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
ShortTimeFFTby usingget_window.The method
get_windowis 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. Seeget_windowfor more details.- fsfloat
Sampling frequency of input signal. Its relation to the sampling interval
TisT = 1 / fs.- nperseg: int
Window length in samples, which corresponds to the
m_num.- noverlap: int
Window overlap in samples. It relates to the
hopincrement byhop = npsereg - noverlap.- symmetric_win: bool
If
Truethen 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 ofget_window.- fft_mode‘twosided’, ‘centered’, ‘onesided’, ‘onesided2X’
Mode of FFT to be used (default ‘onesided’). See property
fft_modefor details.- mfft: int | None
Length of the FFT used, if a zero padded FFT is desired. If
None(default), the length of the windowwinis 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 propertyscalingto the same value. See methodscale_tofor details.- phase_shiftint | None
If set, add a linear phase
phase_shift/mfft*fto each frequencyf. The default value 0 ensures that there is no phase shift on the zeroth slice (in which t=0 is centered). See propertyphase_shiftfor more details.
See also
scipy.signal.get_windowReturn a window of a given length and type.
from_dualCreate instance using dual window.
ShortTimeFFTCreate instance using standard initializer.
Examples
The following instances
SFT0andSFT1are 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)