[hpsdr] HERMES schedule question

[Ray Page]

Phil,

The more I think about it, I wonder if it would make more sense for me to
plan on using the Atlas architecture rather than the HERMES board as the
basis of the DSDR. I assume the Atlas backplane can handle a large number of
concurrent RX/TX baseband channels? If I took this path then I would combine
low-level RX/TX (Mercury/Penelope) DSP functions into a single FPGA and put
an FO transceiver on the board. The endpoint RX/TX modules would be the same
as I envisioned for HERMES. So, the rig would comprise a PS, Atlas, Ozy I/II
and my board. The antenna side would either be a combo RX/TX, or discrete RX
and TX boards. At a later point, the lessons of HERMES could be applied to a
single board derivative that could also interface the the FO RX/TX modules.

The actual FO link speed would be 20 x 122.88MHz = 2.4576Gbps. With a 97%
payload efficiency I am left with 2.384Gbps, where 1.966Gbps is for DDC/DUC
data and the rest is for ancillary data. I like this because it simplifies
the clocking schemes. If a disciplined 10MHz reference is available on the
Atlas bus, then this reference will propagate to the RX/TX modules via the
embedded FO clock.

Is this really all that appealing to anyone? I don't know if it is the
challenge or the end result that is driving me.

-Ray
Georgetown, TX



On Fri, Jun 18, 2010 at 8:55 PM, Phil Harman <phil at pharman.org> wrote:

>  Hi Ray,
>
> You are quite correct. The receiver board (Mercury) incorporates a Digital
> Down Converter that takes the 1.966Gbps ADC data at 16 bits per sample and
> reduces it to 48/96/192ksps at 24 bits per sample.  This slower data is
> passed over the Atlas bus to either an Ozy board (USB interface to the PC)
> or shortly an OzyII  board (Gigabit Ethernet).
>
> Hermes does the same except the functions of Mercury and Ozy are combined
> on the one board.
>
> 73's Phil...VK6APH
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.openhpsdr.org/pipermail/hpsdr-openhpsdr.org/attachments/20100618/24ae3683/attachment-0004.htm>