[time-nuts] filtering a 10Mhz frequency standard?
lists at lazygranch.com
Tue Dec 13 16:27:54 EST 2011
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.
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