[USRP-users] N210 DDC gain

Marcus D. Leech mleech at ripnet.com
Wed Sep 12 10:58:45 EDT 2012


> On 12/09/12 10:04, Josh Blum wrote:
>>
>
> Great, thanks very much! I can confirm that, with the patch, I now see 
> a sensitivity of 54500 counts/V with 6 dB gain enabled. As expected, 
> this is twice what I saw before +/- measurement error.
>
> It still seems to be ~1.6 dB short of what I'd expect though. I guess 
> maybe losses in the analogue circuitry in the Basic RX board might 
> account for ~0.5 dB, but I'm not sure about the rest. I wonder if this 
> sort of result is typical of real-world measurements?
>
> Andrew.
>
I'll observe that if you're relying on a particular mapping of volts-in 
to bits-out, then you're thinking digitally, and you need to stop it :-)

The main thing to worry about is whether things are largely linear. 
  Does a doubling in input voltage result in doubling the binary
   magnitude, more-or-less?


-- 
Marcus Leech
Principal Investigator
Shirleys Bay Radio Astronomy Consortium
http://www.sbrac.org






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