Plot the spectrogram of signal. — spectrogram • rsleep

`spectrogram` resamples signal and use the `specgram` function from the `signal` library to compute the spectrogram. Results resolution can be then reduced to quickly plot large signals.

spectrogram(
  signal,
  sRate,
  maxFreq = 25,
  n = 1024,
  window = n,
  overlap = 0,
  cols = c(rep("#3B9AB2", 9), "#78B7C5", "#EBCC2A", "#E1AF00", rep("#F21A00", 6)),
  freq = 4,
  plot = TRUE,
  startTime = as.POSIXct("1970/01/01 00:00:00")
)

Arguments

signal: Numerical vector of the signal.
sRate: Signal sample rate in Hertz.
maxFreq: Maximal frequency to plot in Hertz. Signal will be resampled at maxFreq*2 sample rate.
n: The size of the Fourier transform window.
window: Shape of the fourier transform window, defaults to n.
overlap: Overlap with previous window, defaults to 0.
cols: Color scale used for the underlying plot function.
freq: Aggregate frequency used to lower spectrogram resolution. Defaults to 4.
plot: Boolean, plot or not the spectrogram.
startTime: Posixct of the signal start. Adjust the x axis labels accordingly.

Value

A spectrogram.

Examples

library(signal)
#> 
#> Attaching package: ‘signal’
#> The following objects are masked from ‘package:stats’:
#> 
#>     filter, poly
spectrogram(chirp(seq(-2, 15, by = 0.001), 400, 10, 100, 'quadratic'),20,n=1024)