pwelch: Estimate Power Spectral Density Using Welch's Method
In TaikiSan21/PAMmisc: Miscellaneous Functions for Passive Acoustic Analysis

pwelch

R Documentation

Estimate Power Spectral Density Using Welch's Method

Description

Estimates the power spectral density (PSD) of an input signal using Welch's method. This should function similarly to the Matlab function pwelch, but results may not be identical. Breaks the input signal into (usually) overlapping frames and averages the resulting PSD estimates

Usage

pwelch(
  x,
  nfft,
  noverlap = 0,
  sr = NULL,
  demean = c("long", "short", "none"),
  channel = 1
)

Arguments

`x`	input signal, either a numeric vector, Wave, WaveMC, or `audioSample` object. Can also be a path to a wav file and it will be read in
`nfft`	length of FFT window to use for individual frames
`noverlap`	number of samples each frame should overlap
`sr`	sample rate of data, only necessary if `x` is a vector
`demean`	method of demeaning the signal, one of `'long'`, `'short'`, or `'none'`. Long subtracts the mean of the entire signal `x`, short subtracts the mean of each individual frame, none does no mean subtraction.
`channel`	channel number to analyse, ignored if `x` is a vector

Value

returns a list with items spec, the PSD estimate of the input signal, and freq, the frequency values (Hz) at each value of spec

Author(s)

Taiki Sakai taiki.sakai@noaa.gov

Examples

# wav example is synthetic echolocation clicks at 4kHz
wavFile <- system.file('extdata/testWav.wav', package='PAMmisc')
psd <- pwelch(wavFile, nfft=1e3, noverlap=500, demean='long')
plot(x=psd$freq, y=10*log10(psd$spec), type='l')

TaikiSan21/PAMmisc documentation built on Oct. 15, 2024, 9:29 p.m.