Fast Slope HPF Filter

[stw]

If you don't want to install stuff on your PC then you can access Octave online via browser interface here. Apparently the relevant packages are already loaded.

Hey cool, haven't seen that before

[Rocko]

So, I reckon 'octave' is a recommended platform for filter/audio playing-around, similar to matlab but free??

[martinvicanek]

Sort of, yes. I have no access to Matlab though. If you google you will find pros and cons for both Matlab and Octave. Matlab is probably too expensive to buy just for entertainment, but if you have access to it the advantage it that there is vast material out there (like the DAFX book). Sharing code within academia is probably also easier with Matlab.

[Rocko]

Thanks.

In the module you had sent, cold I replace '2p2z' with a piece of my own logic?
Like I've done to comupte the Biquads for a second order IIR filter?
Can you suggest what mathemtical function does the 2p2z run?

Appreciated,
Rocko

[Rocko]

Let me calrify my last question.

Is the 2p2z (2pole 2zero) module in the fsm something of the shape:
Y[n]=a0*x[n]+a1*X[N-1]+a2*x[n-2]-b1*x[n-1]-b2*x[n-2]

?

[martinvicanek]

The 2p2z is a biquad prim. It implements the following recursion:

Code: Select all

y[n] = a0*x[n] + a1*x[n-1] + a2*x[n-2] - b1*y[n-1] - b2*y[n-2]

Note that often the a's and b's are defined the other way around. And yes, of course you can use your own biquad impementation instead.

[Rocko]

Believe it or not, I can still not run the CNX utility.

I had tried Firefox, Chrome and IE browsers and they inform me that an external plug in is needed to run it (except for IE which doesn't show me anything).
I do not know which plug-in is needed to run this. I guess some kind of flash ?

I tried to download the off-line version and failed as well.
'help' tabs send me to 'page unknown' in NI's web-site...

Can you tell me which browser are you using and what plug-in is used to run this utility?

Appreciated,
Rocko

[Rocko]

Could I ask you to send over a FSM example of an elliptical 4th order HPF with (-40 Db) stop band ripple, for me to play around in FS and try to correlate it to the 'Iowa hills' calculator ??

I hope this is not to much to ask.

Appreciated

[martinvicanek]

Yes, the cnx site requires you to install a plugin. I have done this a while ago so I don't remember the details, I am using Opera but any Java capable browser will do. If you can't make it work then try the Iowa Hills app. I did an example and it worked. Just remember to reorder the coefficients so they go into the right place.

Here is the example that you asked for. Hope that helps!

[tulamide]

Hey Rocko,

maybe this helps you? http://digital.ni.com/public.nsf/allkb/151BE12C055F57CE86257043006CB4B3