I tried to explore the changes to the frequency response of simple passive RC low pass filters when a second and third cascaded filter section is added. Unexpectedly, the phase response of the 3rd order filter shows a "jump" in the output. Why is this? NB: Please ignore the OpAmp in the circuit. |
by Dan.Ka
November 11, 2020 |
Perfectly normal. When the phase becomes far enough lagging it is leading |
by Foxx
November 11, 2020 |
So you are saying it's just the presentation style of CL's graphing engine. Fair enough. I prefer, however, the graphing engine to draw phases below - 180° in the negative axis region, as for example here: https://www.multisim.com/content/nDvUVFQCHVPrhDZSDeYmMU/third-order-rc-low-pass-filter/ |
by Dan.Ka
November 11, 2020 |
Yes it's CL's presentation. I have no problem with it once I figured it out |
by Foxx
November 12, 2020 |
@Dan.Ka This has been fixed now. See blog post: Complex Numbers, Math.atan2, and Phase Unwrapping |
ACCEPTED
+2 votes by mrobbins November 30, 2020 |
Thanks. Looks much better now in my opinion. |
by Dan.Ka
December 01, 2020 |
And additionally a great blog positing explaining this change. Perfect! |
by Dan.Ka
December 01, 2020 |
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