[time-nuts] Comparing 10 MHz Oscillators at 10 GHz- an alternative method?
Bob Camp
lists at rtty.us
Tue Jan 11 12:25:11 UTC 2011
Hi
The normal term for a gizmo that multiplies and then mixes down is an error multiplier. They were a very common lab item back when I had more hair than I do now.. Various people made them in the 1950's and 1960's.
Bob
On Jan 10, 2011, at 9:35 PM, 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
>
>
>
>
>
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