[time-nuts] 5 MHZ PIC PPS Divider?

Pete peterawson at earthlink.net
Tue Apr 15 16:13:02 EDT 2008


Stanley,

Jitter measurements of moderately high frequency
sources can be made directly with relatively cheap
used instruments.

Older sampling 'scopes from H-P and TEK appear
on *Bay frequently. The H-P 54120 family boxes
are down to US$500 to 800 with sampling heads 
capable of 12.4GHz measurements. These show up
about once per month. If you're trying to buy one,
wait for a complete system (mainframe+sampling 
head) which is listed as operational & you have
confidence it's actually working. These things are
HEAVY & having to return a junker is painful;
even if you get your money back.

These mainframes have jitter capture & analysis
built in. The internal trigger jitter floor is about 1ps,
good enough for most measurements. The internal
timebase delay feature allows measuring multi-
cycle jitter out to many screens width of data.
Obviously, long delays will introduce added
jitter floor contribution, but it's still quite good.

Regards,
Pete Rawson



More information about the time-nuts mailing list