On Feb 25, 2012, at 10:31 AM, Robert T. Short wrote: > On 02/24/2012 01:25 AM, Jerry wrote: >> I am an occasional user of Octave but yet it is an essential part of my work. >> >> I have investigated using some features in the Signal package and am either >> badly ignorant of what is supposed to happen or there are some major >> problems with it. A casual perusal of the functions included in the Signal >> documentation at http://octave.sourceforge.net/signal/overview.html >> indicates that there are supposed to be functions remez, qp_kaiser, cl2bp, >> and sosfilt, yet all of these seem to be missing. And I really need remez >> and I think really need qp_kaiser. >> >> Further, the documentation for qp_kaiser is woefully lacking, not even >> providing the form of the returned result and including an argument "linear" >> which is not explained and not mentioned. When I try to run the function >> with "linear" as an argument I get an error, "error: `linear' undefined near >> line 1 column 21". There is no example and no reference. >> >> The documentation for remez mentions band edges [ b1 e1 b2 e2 b3 e3 ...] but >> doesn't explain what these quantities mean. (Normally the edge of pass bands >> and stop bands are specified but these bs and es don't make sense in that >> conventional way and the notation is not enlightening.) >> >> Is the Signal package actively maintained? Where are the missing pieces >> (assuming that they are missing and I'm not broken.) How can I find better >> documentation? >> >> This experience today is after my initial attempt to use filter (not part of >> Signal) which gave me an unstable output even which I gave it stable poles >> and the function zp2sos returning an incorrect gain factor. >> >> Please consider these comments as constructive criticism / bug reports but >> please also consider my frustration in the event that any of this seems >> impolite. >> >> My installed version of Signal is 1.1.1 and my version of Octave is 3.4.0. >> My OS is OS X 10.6.8. >> >> Thanks, >> Jerry >> >> P.S. Every time I launch Octave I get the following warning: >> warning: function /bla/bla/specfun-1.0.9/erfcx.m shadows a built-in function >> I have specfun-1.0.9 installed. >> ------------------------------------------------------------------------------ >> Virtualization& Cloud Management Using Capacity Planning >> Cloud computing makes use of virtualization - but cloud computing >> also focuses on allowing computing to be delivered as a service. >> http://www.accelacomm.com/jaw/sfnl/114/51521223/ >> _______________________________________________ >> Octave-dev mailing list >> Octave-dev@lists.sourceforge.net >> https://lists.sourceforge.net/lists/listinfo/octave-dev >> >> > You should be aware that there is a lot of excellent code in > octave-forge project there is also a lot of stuff that really doesn't > work. The remez function in particular hasn't worked in a long time (if > ever). I have a hard time believing that filter has a problem though.
This was discussed on this list January 11-13, 2012. ***If*** filter is implemented in an unfactored direct form, then this is a problem. Higher-order direct form implementations (and "higher-order" doesn't have to be all that high for high-Q poles) are notoriously sensitive and most textbooks recommend against this. Jerry > > All of the code in octave and octave forge is created by folks just like > yourself. If there is a problem, just dive in and fix it. > > Bob > ------------------------------------------------------------------------------ Keep Your Developer Skills Current with LearnDevNow! The most comprehensive online learning library for Microsoft developers is just $99.99! Visual Studio, SharePoint, SQL - plus HTML5, CSS3, MVC3, Metro Style Apps, more. Free future releases when you subscribe now! http://p.sf.net/sfu/learndevnow-d2d _______________________________________________ Octave-dev mailing list Octave-dev@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/octave-dev
