[casper] Availability of SNAP board for the Mauritius Deuterium Telescope
Hi all, We are looking at building a telescope in Mauritius which is called the Mauritius Deuterium Telescope, MDT for short. As the name suggests it is a Deuterium focused experiment. We have planned for a pathfinder station to be built for the end of this year and had in mind the SNAP boards for the digital back-end. We were set to buy four SNAPs by the end of next month but a sudden slash in funding has put a dent in our plans. I was wondering if anyone has any unused SNAPs that we can get off their hands at a reduced price. Currently one SNAP is sitting at $3500 from Digicom. Anything below $3000 will greatly help us. We will obviously be extremely grateful for donations. Hope to have some positive feedback from some of you. Kind Regards, Vinand Prayag -- You received this message because you are subscribed to the Google Groups "casper@lists.berkeley.edu" group. To unsubscribe from this group and stop receiving emails from it, send an email to casper+unsubscr...@lists.berkeley.edu. To post to this group, send email to casper@lists.berkeley.edu.
Re: [casper] Availability of SNAP board for the Mauritius Deuterium Telescope
Hi, Please find attached the User Requirement. The bandwidth is actually only 250KHz Cheers, Vinand On Fri, May 25, 2018 at 5:20 PM Marcus D. Leech <mle...@ripnet.com> wrote: > On 05/25/2018 07:28 AM, Vinand Prayag wrote: > > Hi all, > > We are looking at building a telescope in Mauritius which is called the > Mauritius Deuterium Telescope, MDT for short. As the name suggests it is a > Deuterium focused experiment. We have planned for a pathfinder station to > be built for the end of this year and had in mind the SNAP boards for the > digital back-end. We were set to buy four SNAPs by the end of next month > but a sudden slash in funding has put a dent in our plans. I was wondering > if anyone has any unused SNAPs that we can get off their hands at a reduced > price. Currently one SNAP is sitting at $3500 from Digicom. Anything below > $3000 will greatly help us. We will obviously be extremely grateful for > donations. Hope to have some positive feedback from some of you. > > > Kind Regards, > Vinand Prayag > > Do you have a pointer to a project description? > > Why such high bandwidth if you're looking at Deuterium? > > > > -- > You received this message because you are subscribed to the Google Groups " > casper@lists.berkeley.edu" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to casper+unsubscr...@lists.berkeley.edu. > To post to this group, send email to casper@lists.berkeley.edu. > -- You received this message because you are subscribed to the Google Groups "casper@lists.berkeley.edu" group. To unsubscribe from this group and stop receiving emails from it, send an email to casper+unsubscr...@lists.berkeley.edu. To post to this group, send email to casper@lists.berkeley.edu. User_Requirement_Version_D.pdf Description: Adobe PDF document
Re: [casper] Availability of SNAP board for the Mauritius Deuterium Telescope
Marcus: Yes, each station should normally have the same number of antennas which are dual pol. So each pol gets digitised and then we intend to just track a source in the main beam in the first instance, and then move to beam forming. We are still investigating the possibility of fewer channels per station but the maximum will be 48. Vinand On Fri, May 25, 2018 at 7:23 PM Marcus D. Leech <mle...@ripnet.com> wrote: > On 05/25/2018 11:01 AM, Vinand Prayag wrote: > > Yes, you are absolutely right. I have had numerous conversations with Prof > Rogers about building a new Deuterium focused array in the Southern > Hemisphere and we found out that the scientific contributions that the > instrument would be extremely valuable. > > Vinand Prayag > Research Assistant > University of Mauritius > > So, when you say 48 channels, you're talking 48 sky channels rather than > 48 spectral channels, and you want to beam-form like they > do at Haystack? > > > > > On Fri, May 25, 2018 at 5:36 PM Marcus D. Leech <mle...@ripnet.com> wrote: > >> On 05/25/2018 09:24 AM, Vinand Prayag wrote: >> >> Hi, >> >> Please find attached the User Requirement. The bandwidth is actually only >> 250KHz >> >> Cheers, >> Vinand >> >> Are you envisaging an array, like the D1 telescope at Haystack? >> >> >> >> >> On Fri, May 25, 2018 at 5:20 PM Marcus D. Leech <mle...@ripnet.com> >> wrote: >> >>> On 05/25/2018 07:28 AM, Vinand Prayag wrote: >>> >>> Hi all, >>> >>> We are looking at building a telescope in Mauritius which is called the >>> Mauritius Deuterium Telescope, MDT for short. As the name suggests it is a >>> Deuterium focused experiment. We have planned for a pathfinder station to >>> be built for the end of this year and had in mind the SNAP boards for the >>> digital back-end. We were set to buy four SNAPs by the end of next month >>> but a sudden slash in funding has put a dent in our plans. I was wondering >>> if anyone has any unused SNAPs that we can get off their hands at a reduced >>> price. Currently one SNAP is sitting at $3500 from Digicom. Anything below >>> $3000 will greatly help us. We will obviously be extremely grateful for >>> donations. Hope to have some positive feedback from some of you. >>> >>> >>> Kind Regards, >>> Vinand Prayag >>> >>> Do you have a pointer to a project description? >>> >>> Why such high bandwidth if you're looking at Deuterium? >>> >>> >>> >>> -- >>> You received this message because you are subscribed to the Google >>> Groups "casper@lists.berkeley.edu" group. >>> To unsubscribe from this group and stop receiving emails from it, send >>> an email to casper+unsubscr...@lists.berkeley.edu. >>> To post to this group, send email to casper@lists.berkeley.edu. >>> >> -- >> You received this message because you are subscribed to the Google Groups >> "casper@lists.berkeley.edu" <casper@lists.berkeley.edu> group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to casper+unsubscr...@lists.berkeley.edu. >> To post to this group, send email to casper@lists.berkeley.edu. >> >> >> -- >> You received this message because you are subscribed to the Google Groups >> "casper@lists.berkeley.edu" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to casper+unsubscr...@lists.berkeley.edu. >> To post to this group, send email to casper@lists.berkeley.edu. >> > -- > You received this message because you are subscribed to the Google Groups > "casper@lists.berkeley.edu" <casper@lists.berkeley.edu> group. > To unsubscribe from this group and stop receiving emails from it, send an > email to casper+unsubscr...@lists.berkeley.edu. > To post to this group, send email to casper@lists.berkeley.edu. > > > -- > You received this message because you are subscribed to the Google Groups " > casper@lists.berkeley.edu" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to casper+unsubscr...@lists.berkeley.edu. > To post to this group, send email to casper@lists.berkeley.edu. > -- You received this message because you are subscribed to the Google Groups "casper@lists.berkeley.edu" group. To unsubscribe from this group and stop receiving emails from it, send an email to casper+unsubscr...@lists.berkeley.edu. To post to this group, send email to casper@lists.berkeley.edu.
Re: [casper] Availability of SNAP board for the Mauritius Deuterium Telescope
Yes, you are absolutely right. I have had numerous conversations with Prof Rogers about building a new Deuterium focused array in the Southern Hemisphere and we found out that the scientific contributions that the instrument would be extremely valuable. Vinand Prayag Research Assistant University of Mauritius On Fri, May 25, 2018 at 5:36 PM Marcus D. Leech <mle...@ripnet.com> wrote: > On 05/25/2018 09:24 AM, Vinand Prayag wrote: > > Hi, > > Please find attached the User Requirement. The bandwidth is actually only > 250KHz > > Cheers, > Vinand > > Are you envisaging an array, like the D1 telescope at Haystack? > > > > > On Fri, May 25, 2018 at 5:20 PM Marcus D. Leech <mle...@ripnet.com> wrote: > >> On 05/25/2018 07:28 AM, Vinand Prayag wrote: >> >> Hi all, >> >> We are looking at building a telescope in Mauritius which is called the >> Mauritius Deuterium Telescope, MDT for short. As the name suggests it is a >> Deuterium focused experiment. We have planned for a pathfinder station to >> be built for the end of this year and had in mind the SNAP boards for the >> digital back-end. We were set to buy four SNAPs by the end of next month >> but a sudden slash in funding has put a dent in our plans. I was wondering >> if anyone has any unused SNAPs that we can get off their hands at a reduced >> price. Currently one SNAP is sitting at $3500 from Digicom. Anything below >> $3000 will greatly help us. We will obviously be extremely grateful for >> donations. Hope to have some positive feedback from some of you. >> >> >> Kind Regards, >> Vinand Prayag >> >> Do you have a pointer to a project description? >> >> Why such high bandwidth if you're looking at Deuterium? >> >> >> >> -- >> You received this message because you are subscribed to the Google Groups >> "casper@lists.berkeley.edu" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to casper+unsubscr...@lists.berkeley.edu. >> To post to this group, send email to casper@lists.berkeley.edu. >> > -- > You received this message because you are subscribed to the Google Groups > "casper@lists.berkeley.edu" <casper@lists.berkeley.edu> group. > To unsubscribe from this group and stop receiving emails from it, send an > email to casper+unsubscr...@lists.berkeley.edu. > To post to this group, send email to casper@lists.berkeley.edu. > > > -- > You received this message because you are subscribed to the Google Groups " > casper@lists.berkeley.edu" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to casper+unsubscr...@lists.berkeley.edu. > To post to this group, send email to casper@lists.berkeley.edu. > -- You received this message because you are subscribed to the Google Groups "casper@lists.berkeley.edu" group. To unsubscribe from this group and stop receiving emails from it, send an email to casper+unsubscr...@lists.berkeley.edu. To post to this group, send email to casper@lists.berkeley.edu.
Re: [casper] Availability of SNAP board for the Mauritius Deuterium Telescope
Hi Dan, The downconversion was the first idea that we had before Prof Inggs steered us towards the SNAPs. I made a quick costs overview: If each channel cost $100. Total cost for 48 is $4800. PCIe ADC with 16channels at 1MSPs will come at $500 each. Three of these will be $1500. Add to that the cost of three mainframes which would be around $1500 as well plus the need of a switch(1GbE 24 channels is atleast $2000). This should bring the total cost to $9800. Four SNAPs will come around $14000 at $3500 with much less complexity. There is a $4000 difference and this is one of the reasons I am seeking out the CASPER group in case someone can get us the SNAPs at a reduced price. I may have forgotten to mention that while we are only building a one station pathfinder, the plan is for 20 or so stations which will give us over a 1000 channels. The added advantage of using something like the SNAP is that I get to expose the radio astronomy community to SDR and FPGA development and once the experiment is over the SNAP can be reused for any other experiment. Prof Inngs and I agreed that to build expertise for hosting SKA type telescopes it is essential we get started with what the astronomy community is using. Cheers, Vinand On Sat, May 26, 2018 at 2:44 AM Dan Werthimer <d...@ssl.berkeley.edu> wrote: > > hi michael, > > if you decide you want to have 48 downconverters, and then use a low rate > 48 input ADC board, then > > a) you could implement downconverters with connectorized > (eg:minicircuits) mixers, filters, amplifiers >about $100 per channel > > > b) you could make your own PCB, or perhaps use the downconverter boards we > made for arecibo multibeam receiver: >see section 4: "16-Channel Quadrature Downconverter (IF to IQ > Baseband Converter) of > https://casper.berkeley.edu/galfa/ > > lower parts cost but more work. > > photos of this 16 channel downconverter are at: > https://casper.berkeley.edu/galfa/pictures/pictures.html > > best wishes, > > dan > > > On Fri, May 25, 2018 at 9:04 AM, Michael Inggs <miki...@gmail.com> wrote: > >> Hi Dan >> >> One of the tradeoff studies the guys are doing is the cost of a 48 >> channel analogue downconverter and low sample rate ADC. At present, direct >> demod with a SNAP looks simpler in terms of hardware complexity, but has >> not been costed. >> >> One of the team has actually implemented all the digital backend >> (including RFI excision) on a GPU, so in principle, all we need are time >> stamped packets of samples, and nothing on the FPGA, except demod, >> decimation. >> >> Thanks for the ideas coming in to the team. >> >> Regards >> >> >> On Fri, 25 May 2018 at 18:59, Dan Werthimer <d...@ssl.berkeley.edu> >> wrote: >> >>> >>> >>> if vinand, >>> >>> if you want to digitize 48 signals with 250 KHz bandwidth, you might >>> want to consider >>> purchasing a 48 input PCIe ADC board and doing the signal processing in >>> a computer (in software). >>> (not use FPGA boards). >>> but then you'd have to mix the deuterium line to baseband, so you'd need >>> 48 downconverters. >>> >>> if you want to use snaps, and you don't have much processing to do on >>> the fpga, and you want to save money, you could >>> plug in a ADC16 board into the snap - >>> this is a bit of a cludge, but would give you 28 channels per snap (16 >>> external ADC channels, and 12 on board ADC channels). >>> >>> if you have a roach1 or roach2 lying around, there's a 64 channel adc >>> board you could use that sample at up to 50 Msps; >>> i'm not sure about the analog bandwidth - you might not have to use >>> downconverters... >>> >>> best wishes, >>> >>> dan >>> >>> >>> >>> >>> On Fri, May 25, 2018 at 6:24 AM, Vinand Prayag <vinan...@gmail.com> >>> wrote: >>> >>>> Hi, >>>> >>>> Please find attached the User Requirement. The bandwidth is actually >>>> only 250KHz >>>> >>>> Cheers, >>>> Vinand >>>> >>>> On Fri, May 25, 2018 at 5:20 PM Marcus D. Leech <mle...@ripnet.com> >>>> wrote: >>>> >>>>> On 05/25/2018 07:28 AM, Vinand Prayag wrote: >>>>> >>>>> Hi all, >>>>> >>>>> We are looking at building a telescope in Mauritius which is called >>>>> the Mauritius Deuterium Telescope, MDT for short. As the name suggests it >&g
[casper] Re: SNAP external clock inputs
Hi Jack, Thanks for your reply. Yes it does help. Much appreciated as usual. Nitish and I were actually quite confused about the availability of the two external clocks and the one synthesizer output on the SMA. Hence his email to the list and you. Thank you for clearing that up. I would like to ask if you had any suggestions for a reference and PPS clock? Again as you know, costs is an issue. We had looked at a Meinberg product( https://www.meinbergglobal.com/english/products/modular-railmount-ntp-server-ieee-1588-solution.htm) but it don't think it provides the appropriate PPS signal. Cheers, Vinand On Fri, Oct 19, 2018 at 7:57 PM Jack Hickish wrote: > Hi Nitish, > > Hope you don't mind, but I'm taking this back on the list. > > Your understanding of the PPS signal is correct. > > If you with to use the on-board SNAP ADCs, you have two clocking options, > both of which require an external signal to be provided. > > 1) Provide a timing reference (usually, but not necessarily, 10 MHz) to > the on-board synthesizer, and use that to generate your sampling clock > (see, for example > https://github.com/casper-astro/tutorials_devel/blob/ba099ddefc8c1f74725bc3d5531e9641c1a41dee/vivado/snap/tut_spec/snap_tut_spec.py#L99 > ) > > 2) Provide a clock at your sampling rate direct to the board. > > You only need to do one of these -- you should either provide a > synthesizer reference on SMATP14 **or** a clock at your sampling rate on > SMATP15. > > The synthesizer on the board has two outputs. One is used to drive the > ADCs (option 1, above) the other is available on the SMA connector you > mention. It's not obvious to me how that would be useful in most > situations, though potentially you could use it to clock an external ZDOK > ADC card. I've only ever used this output for debugging the synthesizer. I > think python software probably exists to control this output (see > https://github.com/casper-astro/casperfpga/blob/master/src/synth.py) > though I don't know how complete it is. > > Hope that helps a bit, > > Jack > > On Fri, 19 Oct 2018 at 04:58 Nitish Ragoomundun < > nitish.ragoomun...@gmail.com> wrote: > >> >> Hello, >> >> We recently bought a SNAP board and we are having a few issues about >> clocking. I just mailed the CASPER group and got a few interesting >> responses. We would just like to have an explanation about the external >> clock inputs to the board. >> >> Our project basically consists in building a low-frequency array for the >> observation of the deuterium hyperfine line at 327.4 MHz with a bandwidth >> of 250 kHz. The SNAP boards will operate at full 12 channels input, thus >> the ADCs at 250 MSps. We will subsequently decimate the data rate, as our >> working bandwidth is narrow. >> >> Now, can you please shed some light on these statements from the SNAP >> wiki (https://casper.berkeley.edu/wiki/SNAP): >> >>- * Digital 1 PPS: 50 ohm single-ended LVTTL logic levels * >>- >> *... * >>- * External ADC clock: 50 ohm single-ended about +2 dB* >>- >> *... * >>- * External reference for on-board frequency synthesizer: 50 ohm >>about +10dBm * >>- *...* >> >> We understand that the Digital 1 PPS is for synchronisation with a time >> server. And, that the external reference for the frequency synthesizer will >> enable all samples acquired from different boards to be phased properly. >> Please correct us if we are wrong. >> >> We would like to know if the external ADC clock is *required*, and if >> yes, what frequency should we input? >> Furthermore, we observed that there is an output for frequency >> synthesizer as well. Can you please indicate in what way one could use it? >> >> We thank you for your patience. >> >> Kind regards, >> Nitish Ragoomundun >> Department of Physics >> University of Mauritius >> >> -- You received this message because you are subscribed to the Google Groups "casper@lists.berkeley.edu" group. To unsubscribe from this group and stop receiving emails from it, send an email to casper+unsubscr...@lists.berkeley.edu. To post to this group, send email to casper@lists.berkeley.edu.
