astrochron (version 0.4.3)

mtm: Multitaper Method Spectral Analysis

Description

Multitaper Method (MTM) Spectral Analysis

Usage

mtm(dat,tbw=3,ntap=NULL,padfac=5,demean=T,detrend=F,siglevel=0.9,ar1=T,output=0,
     CLpwr=T,xmin,xmax,pl=1,sigID=F,genplot=T,verbose=T)

Arguments

dat

Stratigraphic series for MTM spectral analysis. First column should be location (e.g., depth), second column should be data value.

tbw

MTM time-bandwidth product.

ntap

Number of DPSS tapers to use. By default, this is set to (2*tbw)-1.

padfac

Pad with zeros to (padfac*npts) points, where npts is the original number of data points.

demean

Remove mean from data series? (T or F)

detrend

Remove linear trend from data series? (T or F)

siglevel

Significance level for peak identification.

ar1

Estimate conventional AR(1) noise spectrum and confidence levels? (T or F)

CLpwr

Plot AR(1) noise confidence levels on power spectrum? (T or F)

output

What should be returned as a data frame? (0=nothing; 1=spectrum + CLs + AR1 fit; 2=sig peak freqs; 3=sig peak freqs + prob; 4=all)

xmin

Smallest frequency for plotting.

xmax

Largest frequency for plotting.

pl

Plot logarithm of spectral power (1) or linear spectral power (2)?

sigID

Identify signficant frequencies on power and probabilty plots? (T or F)

genplot

Generate summary plots? (T or F)

verbose

Verbose output? (T or F)

References

Rahim, K.J. and Burr W.S. and Thomson, D.J., 2014, Appendix A: Multitaper R package in "Applications of Multitaper Spectral Analysis to Nonstationary Data", PhD diss., Queen's Univieristy, pp 149-183. http://hdl.handle.net/1974/12584

Thomson, D. J., 1982, Spectrum estimation and harmonic analysis, Proc. IEEE, 70, 1055-1096, doi:10.1109/PROC.1982.12433.

See Also

spec.mtm, lowspec, and periodogram

Examples

# generate example series with periods of 400 ka, 100 ka, 40 ka and 20 ka
ex = cycles(freqs=c(1/400,1/100,1/40,1/20),start=1,end=1000,dt=5)

# add AR1 noise
noise = ar1(npts=200,dt=5,sd=.5)
ex[2] = ex[2] + noise[2]

# MTM spectral analysis, with conventional AR1 noise test
pl(1,title="mtm")
mtm(ex,ar1=TRUE)

# compare to ML96 analysis
pl(1, title="mtmML96")
mtmML96(ex)

# compare to analysis with LOWSPEC
pl(1, title="lowspec")
lowspec(ex)

# compare to amplitudes from eha
pl(1,title="eha")
eha(ex,tbw=3,win=1000,pad=1000)