[time-nuts] Re: repair of an HP E1938A OCXO
Chris Caudle
chris at chriscaudle.org
Tue Jul 1 12:43:05 UTC 2025
On Thursday, June 26, 2025 3:47:48â¯PM Central Daylight Time Bob Camp via time-
nuts wrote:
> There really is no practical way to get an accurate temperature sensor
> inside the oven / on the crystal, without upsetting the operation of the
> device.
Do you really need to measure the temperature independently? I don't fully
understand the control scheme and the differences between C mode and B mode,
but if you get the oven to the right temperature, will that not set the
oscillator output back to within spec? I recall the original description was
the measurement was with EFC connected to 0V, so I guess you would need to
know what the nominal value of the EFC should be for on-target frequency.
Am I thinking too simplistically? Is there a range of oven temperatures where
the output is close to nominal but the temperature coefficient is not optimal?
--
Chris Caudle
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