For frequency domain analysis, fast Fourier transformation was done using Welch's periodogram
method with a Hann window.
The PSD was estimated with Lomb-Scargle periodogram
(Lomb, 1976; Scargle, 1982), stacked and averaged with a moving window.
Then, in the frequency domain using the periodogram
method and smoothed averages.
In the procedure of solving the Hurst coefficient, the most commonly used methods include variance-time plot method, absolute values of the aggregated series, differenced variance method, regression residual method, R/S plot, periodogram
, wavelet analysis method and so on.
the second derivative of speed trace, is transformed from time-domain to frequency domain via Fast Fourier Transform (FFT) illustrated by periodogram
in Figure 2.
In this work, the value is fixed as one more than the number of peaks in the periodogram
of the received signal x (n), aiming to find an approximate number of expected sources.
The power spectral density was obtained by Welch's periodogram
, using window width of 512 data points with an overlap of 256 points.
This can be termed as Periodogram
which is the estimation of the spectral density of the signal.
Most alternative techniques for periodicity detection, like Fourier transform and least squares spectral analysis (LSSA , also known as Lomb-Scargle periodogram
), include the use of trigonometric functions and are therefore inappropriate for embedded systems with limited computational capacity.
The PSDs are computed by averaging several periodogram
MA, USA) functions based on Welch's averaged and modified periodogram
For each frame, calculate the periodogram
estimate of power spectrum.