from_window — SciPy v1.15.3 Manual (original) (raw)

scipy.signal.ShortTimeFFT.

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 byhop = 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 propertyscaling 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 propertyphase_shift for more details.

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)