Discrete-time method for signal and noise measurement

摘要

Signal and noise measurement, especially the measurement of signalto noise power ratio (SNR) is of fundamental importance in many areas ofelectrical engineering, such as communications, signal processing, testand measurements, circuits and systems, etc. In this paper we proposetwo algorithms for estimating the signal to noise ratio of a noisysinewave from discrete-time data obtained by sampling the input signal.One algorithm is based on the estimation of the four parameters of theunderline sinewave. The second algorithm is based on estimating theaverage noise power by averaging the squared magnitude of the FFT binsattributed to the noise. Both methods shows excellent performance.Simulation results indicate that the lour parameter method requires theinput SNR to be at least 10 dS and the input signal frequency notexceeding one third of the sampling frequency. On the other hand, thesecond approach, the spectrum average method, shows a remarkablerobustness over a very wide range of normalized frequencies (withrespect to the Nyquist frequency) and SNRs (well over 100 dB). Thisspectrum average method should prove to be very useful in a wide rangeof applications