pwelch: Calculate 'Welch Periodogram'

Description

pwelch is for single signal trace only; mv_pwelch is for multiple traces. Currently mv_pwelch is experimental and should not be called directly.

Usage

pwelch(
  x,
  fs,
  window = 64,
  noverlap = 8,
  nfft = 256,
  col = "black",
  xlim = NULL,
  ylim = NULL,
  main = "Welch periodogram",
  plot = 0,
  log = c("xy", "", "x", "y"),
  ...
)
# S3 method for pwelch
print(x, ...)
# S3 method for pwelch
plot(
  x,
  log = c("xy", "x", "y", ""),
  se = FALSE,
  xticks,
  type = "l",
  add = FALSE,
  col = graphics::par("fg"),
  col.se = "orange",
  alpha.se = 0.5,
  lty = 1,
  lwd = 1,
  cex = 1,
  las = 1,
  main = "Welch periodogram",
  xlab,
  ylab,
  xlim = NULL,
  ylim = NULL,
  xaxs = "i",
  yaxs = "i",
  xline = 1.2 * cex,
  yline = 2 * cex,
  mar = c(2.6, 3.8, 2.1, 0.6) * (0.5 + cex/2),
  mgp = cex * c(2, 0.5, 0),
  tck = -0.02 * cex,
  grid = TRUE,
  ...
)
mv_pwelch(x, margin, fs, nfft)

Value

A list with class 'ravetools-pwelch' that contains the following items:

freq: frequencies used to calculate the 'periodogram'
spec: resulting spectral power for each frequency
window: window function (in numerical vector) used
noverlap: number of overlapping time-points between two adjacent windows
nfft: number of basis functions
fs: sample rate
x_len: input signal length
method: a character string 'Welch'

Arguments

x: 'pwelch' instance returned by pwelch function
fs: sample rate, average number of time points per second
window: window length in time points, default size is 64
noverlap: overlap between two adjacent windows, measured in time points; default is 8
nfft: number of basis functions to apply
col, xlim, ylim, main, type, cex, las, xlab, ylab, lty, lwd, xaxs, yaxs, mar, mgp, tck: parameters passed to plot.default
plot: integer, whether to plot the result or not; choices are 0, no plot; 1 plot on a new canvas; 2 add to existing canvas
log: indicates which axis should be log10-transformed, used by the plot function. For 'x' axis, it's log10-transform; for 'y' axis, it's 10log10-transform (decibel unit). Choices are "xy", "x", "y", and "".
...: will be passed to plot.pwelch or ignored
se: logical or a positive number indicating whether to plot standard error of mean; default is false. If provided with a number, then a multiple of standard error will be drawn. This option is only available when power is in log-scale (decibel unit)
xticks: ticks to show on frequency axis
add: logical, whether the plot should be added to existing canvas
col.se, alpha.se: controls the color and opacity of the standard error
xline, yline: controls how close the axis labels to the corresponding axes
grid: whether to draw rectangular grid lines to the plot; only respected when add=FALSE; default is true
margin: the margin in which pwelch should be applied to

Examples

Run this code


x <- rnorm(1000)
pwel <- pwelch(x, 100)
pwel

plot(pwel, log = "xy")

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