hi tom, you might consider using the vegas mode 1 spectrometer design: 1024 channels, dual pol, 1.5 GHz bandwidth (3 Gsps), full stokes, roach I, 4 tap polyphase,
best wishes, dan On Wed, Aug 29, 2012 at 2:32 AM, Tom Kuiper <kui...@jpl.nasa.gov> wrote: > On 08/29/2012 02:30 AM, Jason Manley wrote: > >> If you take a look at the pocket correlator design (tutorial 4), you'll >> find that it does four inputs of 400MHz bandwidth (800Msps). I think it has >> 4-tap PFBs with 1024 channels by default, which fits into a ROACH-1. If you >> forfeit two of the inputs, you should be able to get at least twice the >> channel resolution. If there's BRAM left over, you should be able to get >> even more. >> >> > I forgot to mention that we need a bandwidth of at least 640 MHz. > > Tom > >> Jason >> >> On 29 Aug 2012, at 11:19, Tom Kuiper wrote: >> >> >> >>> Thanks for that, Jason! It is very timely. The reason I went down this >>> path is because I have a spectrometer design, by Joseph Trinh, which takes >>> a slightly different approach to bram access and so I could not use the >>> katcp_wrapper which I'd been using with your 16K spectrometer. He'd >>> offered to modify it but I thought it cool to try the file access I/O. I >>> think as a result of this exchange, I'll ask Joseph to modify his design >>> and I'll start using pyro. >>> >>> I hope he can squeeze it into a ROACH-1. He's got a 2x1024 spectrometer >>> design for me now but had to drop the PFBs because of insufficient >>> resources. I'm asking him to try 2x512 with PFBs. Does anyone already >>> have something like that? >>> >>> Next time around we'll use ROACH-2 but at the time we placed the orders >>> we weren't sure that the support for that would evolve fast enough to meet >>> our deadline (next month). >>> >>> Cheers >>> >>> Tom >>> >>> On 08/29/2012 01:09 AM, Jason Manley wrote: >>> >>> >>>> On 29 Aug 2012, at 02:44, Adam Barta wrote: >>>> >>>> >>>> >>>>> You could also try an ssh port forward to the katcp port ssh -vNL >>>>> 7147:roach:7147 gateway >>>>> Then use the katcp interface to read / write the registers. There is a >>>>> katcp_wrapper.py in the corr library >>>>> >>>>> >>>>> >>>> I would like to re-inforce this suggestion if you need SSH tunnelling >>>> through a firewall. A general word of warning to the CASPER community, >>>> which we also explained at the recent workshop... >>>> >>>> MeerKAT will not be supporting filesystem-level access in future boards >>>> (quite possibly starting with ROACH-2 already) and so, unless someone else >>>> in the collaboration picks it up, you'll be on your own if you write custom >>>> software to run on the PPC/BORPH because new platforms might not even run >>>> BORPH at all. There are a number of reasons for this decision, one being >>>> that we've run into performance limitations with BORPH, but also that it's >>>> a big overhead to port and debug and to keep it running reliably. >>>> >>>> The only interface supported by SKA-SA will be through KATCP. So if you >>>> start using the KATCP interface now, you'll have a transparent upgrade path >>>> to future boards. I'd suggest you don't worry yourself too much with the >>>> low-level detail... this is part of what CASPER tries to abstract away to >>>> ease your life as an instrument designer. >>>> >>>> If you don't want to write your own KATCP interface (and who does?!), >>>> consider using one of the existing ones. The best developed ones are in c >>>> (which includes a command-line executable for a single-line, ipython-like >>>> interactive experience from the shell prompt if you just want to call a >>>> shell script with a bunch of commands), available at >>>> https://github.com/ska-sa/**katcp_devel<https://github.com/ska-sa/katcp_devel>, >>>> or a number of CASPER collaborators are using the python wrapper from corr >>>> if you want to build a higher-level GUI application. You can find a >>>> one-page getting started guide here: https://casper.berkeley.edu/** >>>> wiki/Corr <https://casper.berkeley.edu/wiki/Corr> >>>> >>>> Jason >>>> >>>> >>>> >>>> >>> >>> -- >>> I or me? >>> http://www.oxforddictionaries.**com/page/145<http://www.oxforddictionaries.com/page/145> >>> >>> >>> >>> >> >> > > > -- > I or me? > http://www.oxforddictionaries.**com/page/145<http://www.oxforddictionaries.com/page/145> > > > >
