R: Evolutive MTM Spectrum

doGABOR.MTM {RSEIS} | R Documentation

## 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<jonathan.lees@unc.edu>

### 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)
    ###   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)

[Package RSEIS version 3.7-4 Index]