Abstract: A method and system for detecting a coherent signal of unknown frequency from an incoming electrical signal comprising a multiplicity of frequencies is disclosed. A time sequence of sample data signals generated from the incoming electrical signal is decomposed into a plurality of frequency range signals using wavelet functions. The coherent signal is detected in the time sequence based on the frequency range signals. In one embodiment, a program gate array is used to process the time sequence of data samples using wavelet functions. In another embodiment, the data samples are decomposed using Haar scaling and wavelet functions to form smoothed and detailed components of the frequency range signals. The frequency range signals may be compared to at least one predetermined threshold signal to detect the coherent signal in the time sequence of sample data signals.