Hi Peter - I believe the graphs are showing phase delay, which people often graph because it's positive. But you're right that the phase response, if measured as (phase out) - (phase in), is negative. I think this is probably best fixed by fixing the example to say that it's showing phase delay, not phase response, or equivalently, saying it's -arg(H) instead of arg(H)... this is probably also wrong in the book. I'd better go look when I have a moment...
thanks Miller On Thu, Feb 13, 2014 at 11:35:20PM +0100, Peter P. wrote: > Hi list, > > just wondering if I am getting something wrong plotting the phase > response of lop~ using the abstractions filter-graph1.pd and > filter-graph2.pd as exemplified in 3.audio.examples/H10.measurement.pd > > For a simple one-zero lowpass filter using [rzero~ -1] the phase > response is plotted going from 0 to pi/2 (eg. 90°) at nyquist > frequency. > I always thought that it would be 0^ to -90° though. > > Also a highpass [rzero~ 1] filter's phase is plotted as > going from -90° to 0° instead of the 90° to 0° I know from some > textbooks. > > Is there a mistake I could have had made? I mean, things sound > alright, but I am just wondering. > > best, > P > > _______________________________________________ > [email protected] mailing list > UNSUBSCRIBE and account-management -> > http://lists.puredata.info/listinfo/pd-list _______________________________________________ [email protected] mailing list UNSUBSCRIBE and account-management -> http://lists.puredata.info/listinfo/pd-list
