Timeline for Transfer functions for Scipy and Matlab's Butterworth filter don't seem to match theory
Current License: CC BY-SA 4.0
10 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Jun 20, 2021 at 15:14 | vote | accept | hugke729 | ||
| Jun 19, 2021 at 4:58 | answer | added | Juha P | timeline score: 2 | |
| Jun 19, 2021 at 4:10 | history | became hot network question | |||
| S Jun 18, 2021 at 23:36 | history | suggested | Envidia | CC BY-SA 4.0 |
Corrected exponent in magnitude response equation and reformatted fraction.
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| Jun 18, 2021 at 19:18 | review | Suggested edits | |||
| S Jun 18, 2021 at 23:36 | |||||
| Jun 18, 2021 at 18:45 | comment | added | hugke729 | A simpler corollary of @Hilmar's comment is that my discrepancy arose because the cut-off frequency was comparable to the Nyquist frequency (20 Hz vs 50 Hz). If I use a sampling frequency, say, 10 times larger, then the theory matches Matlab/Python result. | |
| Jun 18, 2021 at 18:07 | answer | added | Envidia | timeline score: 3 | |
| Jun 18, 2021 at 17:31 | comment | added | Hilmar | Bilinear warping of the frequency axis. The bilinear transform maps the imaginary axis of the s-plane onto the unit circle of z-plane. That means the digital frequency $\omega = \pi$ maps to the analog frequency of infinity, not $fs/2$. That's why the digital lowpass filter has $H_z(\pi) = 0$ and not $H_z(\pi) = H_s(fs/2)$ | |
| Jun 18, 2021 at 17:05 | review | First posts | |||
| Jun 19, 2021 at 13:13 | |||||
| Jun 18, 2021 at 16:59 | history | asked | hugke729 | CC BY-SA 4.0 |