Signal characterization using spectral microanalysis

The dynamic history of narrow band ’’line’’ components in spectrograms has customarily been characterized by bandwidth variations and changes in the center frequency of the ’’line.’’ Analysis techniques are described that enable ’’instantaneous’’ amplitude and frequency estimates to be obtained. Characterization by the new techniques describes significant spectral features in terms more closely related intuitively to the mechanisms causing them and helps visual identification of correlated effects in a frequency versus time spectrogram display. Spectrograms obtained with the new techniques are shown to illustrate the improvements obtainable. The term ’’microanalysis’’ is suggested here to describe the new techniques, since they allow feature resolution to be improved in the time and frequency domains simultaneously for sufficiently strong signals.