Thanks Marcus. You did manage to tie up several loose ends, and I really appreciate it! All the best.
Vlad. Marcus D. Leech wrote: > > On 11/28/2010 06:53 PM, Vladutzzz wrote: >> Marcus, >> First of all thank you for your reply! >> I have some questions about your very much appreciated explanations: >> After using the complex-to-mag-squared block, should I consider the >> coefficients as being in W or mW (should I use 10*log10 or 30 + 10*log10 >> to >> get the power value in dBm)? >> What is the function of the single-pole-iir_filter? What does it actualy >> do? >> I'm asking this so I will know how to calculate its parameters. Does it >> give >> the frequency bin based signal band, a more rounded appearance? >> Again thank you for your help! >> I hope other people will also find this useful. >> >> Vlad. >> >> > You expressed a desire to measure power over a finite bandwidth (at > least, that's what I think > you were asking). > > The values after the complex-to-mag-squared block are *unscaled* total > power estimates over > the input bandwidth. The IIR filter is used to smooth the result--in > a hardware power detector, > it would be a simple R-C network, here we use a simple single-pole > IIR filter, although you could > use a simple FIR low-pass as well, but the single-pole IIR is cheap, > and has adequate > behaviour for total-power detection--it's what I use in radiometry. > > In order to convert to your favourite units (like dBm), you'll have to > take some > *experimental measurements*, and scale the output values > accordingly. Please re-read > my original reply, I'm not going to repeat it here. > > > > > -- > Marcus Leech > Principal Investigator > Shirleys Bay Radio Astronomy Consortium > http://www.sbrac.org > > > > _______________________________________________ > Discuss-gnuradio mailing list > Discuss-gnuradio@gnu.org > http://lists.gnu.org/mailman/listinfo/discuss-gnuradio > > -- View this message in context: http://old.nabble.com/Bandpower-measurment-USRP2-tp30323488p30335394.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
