On Sat, 17 Mar 2012 06:13:28 -0700 gary <li...@lazygranch.com> wrote:
> On 3/17/2012 5:44 AM, Attila Kinali wrote: > > On Sat, 17 Mar 2012 10:15:17 +0000 > > "Poul-Henning Kamp"<p...@phk.freebsd.dk> wrote: > > > >> 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. > > > > BTW: how do you compensate for the filter characteristics of your > > magnetic loop antenna? > Any filter's group delay can be equalized by all pass filters. > > Delay builds up at the filter corner. Since everything in the real world > is causal, you add delay outside that corner frequency but in the > passband to equalize it. This is to say, you can't remove delay, but > just add it to flatten out the group delay. Sorry, i asked in a misleading way. I didnt mean to ask what technique to use to flaten the phase delay, but rather how does phk know how the compensating filter should look like? For this, one needs to exactly characterize the antenna-amplifier chain...AFAIK 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.