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 = ex + noise

# calculate periodogram