I can imagine it's on the large size, but it’s the thought that counts 😊.
-----Original Message----- From: Mark Halpern <[email protected]> Sent: 20 July 2020 18:58 To: [email protected] Subject: Re: [casper] references to recent cross-correlator technology developments CHIME runs 2048 feeds into an FX correlator with 1/2 GHz bandwidth. We form beams in real time and interrogate them at better than ms cadence for transients (frb). The system is a bit big to picture hiding it in an airport. mark On 2020-07-20 07:12, Neil Salmon wrote: > Hi Danny, > > Yes I can appreciate the difference here with respect to integration > times. Furthermore, as our arrays tend to be more fully filled, some > form of FT beam-former might be more efficient than a correlator. > However, things do get more complicated in the near-field security > screening scenarios where the FT relationship between physical space > and spatial frequency space breaks down. > > Cheers, > > Neil > > *From:*Danny Price <[email protected]> > *Sent:* 20 July 2020 14:44 > *To:* Neil Salmon <[email protected]>; [email protected] > *Subject:* RE: [casper] references to recent cross-correlator > technology developments > > Hi Neil, > > The correlation is indeed done in real time using stream processing > frameworks for most interferometer telescopes. Conversion from (very > sparse) visibilities to images is generally done offline (this can be > very time consuming!). > > There are a few real-time imaging systems: the EPIC correlator that > Jack mentioned, and the realfast system on the VLA > (https://science.nrao.edu/facilities/vla/observing/realfast) are good > examples. > > Cheers, > > Danny > > On 20 July 2020 at 9:55:06 pm, Neil Salmon ([email protected] > <mailto:[email protected]>) wrote: > > Hi Danny, > > Thank you for these references. > > For security screening systems the name of the game is real-time, ie > an image in less than 1 second. However, I see a great many > references to GPU based correlators. I was used to seeing these > devices as off-line correlators, as in software correlators. Are the > GPUs being used by the radio astronomy community as real-time > correlators, or as software correlators? > > Many thanks, > > Neil > > *From:*Danny Price <[email protected] <mailto:[email protected]>> > *Sent:* 20 July 2020 12:21 > *To:* [email protected] <mailto:[email protected]> > *Subject:* Re: [casper] references to recent cross-correlator > technology developments > > Hi Neil, > > To add to Jack's post, allow me to plug some overview articles that > may be of interest. The first, https://arxiv.org/abs/1702.00442, was > for an introduction for a special issue of JAI on DSP in radio > astronomy in 2016. Table 1 summarises some of the larger > correlators: the references therein may be of use. Jack (et al)'s > CASPER article in said JAI special issue is also a font of > references: https://arxiv.org/abs/1611.01826. The full special issue > article listing is up here: > https://www.worldscientific.com/toc/jai/05/04. > > More recently, here's my book chapter on real-time stream processing > in radio astronomy, https://arxiv.org/abs/1912.09041, which delves a > bit deeper into technical details for common approaches. > > In terms of cutting edge, there are various groups working with the > Xilinx RFSoC components for next-gen systems -- you will no doubt > have seen some traffic on this list. The ASKAP telescope group have > plans to use an Alveo Xilinx U280 accelerator card for high time > resolution imaging + dedispersion, which is an alternative to the > GPU correlator. > > GPU correlators are still the most widespread for O(100) antennas. > There's some discussion on GPU correlator performance in J. Kocz et > al 2014 (https://arxiv.org/abs/1401.8288); for O(100) inputs a GPU > correlator will likely be memory bandwidth bound. > > Cheers, > > Danny > > On 18 July 2020 at 7:54:49 pm, Neil Salmon ([email protected] > <mailto:[email protected]>) wrote: > > I need references on recent developments in cross-correlator > technology for an IEEE paper on the subject of aperture > synthesis imaging in the area of security screening of people > for concealed weapons. Typical requirements for this application > are cross-correlators that can process in real-time signals from > hundreds of receiver channels with around 1 GHz of RF bandwidth. > As none of this technology is commercially available > off-the-shelf I’m dependent on the radio astronomy community to > get the latest information of correlator development. This might > be just technical knowhow on the building of correlators, or > communities who would be willing to supply for a fee correlators > to a security screening technology development company. > > Could anyone provide me with any references of papers on recent > correlator development that I could include in this paper? > > Many thanks, > > 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 " > > -- > You received this message because you are subscribed to the > Google Groups "[email protected] > <mailto:[email protected]>" group. > To unsubscribe from this group and stop receiving emails from > it, send an email to [email protected] > <mailto:[email protected]>. > To view this discussion on the web visit > > https://groups.google.com/a/lists.berkeley.edu/d/msgid/casper/7aff8f2f6ed3482a8283e2994bbd9fc6%40ASEX03.ad.mmu.ac.uk > > <https://groups.google.com/a/lists.berkeley.edu/d/msgid/casper/7aff8f2f6ed3482a8283e2994bbd9fc6%40ASEX03.ad.mmu.ac.uk?utm_medium=email&utm_source=footer>. > > -- > You received this message because you are subscribed to the Google > Groups "[email protected] > <mailto:[email protected]>" group. > To unsubscribe from this group and stop receiving emails from it, > send an email to [email protected] > <mailto:[email protected]>. > To view this discussion on the web visit > > https://groups.google.com/a/lists.berkeley.edu/d/msgid/casper/CAAtMgq%3D_nce72fbSUWBZ62EiCxW5ojUgy%2ByAbPXHMNRd%3DXbLDw%40mail.gmail.com > > <https://groups.google.com/a/lists.berkeley.edu/d/msgid/casper/CAAtMgq%3D_nce72fbSUWBZ62EiCxW5ojUgy%2ByAbPXHMNRd%3DXbLDw%40mail.gmail.com?utm_medium=email&utm_source=footer>. > > -- > You received this message because you are subscribed to the Google > Groups "[email protected] > <mailto:[email protected]>" group. > To unsubscribe from this group and stop receiving emails from it, > send an email to [email protected] > <mailto:[email protected]>. > To view this discussion on the web visit > > https://groups.google.com/a/lists.berkeley.edu/d/msgid/casper/46372fbec8c34c909df5b72793ec1d09%40ASEX01.ad.mmu.ac.uk > > <https://groups.google.com/a/lists.berkeley.edu/d/msgid/casper/46372fbec8c34c909df5b72793ec1d09%40ASEX01.ad.mmu.ac.uk?utm_medium=email&utm_source=footer>. > > -- > You received this message because you are subscribed to the Google > Groups "[email protected]" group. > To unsubscribe from this group and stop receiving emails from it, send > an email to [email protected] > <mailto:[email protected]>. > To view this discussion on the web visit > https://groups.google.com/a/lists.berkeley.edu/d/msgid/casper/12ede958 > 28e241ef86cac75cd8854a3d%40ASEX01.ad.mmu.ac.uk > <https://groups.google.com/a/lists.berkeley.edu/d/msgid/casper/12ede95828e241ef86cac75cd8854a3d%40ASEX01.ad.mmu.ac.uk?utm_medium=email&utm_source=footer>. -- Mark Halpern Department of Physics and Astronomy, UBC 604 822-6435 [he.him.his] skype: mlhalpern 6224 Agricultural Road, UBC V6T 1Z1 -- You received this message because you are subscribed to the Google Groups "[email protected]" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/a/lists.berkeley.edu/d/msgid/casper/a221837a-7db0-741f-ce13-3c23f870e01a%40physics.ubc.ca. "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 " -- You received this message because you are subscribed to the Google Groups "[email protected]" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/a/lists.berkeley.edu/d/msgid/casper/6572499430594ddab7de9478148870e1%40ASEX01.ad.mmu.ac.uk.
