On Sat, 17 Mar 2012 10:15:17 +0000 "Poul-Henning Kamp" <p...@phk.freebsd.dk> wrote:
> In message <20120317111119.9536107ebf82050fe14ee...@kinali.ch>, Attila Kinali > w > rites: > >On Sat, 17 Mar 2012 10:01:13 +0000 > > >Could you explain why? Yes, you need a higher BW for Loran-C, > >but the phase(f) function will give you only a distortion of > >the signal and a constant time delay in your signal recovery. > >But that shouldnt degrade the usefullness of the system. > >What am i missing here? > > Either you need to characterize the exact behaviour of your filter > and build the necessary compensation for its phase/frequency behaviour > into your receiver, or you need a very flat filter (both freq+phase) > in order to reliably recognize the proper zero-crossing to track. > > The more you disturb a Loran-C pulse, the more it just looks like > a bit of a sine-function, and the harder it is to lock on the right > zero-crossing. Ah.. so it is because Loran-C uses the third zero crossing as specified measurement point, which you thus have to capture with the greates possible resolution. Am i right that for DCF77, WWVB and the like, where there is no such requirement on the zero crossing of a pulse, one can just lock to the carrier and the distortions from filters are not so relevant? Attila Kinali -- Why does it take years to find the answers to the questions one should have asked long ago? _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.