AnsweredAssumed Answered


Question asked by izhmel on May 1, 2016

Good day,

How can I use a potentiometer to control the Zoltzer  or the NF Filter in the sigmastudio ? , I want to use an external    potentiometer to make adjustments  to Gain , Frequency , Q using the auxiliary ADC GPIO



Thanks in advance

Comment Share

Show more

Actions Hide new activityMark unread

2 replies2 new updates





KJBob  (to Hopeton Brown) 3 weeks ago





     For GPIO control you would need filters with control input "pins."  Unfortunately, the only such filters presently available are the State-Variable filters, which are unsuitable for general EQ application.


     Up to now, SigmaStudio has not included external-control EQ filters because their bilinear coefficient calculations are rather complex to do at runtime inside the DSP.  However, the -1452 could change all this.  In fact, I just noticed in Beta version 3.12.4,  a  filter featuring runtime coefficient calculations!



     Since this is arguably the most difficult portion of the work needed for a General Second-Order filter with external inputs, perhaps such is on its way (of course I'm only speculating...).


     Yet this is still not what you're asking for (Zoltzer or NF filter).  Honestly I have no idea what these are.  Perhaps I could ask you what a Zoltzer filter is, and what advantages it might have over other filters.



     Best regards,




Helpful  YesNo Reply Actions

Hopeton Brown

Hopeton Brown  (to Hopeton Brown) 3 weeks ago

Look under custom algorithms./ second order