IMHO, The dual oven 10811 oscillators I've seen are not designed as some hack JUST to do a quick warm-up. The six sided heater and all the trouble they went thru to insulate the inside oven from any effects from the outside is a design meant to keep the inside oven highly isolated from wide ambient temperature changes. The fact that the outside oven is such an overkill in both the total power it can supply and how isolated it keeps the inside, It will surely do both. The outside oven on mine runs at 1/100 of it's max heating power, and any osc frequency change caused by normal room temperature changes is will below the oscillator's noise level. In other words, normal lab temperature variations, have NO measurable effect on the Dual Oven 10811's frequency, something that can NOT be said of the single oven unit's I've tested.
ws
******************* At 07:59 AM 1/10/2011, Bob Camp wrote...
The spec they were after was a warmup to "on frequency +/- 1x10^-8" from -40 C sort of thing. I believe the warmup time was under 15 minutes, but I don't know the exact number.
Nope. It was only spec'd for operation from 0-50C. It was required to achieve satellite lock within 60 minutes of powerup, but only had to achieve +/- 1 us (PPS) while locked. Freq spec was < 10E-9 one day average. You don't even need an OCXO to do all of that. As I already stated, the warmup/training spec allowed 24 hours, after which it was expected to be able to holdover for 24 hours within 7 us. This, while experiencing temperature cycles (0-30C, 20-50C). The successor, the GPSTM, doubled the warmup to 48 hours, but added an additional temperature range (35-65C) to the holdover requirement. The double oven was there for holdover stability, not warmup time.
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