback Interferometry

In this article, a zero-crossing (ZC)-based method is proposed to improve the displacement sensing performance of nonuniform sampling (NUS) theory-based use optical feedback interferometry (OFI) under moderate regime. The incorporation ZCs as phase quantization levels (PQLs) allows doubling samples for subsequent interpolation, without using any dithering scheme. When compared simple dither-free NUS method, yields an overall improvement in rms error over wide range target motion amplitudes and frequencies, with maximum at low amplitudes. Experimentally, up 87% obtained precision when system OFI sensor laser wavelength 785 nm.