Bruce Griffiths skrev: > Hal > > Hal Murray wrote: >>> JPL have used ECL dividers throughout to produce 10MHz, 1MHz and >>> 100KHz outputs from the 100MHz signal derived from a Hydrogen maser: >>> http://tmo.jpl.nasa.gov/progress_report2/42-30/30I.PDF >>> >> We've been discussion converting sine to TTL. JPL seems to be distributing >> ECL rather than sine. >> >> This seems like more bait for a FAQ. >> >> What are the (dis)advantages of using ECL or TTL vs sine for distribution? >> (I'm assuming "TTL" covers HC/AHC and 3V CMOS levels too.) >> >> > > CMOS dividers are supposed to have a lower phase noise floor than ECL > dividers but the measurements in the literature are poorly specified. > Comparing a CMOS divider with at 20MHz input with an ECL divider with a > 200MHz input probably isnt very helpful.
CMOS is moving fast. Using old measurements may not indicate anything meaningful of today with modern devices. CMOS is also not as homogenic as one may first believe since there exists various tricks to speed CMOS up in especially clocked environments. CMOS is nothing but a collective name these days rather than a very particular technique as it once where, if ever. Cheers, Magnus _______________________________________________ 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.
