pwrLawFit {astrochron} R Documentation

## Estimate power law (1/f) fit to power spectrum

### Description

Estimate power law (1/f) fit to power spectrum, following the algorithm of Vaughan (2005).

### Usage

pwrLawFit(spec,dof=2,flow=NULL,fhigh=NULL,output=1,genplot=T,verbose=T)



### Arguments

 spec Power spectrum. First column is frequency, second column is raw power (linear). Do not include the zero frequency and Nyquist. dof Degrees of freedom for power spectral estimate. Default is 2, for a simple periodogram. flow Lowest frequency to include in 1/f fit fhigh Highest frequency to include in 1/f fit output Output results of 1/f fit? (0=none; 1=Frequency,Power,Power Law CL,Unbiased Power Law fit,CL_90,CL_95,CL_99; 2=beta, unbiased log10N, biased log10N) genplot generate summary plots (T or F) verbose verbose output (T or F)

### References

Vaughan, S. (2005), A simple test for periodic signals in red noise, Astronomy & Astrophysics.

### 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)

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

# calculate periodogram