parametric detector

Hi,
Im looking at using a parametric method for a phase detector,
The source (~4mhz) is already very strong but the sideband, @ 1-10hz, is
extremely low, I am considering using a quartz crystal as the most sensitive
slope detector but to get a significant signal to noise ratio I would need a
crystal with a Q of over a million. I dont expect acheiving such a high Q is
practical, unless cooling it drasticaly would help ?

The main noise problem is 1/f noise especialy as a high Q circuit would need
a high impedance amplifier and a mosfet would have too high 1/f noise at
<10hz.

However I cant see a way of using a paramatric method for a detector, at
least not with any gain, I havnt realy looked at them much before, although
I know the basic principles of operation of using as using variable
reactance in a ac voltage dividor or charge/voltage pump.

I came accros an old parametric amplifier by AD the 310/311 but I doubt they
make this any more, at least something like this might be usefull after a
diode detector, although I am not sure about how much the diode noise
particularly 1/f noise would be.

Colin =^.^=


.

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