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Re: [Xylo-SDR] Some design thoughts requested



Phil

AH HA! The 'working stiff' comments again! (smile)

What kind of enclosure, mounting etc are you considering?

Eric
 

-----Original Message-----
From: xylo-sdr-bounces@lists.ae5k.us [mailto:xylo-sdr-bounces@lists.ae5k.us]
On Behalf Of Philip Covington
Sent: Tuesday, January 03, 2006 7:47 PM
To: Xylo-SDR Discussion
Subject: Re: [Xylo-SDR] Some design thoughts requested

Eric,

Another possibility is SO DIMM which would require the boards to be
smaller in width.  We are considering using the DDR DIMM sockets for a
18 bit ADC post amp board for an astronomy CCD imager at OSU.  I
created the PCB decal in PADS for it the other day.  The nice thing is
that you do not need a mating connector on the PCB and you can achieve
pretty dense spacing with it.

The system that we are designing for the CCD camera has multiple 18
bit, 500 kSPS ADCs that will plug into a "motherboard" with an FPGA
and 1.2 GbPS fiber optic link to a PC.  The Lab is considering
developing a PCI Express interface card to go along with it (they have
a dated ISA design).

73 de Phil N8VB




On 1/3/06, Eric Ellison <ecellison@comcast.net> wrote:
> Phil
>
> Thanks! I'll take a look at this again. The only reason I did not proceed
> along this track, is that "Hunt as I might" I could not find commercial
> riser cards, and symstik had too few connections. Even If I did find a
riser
> the spacing would be too close. The sockets are available, but we would
have
> to design our own motherboard. I don't think is that farfetched an idea
> since we could define the spacing and put the raw voltage regulators (5,
12,
> and perhaps -12) on the motherboard.
>
> I am sort of tired of sending out stuff without the forthought for
> packaging. I think in this project it is especially important, since we
can
> do A LOT of things with the PGA if we think about the project design from
> the outside - in, and create something which can be an anything design
based
> on the FPGA like a Scope card, a Spectrum analyzer card, a Radio etc!
>
> I think that 184 pins should give us all we need even if we ground every
> other pin for better noise immunity.
>
> Comments?
>
> Eric
>
>
>
>
> -----Original Message-----
> From: xylo-sdr-bounces@lists.ae5k.us
[mailto:xylo-sdr-bounces@lists.ae5k.us]
> On Behalf Of Philip Covington
> Sent: Tuesday, January 03, 2006 1:12 PM
> To: Xylo-SDR Discussion
> Subject: Re: [Xylo-SDR] Some design thoughts requested
>
> Hello all,
>
> I considered using DDR SIMM sockets for a project.  You get 184
> contacts and they give you a card width of 5.25".  The height of the
> card is not restricted (within reason).
>
> http://www.molex.com/pdm_docs/sd/876362002_sd.pdf
>
> It is kind of like the SIMMStick idea, but with more contacts (184 vs
> 30).  30 pin SIMM sockets are very hard to get these days and I see
> that Molex has scheduled the 72 pin SIMM sockets for obsolescence.
> The DDR DIMM sockets should be around for a while yet.  They are
> relatively cheap ($1.92 ea Digikey).
>
> 73 de Phil N8VB
>
>
> On 1/2/06, Eric Ellison <ecellison@comcast.net> wrote:
> >
> >
> >
> > Cecil
> >
> >
> >
> > Yes, I'll go back and look at Eurocard standard. This looks great. GUD
> > HUNTING! Thanks for all the links. One way or tother I think we need a
> buss
> > for our end product. Your point about size of the boards we might want
to
> > manufacture is well taken. They should be able to go on a little more
than
> a
> > postage stamp, and be VERY inexpensive to produce - external connectors
> > being the limiting size factor! One reason I was looking at Memory Chip
> > risers.
> >
> >
> >
> > I moused around a little today, and really can't see where I can justify
> > Eagle Software in any serious production version. So I'll probably
monkey
> > around with Kicad, which is a really nice GPL product. I mentioned
earlier
> > that there was some problem with the Drill files, which they have
> corrected.
> > Only benefit of Eagle IS the plethora of template files available. I
don't
> > mind eating on my lunchtime and creating new parts! Good exercise and I
am
> > getting fatter! (No Testosterone!)
> >
> >
> >
> > Sparkfun has a pretty good batch deal for prototype boards and also a
lot
> of
> > interesting new products. I like their little 3 buck power supplies.
Also
> > have a some 28 pin SOIC to DIP experimenter stuff for about the same
> price.
> >
> >
> >
> >
>
http://www.sparkfun.com/shop/index.php?shop=1&cart=525299&cat=1&PHPSESSID=ab
> ce58b426cb8d0d0c3cf4b1495f0312
> >
> >
> >
> > Other prototype boards can be had at:
> >
> >
> >
> > http://protoboards.theshoppe.com/index.html
> >
> >
> >
> > Will return!
> >
> >
> >
> > Viva the Project
> >
> >
> >
> > Eric
> >
> >
> >
> >  ________________________________
> >
> >
> > From: xylo-sdr-bounces@lists.ae5k.us
> [mailto:xylo-sdr-bounces@lists.ae5k.us]
> > On Behalf Of KD5NWA
> >  Sent: Monday, January 02, 2006 2:06 PM
> >  To: Xylo-SDR Discussion
> >  Subject: Re: [Xylo-SDR] Some design thoughts requested
> >
> >
> >
> >
> > I'll second the DIN connectors,they are very reliable, and come in
> different
> > sizes, single, and dual connector cards. I have used them in an
industrial
> > environment and they worked flawlessly for years. But I'll go one more
> step
> > forward.
> >
> >  The Eurocard standard allows for mix of one 96 pin connector,  two
> > connectors or even three connectors (not needed). Prototype boards are
> > cheap, most PCB houses have specials on Eurocard size boards. Card cages
> are
> > available for low prices for the Eurocard format
> >
> >  Like Leon said the connectors are expensive but they are self aligning,
> and
> > I've seen then for under $3 on the Internet.
> >
> >  Although the PCI is tempting and cheap for the backplane, it's a bus
that
> > is designed for digital logic, all pins are tied to the same pins in all
> > cards. Prototype cards tend to be large and expensive.
> >
> >  A brief blurb on Eurocards;
> >
> >  < http://www.yotor.org/wiki/en/eu/Eurocard.htm >
> >
> >  Cheap prototype boards are available for $10 or less, a very important
> > point, $50 to $60 for a PCI card is very expensive, maybe I'm too cheap,
> but
> > the blank board should not cost more than the components.
> >  < http://www.sbszoo.com/ve6sbs/sale/cct-brds.htm >
> >
> >  Here are some available at Mouse;
> >  <
> >
>
http://www.mouser.com/index.cfm?handler=data.getPcodes&pcode=BPS%2BPrototype
> %2BBoards&pcodenumber=85400
> > >
> >
> >  Sample enclosure, can be home made from aluminum extrusions.
> >  < http://www.busboard.net/bps-enc.htm >
> >
> >
> >
> >  At 03:34 AM 1/2/2006, Leon Heller wrote:
> >
> > ----- Original Message -----
> >
> > From: Eric Ellison
> >
> > To: 'Xylo-SDR Discussion'
> >
> > Sent: Monday, January 02, 2006 5:17 AM
> >
> > Subject: [Xylo-SDR] Some design thoughts requested
> >
> > Folks
> >
> >
> >
> > Even since the PIC 4550 days I have been thinking on how we might
conduct
> > experiments as well as have a reasonable environment for adding on to
> the
> > project. The obvious answer is a buss of some sort. I have looked at
> > everything from Simm riser boards to ISA buss stuff. PCI risers might be
> the
> > way to go since they are inexpensive ($15) for 3 slot extenders. Also in
> an
> > end product they fit into the L-brackets of a computer case, or 2U
mounts.
> > They have assigned power buss we can use, fairly inexpensive
> prototyping
> > boards. ($50 - $60), are four layer and designed to minimize intra trace
> > noise. The buss wouldnt be used for PCI, however it would allow power,
> (on
> > designated standards based lines), intra board connections, and FPGA,
> > I2C,signals etc.
> >
> >
> >
> > PCI seems to be a little large for what we are proposing, and the
> product
> > boards would cost more to produce, however, with an established buss we
> > could put a radio on one card, FPGA on another Audio on another etc.
> >
> >
> >
> > $15 Board amongst others:
> >
> >
> >
> >
> >
> > http://www.plinkusa.net/riser.htm
> >
> >
> >
> >
> >
> >
> >
> >
> >
> > Am I off the wall here?
> >
> >
> >
> > That's the sort of thing I was thinking of doing. I used to work for
Racal
> > and they used to build their military radios from separate screened
> plug-in
> > modules on a backplane.
> >
> >
> >
> >  I favour DIN41612 connectors for this sort of thing. They are
expensive,
> > but very reliable, and have pins on 0.1" centres. They can even
accomodate
> > co-axial connectors. They are more commonly used in Europe than the USA,
> but
> > you can get them over there without any problems.
> >
> >
> >
> >  73, Leon
> >
> >  --
> >  Leon Heller, G1HSM
> >  leon.heller@bulldoghome.com
> >  http://www.geocities.com/leon_heller
> >  _______________________________________________
> >  Xylo-SDR mailing list
> >  To post msg: Xylo-SDR@ae5k.us
> >  Subscription help:
> > http://lists.ae5k.us/listinfo.cgi/xylo-sdr-ae5k.us
> >  Xylo-SDR web page: http://xylo-sdr.ae5k.us
> >  Forum pages: http://www.hamsdr.com/hamsdrforum/
> >
> >
> >  Cecil Bayona
> >  KD5NWA
> >  www.qrpradio.com
> >
> >  "I fail to see why doing the same thing over and over and getting the
> same
> > results every time is insanity: I've almost proved it isn't; only a few
> more
> > tests now and I'm sure results will differ this time ... "
> > _______________________________________________
> > Xylo-SDR mailing list
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> > Forum pages: http://www.hamsdr.com/hamsdrforum/
> >
> >
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