Forums

Announcing ScopeIIR 5.0

Started by Grant Griffin July 20, 2010
Hi All,

This is to announce the release of ScopeIIR 5.0, which is a 
comprehensive Windows tool for designing and analyzing Infinite Impulse 
Response (IIR) filters.  The Trial Edition is free for 30 days.

ScopeIIR designs high-order IIR filters based on Butterworth, Chebyshev, 
and Elliptic prototypes. It designs lowpass, highpass, bandpass, and 
bandstop filters.

ScopeIIR provides a comprehensive set of plots including magnitude, 
phase, unwrapped phase, group delay, phase delay, impulse response, step 
response, and poles/zeros. The pole-zero plot features a powerful 
capability for customizing your design by directly manipulating 
pole/zero locations via the mouse or keyboard; The IIR frequency and 
time response plots are instantly updated as you move them, so if you're 
still a little fuzzy about what poles and zeros really do, ScopeIIR can 
be a great interactive learning tool!

ScopeIIR provides a comprehensive set of data displays and outputs, 
including biquad coefficients, direct form coefficients, poles and zero 
locations, design specifications, impulse response, and step response. 
Biquads are optimized to minimize numerical effects and maximize 
stability.  Data outputs are in your choice of plain text, C, C++, or 
Matlab formats.

ScopeIIR greatly simplifies the process of implementing IIR filters by 
providing comprehensive example implementations in both C and C++. You 
can implement your own IIR filter design in a matter of seconds simply 
by changing the specifications of the example design files and recompiling!

ScopeIIR Links:
- Product information: http://www.iowegian.com/scopeiir
- Screen shot: http://www.iowegian.com/iir/img/ScopeIIR_screenshot.png
- Download: http://www.iowegian.com/download
- Purchase: http://www.iowegian.com/purchase

thanks,

Grant

_____________________________________________________________________

Grant R. Griffin
Publisher of dspGuru                          http://www.dspguru.com
Iowegian International Corporation            http://www.iowegian.com
See http://www.iowegian.com/img/contact.gif for e-mail address
On 7/20/2010 9:05 AM, Grant Griffin wrote:
> Hi All, > > This is to announce the release of ScopeIIR 5.0, which is a > comprehensive Windows tool for designing and analyzing Infinite Impulse > Response (IIR) filters. The Trial Edition is free for 30 days.
...
> Grant R. Griffin > Publisher of dspGuru http://www.dspguru.com > Iowegian International Corporation http://www.iowegian.com > See http://www.iowegian.com/img/contact.gif for e-mail address
Congratulations! Jerry -- Engineering is the art of making what you want from things you can get. �����������������������������������������������������������������������
Grant, it's not clear from the description whether this produces continuous time
or discrete time filters.  If discrete time, by what approximation method do you
convert them from their continuous time prototypes?

Greg
On Tue, 20 Jul 2010 10:25:34 -0400, Greg Berchin <gberchin@comicast.net.invalid>
wrote:

>Grant, it's not clear from the description whether this produces continuous time >or discrete time filters.
Never mind. Once I read down to the part about "biquads", the ambiguity disappeared. Greg
On 7/20/2010 6:05 AM, Grant Griffin wrote:
> Hi All, > > This is to announce the release of ScopeIIR 5.0, which is a > comprehensive Windows tool for designing and analyzing Infinite Impulse > Response (IIR) filters. The Trial Edition is free for 30 days. > > ScopeIIR designs high-order IIR filters based on Butterworth, Chebyshev, > and Elliptic prototypes. It designs lowpass, highpass, bandpass, and > bandstop filters. >
Hi; How does it compare to Matlab fdatool? do you have a chart comparison? I am asking, because I have matlab student version, and fdatool comes bundled with it. http://www.mathworks.com/products/signal/demos.html?file=/products/demos/shipping/signal/introfdatooldemo.html I am also writing my own small IIR program in Mathematica (only butterworth so far), for learning digital filters, and could also use your program to double verify my results. I now use fdatool to verify my result. Main problems I see now is in numerical problems when the filter order gets too large. Matlab uses state space approach to convert analog to digital, I think they do this for better numerical stability. thanks --Nasser
On Jul 20, 10:30&#2013266080;am, Greg Berchin <gberc...@comicast.net.invalid>
wrote:
> On Tue, 20 Jul 2010 10:25:34 -0400, Greg Berchin <gberc...@comicast.net.invalid> > wrote: > > >Grant, it's not clear from the description whether this produces continuous time > >or discrete time filters. &#2013266080; > > Never mind. &#2013266080;Once I read down to the part about "biquads", the ambiguity > disappeared.
the question remains with me. it seems likely that Grant is using Bilinear Transform (with prewarped corner frequency placement) because that will retain the equal ripples of the Butterworth, Chebyshev, or Elliptic analog prototypes (just bump the frequency locations of the ripples slightly). but he could be using Impulse Invariant. or something else? any of those methods can be factored into biquads. Grant, do you mind telling us? and what does the "Adjust for Ripple" check-box option do? does it adjust the DC gain in the case where the bottom of the ripple is on DC (i can't remember if that is for even or odd order)? just curious. looks like a useful little addition to scopeFIR for PCers. probably won't run too good on my Mac. r b-j
robert bristow-johnson wrote:
> On Jul 20, 10:30 am, Greg Berchin <gberc...@comicast.net.invalid> > wrote: >> On Tue, 20 Jul 2010 10:25:34 -0400, Greg Berchin <gberc...@comicast.net.invalid> >> wrote: >> >>> Grant, it's not clear from the description whether this produces continuous time >>> or discrete time filters. >> Never mind. Once I read down to the part about "biquads", the ambiguity >> disappeared. > > the question remains with me. it seems likely that Grant is using > Bilinear Transform (with prewarped corner frequency placement) because > that will retain the equal ripples of the Butterworth, Chebyshev, or > Elliptic analog prototypes (just bump the frequency locations of the > ripples slightly). but he could be using Impulse Invariant. or > something else?
Hi r, You're right that ScopeIIR uses the bilinear transform with pre-warping. As best I can tell, that seems to be the preferred method for basic IIR design - I'm not aware that any other methods offer any significant advantages
> any of those methods can be factored into biquads. Grant, do you mind > telling us? and what does the "Adjust for Ripple" check-box option > do? does it adjust the DC gain in the case where the bottom of the > ripple is on DC (i can't remember if that is for even or odd order)?
Right again - it just automatically boosts the gain to center the ripple on zero.
> just curious. looks like a useful little addition to scopeFIR for > PCers. probably won't run too good on my Mac.
I dunno...if you've got an x86 Mac, you could probably run Linux and Wine. My other products run just fine on Wine, though I haven't checked ScopeIIR for that yet. (If anybody out there in comp.dsp land wants to do that for me, I'd be eternally grateful.) Grant -- _____________________________________________________________________ Grant R. Griffin Publisher of dspGuru http://www.dspguru.com Iowegian International Corporation http://www.iowegian.com See http://www.iowegian.com/img/contact.gif for e-mail address
Nasser M. Abbasi wrote:
> On 7/20/2010 6:05 AM, Grant Griffin wrote: >> Hi All, >> >> This is to announce the release of ScopeIIR 5.0, which is a >> comprehensive Windows tool for designing and analyzing Infinite Impulse >> Response (IIR) filters. The Trial Edition is free for 30 days. >> >> ScopeIIR designs high-order IIR filters based on Butterworth, Chebyshev, >> and Elliptic prototypes. It designs lowpass, highpass, bandpass, and >> bandstop filters. >> > > Hi; > > How does it compare to Matlab fdatool? do you have a chart comparison?
I don't have anything like a comparison chart but maybe I should - thanks for the idea! I created ScopeIIR completely independently of fdatool, but I tried fdatool out yesterday and I was surprised to find that its IIR filter design capability is actually fairly similar to ScopeIIR's at a basic level. However, there's a _big_ difference in terms of usability. fdatool seems to be an answer to the question, "What filter design program can we build with Matlab's filter design scripting capability and Matlab's GUI capability?" Since Matlab's GUI capability is pretty primitive, the result is pretty primitive, even though Matlab's filter design capability is pretty sophisticated. ScopeIIR takes the opposite approach: given the full-capability GUI system provided by C++ with MFC, what can be done to make IIR filter design as easy and productive as possible? For example, ScopeIIR provides a six-panel interface for showing plots and data. Each pane can be assigned to any plot or data display, and it can also create an unlimited number of external windows for additional displays. In comparison, as best I can tell, fdatool has only two display areas: it can show only a single response plot, and has another area that can be either design specifications or a pole-zero plot. (It wastes a _lot_ of precious screen space.) So, it can't even display a phase and magnitude plot at the same time. ScopeIIR (and my other products) all provide a sophisticated, multi-level, mouse-wheel-controlled zooming capability. In contrast, fdatool (and Matlab's other products) provide a clunky system of zooming based on hitting zoom-in and zoom-out buttons. This may seem like a small point, but it's critical to your productivity, since zooming is a primary activity during filter design. (Matlab's zooming drives me crazy whenever I have to suffer with it.) ScopeIIR also comes with ready-made IIR implementation examples in C and C++, whereas fdatool lets you roll your own. (The Matlab folks are primarily in the business of selling Matlab, not C and C++.) So, although fdatool is undeniably useful, it's really more of a demo than something you'd want to use interactively on a daily basis. My guess is that most folks use it for some quick experiments or simple filter design jobs, then do Matlab scripting for more complicated filter designs - or to see phase and magnitude plots at the same time.
> > I am asking, because I have matlab student version, and fdatool comes > bundled with it.
I'm gonna resist the urge to point out that you get what you pay for. :-)
> > http://www.mathworks.com/products/signal/demos.html?file=/products/demos/shipping/signal/introfdatooldemo.html > > > I am also writing my own small IIR program in Mathematica (only > butterworth so far), for learning digital filters, and could also use > your program to double verify my results. > > I now use fdatool to verify my result. Main problems I see now is in > numerical problems when the filter order gets too large. Matlab uses > state space approach to convert analog to digital, I think they do this > for better numerical stability.
ScopeIIR doesn't use state-space, it just uses the pole-zero centric approach described in most DSP textbooks. It's hard to generalize regarding design of large filters, but you can just try ScopeIIR on your specific problem and see how it goes. (The Trial Edition will design high-order filters, though it won't export their coefficients - I've discovered that most users won't pay unless you make them.) In my experience, though, ScopeIIR can design much higher-order filters than one would generally ever use in practice.
> > thanks > --Nasser
Thanks for some interesting questions, Nasser! Grant -- _____________________________________________________________________ Grant R. Griffin Publisher of dspGuru http://www.dspguru.com Iowegian International Corporation http://www.iowegian.com See http://www.iowegian.com/img/contact.gif for e-mail address
On 7/21/2010 8:16 AM, Grant Griffin wrote:
> robert bristow-johnson wrote:
...
>> does it adjust the DC gain in the case where the bottom of the >> ripple is on DC (i can't remember if that is for even or odd order)? > > Right again - it just automatically boosts the gain to center the ripple > on zero.
As far as I know, that's an unusual choice. Making the peak gain unity tends to avoid hidden gotchas. ... Jerry -- Engineering is the art of making what you want from things you can get. &#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;
On Wed, 21 Jul 2010 07:16:52 -0500, Grant Griffin <nobody@example.com>
wrote:

>I dunno...if you've got an x86 Mac, you could probably run Linux and >Wine. My other products run just fine on Wine, though I haven't checked >ScopeIIR for that yet. (If anybody out there in comp.dsp land wants to >do that for me, I'd be eternally grateful.)
Took a quick look at it under openSUSE 11.2 and Wine 1.1.28. After figuring out the magic words necessary to run an install via an .msi file (turns out to be easy if one knows the right magic), it installed okay and runs mostly well. I only looked at the four projects in the example directory: ChebychevLowpass4.sip caused an exception that put up Wine's Something Bad Happened dialog box and terminated the app. The other three all seemed to execute/behave properly. I did note that there's a new stable Wine release out, as of a week or so ago. Haven't picked it up yet. -- Rich Webb Norfolk, VA