[SciPy-dev] bug in scipy.signal.waveforms

Austyn Bontrager austyn at getcontrol.com
Fri Apr 14 13:52:32 CDT 2006


Hi all

There is a bug in the chirp() routine in scipy.signal.waveforms.
chirp() generates a frequency-swept cosine waveform.

I filed a defect report in scipy trac:
http://projects.scipy.org/scipy/scipy/ticket/193

In summary, the waveform is currently generated as:
cos((frequency*time) + phi)

However, it should really be:
cos((integral of frequency over time) + phi)

There is also a bug regarding the phi parameter: It ought to be 
multiplied by 2*pi, but it's not.  I didn't test that at first, so 
ignore the first patch that I uploaded.

Austyn Bontrager




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