R: Evolutive MTM Spectrum

MTMgabor {RSEIS} | R Documentation

## Evolutive MTM Spectrum

### Description

Time varying Auto-Regressive Spectrum (Gabor Transform) using MTM

### Usage

    MTMgabor(a, dt = 0, ppoint=95 , numf = 1024, Ns = 0, Nov = 0, fl = 0, fh = 10)

### Arguments

`a` | signal
`dt` | sample rate interval (s)
`ppoint` | percent confidence for F-test (default=95)
`numf` | Number of frequencies
`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 MTM (multi-taper method) for spectrum estimation. This is a non-interactive version of MTM.drive.

### Value

List

`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)

### Author(s)

Jonathan M. Lees<jonathan.lees@unc.edu>

### References

Percival and Walden;

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

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

### Examples

    ## Not run:
    data(KH)
    ###   swig(KH)

    Xamp <- KH$JSTR[[1]]
    Nfft <- 1024   ###  fft length
    Ns <- 512      ###  number of samples in a window
    Nov <- 480    ###  number of samples of overlap per window
    fl <- 0        ###  low frequency to return
    fh <- 12     ###  high frequency to return
     dt  <-  KH$dt[1]

    EV <-   MTMgabor(Xamp, dt = dt, numf =Nfft , 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")

    ## End(Not run)

[Package RSEIS version 3.7-4 Index]