The knowledge of amplitude, frequency, phase, and of the change law of instantaneous spectral components in time-varying signals is important for the experts in various areas of interest, such as signal processing, theory of systems, design and control of machines and automatic systems. This paper deals with an analysis of the systematic error, caused by instantaneous parameter variation, and of the casual error, due to noise presence, in short-time Fourier transform (STFT) applications on these signals. With reference to the first component of inaccuracy, the exact expression in terms of both the used filter and the parameters of signal is carried out. Moreover, its relation with the systematic error in the stationary case is shown; then, an interpolation technique is proposed to correct these errors. For the latter, the Cramer-Rao (CR) bounds of the instantaneous frequency and amplitude are derived in terms of the characteristics of noise and of the time-varying parameters of digitized signals.
|Autori interni:||ATTIVISSIMO, Filippo|
|Titolo:||High-accuracy measurements on noisy nonstationary signals via interpolated STFT|
|Data di pubblicazione:||1996|
|Nome del convegno:||8th International IMEKO TC4 Symposium on New Measurements and Calibration Methods of Electrical Quantities and Instruments|
|Appare nelle tipologie:||4.1 Contributo in Atti di convegno|