hmmm, I re-read Bob's comments about lengthening the FFT bin containing the FMT, frequency of interest.
"If you have a carrier and apply successive FFT blocks to it..." That technique will produce a longer sample bin, a longer 'yardstick' with which the phase of the FMT can be better measured. Also, the longer 'yardstick' will help average out the noise any one bin may have. My comment about the phase display rotation would only apply to calibrating against WWV. my bad. note: please excuse my English, math is not my native tongue. ;-) ________________________________ From: "FlexRadio Support, Dudley Hurry" <[email protected]> To: Ted <[email protected]> Cc: "[email protected]" <[email protected]> Sent: Tue, November 16, 2010 9:02:40 AM Subject: Re: [FlexEdge] FMT next time Maybe have the DDS offset take decimal increments? Dudley 73, Dudley WA5QPZ FlexRadio Systems (512) 250-8595, Option 2 Email: [email protected] Web: www.flexradio.com "Tune in excitement!" ™ On Tue, Nov 16, 2010 at 10:22 AM, Ted <[email protected]> wrote: > >Until the enhancement is coded can we use a low tech stop watch to time the >rotation of the phase display and average the time over many rotations? i.e. >does the phase rotation of the bin correlate closely to the rotation of the >phase display? > > >Ted >NX6C > > > >________________________________ >From: Tim Ellison <[email protected]> >To: Bob McGwier <[email protected]>; Flex Edge <[email protected]> >Sent: Tue, November 16, 2010 4:47:18 AM >Subject: Re: [FlexEdge] FMT next time > > >Sounds like an enhancement for the Frequency calibration routine in PowerSDR ><wink>. > > >-Tim > > >-----Original Message----- >From: [email protected] [mailto:[email protected]] >On Behalf Of Bob McGwier >Sent: Tuesday, November 16, 2010 6:47 AM >To: Flex Edge >Subject: [FlexEdge] FMT next time > > >1) I want to listen to WWV with a larger FFT than we currently listen to in the >the code. >2) I want to listen to contiguous blocks of these FFT results. > >The phase spin of the WWV carrier is DIRECTLY usable to compute the frequency >offset (up to ionospheric disturbance) and should lead to mHz accuracy. > >Using this computed estimate of the oscillator inaccuracy in the receiver we can >then apply the same process in an FMT with the calibrated receiver. > >If you have a carrier and apply successive FFT blocks to it, the phase rotation >of the bin containing the FMT carrier gives the frequency offset from the center >of the block and can be made more accurate by filtering the resulting offsets to >get a more noise free version. > >Bob >N4HY >-- >(Co)Author: DttSP, Quiktrak, PowerSDR, GnuRadio >Member: ARRL, AMSAT, AMSAT-DL, TAPR, Packrats, NJQRP, QRP ARCI, QCWA, FRC. >"Be yourself, because the people who mind don't matter. And the people that >matter don't mind." >-Dr. Seuss >Active: Facebook,Twitter,LinkedIn > >_______________________________________________ >Flexedge mailing list >[email protected] >http://mail.flex-radio.biz/mailman/listinfo/flexedge_flex-radio.biz >This is the FlexRadio Systems e-mail Reflector called FlexEdge. It is used for >posting topics related to SDR software development and experimentalist who are >using beta versions of the software. > >_______________________________________________ >Flexedge mailing list >[email protected] >http://mail.flex-radio.biz/mailman/listinfo/flexedge_flex-radio.biz >This is the FlexRadio Systems e-mail Reflector called FlexEdge. It is used for >posting topics related to SDR software development and experimentalist who are >using beta versions of the software. > > > >_______________________________________________ >Flexedge mailing list >[email protected] >http://mail.flex-radio.biz/mailman/listinfo/flexedge_flex-radio.biz >This is the FlexRadio Systems e-mail Reflector called FlexEdge. It is used >for >posting topics related to SDR software development and experimentalist who are >using beta versions of the software. > _______________________________________________ Flexedge mailing list [email protected] http://mail.flex-radio.biz/mailman/listinfo/flexedge_flex-radio.biz This is the FlexRadio Systems e-mail Reflector called FlexEdge. It is used for posting topics related to SDR software development and experimentalist who are using beta versions of the software.
