PlanetZ forums - scopeusers.com

hey you guys

can someone please upload a scheme of a filter made only with
add and multyply components ... Not an already build module

http://en.wikipedia.org/wiki/File:IIRFilter2.svg

i need to ilustrate a real dsp engine with the z transform
and make it work



i need your imidit help
thnx

This sounds like a homework problem. And you should read a bit more on IIR filters, because the picture you chose is a poor example...there are no coefficients to tweak (ie - no multiply or scaling!!)

Read this:
http://www.eas.uccs.edu/wickert/ece2610 ... _chap8.pdf

Then go to page 8-13. Then work you're way through the direct form I, into form II (reduced memory elements (Z^-1)), and finally a few pages later, the transposed Direct Form II (reduced summing points). Those diagrams are an exact layout of how you'd connect things in modular.

The only tips you need to do them are these:
Z^-1 == Feedback module (1 sample delay)
Multiply == VCA with constant used for coefficients.
Add == 2 input Mixer with both inputs set to 12 o'clock.

The other tick, is in calculating the coefficients a0, a1, b0, b1 and so on!

can i use the math moudules ???
add is add ...
etc,,,

sure, and there's other ways to do multiply. But I do think the feedback module is the guaranteed way to get 1 sample delay.

fir is more relevant ..

does the frequency changes through the coefficients ???

I made a few IRR filters. Even one with a complete matrix.
The FB module is needed but doesn't give you the 1-sample Delay.
You need the Flexor Sample Delay module for that.
On the other hand, the Flexor Sample Delay module can't be used as a feedback module.

the feedback IS a 1 sample delay_
good vibes

Thank you tgstgs .
That's why I mentioned the Flexor Sample Delay module in specific.
I was wondering why it cannot be used as a Feedback module.
Any ideas?

it is 1 object;
the algo checking to protect for recursion without delay doesnt know that it is a delay_
how could he;

good vibes

Ahhhh, that is really good to know, and I am glad (or lucky) not to have run into that problem!

Thanks!

heres a 1 tap sitting in PM // no feedback
im a feedforward freak you know
good vibes

with sdk look into the feedback modul to see how they fool their algo_

Happy feedfoward! Thanks!

With compliments to tgstgs modules:
A Schroeders All pass filter

Looks good Roland

Thanks Shark, but I have to test the mixers. In this case they must be linear.
Tomorrow an other day.

yes looks good roland