[time-nuts] Comparing 10 MHz Oscillators at 10 GHz- an alternative method?

[Bruce Griffiths]

Perry Sandeen wrote:
> List,
>
> 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?
>
> Regards,
>
> Perrier
>
>    
Eliminate the PLL's as they are not necessary.

However the exercise is probably pointless as the frequency difference 
between the 2 signals as seen at the output of the cascaded divide and 
mix chains are reduced by this scheme.
You need to multiply the input signals to a nominal 100MHz then subtract 
90MHz using a mixer and repeat the process.

Bruce