Re: [Discuss-gnuradio] Support for 8-bit USB samples in GRC

[Marcus D. Leech]

Marcus D. Leech wrote:
> Josh Blum wrote:
>   
>> svn up!
>>
>> let me know if something goes wrong
>>
>>     
> Intersesting.
>
> When I use 8-bit samples with decim=8 or higher, things are peachy.
>
> But when I use decim=16 with 8-bits samples, I get a continuous stream
> of -423dB out of the FFT Log Power sink.
>
> I think what I'm getting is a pile of 0s from the USRP when decim=4.
>
> Can anybody confirm that decim < 8 actually works on the USRP?
>
>
>
>   
OK, let's try that again with my brain actually engaged.

Anything with decim=8 or higher, in 8-bit mode, produces "sensible" samples.

Anything with decim lower than 8 (like 4) produces nonsensical results
in the Log Power FFT sink (a continuous block
  of -423dB).  I suspect that with decim=4, there ain't nothing but
zeros going across the USB.

So, does decim=4 actually work on the USRP, or do I need different firmware?




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