[time-nuts] Setting Osc Frequencies
Dr Bruce Griffiths
bruce.griffiths at xtra.co.nz
Sat Mar 3 22:52:40 EST 2007
Bill Janssen wrote:
> I built my own version of this scheme and it works OK but mine has some
> So I would like to have at least three of these.to replace my one.
> Anyone willing to take on the job of designing a circuit board?
> I log my results with a A-D converter and my Basic program
> Bill K7NOM
I can design a suitable circuit but may need someone else to do the
layout as my PCB layout software is rather ancient.
There are several options.
1) A CMOS design that operates with input frequencies up to about 20MHz
or so but is relatively inexpensive.
2) A modern ECL design that will operate with input frequencies up to
about 500MHz at a significantly greater cost.
3) A state of the art SiGe ECL design that will operate with input
frequencies up to 1GHz or so. The components wont be much more expensive
than option 2 but will probably need a PCB with a good high frequency
dielectric (teflon etc).
I would suggest that option 1 would be perfectly adequate for comparing
5 and 10MHz sources, whereas comparing 100MHz sources would require
either option 2 or option 3. If anyone wants to compare 1GHz sources
then option 3 would be useful.
Of course one can always use an external divider to produce frequencies
within the input range of the comparator.
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