Leon
Yes, this does make it smaller and also a
sturdier positive contact mount. This is the way Phil Covington has designed
his HPSDR, I think he is using 40 pin types. My feeling is that 40 pins is not
enough, especially if we ground every other pin to try to make it more noise
immune. That also grounds the backplane side of each board reducing noise. In
that case, I really don’t think that 40 pins is enough, especially if we
use 2 pins for each raw power supply (2 or 3) + Grounds. Two 40 pin connectors
(like HDD connectors could be stacked together. I’m not sure how many
there are on PCI but will take a look. The new PCI Express or mini PCI? Is
higher density, but more expensive.
Just thinking out loud. We need something,
especially if we want to mount a ‘radio’ board. PCI gives us the “L
Bracket edge” for connections to the outside world. But it is a little
big.
Eric
From:
xylo-sdr-bounces@lists.ae5k.us [mailto:xylo-sdr-bounces@lists.ae5k.us] On Behalf Of Leon Heller
Sent: Monday, January 02, 2006
4:35 AM
To: Xylo-SDR
Discussion
Subject: Re: [Xylo-SDR] Some
design thoughts requested
----- Original Message -----
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 wouldn’t 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 usedin Europe than
the USA,
but you can get them over there without any problems.
73, Leon
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