[hpsdr] Some thoughts on plug-in board layout

[Philip Covington]

Hi Phil,

On 5/25/06, pvharman at arach.net.au <pvharman at arach.net.au> wrote:
> All,
>
> A couple of comments on the new board design. I assume that the location of
> the DIN connector will be fixed such that any connectors on the edge of the
> board will always line up with the inside edge of the  enclosure i.e. any
> increase in card size will be on the opposite edge to where the  connectors
> are fitted.

Yep, we need to time down that location.  Steve has done and is
redoing a plug-in card drawing that will give us location for the
DIN41612.  We may have to modify it a bit depending on Lyle's results.

The external connector end of the plug-in board needs to over-hang the
ATLAS board by 15mm.  That will ensure that the ATLAS board will have
enough clearance inside an ATX case for the plug-in card to be mounted
in the slots like a PCI card mounts.

> Re the Janus connectors.  The prototype Janus board is showing a sensitivity
> in the uV region. The reason for keeping the outputs  (Left/Right audio and
> I/Q) well away from either the 3.5mm jack or  5 pin header is to try and keep
> as much separation as possible between these outputs and inputs.  We did
> debate a Delta 44 style break-out box some time ago, as well as the use of
> 3.5mm jacks, and the current design reflects what was decided.
>
> My only concern with moving to the  new board layout is that we can keep all
> the digital signals out of the A/D front end.  At the moment at 192k
> bandscope width I can see the 48k clock feeding the TLV320 at about -120dBm.
> That may get better once we move to a PCB rather than dead-bug construction….
> Time will tell.
>
> Phil….VK6APH

We will keep our fingers crossed.  Lyle should be able to tell us soon
how the new layout is going with the JANUS.

73 de Phil N8VB

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