Abstract: The signals of a danger detector that has at least one sensor (2, 3, 4) for monitoring danger parameters and an electronic evaluation system (1) assigned to the at least one sensor (2, 3, 4) are compared with specified parameters. In addition, the signals are analysed with regard to whether they occur increasingly frequently or regularly, and signals that occur increasingly frequently or regularly are classified as interference signals. The classification of signals as interference signals triggers an appropriate adjustment of the parameters. If interference signals occur, the validity of the result of the analysis of the signals of the at least one sensor (2, 3, 4) is checked prior to the adjustment of the parameters, and the parameters are adjusted as a function of the result of said validity test.

Abstract: In a method for frequency analysis of a signal of a hazard detector, wavelet transformation is combined with fuzzy logic analysis. In the transformation, based on orthonormal or semi-orthonormal wavelets, an original signal is fed to a multi-stage filter cascade of pairs of high-pass/low-pass filters. From the output of the high-pass filter, wavelet coefficients and values of the original signal, each filter stage produces an association function. The functions are normalized and analyzed further in accordance with fuzzy logic rules. The method is particularly suitable for analyzing signals from flame detectors, noise detectors and the like. As processor code for transformation and analysis is kept short, high speed and accuracy are achieved at low cost.