[time-nuts] Fury Interface Board: 5MHz needed?

[Peter Schmelcher]

>Date: Sun, 04 Nov 2007 10:24:59 -0500
>From: xaos <xaos at darksmile.net>
>Subject: Re: [time-nuts] Fury Interface Board: 5MHz needed?
>To: Discussion of precise time and frequency measurement
>         <time-nuts at febo.com>
>Message-ID: <472DE44B.7050407 at darksmile.net>
>Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>
>Hello everyone,
>
>Shall we consider 5MHz OCXO's?
>
>I have a BUNCH of those. Most are really low end devices but I also have
>a few gems.

George for a single ground pin OXCO you might want to consider compensating 
for the oven's internal ground bounce. The voltage drop caused by a normal 
heater current is around 1/4 to 1/2mV for an MTI 260 oven. Calibration 
would be to run the oven at different heater currents and adjust the ground 
bounce circuit until the EFC reading does not change. Current sensing the 
ground pin also has the potential advantage of partially compensating for a 
misadjusted turning point. A much simpler alternative might be to just 
reference the EFC voltage to the oven's reference voltage pin rather than 
the oven's ground pin and avoid the ground bounce problem altogether.
Just a thought
Peter