Frequency accuracy?

[Jim Coleman, Sr.]

Hi Robert:

In the calibrate mode, the program and machine are being calibrated to
the internal quartz crystal frequency.

On the newer machine which are temperature compensated, they stay in
calibration very well.

The older machines tend to drift a bit, hence the need for calibration.

Jim Coleman, Sr.

On Fri, 18 Jun 1999, Robert Scott wrote:

> Newton, when you say:
> 
> >If the lights on the SAT are unchanging for several seconds after
> >turning it on then it is calibrated.  If your fork does not agree
> >then the fork is off...period...end of story. 
> 
> are you implying that the SAT can check its own calibration without
> making reference to any external source of frequency?  That
> doesn't seem possible.  Whatever calibration the SAT has must be
> the result of an initial trimming in the factory.  After that,
> you are just trusting that the circuitry won't drift too much
> (probably a safe assumption, but still only an assumption).
> I don't know what is being checked when the unit is first
> turned on.  Does anyone know for sure?
> 
> -Bob Scott
>  Ann Arbor, Michigan
> 
> 
>