doGABOR.MTM: Evolutive MTM Spectrum

In RSEIS: Seismic Time Series Analysis Tools

Evolutive MTM Spectrum

Description

Time varying Auto-Regressive Spectrum (Gabor Transform) using MTM. This is a driver for MTMgabor.

Usage

doGABOR.MTM(Xamp, DT = 0.008, ppoint=95 , multi = 1,
 scale.def = 0, TWIN = 2, TSKIP = 0.2, PCTTAP = 0.05,  PLOT=TRUE)

Arguments

Xamp	signal
DT	sample rate interval (s)
ppoint	percent confidence for F-test (default=95)
multi	Multiples of time window estimate
scale.def	scaling flag for plotting (0=raw, 1=log, 2=sqrt)
TWIN	time for window
TSKIP	time for skip
PCTTAP	percent of taper to apply to individual windows
PLOT	logical, TRUE=plot to device

Details

This is a spectrogram function similar to the Gabor Transform but uses the MTM (multi-taper method) for spectrum estimation. This is a non-interactive version of MTM.drive.

Value

list output of MTMgabor:

sig	input signal
dt	deltat
numfreqs	Number of frequencies output
wpars	input parameters list(Nfft=numfreqs, Ns=Ns, Nov=Nov, fl=fl, fh=fh)
DSPEC	spectrum image
HIMAT	matrix with high values of F-test at 90 percent confidence
DOFMAT	Matrix image of degrees of freedom
FVMAT	Matrix image of F-test values
kdof	test degrees of freedom=2*nwin-2
ppoint	percentage point for confidence bounds
freqs	output frequencies (y axis)
tims	output times (x-axis)

Note

The main difference between this and other similar calls is the way the windows are determined.

Author(s)

Jonathan M. Lees<[e-mail]>

References

Lees, J. M. and Park, J., 1995: Multiple-taper spectral analysis: A stand-alone C-subroutine, Computers and Geology, 21(2), 199-236.

Percival, Donald B.,Walden, Andrew T. (1993):Spectral Analysis for Physical Applications,Cambridge University Press, Cambridge, 583p.

See Also

MTMgabor, evolfft, evolMTM, MTM.drive, GETARAIC, doGABOR.AR, DOsgram

Examples

data(KH)
###   swig(KH)

Xamp = KH$JSTR[[1]]
Xamp = Xamp[57914:64914]

EV = doGABOR.MTM(Xamp, DT = KH$dt[1], multi = 1, scale.def = 0,
TWIN = 1, TSKIP = .1, PCTTAP = 0.05)

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