RSEIS (version 3.5-2)

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)
###   swig(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")