The instantaneous frequency rate spectrogram. (January 2016)

• Record Type: Journal Article
• Authors: Czarnecki, Krzysztof
• Is Part Of: Mechanical systems and signal processing. Volume 66/67(2016)
• Page Start: 361
• Page End: 373
• Publication Date: 2016-01
• Subjects: Time–frequency analysis -- Short-time Fourier transform -- Time–frequency reassignment -- Instantaneous frequency rate and chirp rate estimation -- Analysis of nonstationary signals -- Analysis of acoustic emissions of engine; Structural dynamics -- Periodicals; Vibration -- Periodicals; Constructions -- Dynamique -- Périodiques; Vibration -- Périodiques; Structural dynamics; Vibration; Periodicals; 621
• DOI: 10.1016/j.ymssp.2015.06.029
• Languages: English
• ISSNs: 0888-3270

Abstract

Abstract: An accelerogram of the instantaneous phase of signal components referred to as an instantaneous frequency rate spectrogram (IFRS) is presented as a joint time-frequency distribution. The distribution is directly obtained by processing the short-time Fourier transform (STFT) locally. A novel approach to amplitude demodulation based upon the reassignment method is introduced as a useful by-product. Additionally, an estimator of energy density versus the instantaneous frequency rate (IFR) is proposed and referred to as the IFR profile. The energy density is estimated based upon both the classical energy spectrogram and the IFRS smoothened by the median filter. Moreover, the impact of an analyzing window width, additive white Gaussian noise and observation time is tested. Finally, the introduced method is used for the analysis of the acoustic emission of an automotive engine. The recording of the engine of a Lamborghini Gallardo is analyzed as an example. Abstract : Highlights: Instantaneous frequency rate estimation in the time-frequency domain is presented. The proposed estimators are based on the STFT and the reassignment method. A novel method of amplitude demodulation in the time-frequency domain is presented. Energy density versus the estimated instantaneous frequency rate is introduced. The acoustic emission of an automotive engine is analyzed for example.