evolAR: Evolutive Auto-Regressive Spectrum

In RSEIS: Seismic Time Series Analysis Tools

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

Details

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

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<[e-mail]>

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")

RSEIS documentation built on Sept. 13, 2024, 1:09 a.m.