[time-nuts] up converting 10MHz to 20MHz

ed breya eb at telight.com
Wed Dec 10 15:41:50 UTC 2014


There are a number of ways to multiply-up the 10 MHz, but what about 
just changing things around to make the 20 MHz VCTXO phase-locked to 
the 10 MHz OCXO, and then discipline the 10 MHz. There will be phase 
noise issues, whether doubling one thing, or dividing the other by 
two, but overall, I think it's easier to divide or subtract with some 
type of mixing process, and then drive the VCTCXO from the result, 
forming a PLL. The overall process should be OK as long as the uP 
gets the right answer on average, over the necessary time frame.

Ed




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