[hpsdr] Angelia external clock input?

[Jim Barber]

Thanks, Glenn. That's definitive enough for me.

I've been in touch with John, K5IT about the Angelia board he's working on.
I've seen boards on the Apache site as well, but they don't have prices 
listed,
just "$" with nothing after .  Not sure what that's all about .

Thanks for the reply,
Jim N7CXI


On 5/5/2015 5:42 PM, Glenn Elmore wrote:
> ***** High Performance Software Defined Radio Discussion List *****
>
>
> Jim,
> I can't provide any information as to a consensus but after studying 
> my new Angelia and analyzing why it didn't lock properly with an 
> external input, I came to the conclusion that the differential pair 
> external-10MHz condition circuit, which is essentially RTL, does not 
> have sufficient drive capability to provide the fast edges into the PC 
> track/TL and loading of the FPGA input.
> Mine almost worked on receive but came unglued on transmit.
>
> I wrote to Apache Labs who kindly sent me a new board - just installed 
> last night.  This board appears to solve the problem by inserting a 
> fast totem-pole output logic driver between the diff pair and the FPGA 
> line/input.  The result is that my Angelia now works properly on both 
> receive and transmit.
>
> I can see no combination of input levels or wave shape that will 
> likely accomplish this same goal.  I think you need a daughter board 
> or the equivalent.
>
> Just my opinion, not a consensus.
>
> Glenn n6gn
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