RSEIS (version 2.4-5)

doGABOR.MTM: 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

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)

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.

References

Lees, J. M. and Park, J., 1995: Multiple-taper spectral analysis: A stand-alone C-subroutine, Computers & 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)
###   PICK.GEN(KH)

Xamp = KH$JSTR[[1]]
Xamp = Xamp[57914:72989]

EV = doGABOR.MTM(Xamp, DT = KH$dt[1], multi = 1, scale.def = 0, TWIN = 2, TSKIP = 0.2, PCTTAP = 0.05)