evolfft {RSEIS}R Documentation

spectrogram

Description

spectrogram using Welsh's Method

Usage

evolfft(a, dt = 0, Nfft = 0, Ns = 0, Nov = 0, fl = 0, fh = 10)

Arguments

a signal
dt sample rate interval (s)
Nfft Number of points in fft
Ns NUmber of sample in sub-window
Nov number of sample to overlap
fl low frequency to display
fh high frequency to display

Details

This is a duplication of the spectrogram function in matlab which applies Welsh's Method.

Value

List

sig input signal
dt deltat
wpars input parameters
DSPEC spectrum image
freqs output frequencies (y axis)
tims output times (x-axis)

Author(s)

Jonathan M. Lees<jonathan.lees.edu>

See Also

MTM

Examples


data(CE1)
plot(CE1$x, CE1$y, type='l')
Nfft=1024
Ns=250
Nov=240
fl=0
fh=1/(2*CE1$dt)

EV = evolfft(CE1$y, dt =CE1$dt , Nfft = Nfft, Ns =Ns , Nov =Nov , fl =fl , fh
= 25)
image(EV$DSPEC)



[Package RSEIS version 1.1-0 Index]