What does "combination of the LO in the front end and the digital downconverter" mean please?
Eric Blossom wrote: > > On Fri, Jul 25, 2008 at 10:11:34AM -0700, Y. Zhuang wrote: >> http://en.wikipedia.org/wiki/List_of_WLAN_channels >> >> Is it because the channel for 802.11 in 2.432G there, so the front end >> was tuned to 2.432G? But there is 2.437G as well. >> Or the font end is just picking the strongest channel it finds? Thanks >> >> Y > > None of the above. I'm just decoding the details of how the usrp was > tuned using a combination of the LO in the front end and the digital > downconverter. The command line shows -f 2.437G. See the excellent > USRP FAQ for additional info. http://gnuradio.org/trac/wiki/UsrpFAQ > > Eric > > >> >> 2008/7/25 Eric Blossom <[EMAIL PROTECTED]>: >> > 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 >> > > > > _______________________________________________ > Discuss-gnuradio mailing list > Discuss-gnuradio@gnu.org > http://lists.gnu.org/mailman/listinfo/discuss-gnuradio > > -- View this message in context: http://www.nabble.com/BBN-802.11-bbn_80211b_rx.py-tp18642793p18693934.html Sent from the GnuRadio mailing list archive at Nabble.com. _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
