EvolutiveFFT: Calculate the evolutive Fourier spectrogram.

In hht: The Hilbert-Huang Transform: Tools and Methods

Calculate the evolutive Fourier spectrogram.

Description

Generates the evolutive Fourier spectrogram of a signal, and returns it for use in FTGramImage.

Usage

EvolutiveFFT(sig, dt, ft, freq.span, taper = 0.05)

Arguments

sig	Signal to analyze.
dt	Sample rate (must be constant).
ft	Fourier transform input parameters ft$nfft The frequency resolution, should be in powers of 2 ft$ns Number of samples in a window ft$nov Number of samples to overlap, must be less than ft$ns
freq.span	Frequency range to return.
taper	Amount of cosine taper to apply.

Details

This is an internal function and users will likely not call it directly.

Value

z	Power spectrum
y	Frequency
x	Time
original.signal	The input signal
tt	Sample times based on input sample rate dt

Note

This is a modification of the evolfft function in the RSEIS package.

Author(s)

Daniel C. Bowman [e-mail], Jonathan M. Lees

References

Jonathan M. Lees (2012). RSEIS: Seismic Time Series Analysis Tools. R package version 3.1-3.

hht documentation built on March 31, 2023, 10:08 p.m.