[time-nuts] 5>10 doubler

[Fuqua, Bill L]

  Ok, lets get real  here. 
Temperature variations, could cause a phase shift but a very very slow one, the degree would depend on the
Q of the filter, temperature coefficient of the crystal, and capacitor and how well it is isolated from turbulent air.
 I am not new to the game of making sensitive measurements using high Q filters.
 I would be more concerned with the phase changes due to the fractional Hz 1/f noise of the input threshold voltages of the FET's
also any trigger circuit that may follow used to feed counters etc in instruments preceding and following the doubler. I am surprised
that you aren't complaining about the sideband noise produced by the Brownian motion of nitrogen molecules inside the crystal case. 
  In this case it is a 2 pole filter and once the phasing capacitor is adjusted the only the mechanical vibrational resonance of the
crystal really counts. 
  If you are interested in High Q resonators, phase shift, etc.  you might want to take a look at  Review of Scientific Instruments 60, 3035 (1989),
"Use of a helical resonator as a capacitive transducer in vibrating reed measurements" where a helical resonator
is used to measure the vibrations of small crystals with an sensitivity of 10e-7 Angstroms per square root Hertz bandwith.
  Also, take a look at citations in other papers and patents referencing this design.
  I just tried to describe a simple very pure sine wave doubler for your readers.