Stft

class ansys.sound.core.spectrogram_processing.Stft(signal=None, fft_size=2048, window_type='HANN', window_overlap=0.5)

Compute the short-time Fourier transform (STFT) of a signal.

See also

Istft, PowerSpectralDensity

Examples

Compute the STFT of a signal, and display the resulting spectrogram in a colormap.

>>> from ansys.sound.core.spectrogram_processing import Stft
>>> stft = Stft(signal=signal)
>>> stft.process()
>>> spectrogram = stft.get_output()
>>> stft.plot()

See also

Spectrogram: compute the STFT and ISTFT

Example demonstrating how to compute the STFT and ISTFT.

Class instantiation takes the following parameters.

Parameters:

signalField, default: None

Input signal on which to compute the STFT.

fft_sizeint, default: 2048

Size of the FFT to compute the STFT. Use a power of 2 for better performance.

window_typestr, default: ‘HANN’

Window type used for the FFT computation. Options are 'TRIANGULAR', 'BLACKMAN', 'BLACKMANHARRIS', 'HAMMING', 'HANN', 'GAUSS', 'FLATTOP', 'RECTANGULAR', and 'BARTLETT'.

window_overlapfloat, default: 0.5

Overlap value between two successive FFT computations. Values can range from 0 to 1. For example, 0 means no overlap, and 0.5 means 50% overlap.

Methods

Stft.get_frequencies()	Get the frequency scale of the STFT magnitude and phase.
Stft.get_magnitude()	Get the magnitude of the STFT.
Stft.get_output()	Get the STFT of the signal as a DPF fields container.
Stft.get_output_as_nparray()	Get the STFT of the signal as a tuple of NumPy arrays.
Stft.get_phase()	Get the phase of the STFT.
Stft.get_time_scale()	Get the time scale of the STFT.
Stft.plot()	Plot the STFT.
Stft.plot_custom([display_phase, ...])	Plot the STFT with custom display settings.
Stft.process()	Compute the STFT.

Attributes

Stft.fft_size	Number of FFT points.
Stft.signal	Input signal as a DPF field.
Stft.window_overlap	Window overlap in %.
Stft.window_type	Window type.