RSEIS (version 2.1-6)

evolAR: Evolutive Auto-Regressive Spectrum

Description

Time varying Auto-Regressive Spectrum (Gabor Transform)

Usage

evolAR(a, dt = 0, numf = 1024, pord = 100, Ns = 0, Nov = 0, fl = 0, fh = 10)

Arguments

a

signal

dt

sample rate interval (s)

numf

Number of frequencies

pord

Order for Auto-regressive calculation

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 spectrogram function similar to the Gabor Transform but uses the Auto-Regressive method for spectrum estimation.

See Also

evolfft, evolMTM, MTM.drive, GETARAIC

Examples

data(KH)
###   PICK.GEN(KH)

Xamp = KH$JSTR[[1]]

dt = KH$dt[1]
plot(seq(from=0, length=length(Xamp), by=dt), Xamp, type='l')
##  limit the trace, somewhat
Xamp = Xamp[12670:22669]
plot(seq(from=0, length=length(Xamp), by=dt), Xamp, type='l')


Nfft=1024   ###  fft length
Ns=512      ###  number of samples in a window
Nov=480    ###  number of samples of overlap per window
fl=0        ###  low frequency to return
fh=12     ###  high frequency to return

EV = evolAR(Xamp, dt = dt, numf =Nfft , pord = 100, Ns = Ns, Nov = Nov, fl = fl, fh
= fh)


PE = plotevol(EV, log=1, fl=0.01, fh=fh, col=rainbow(100), ygrid=FALSE,
STAMP="", STYLE="ar")