see also: http://www.timeok.it/files/10_mhz_bandpass_filter.pdf -- Luciano P. S. Paramithiotti IZ5JHJ
--------- Original Message -------- From: Discussion of precise time and frequency measurement <time-nuts@febo.com> To: Discussion of precise time and frequency measurement <time-nuts@febo.com> Subject: Re: [time-nuts] filtering a 10Mhz frequency standard? Date: Dec 13, 2011 10:29 PM > If you are going to buffer the output, why does the filter have to be > passive? Did I miss something here? Today 10MHz is in the realm of > active filters. [Hey, not that I made an active filter at 10MHz.] > > Sensitivity is a function of the denominator. The only advantage to a > LPF over a BPF is the BPF has to be centered at 10MHz, while you could > bump the corner of the LPF to a higher frequency so there is less > sensitivity at 10MHz This presumes you are only getting rid of harmonics > and not spurs. > > For lowest component sensitivity, leap frog designs are best. But in > continuous time designs, they require many op amps per pole. > > _______________________________________________ > 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. > Sent to you using Uebimiau Webmail version 3.11 Developed by Dave and Todd at http://www.manvel.net and http://www.tdah.us _______________________________________________ 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.