[sdiy] More Xilinx 3E board comments

[Magnus Danielson]

From: James Patchell <patchell at cox.net>
Subject: Re: [sdiy] More Xilinx 3E board comments
Date: Thu, 08 Jun 2006 12:36:27 -0700
Message-ID: <5.2.1.1.2.20060608122823.01807ba0 at pop.west.cox.net>

James,

> Yes!....and more....
> 
> For instance...You could easily build up a bank of 512 NCO sawtooth 
> oscilators...and it would barely be a hicup...with a sample rate of 
> 97656.25hz @ clk=50MHz...
> 
> why 512 oscillators?....because the RAM blocks can be configured as 512wx32b
> 
> You would need two banks of these to make an NCO...one for the frequency 
> control, and the second for the accumulators...
> 
> You then just need a 32 bit adder...and there you go....

Actually, you could go 36 bit for free, since those blockrams is really 36 bit
x 512. Running a 36-bit DDS at 50 MHz is trivial. However, you really consume
2 blockrams if you want to go to 512 oscillators. You need to store the
increments somewhere. Still, keeping down at 50 MHz makes is yawn.

> Sampler...the thing has 32MB of ram on board...and 16MB of flash rom....

Handy.

> filters...4 ram banks and you would have 512 biquad filters...(Frequency, 
> Q, Z1,Z2) (well, I hope 4 ram banks would do it :-)

Should work. However, I bet you end up wanting to mix between the outputs, so
at least one blockram more.

> .....
> 
> It only takes TIME!

These things doesn't take much time. They are pretty quickly done.

Cheers,
Magnus