[hpsdr] Call for Comments and Discussion - OzyII

[Bob Cowdery]

Eric Blossom wrote:
> On Tue, Jul 21, 2009 at 12:29:20PM +0100, Bob Cowdery wrote:
>   
>> ***** High Performance Software Defined Radio Discussion List *****
>>
>> Hi all,
>>
>> A few extracts and comments below. These make me think that the first  
>> step should be to establish what the objectives are because the  
>> possibilities are wide ranging.
>>
>> Bob
>> G3UKB
>>
>>
>> "I'd say UDP is the way to go. Not only is UDP almost trivial to  
>> implement into an FPGA once you have raw Ethernet TX/RX working, its  
>> functionality is easily sufficient for modern HDR systems. Datagram loss  
>> is not an issue when streaming over a (dedicated) local net, and a host  
>> that can't keep up with an UDP flow will certainly choke on the same  
>> flow over TCP."
>>
>> This seems to be a pragmatic proven option but doesn't add huge value  
>> over OZY1 except cable length and multicast. These two alone may be  
>> sufficient justification.
>>     
>
> With gigabit ethernet and jumbo frames it's possible to transfer
> 120MB/s to/from the host.  That about 4x what you can do with USB
> _and_ it's full duplex.  (When you start sending 120MB/s to/from the
> host you'll find you have a whole new set of problems ;-))
>
> Eric
>   
That may be so, but is it a requirement to have such a data rate. Could 
you use it in any sensible way. Could you run multiple Mercury cards for 
example.

Bob



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