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 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. >>> >> >> -- >> 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. >> > > > -- > Michael Inggs > 10 Devon Street, Simon > <https://maps.google.com/?q=10+Devon+Street,+Simon+s+Town,+South+Africa&entry=gmail&source=g> > 's Town, South Africa > <https://maps.google.com/?q=10+Devon+Street,+Simon+s+Town,+South+Africa&entry=gmail&source=g>. > Tel: > +27 21 786 1723 Fax: +27 21 786 1151 Skype: mikings Cell: +27 83 776 7304 > "Ex Africa semper aliquid novi" > > -- > 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.