Frequency utilities

Provides frequency and fractional octave frequency bands functionalities.

@author: João Vitor Gutkoski Paes

ossom.utils.freq.freq_to_band(freq: float, nthOct: int, ref: float, base: int) → int[source]

Band number from frequency value.

Parameters:
  • freq (float) – The frequency value.
  • nthOct (int) – How many bands per octave.
  • ref (float) – Frequency of reference, or band number 0.
  • base (int) – Either 10 or 2.
Raises:

ValueError – If base is not 10 nor 2 raises value error.
Returns:

The band number from center.
Return type:

int
ossom.utils.freq.fractional_octave_frequencies(nthOct: int = 3, freqRange: Tuple[float] = (20.0, 20000.0), refFreq: float = 1000.0, base: int = 10) → numpy.ndarray[source]

Lower, center and upper frequency values of all bands within range.

Parameters:
  • nthOct (int, optional) – bands of octave/nthOct. The default is 3.
  • freqRange (Tuple[float], optional) – frequency range. These frequencies are inside the lower and higher band, respectively. The default is (20., 20000.).
  • refFreq (float, optional) – Center frequency of center band. The default is 1000..
  • base (int, optional) – Either 10 or 2. The default is 10.
Returns:

freqs – Array with shape (N, 3).
Return type:

numpy.ndarray
ossom.utils.freq.normalize_frequencies(freqs: numpy.ndarray, samplingRate: int = 44100) → numpy.ndarray[source]

Normalize frequencies for any sampling rate.

Parameters:
  • freqs (np.ndarray) – DESCRIPTION.
  • samplingRate (int, optional) – DESCRIPTION. The default is 44100.
Returns:

DESCRIPTION.
Return type:

TYPE
ossom.utils.freq.freqs_to_center_and_edges(freqs: numpy.ndarray) → Tuple[numpy.ndarray][source]

Separate the array returned from fractional_octave_frequencies.

The returned arrays corresponde to the center and edge frequencies of the fractional octave bands

Parameters:freqs (np.ndarray) – Array returned from fractional_octave_frequencies.
Returns:
  • center (np.ndarray) – Center frequencies of the bands.
  • edges (np.ndarray) – Edge frequencies (lower and upper) of the bands.