Three methods of waveform recovery for signals in the presence of noise are discussed in this paper. LIA (Lock-in Amplifier) is used to detect the DC signal or slowly varying signal with low SNR (signal noise ratio), the core part of which is PSD (phase sensitive detector). As a special case, the orthogonal vector LIA is discussed in detail, which is capable of vector analysis of signal. Sampling integral and digital average can recover the impulse waveform with rapid rising and roll-off edges, which have lots of harmonic components in the presence of noise. But many periods of signals are usually needed in this method. On the contrary, the correlation detection method is effective for waveform recovery of the periodical signal when signal of enough duration is not available. By simulation in Matlab, the effectiveness of digital average as well as correlation detection was verified in their specific application conditions.

Date Published: 24 October 2006
PDF: 5 pages
Proc. SPIE 6357, Sixth International Symposium on Instrumentation and Control Technology: Signal Analysis, Measurement Theory, Photo-Electronic Technology, and Artificial Intelligence, 635706 (24 October 2006); doi: 10.1117/12.716688

Published in SPIE Proceedings Vol. 6357:
Sixth International Symposium on Instrumentation and Control Technology: Signal Analysis, Measurement Theory, Photo-Electronic Technology, and Artificial Intelligence
Jiancheng Fang; Zhongyu Wang, Editor(s)