Many thanks Dan, cheers, Neil
From: salmon.na via [email protected] <[email protected]> Sent: 11 November 2023 20:43 To: [email protected] Subject: RE: [casper] state of the art single bit correlators Thanks Dan, Yes, one antenna for one receiver, and there is only one frequency channel, and a single polarisation, so quite a simple configuration. A good idea to use differential inputs as single bit ADCs. So the FX correlator looks the better architecture. So are you saying the FPGA FX correlator would manage making the cross-correlations of 512 single bit channels at 1 GbpS, on say a single FPGA, Xilinx or Altera ? Cheers, Neil From: [email protected] <mailto:[email protected]> <[email protected] <mailto:[email protected]> > On Behalf Of Dan Werthimer Sent: 11 November 2023 20:23 To: [email protected] <mailto:[email protected]> Subject: Re: [casper] state of the art single bit correlators hi neil, by number of receiver channels, i presume you mean number of antennas? are these single or dual polarization? how many spectral channels do you need in your correlator ? for a large number of spectral channels, you'll likely want to use an FX architecture correlator (not XF). in an FX correlator the number of ADC bits doesn't change the FPGA utilization for the DSP very much. one fun thing you can do with a 1 bit correlator, is use the LVDS differential inputs on the FPGA as 1 Gsps digitizers. on a large FPGA with a lot of pins you can get about 512 ADC's (256 antennas, dual pol) built into the FPGA, so the FPGA can be your digitizer and your correlator... if you only need a small number of spectral channels, you could build an XF correlator with ~512 inputs... (~256 antennas, dual pol, or ~512 antennas single pol) in a large FPGA. with an XF architecture, the FPGA utilization is J x number_of_spectral_channels. for FX, the utilization goes as K x log_base_2(spectral_channels). but constant K >> constant J, so sometimes (rarely) it is better to use XF, depending on the number of spectral channels. best wishes, dan On Sat, Nov 11, 2023 at 11:47 AM salmon.na <http://salmon.na> via [email protected] <mailto:[email protected]> <[email protected] <mailto:[email protected]> > wrote: For a paper on non-radioastronomy aperture synthesis technology I need to know how many receiver channels can run into an almost top of the range FPGA optimally designed single-bit cross-correlator running a 2 Gbps. So each receiver is digitised (sine and cosine) in single bits 1 Gbps. I’m wondering if there are scaling laws for this and I only need to have a ball park figure, ie a precision of say a factor of three or thereabouts. Any associate papers related to that which might have clues to the capabilities would be helpful. Many thanks, Neil Salmon -- 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/005601da14d7%24ede171b0%24c9a45510%24%40tiscali.co.uk <https://groups.google.com/a/lists.berkeley.edu/d/msgid/casper/005601da14d7%24ede171b0%24c9a45510%24%40tiscali.co.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/CAGHS_vEdvQAJ9Q5-JOAS1QfJ%3DW8AfQMU9D48cnt_gQ56GA%3DqiA%40mail.gmail.com <https://groups.google.com/a/lists.berkeley.edu/d/msgid/casper/CAGHS_vEdvQAJ9Q5-JOAS1QfJ%3DW8AfQMU9D48cnt_gQ56GA%3DqiA%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/007b01da14df%24a643ba90%24f2cb2fb0%24%40tiscali.co.uk <https://groups.google.com/a/lists.berkeley.edu/d/msgid/casper/007b01da14df%24a643ba90%24f2cb2fb0%24%40tiscali.co.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]. To view this discussion on the web visit https://groups.google.com/a/lists.berkeley.edu/d/msgid/casper/008a01da14e4%24e9f94f20%24bdebed60%24%40tiscali.co.uk.
