Since the very first C language version of the sdr, we integrated the received power in the filter (by summing the bins of the filter and relying on parseval's relation). This is indeed in do_rx_meter in sdr.c The thing to be aware of is that do_rx_meter is used for all metering in the receiver and it operates in many different states.
A few more minutes of looking and this would have all been trivially obvious. Tune to a place with no signal and have a (say) 500 Hz filter selected. The S meter will read above the noise floor in the power spectrum and the wider you make the filter, the more it goes up. This is exactly because it is the integrated power that passes through the filter and exactly how it should operate. Bob On Mon, Apr 13, 2009 at 1:34 PM, Eric Wachsmann <e...@flex-radio.com> wrote: > Actually, it will. There is an option for this in the Setup Form -> Display > Tab called "Show Decimal". > > > Eric > > On Mon, Apr 13, 2009 at 10:59 AM, Brian Lloyd <brian-wb6...@lloyd.com> > wrote: >> >> On Mon, Apr 13, 2009 at 5:29 AM, Bob McGwier <rwmcgw...@gmail.com> wrote: >> > You are not reading this correctly. >> > >> > The power displayed on the meter is integrated power in the receive >> > filter, >> > just as it should be. The computation is accurate to much more than 0.1 >> > dB >> > irrespective of what the display is doing. But as in all cases of such >> > compromises, it is designed to work for the use case of 99.9% of >> > amateurs >> > (and others) and that is to measure the strength of the signals that are >> > well above the noise floor. That is how it is calibrated. >> > >> > I do not believe your 1-2 dB number and will not without demonstration. >> > You provide proof, I will believe and see what we can do. >> >> Michael's (KI6QOC) science fair project supports your statement. His >> science fair experiment comparing antennas using the two receivers in >> the F5K was within a few tenths of a dB of the theoretical after >> averaging many samples. I only wish the S-meter read out in tenths of >> a dB. It would have made his project easier. >> >> 73 de Brian, WB6RQN/J79BPL >> >> _______________________________________________ >> FlexRadio Systems Mailing List >> FlexRadio@flex-radio.biz >> http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz >> Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ >> Knowledge Base: http://kc.flex-radio.com/ Homepage: >> http://www.flex-radio.com/ > > _______________________________________________ FlexRadio Systems Mailing List FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ Knowledge Base: http://kc.flex-radio.com/ Homepage: http://www.flex-radio.com/
