LowPSD {RespirAnalyzer}

Function to calculate the power spectral density (PSD)

Description

function to calculate the power spectral density (PSD) of a time series. Methods derived from A. Eke (2000) "Physiological time series: distinguishing fractal noises from motions" <doi:10.1007/s004249900135>.

Usage

LowPSD(series, plot = TRUE, min = 1/8, max = 1/2)

Arguments

series

a numeric vector, with data for a regularly spaced time series.

plot

logical. whether to draw the plot of log power vs. log frequency

min, max

the optional values. Frequency range of power spectral density. The default value is 1/2 and 1/8 and cannot be set to a negative number

Value

a value of spectral exponent(beta) which the the slope of the of the fitting line on plot of log power vs. log frequency

References

Zhang T, Dong X, Chen C, Wang D, Zhang XD. RespirAnalyzer: an R package for continuous monitoring of respiratory signals.

Examples

data("TestData")
Fs <- 50
Peaks <- find.peaks(Data[,2],Fs,lowpass=TRUE,freq=1,MovingAv=FALSE,
                    W=FALSE,filter=TRUE,threshold=0.05)
PP_interval=diff(Peaks[,1])/Fs
LowPSD(series=PP_interval,plot=TRUE,min=1/64, max=1/2)