Detection of sinusoidal waveform in noise

摘要

A signal processing method is disclosed for detecting the presence of a sinusoidal waveform embedded in noise. The method is particularly applicable to detecting multiple sine-wave pulses embedded in noise when each pulse has a random phase and a pulse amplitude that may fluctuate in any arbitrary manner. The method comprises the steps of processing a received signal to calculate a measure of the mean level of the signal and a measure of the concordance of a zero-crossing pattern of the signal with a uniform pattern exhibited by a sinusoidal waveform having a frequency equal to the centre frequency of the signal, calculating a product using the measure of the mean level of the signal and the measure of the concordance in accordance with the formula LΓHΩ (C) or LΓCΩ en, where L is the measure of the mean level of the signal, C is the measure of the concordance, H is a weighting function, Γ is a, not necessarily integer, value greater than or equal to 1, and Ω is a non-zero, not necessarily integer, value not exceeding that of Γ, wherein the product is calculated for each of a plurality of disjoint signal segments, the plurality of products are summed or averaged and determination is made whether the received signal contains a sinusoidal waveform in dependence upon the calculated sum or average of the products and a decision threshold.