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scipy tutorial - Baustatik-Info-Server

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Notes<br />

Number of Fourier components. Default: x.shape[axis]<br />

axis : int, optional<br />

Returns<br />

xa : ndarray<br />

Analytic signal of x, of each 1d array along axis<br />

The analytic signal x_a(t) of x(t) is:<br />

x_a = F^{-1}(F(x) 2U) = x + i y<br />

SciPy Reference Guide, Release 0.8.dev<br />

where F is the Fourier transform, U the unit step function, and y the Hilbert transform of x. [1]<br />

changes in <strong>scipy</strong> 0.8.0: new axis argument, new default axis=-1<br />

References<br />

[R5]<br />

get_window(window, Nx, fftbins=1)<br />

Return a window of length Nx and type window.<br />

If fftbins is 1, create a “periodic” window ready to use with ifftshift and be multiplied by the result of an fft<br />

(SEE ALSO fftfreq).<br />

Window types: boxcar, triang, blackman, hamming, hanning, bartlett,<br />

parzen, bohman, blackmanharris, nuttall, barthann, kaiser (needs beta), gaussian (needs std), general_gaussian<br />

(needs power, width), slepian (needs width)<br />

If the window requires no parameters, then it can be a string. If the window requires parameters, the window<br />

argument should be a tuple<br />

with the first argument the string name of the window, and the next arguments the needed parameters.<br />

If window is a floating point number, it is interpreted as the beta<br />

parameter of the kaiser window.<br />

detrend(data, axis=-1, type=’linear’, bp=0)<br />

Remove linear trend along axis from data.<br />

If type is ‘constant’ then remove mean only.<br />

If bp is given, then it is a sequence of points at which to<br />

break a piecewise-linear fit to the data.<br />

resample(x, num, t=None, axis=0, window=None)<br />

Resample to num samples using Fourier method along the given axis.<br />

The resampled signal starts at the same value of x but is sampled with a spacing of len(x) / num * (spacing of<br />

x). Because a Fourier method is used, the signal is assumed periodic.<br />

Window controls a Fourier-domain window that tapers the Fourier spectrum before zero-padding to alleviate<br />

ringing in the resampled values for sampled signals you didn’t intend to be interpreted as band-limited.<br />

If window is a function, then it is called with a vector of inputs indicating the frequency bins (i.e. fftfreq(x.shape[axis])<br />

)<br />

3.13. Signal processing (<strong>scipy</strong>.signal) 333

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