# All-pass filter implementation in numpy

I'm playing with Python & numpy to filter audio. It is relatively straightforward to design and us low-high-bandpass/stop FIR and IIR filters, stuff can be done in a couple of lines.

I'm implementing a small software defined radio software, and I need an all-pass filter that has 90 degrees phase shift everywhere, and is flat (as much as possible).

Unfortunately I was unable to find any quick solution for this.

Thank you,

Tamás.

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Welcome to DSP.stackexchange. This site can help you if you need to answer a question of how or why something works, or do not understand a concept, help you devise an algorithm from the domain if signal processing. What you're looking for is more programming - maybe you should flag your own question and request it be moved to stackoverflow.com , it might be more suitable there. Also, try providing the information about what you have tried and which precise part gives you problems. – penelope Jan 14 '13 at 9:43
Ok, thank you very much! – netom Jan 14 '13 at 12:20

Note that hilbert actually computes the analytic signal, you have to take the imaginary part to get the actual hilbert transform. This is copied from Matlab – endolith Mar 26 '14 at 16:28