On 10/02/2014 06:03 AM, Richard (Rick) Karlquist wrote:
On 10/1/2014 1:04 PM, Hal Murray wrote:
drkir...@kirkbymicrowave.co.uk said:
Anyway, later today (tomorrow ??) I will post a plot of frequency vs
time.
The question is though, how long is thing thing likely to take too cool?
I'd
David,
The character of starting high/low and then stabilize some 5-30 min
later is typical of oven oscillators. Underdamped ovens have been seen
before, I have even seen one on the brink of oscillation.
TCXO will not have the same wide range, as it compensate for the
temperature.
Cheers,
Would it not be better for phase noise to use a logic gate with a fast
transition than a resistive divider that would be slower due to the load
capacitance?
David
On 10/1/14 7:09 AM, Bob Camp wrote:
Hi
Ok, so it’s not a super duper low phase noise OCXO. It’s also at a reasonably
high
On 2 Oct 2014 07:10, Magnus Danielson mag...@rubidium.dyndns.org wrote:
David,
The character of starting high/low and then stabilize some 5-30 min later
is typical of oven oscillators. Underdamped ovens have been seen before, I
have even seen one on the brink of oscillation.
Thank you. Do you
Hi
It will indeed be better for phase noise to do away with the resistive divider
and get faster edges.
Of course there are indeed resistive dividers that don’t slow things down. It’s
unlikely that a divider with a 10 ohm output impedance is going to tack on to
the output of an OCXO.
The overshoot behavior from 150 to 220 seconds is exactly what you expect
for slightly less than critical damping which is where many closed loops
end up when rapid lock or warmup is a criteria. Most rapid warmup is almost
always the design point of an OCXO oven.
Tim N3QE
On Thu, Oct 2, 2014 at
As to oscillation: most older octal style crystal ovens have no
proportional control at all, they are simply a bimetallic
click-on-click-off thermostatic switch that is on or off, and after initial
warmup they cycle up and down every few minutes.
A tiny fraction of the better octal crystal ovens
The most extreme example of slow ovenized oscillator warm-up I've seen is the
vintage hp106. These mid-1960's oscillators were designed as the ultimate, hp
way, pre-atomic, frequency standard -- expected to be powered up,
uninterrupted, for years and decades. So there was no hurry in the
Tom,
Nice performance. Wish we could get that today! My fairly modern BVA is nowhere
near that stability.
If you open up a brand new DOCXO you will see a crystal designed in the 70's
and an oscillator circuit designed sometime in the 30's or 40's, maybe updated
to a more or less modern
Len Cutler was pretty much allowed to do whatever he wanted
on the HP106 and he produced the proverbial doomsday machine.
I think the SR-71 analogy is good here, except that Kelly
Johnson had a lot more support from his management. Len always wanted
to make an optically pumped cesium as his
Hi
That 106 comes up *fast*. Take a look at the GR equivalent if you want to see
slow…..
Bob
On Oct 2, 2014, at 2:58 PM, Tom Van Baak t...@leapsecond.com wrote:
The most extreme example of slow ovenized oscillator warm-up I've seen is the
vintage hp106. These mid-1960's oscillators were
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