[time-nuts] Comparing 10 MHz Oscillators at 10 GHz- an alternative method?
sandeenpa at yahoo.com
Tue Jan 11 02:35:09 UTC 2011
While comparing oscillators at 10 GHz might work for some it is indeed a daunting challenge at the very least.
I would like to propose what may be cheaper and more readily achieved method for Comparing 10 MHz Oscillators by more of us time-nuts. (This is still theoretical)
What I propose is this:
Make two separate, but exactly the same, circuits, one for the reference and the other for the unknown to be measured. They would be located parallel to each on a circuit board.
The input would be divided by a decade counter giving us a 1 MHz signal. Then we use this signal to phase lock the oscillator section of a CD 4046 to 10MHz. The 10 MHz signal goes into one port of a LM 1496 double balanced mixer. The other input would be from a reasonably stable 9 MHz oscillator. Taking the DBM output into a simple low pass filter we use that 1MHz signal to phase lock the next CD 4046 oscillator to 10 MHz. Then we start the whole process again.
At any point we chose along the chain or at the end we feed both 10 Mhz signals into a single CD 4046 or similar phase detector and obtain our offset.
Since each set of circuits is fed with the same 9 MHz subtraction oscillator, any deviation of its performance is cancelled.
The required chips are inexpensive and these frequencies are far more manageable than microwaves.
Constructive criticism? Comments? Improvements?
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