[time-nuts] 10 MHz -> 16 MHz

ed breya eb at telight.com
Sun Sep 30 13:32:19 EDT 2018


I'd recommend keeping the involved frequencies and power as low as 
possible. The VCO/PLL route is probably the most straightforward, but 
using arithmetic operations instead can be simpler at this frequency, 
because the filtering can be readily done with common crystals.

If you divide the 10 MHz by 5, then mix the resulting 2 MHz back with 
the 10, you'll get mostly 12 and 8 MHz. Double that result to get mostly 
24 and 16 MHz, then filter the 16 MHz out with as fancy a filter as 
necessary. 16 MHz is a very common crystal frequency, so you could do 
that for filtering, or even make a ladder filter with a bunch of them.

With the VCO/PLL approach, the desired 16 MHz will be the highest 
frequency, while the arithmetic one uses 24 MHz maximum working 
frequency, neglecting harmonics. The logic can all be done with 74HC, at 
reasonable quietness and power.

Ed



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