specToMS_1D: Spectrogram to modulation spectrum 1D
In soundgen: Sound Synthesis and Acoustic Analysis

View source: R/modulationSpectrum_utilities.R

specToMS_1D

R Documentation

Spectrogram to modulation spectrum 1D

Description

Takes a spectrogram and returns a MS - that is, the spectrum of each channel. The input can be an ordinary STFT spectrogram or an auditory spectrogram (a signal convolved with a bank of bandpass filters). The difference from specToMS is that, instead of taking a two-dimensional transform of the spectrogram, here the spectra are calculated independently for each frequency bin.

Usage

specToMS_1D(
  fb,
  samplingRate,
  windowLength = 250,
  step = windowLength/2,
  method = c("spec", "meanspec")[2]
)

Arguments

`fb`	input spectrogram (numeric matrix with frequency in rows and time in columns)
`samplingRate`	for auditory spectrogram, the sampling rate of input audio; for STFT spectrograms, the number of STFT frames per second
`windowLength`, `step`	determine the resolution of modulation spectra (both in ms)
`method`	calls either `meanspec` or `spec`

Value

Returns a MS - a matrix of real values, with center frequencies of original filters in rows and modulation frequencies in columns.

Examples

data(sheep, package = 'seewave')

# auditory spectrogram
as = audSpectrogram(sheep, filterType = 'butterworth',
  nFilters = 24, plot = FALSE)
fb = t(do.call(cbind, as$filterbank_env))
rownames(fb) = names(as$filterbank_env)
ms = soundgen:::specToMS_1D(fb, sheep@samp.rate)
plotMS(log(ms+.01), logWarpX = c(10, 2), quantile = NULL, ylab = 'kHz')

# ordinary STFT spectrogram
sp = spectrogram(sheep, windowLength = 15, step = 0.5,
  output = 'original', plot = FALSE)
ms2 = soundgen:::specToMS_1D(sp, 1000 / 0.5)  # 1000/0.5 frames per s
plotMS(log(ms2+.01), quantile = NULL, ylab = 'kHz')
## Not run: 
ms_spec = soundgen:::specToMS_1D(fb, sheep@samp.rate, method = 'spec')
plotMS(log(ms_spec+.01), logWarpX = c(10, 2), quantile = NULL, ylab = 'kHz')

## End(Not run)

soundgen documentation built on Sept. 12, 2024, 6:29 a.m.