RSEIS (version 1.0-9)

evolfft: 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

Value

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

Details

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

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)