FREQUENCY ANALYSIS USING ZOOM-FFT.

Ordinary FFT techniques produce a frequency spectrum ranging from dc to a given maximum frequency, having a resolution determined by the number of frequency lines. Zoom-FFT provides a method by which an increased resolution can be obtained within a smaller part of this range. Today two different principles are used in Zoom-FFT analyzers. The most important difference is found in their ability to store and preserve the original time function during the analysis. The two methods are here compared with respect to typical practical applications of Zoom-FFT analysis. Furthermore, if the time function is stored, new scan-analysis methods become available for the analysis of non-stationary and transient signals.