Patent ID: 8768638

Claim:
A method for spectral analysis of a signal in several adjacent frequency bands with different corresponding frequency resolutions in each case, which comprises at least one data-acquisition step and a subsequent data-evaluation step for each frequency band, wherein the data-acquisition step and the subsequent data-evaluation step proceed cyclically without interruption for each frequency band of the spectral analysis, the data-acquisition step includes a step of sampling the signal at a sampling frequency according to the Nyquist criterion to be at least double the value of the upper frequency of the respective frequency band; and a step of storing the respectively-sampled values of the signal in a ring memory associated with the respective frequency band, the data-evaluation step includes a digital spectral-estimation method, and the sampling step includes for each frequency band at least one subordinate sampling step and the second and each subsequent subordinate sampling step includes a low-pass filtering step having different bandwidth and a subsequent undersampling, wherein the low-pass filtering step filters out the respective frequency band of the previous sampling step and the frequency bands are adjacent to one another, wherein spectral values already calculated in a Fourier analysis of a higher-frequency overlapping frequency band are used as temporary spectral values for lower-frequency frequency bands, until all spectral values in the lower-frequency frequency bands have been calculated by means of Fourier analysis.