Abstract: The factors that influence the performance of the amplitude modulated broad-band signal detection are analyzed by deriving a formula for the output signal to noise ratio of DEMON(Detection of Envelope Modulation on Noise) processing. The analysis shows that the performance of the amplitude modulated broad-band signal detection depends on the following factors:depth of the periodical modulation of the signal, the bandwidth of a preprocessor, the ratio of modulated noise to total noise, the sampling frequency, and the length of DFT, the decimation number, the selection of time window, the overlap of data blocks and the number of averaging in calculating the demon spectra.