[hpsdr] Strange question about Penelope

[Philip Covington]

On Mon, May 19, 2008 at 4:42 PM, Alberto I2PHD <i2phd at weaksignals.com> wrote:
> ***** High Performance Software Defined Radio Discussion List *****
>
> Nobody answered the question I posted a few days ago, probably because I
> wasn't clear enough.
> Let's try with different wording.
> Is it possible to use the Penelope card with a process that is the logical
> reverse of that of Mercury, Qs1r, Perseus, etc. ?
> In those receivers the signal is first digitized, then it passes through a
> DDC, and finally sent to the PC via the USB port with a large bandwidth. My
> question is : can Penelope do the reverse ? I.e. can it accept a large
> bandwidth I/Q data stream via the USB port (with the help of Ozy), bring the
> signal to the frequency of interest via the DUC, then generate with the DAC
> the final output RF signal ?
> Or is it limited to process the audio signal coming from the microphone
> input ? Is it just a matter of reprogramming the FPGA, or are there hardware
> changes involved to do what I am asking about ? Thanks for any answer.
>
> 73  Alberto  I2PHD
> ---------------------------------------

Hi Alberto,

I do not have a Penelope, so I am just guessing at this.  I would
think it would pretty easily take something like a 192 kHz I/Q file
and replay it out it's output.  It would probably be able to process
even wider files as long as you can pass it quickly enough from OZY to
Penelope.  You would need a custom FPGA file to do this, but shouldn't
be a problem.

I have an initial prototype of the QS1T transmitter board and I do
exactly what you describe with 50 kSPS to 1 MSPS I/Q files.   All I/Q
files were generated with the QS1R by recording directly to disk.
These standard files recorded from a known good QS1R makes it easy to
do initial tests on production QS1R boards since all I have to do is
select the proper I/Q file and play it out the DAC to the QS1R under
test.

Regards,

Phil Covington
Software Radio Laboratory LLC
Columbus, Ohio
http://www.srl-llc.com

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