Page 1 of 2

Red Pitaya: Open instruments for everyone

PostPosted: Thu Sep 19, 2013 1:48 pm
by TrikingSheep
Hi Guys,

There's a new board comming to fruition on kick-starter:

http://www.kickstarter.com/projects/652 ... r-everyone

It would be great if this board and Parallella could be connected together.



Kind Regards,


Julian.

Re: Red Pitaya: Open instruments for everyone

PostPosted: Thu Sep 19, 2013 3:07 pm
by tnt
Well you can connect them via ethernet or USB.

Other than that, you might as well just make a front-end board for the parallella directly with the same ADC / DAC.

Re: Red Pitaya: Open instruments for everyone

PostPosted: Thu Sep 19, 2013 4:10 pm
by ysapir
The Pitaya is powered by Zynq - why not use the Parallella's Zynq for the same purpose? Just add the ADC/DAC hardware and you should have something similar.

Much like what @tnt says...

Re: Red Pitaya: Open instruments for everyone

PostPosted: Thu Sep 19, 2013 4:13 pm
by ysapir
Question to those who are familiar with the measurement equipment area and practice - the Pitaya's bandwidth is ~60MHz. How useful is this band for modern electronics circuitry? What would be the price of a commercial scope that supports those freq.s?

Re: Red Pitaya: Open instruments for everyone

PostPosted: Thu Sep 19, 2013 5:10 pm
by tnt
It's not really useful for anything modern. You may have a 60 MHz nyquist bandwidth but you often want 10 or even 20 times more samples than bandwidth in scope so you'd have like 10-20 MHz here or so.

A cheap low end (like 300$) scope is going to be 60 MHz (or even 100 MHz) dual channel with 1 Gsps.
With the lack of a schematic, it's hard to say for sure, but the red pitaya also lacks the various programmable gain and filtering stages of a classic scope front end.

On the other end, it does have a 14 bits resoltion compared to the classic 8 bits of scopes so for some applications, it can be very useful.

The other aspect is of course the presence of DAC to implement siggen on the same board.

And finally the openness of the platform ...

What I find weird though is that their stretch goal for 150k is 4Go of RAM ... how exactly are they planning on doing that on the zynq ...

Re: Red Pitaya: Open instruments for everyone

PostPosted: Thu Sep 19, 2013 10:57 pm
by ticso
Ich lese das als 4Gbit, also nur 512MByte.

Re: Red Pitaya: Open instruments for everyone

PostPosted: Fri Sep 20, 2013 3:22 am
by hochopeper
Interesting

I am planning on something similar but was thinking I'd use either the 2.5 or 5MSPS 18bit SAR ADCs from ADI because I'm looking at up to 1MHz but might want to expand that to 2MHz later (the 5MSPS part didn't exist when I first started daydreaming about that). I want to get higher resolution hence the 18bit parts. Will keep an eye on this project for sure though.

I'm with TNT, use ethernet to connect the two together if you had both but ideally you'd make a sub-board for the parallella to hold the ADC/DAC parts and use the samtech connector to hook it up, which is what I had in mind but for different target bandwidth and bit depth.

Re: Red Pitaya: Open instruments for everyone

PostPosted: Fri Sep 20, 2013 3:36 am
by ticso
Sorry for writing german - was talking with someone earlier in german and failed to switch languages.
But I assume it was still obvious what I mean.

Re: Red Pitaya: Open instruments for everyone

PostPosted: Fri Sep 20, 2013 6:21 am
by tnt
I thought about The Gbits vs Gbytes but if that's the case, that's rather deceiving ... Nobody commonly expresses RAM size in bits when speaking about the specs of a board like this.

Re: Red Pitaya: Open instruments for everyone

PostPosted: Sat Sep 21, 2013 1:05 pm
by theover
Hi,hi,hi 14 bits 125MS/s AD converter ?! Gmmpf, that will be one first class circuit bard design, maybe to be surrounded in a centimeter solid copper, and with special cables and stuff. Sure, the manufacturer of the AD chio specifies what it *ca* do, but will the supplies on the board and the pulses generated by the zinq chip allow these specs to become practically true ? Put an Agilent or other real measument instrument on it, and try, I'd bet a dear amount on it the actual specs of the board are way lower.

T.