On 9/16/2012 12:03 PM, Gerhard Hoffmann wrote:
Am 20.07.2012 00:57, schrieb Richard (Rick) Karlquist:
A fast comparator seems like a good idea, and it
is simple, however it is actually the last thing
you want to use. High thermal sensitivity and high jitter.
Rick
On 7/19/2012 1:35 PM, Dan Kemppainen wrote:
Or use a fast comparator such as an ADCMP600 series. Much lower delays,
and faster rising/falling edges.
FYI, I've had good luck with this at 30Mhz. You could transformer couple
this one, or simply couple it through a cap.
The ADCMP580 could be an excellent choice for the output stage
of a Collins type device. Running quite cool and showing only
180 ps _total_ delay is a good start.
Good rise/fall times on home-etched 0.5 mm FR4 (and some semi-rigid):
http://www.imagesup.de/bild-_Mgif-119362.htm
regards, Gerhard, dk4xp
Again, a really high speed comparator necessarily has a really broad
bandwidth, meaning its noise bandwidth is large. This means more
noise and more jitter than a lower speed comparator. The comparator
cited is much faster than necessary for 30 MHz, by orders of magnitude.
Rick N6RK
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