On Tue, 22 Dec 2015 at 16:19 Neil Salmon <n.sal...@mmu.ac.uk> wrote: > Jack, > > > > I’m thinking the data rate and the computational load is just too large > for Roach2, so it might be easier to design the whole think from scratch > around latest most powerful FPGA, and designing single bit sampling > receiver circuits. The IF centre frequency is likely to be ~3 GHz with the > 300 MHz bandwidth, so I’ll need to design receiver analogue circuits that > operate at these frequencies, with either analogue or digital downshift, > which then interface to the FPGA board. > If rolling out custom hardware is an option, then that will certainly leave you with a smaller system.
> > > Would you happen to know which software packages I might use and have > access to from ac.uk if I wanted to design the digital receiver boards > and FPGA boards at these frequencies? > I don't have any direct experience attempting to obtain board design tools in the UK, but I know there is the europractice software service which can get you licenses to various design packages supposedly at reasonable cost ( http://www.europractice.stfc.ac.uk/). I have to say I'm not entirely sure what's available in the board design realm..... Jack > Many thanks, > > Neil > > > > *From:* Jack Hickish [mailto:jackhick...@gmail.com] > *Sent:* 18 December 2015 17:26 > *To:* Neil Salmon; James Smith > > > *Cc:* casper@lists.berkeley.edu > *Subject:* Re: [casper] building 300-receiver channel cross-correlator > > > > I believe that each ZDOK is good for about 50 Gb/s. A ROACH2 has two ZDOK > ports. Presumably you'll give up a pin or two for clocks so maybe 40Gb/s is > a more realistic rate. We use an ADC that achieves 40Gb/s over 32 of the 40 > ZDOK pin pairs. . But you'll also have to physically interface the > digitizers, so whether you can have multiple digitizers time multiplexed on > the same FPGA pins or whether you need one pin (pair?) per digitizer might > also be limiting. > > > > Jack > > > > On Fri, 18 Dec 2015 at 16:46 Neil Salmon <n.sal...@mmu.ac.uk> wrote: > > Jack, > > Thanks for help. Do you have any idea of the I/O capacity of a single > Roach2 board – just trying to figure out how many I may need? > > Thank you, > > Neil > > > > *From:* Jack Hickish [mailto:jackhick...@gmail.com] > *Sent:* 18 December 2015 15:08 > *To:* James Smith; Neil Salmon > > > *Cc:* casper@lists.berkeley.edu > *Subject:* Re: [casper] building 300-receiver channel cross-correlator > > > > Hi Neil, > > > > A bit more information would be useful, but it sounds like if you could > construct a ZDOK card that interfaced some (40, one per differential pair?) > of your digitizers to a ROACH board you could use a handful of ROACH boards > to perform all of the cross multiplication and accumulation and interface > with CPU data recorders / post-processors. > > > > Jack > > > > On Fri, 18 Dec 2015 at 14:26 James Smith <jsm...@ska.ac.za> wrote: > > Hello Neil, > > > > CASPER tools could probably do what you're looking for, but I found your > description a bit confusing. You're going to need to clarify somewhat. > > > > Regards, > > James > > > > > > On Fri, Dec 18, 2015 at 4:15 PM, Neil Salmon <n.sal...@mmu.ac.uk> wrote: > > Anyone help? > > > > I’m working in academia and need to build a 300-receiver channel > single-bit digitiser / cross-correlator with a single frequency channel > having a bandwidth of 300 MHz, centre frequency ~3 GHz. The single bit > digitisers sample I&Q giving a total data rate of 180 Gbps and using XOR > gates to do the cross-correlations, the total computation rate is 54 T XOR > operations per second. I need to accumulate cross-correlations typically > for times ranging from 10 ms to a few seconds. The system would comprise an > array of single bit digitisers linked via a high speed data bus to FPGA > boards for the cross-correlation/accumulation. I’ve no skills in board > design but could probably learn VHDL. I don’t have funding to commission a > design and build but wondered if anyone in this community could advise how > I should go about building this system at our university. > > > > Thank you for any help you can provide. > > > > Neil > > "Before acting on this email or opening any attachments you should read > the Manchester Metropolitan University email disclaimer available on its > website http://www.mmu.ac.uk/emaildisclaimer " > > > > "Before acting on this email or opening any attachments you should read > the Manchester Metropolitan University email disclaimer available on its > website http://www.mmu.ac.uk/emaildisclaimer " > > "Before acting on this email or opening any attachments you should read > the Manchester Metropolitan University email disclaimer available on its > website http://www.mmu.ac.uk/emaildisclaimer " >
