Re: [Discuss-gnuradio] BBN 802.11 bbn_80211b_rx.py

[Eric Blossom]

On Fri, Jul 25, 2008 at 07:46:58AM -0400, Greg Troxel wrote:
>   BTW, what does that guy mean "Not sure when you updated, but we have changed
>   the checked in code to default to 2437, and run it like this (as a NetBSD
>   rc.d start script)", following the above link?
> 
> details if you care, but surely they have little to do with your issues.
> 
>   http://www.netbsd.org/docs/guide/en/chap-rc.html
> 
> about your output:
> 
>   ./bbn_80211b_rx.py -f 2.437G -v -b
>   Bits Per Encoded Sample = 8
>   adc frequency =  64000000
>   decimation frequency =  16
>   input_rate =  4000000
>   gain =  45.0
>   desired freq =  2437000000.0
>   baseband frequency 2432000000.0
>   dxc frequency -5000000.0
>   Samples per data bit =  8
>   >>> gr_fir_ccf: using SSE
> 
>   2.432G is used instead of 2.437G.  Also the dxc frequency is negative.  And
>   no packets get printed out. 
> 
> I am unclear on dxc.

That part is fine.  dxc = digital down converter (DDC) or DUC depending on the 
context.
In this case he wanted 2.437G.  The front end was tuned to 2.432G, thus
the DDC needed to be set to -5M to get the desired frequency translated
to 0 Hz in the complex baseband.

Eric