Rob wrote:
Terje Mathisen <[email protected]> wrote:
Charles Swiger wrote:
On Feb 12, 2015, at 1:56 AM, Rob <[email protected]> wrote:
However, what I observe is that the plots of the offset show the derivative
of the environment temperature, which unfortunately cannot be controlled
any better. I am considering to locate the crystal that is responsible
for the timing and see if it could be ovenized or replaced by a more
I've considered packing some insulation around the crystal, this would
tend to stabilize (while also increasing) the temperature, but this
would also be likely to reduce its lifetime, and the motherboard would
probably conduct heat too well.
That will only slow down the rate of change, and probably not much.
We tend to have temperature cycles over 24h and this will not help.
At least in my case on occasions the rate of change seems to
be faster than the control loop can handle and offsets of my
various pcs rather than being < 300u rise to 10ms. Only a
small reduction in rate of change would be required to
avoid this. Thermostatic temperature control at the crystal
or a stable external clock source would be better but more
difficult to implement.
David
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