Re: Beagle Board Performance
Then you are not taking the problem from the right perspective...
First, you have to know the bandwidth you need for your application ( mainly "fmax"). This will define your sampling rate.
Then, you have to set your decimation factor depending on the amount of data resulting from the previous choice. On a "fast" pc running Linux, an avg around 30 msps can be achieved. Not tested with Beagleboard yet.
Then.... processing : you need to have one thread reading the USB stream from the USRP and filling a buffer. you need a second thread performing the fft and doing the decision.
the good question now is : what is the frequency resolution you need ( this will set the fft size .... and time needed to compute that).
I would suggest you start by estimating FFT size, then evaluate the time you have to compute that.
But maybe I am completely wrong and in fact you do not need real time processing... ????
2010/6/21 devin kelly <dwwkelly-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Sorry for not being clear. I was just trying to say that, the higher the decimation rate the more data I have to process, I wasn't talking about decimating twice.
So would I'd like to do is record samples for 0.5 to 0.75 seconds (for example), then do some processing on those samples for the remaining, 0.25 to 0.5 seconds, and repeat. The processing I'm thinking of is taking an FFT, making a decision, then recording it to non-volatile storage. So my question is, to do processing like I described, what sort of decimation rates can I choose?
On Mon, Jun 21, 2010 at 9:01 AM, devin kelly <dwwkelly-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
What about a more reasonable decimation rate, like 32 or 64... Could I collect samples 50%-75% of the time and then process that data the rest of the time?
On Fri, Jun 18, 2010 at 10:09 AM, devin kelly <dwwkelly-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
I'm interested in doing a project with the Beagle Board and the USRP1, along with using gnu radio. My lab doesn't have a Beagle Board or USRP1 (only USRP2s), so I need a few questions answered before I commit to this platform.
What type of performance can I expect from the Beagle Board? I'm mostly interested in doing FFTs with some comparatively small processing on that data, is this possible?
What sort of decimation rates can I use and expect near real time performance for this application? I have a few (albeit several years old) machines that struggle with just taking an FFT with a decimation rate of around 8. This is on the USRP2 as well.
Any advice at all is appreciated.