spec_mimic {primer}

Function to mimic the power spectrum of an observed time series.

Description

This function rearranges one vector, X, to mimic the spectrum of another vector, Y.

Usage

spec_mimic(X, Y = NULL, gamma = 1)

Arguments

X

numeric vector.

Y

if not NULL, a numeric vector.

gamma

power of the 1/f noise; used only if Y is NULL.

Details

If Y is NULL, this function will use [one_over_f()] to generate a random series with power = gamma.

Author(s)

Hank Stevens

References

J. M. Halley. Ecology, evolution and 1/f-noise. Trends in Ecology & Evolution, 11:33-37, 1996. O. L. Petchey, A. Gonzalez, and H. B. Wilson. Effects on population persistence: the interaction between environmental noise colour, intra-specific competition and space. Proceedings of the Royal Society of London Series B, 264:1841-1847, 1997. J. E. Cohen, C. M. Newman, A. E. Cohen, O. L. Petchey, and A. Gonzalez. Spectral mimicry: a method of synthesizing matching time series with different Fourier spectra. Circuits, Systems and Signal Processing, 18:431-442, 1999.

See Also

[one_over_f()] to generate 1/f noise; [plot_f()] to plot the time series and the spectrogram of the series.

Examples

N = 50
set.seed(1)
X1 <- runif(N)
Y <- one_over_f(gamma=2, N=N)
X2 <- spec_mimic(X1, Y)
series <- cbind(X1, Y, X2)
matplot(1:50, series, type='l')
legend("bottomright", legend=colnames(series), col=1:3, lty=1:3)