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<DIV><FONT size=2 face=Arial>Hi Ray,</FONT></DIV>
<DIV><FONT size=2 face=Arial></FONT> </DIV>
<DIV><FONT size=2 face=Arial>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).</FONT></DIV>
<DIV><FONT size=2 face=Arial></FONT> </DIV>
<DIV><FONT size=2 face=Arial>Hermes does the same except the functions of
Mercury and Ozy are combined on the one board.</FONT></DIV>
<DIV><FONT size=2 face=Arial></FONT> </DIV>
<DIV><FONT size=2 face=Arial>73's Phil...VK6APH </FONT></DIV>
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style="BORDER-LEFT: #000000 2px solid; PADDING-LEFT: 5px; PADDING-RIGHT: 0px; MARGIN-LEFT: 5px; MARGIN-RIGHT: 0px">
<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV
style="FONT: 10pt arial; BACKGROUND: #e4e4e4; font-color: black"><B>From:</B>
<A title=page.ray@gmail.com href="mailto:page.ray@gmail.com">Ray Page</A>
</DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A title=mcdermj@xenotropic.com
href="mailto:mcdermj@xenotropic.com">Jeremy McDermond</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Cc:</B> <A title=hpsdr@openhpsdr.org
href="mailto:hpsdr@openhpsdr.org">hpsdr@openhpsdr.org</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Saturday, June 19, 2010 6:37
AM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Re: [hpsdr] HERMES schedule
question</DIV>
<DIV><BR></DIV>***** High Performance Software Defined Radio Discussion List
*****<BR><BR>
<P>
<HR>
<P></P>Jeremy,<BR><BR>I thought about that. And will likely incorporate a
Gig-E interface rather than USB due to the time-line that I expect to have. I
may be misunderstanding something though. The Ozy-II will still be processing
baseband, right? In other words, the FPGA is processing the ADC samples to
create I/Q data that _then_ gets passed to the PC via USB, or Ethernet? The
raw data coming out of the ADC is 16 x 122.88 MHz, which translates to
1.966Gbps. So, unless some form of compression is used, I don't see how we can
get this down a Gig-E pipe.<BR><BR>Fiber-optic stuff always seems to have the
WOW factor, but it is really pretty simple once you get into it. Inside the
FPGA, connections will be made nearly identically to how they are now with the
exception that the connections are to the virtual parallel port versus the
actual parallel port of the ADC/DAC, etc. The cool thing is that all the
virtual parallel port/fiber-optic code already exist, it's time-tested, and I
own it, so it's available to us.<BR><BR>Gig-E can go 100m (and maybe this was
your point in the first place), which is well beyond USB, so the entire rig
can live close to the base of the antenna minimizing the advantage of
fiber. Hmmm... have to think about that. It certainly eliminates the
exposure to weather issue that an antenna-mounted device would be subjected
to. I'm sure the expense would be lower as well. I can hear the air leaving my
bubble.<BR><BR>-Ray<BR><BR>
<DIV class=gmail_quote>On Fri, Jun 18, 2010 at 5:08 PM, Jeremy McDermond <SPAN
dir=ltr><<A
href="mailto:mcdermj@xenotropic.com">mcdermj@xenotropic.com</A>></SPAN>
wrote:<BR>
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class=gmail_quote>Wow -- That sounds like a very ambitious project,
Ray. I'm interested in what you come up with. Keep in mind that
software-wise, things are going to be moving towards a Gigabit Ethernet
network interface (See the Ozy II Project) because USB can't handle enough
of what we're sampling at the antenna. So, given that in this case
your data is going to get packetized at some point in time, it might be just
as easy to get a fiber->copper Gig-E converter. I'm not trying to
discourage you in any way, but just trying to let you know that the USB on
Hermes is about to be eclipsed by Ozy II to a certain extent.<BR>
<DIV class=im><BR></DIV></BLOCKQUOTE></DIV><BR>
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