Autocorrelation Analysis in Time and Frequency Domains for Passive Structural Diagnostics

Figure 4

Process of period estimation of fundamental modal frequency. Waveform of framed observed signal (a), triangular windowed framed signal waveform (b), power spectrum of triangular windowed waveform (c), autocorrelation function calculated from power spectrum (d), symmetric triangular windowed autocorrelation function (e), curved power spectrum and unit line spectra (f), period estimation of fundamental modal frequency (g), and average of period estimation results for 30 s long white noise convolved with condition 1’s impulse response (solid line: simulated observed signal; dotted line: original impulse response) (h).