taner {astrochron}R Documentation

Apply Taner bandpass or lowpass filter to stratigraphic series

Description

Apply Taner bandpass or lowpass filter to stratigraphic series. This function can also be used to notch filter or highpass a record (see examples).

Usage

taner(dat,padfac=2,flow=NULL,fhigh=NULL,roll=10^3,demean=T,detrend=F,addmean=T,
       output=1,xmin=0,xmax=Nyq,genplot=T,check=T,verbose=T)

Arguments

dat

Stratigraphic series for bandpass filtering. First column should be location (e.g., depth), second column should be data value.

padfac

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

flow

Low frequency cut-off for Taner filter (half power point). If this value is not set (NULL), it will default to -1*fhigh, which will create a lowpass filter.

fhigh

High frequency cut-off for Taner filter (half power point).

roll

Roll-off rate, in dB/octave. Typical values are 10^3 to 10^12, but can be larger.

demean

Remove mean from data series? (T or F)

detrend

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

addmean

Add mean value to bandpass result? (T or F)

output

Output: (1) filtered series, (2) bandpass filter window.

xmin

Smallest frequency for plotting.

xmax

Largest frequency for plotting.

genplot

Generate summary plots? (T or F)

check

Conduct compliance checks before processing? (T or F) In general this should be activated; the option is included for Monte Carlo simulation.

verbose

Verbose output? (T or F)

Value

bandpassed stratigraphic series.

References

http://www.rocksolidimages.com/pdf/attrib_revisited.htm#_Toc328470897

See Also

bandpass, lowpass, noKernel, noLow, prewhiteAR, and prewhiteAR1

Examples

# generate example series with periods of 405 ka, 100 ka, 40ka, and 20 ka, plus noise
ex=cycles(freqs=c(1/405,1/100,1/40,1/20),end=1000,dt=5,noisevar=.1)

# bandpass precession term using Taner window 
bandpass_ex <- taner(ex,flow=0.045,fhigh=0.055,roll=10^10)

# lowpass filter eccentricity terms using Taner window
lowpass_ex=taner(ex,fhigh=.02,roll=10^10)

# notch filter (remove) obliquity term using Taner window
#  if you'd like the final notch filtered record to be centered on the mean proxy 
#  value, set addmean=FALSE
notch_ex <- taner(ex,flow=0.02,fhigh=0.03,roll=10^10,addmean=FALSE)
notch_ex[2] <- ex[2]-notch_ex[2]
pl(2)
plot(ex,type="l",main="Eccentricity+Obliquity+Precession")
plot(notch_ex,type="l",main="Following application of obliquity notch filter")

# highpass filter obliquity and precession terms using Taner window
#  if you'd like the final highpass filtered record to be centered on the mean proxy 
#  value, set addmean=FALSE
highpass_ex=taner(ex,fhigh=.02,roll=10^10,addmean=FALSE)
highpass_ex[2] <- ex[2]-highpass_ex[2]
pl(2)
plot(ex,type="l",main="Eccentricity+Obliquity+Precession")
plot(highpass_ex,type="l",main="Obliquity+Precession highpassed signal")

[Package astrochron version 1.0 Index]