scipy.signal.ShortTimeFFT.from_window#

classmethod ShortTimeFFT.from_window(win_param, fs, nperseg, noverlap, *, symmetric_win=False, fft_mode='onesided', mfft=None, scale_to=None, phase_shift=0)[source]#

Instantiate ShortTimeFFT by using get_window.

The method get_window is used to create a window of length nperseg. The parameter names noverlap, and nperseg are used here, since they more inline with other classical STFT libraries.

Parameters:

win_param: Union[str, tuple, float],: Parameters passed to get_window. For windows with no parameters, it may be a string (e.g., 'hann'), for parametrized windows a tuple, (e.g., ('gaussian', 2.)) or a single float specifying the shape parameter of a kaiser window (i.e. 4. and ('kaiser', 4.) are equal. See get_window for more details.
fsfloat: Sampling frequency of input signal. Its relation to the sampling interval T is T = 1 / fs.
nperseg: int: Window length in samples, which corresponds to the m_num.
noverlap: int: Window overlap in samples. It relates to the hop increment by hop = npsereg - noverlap.
symmetric_win: bool: If True then a symmetric window is generated, else a periodic window is generated (default). Though symmetric windows seem for most applications to be more sensible, the default of a periodic windows was chosen to correspond to the default of get_window.
fft_mode‘twosided’, ‘centered’, ‘onesided’, ‘onesided2X’: Mode of FFT to be used (default ‘onesided’). See property fft_mode for details.
mfft: int | None: Length of the FFT used, if a zero padded FFT is desired. If None (default), the length of the window win is used.
scale_to‘magnitude’, ‘psd’ | None: If not None (default) the window function is scaled, so each STFT column represents either a ‘magnitude’ or a power spectral density (‘psd’) spectrum. This parameter sets the property scaling to the same value. See method scale_to for details.
phase_shiftint | None: If set, add a linear phase phase_shift / mfft * f to each frequency f. The default value 0 ensures that there is no phase shift on the zeroth slice (in which t=0 is centered). See property phase_shift for more details.

See also

scipy.signal.get_window: Return a window of a given length and type.
from_dual: Create instance using dual window.
ShortTimeFFT: Create instance using standard initializer.

Examples

The following instances SFT0 and SFT1 are equivalent:

>>> from scipy.signal import ShortTimeFFT, get_window
>>> nperseg = 9  # window length
>>> w = get_window(('gaussian', 2.), nperseg)
>>> fs = 128  # sampling frequency
>>> hop = 3  # increment of STFT time slice
>>> SFT0 = ShortTimeFFT(w, hop, fs=fs)
>>> SFT1 = ShortTimeFFT.from_window(('gaussian', 2.), fs, nperseg,
...                                 noverlap=nperseg-hop)