[SciPy-user] Lowpass Filter
Thu Feb 5 11:49:02 CST 2009
On 2/5/2009 6:17 PM, Marco wrote:
> How do I apply a low pass filter (with selected frequency and width)
> to this signal?
What kind of lowpass filter?
Single-pole? Butterworth? Bessel? Gaussian? Cheychev? Elliptic?
Truncated sinc with window? What kind of window?
- First obtain your filter coefficients. Filter design is an extensive
subject; I cannot cover it here. Consult a text book.
- Short FIR or IIR: apply filter to signal with scipy.signal.lfilter.
- Long FIR: use numpy.fft.rfft for convolution in the Fourier plane.
(You will get faster results with FFTW instead of NumPy's FFT.)
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