[time-nuts] ocxo

Don Latham djl at montana.com
Sun Nov 23 19:22:29 EST 2014


No question about that. The morion does run a little warmer than the old unit
apparently did. Fan is temp-controlled, so I think OK. will monitor box temp
with a digital :-) thermometer, very poor resolution, but probably ok.
When I get the last obs done. will do a little blurb to the group.
Don

Bob Camp
> Hi
>
> That sounds fine. Without knowing just what they did or didn’t do, it’s always
> worth being a bit careful.
>
> Bob
>
>> On Nov 23, 2014, at 6:40 PM, Don Latham <djl at montana.com> wrote:
>>
>> Running very nearly continuously for about 4 days now. The self-measured
>> jitter is mean 0 and sdev of 8 ps. I don't think there is a problem with the
>> Morion. I'm using my newly acquired cs source and a couple of z3801's for
>> checking. 1 bit on the SR's frequency calibration dac seems to be about 4-5
>> parts in 10^-10 if I'm reading things right. Next test is a z3801 driving
>> the
>> external freq port on the sr to see if the frequency change direction of the
>> morion is OK.
>> The scope display output from the SR620 is great!
>> Lots to learn. Also have one of Said's units coming. Gone nuts for time,
>> won't
>> do anything much new, but it's new to me. All this to drive moonbounce...
>> Don
>>
>>
>> Bob Camp
>>> Hi
>>>
>>> If all the “good stuff” runs on the 90 MHz, the 5 MHz issue may not be
>>> important at all. It’s just something to watch for. If you start seeing
>>> data
>>> in two groups, each one 20 ps wide and separated by maybe 200 ps, you are
>>> seeing a problem from the 5 MHz.
>>>
>>> Running the box for a while before doing a full detailed cal is a very good
>>> idea. It’s a bit warm inside and some of the stuff is temperature
>>> sensitive.
>>> You want it to reach equilibrium.
>>>
>>> Bob
>>>
>>>> On Nov 23, 2014, at 1:06 AM, Don Latham <djl at montana.com> wrote:
>>>>
>>>> Ah. Got it finally!  Doh. Just finished trying out the Morion this
>>>> afternoon.
>>>> Electrically works very well. Used a 7812 to drop the +15 volts from the
>>>> option 1 ocxo, there is enough power headroom to bring the Morion up from
>>>> cold
>>>> and run it comfortably. As you said, the control voltage for the original
>>>> is
>>>> indeed 5 v, and can be set by the internal d/a. The output of the
>>>> oscillator
>>>> passes through an emitter follower voltage adjuster and through a low-q
>>>> filter
>>>> to three stages of ECL buffer and then out to the 10 MHz system bus clock.
>>>> Another path proceeds to a relay-switched divide by 2 to the phase
>>>> detector
>>>> so
>>>> an external 5/10 MHz source can lock the internal oscillator.
>>>> The external 5/10 MHz source proceeds to the phase detector thru an
>>>> identical
>>>> buffer chain without the switched divider.  The remainder of the clock
>>>> circuits is a multiplier to 90 MHz.
>>>>
>>>> I'll run the autocal tomorrow and then get some jitter stats if possible.
>>>> This
>>>> is an early specimen, s/n about 700 or so. I can imagine seldom used, and
>>>> sitting on standby for 20 years or so, pushing the ocxo out of tolerance.
>>>>
>>>> The saga continues; I may have to look for a 10 MHz replacement on epay,
>>>> there
>>>> isn't room to put in an Hp, unfortunately.
>>>> Don
>>>>
>>>>
>>>>
>>>>
>>>> Bob Camp
>>>>> Hi
>>>>>
>>>>> At least the Morion’s I have seen have 5 MHz crystals in them rather than
>>>>> 10
>>>>> MHz. They have a 10 MHz output due to an internal doubler. Since the
>>>>> circuit
>>>>> is not perfect, there is cycle to cycle variation in the 10 MHz. It’s way
>>>>> more
>>>>> jitter (measured in picoseconds) than the oscillator has due to phase
>>>>> noise.
>>>>> My concern is that a counter might be bothered by this is some subtle
>>>>> way.
>>>>>
>>>>> Bob
>>>>>
>>>>>> On Nov 22, 2014, at 3:55 PM, Don Latham <djl at montana.com> wrote:
>>>>>>
>>>>>> Hi Bob: no. cobble, not double :-)  A little research has me thinking I
>>>>>> can
>>>>>> easily adapt a morion. I can try it at least by starting with the morion
>>>>>> on
>>>>>> an
>>>>>> external power supply and patching the output and control voltages in to
>>>>>> the
>>>>>> sr.
>>>>>>
>>>>>> The sr620 has a control circuit which apparently accomplishes your
>>>>>> suggestions; they claim to use the internal oscillator for short term
>>>>>> and
>>>>>> "lock" it to a supplied external source for longer term. Probably has a
>>>>>> long
>>>>>> time constant on the built-in phase lock to do this.
>>>>>>
>>>>>> Anyhow, autocal calibrates everything except, guess what, the 10 mhz
>>>>>> source.
>>>>>> Thats done separately.
>>>>>> So a bootup self check shows OK even if the frequency standard is way
>>>>>> off.
>>>>>>
>>>>>> Onward and upward.
>>>>>> Don
>>>>>>
>>>>>> Bob Camp
>>>>>>> Hi
>>>>>>>
>>>>>>> I believe that the SR620 uses a “true” 10 MHz OCXO. I would be careful
>>>>>>> using a
>>>>>>> 5 MHz doubled to 10 OCXO. The counter may or may not be happy with
>>>>>>> sub-harmonic induced jitter.
>>>>>>>
>>>>>>> Best bet at the specs:
>>>>>>>
>>>>>>> +12V power
>>>>>>> 0-5V EFC
>>>>>>> Sine wave out +7dbm
>>>>>>>
>>>>>>> +/- 5x10^-9 0 to 70C
>>>>>>>
>>>>>>> Pinout - trace what you have.
>>>>>>>
>>>>>>> Bob
>>>>>>>
>>>>>>>> On Nov 21, 2014, at 6:59 PM, Don Latham <djl at montana.com> wrote:
>>>>>>>>
>>>>>>>>
>>>>>>>> So, I got a reasonable deal on a SR620 ho ho. Know your dealer. The
>>>>>>>> ocxo
>>>>>>>> is
>>>>>>>> out of tolerance. All self tests pass with flying colors, autocal
>>>>>>>> works
>>>>>>>> as
>>>>>>>> well. So the best parts are OK.
>>>>>>>> Does anyone:
>>>>>>>> 1) have a spare Isotemp OCXO36-53 10.000 MHz  p/n 6-00051?
>>>>>>>> 2) know the specs, ie the input voltage/current and the control
>>>>>>>> voltage
>>>>>>>> span
>>>>>>>> and direction? pinout?
>>>>>>>> I have some Morion mv-89's  and could easily cobble one in if it will
>>>>>>>> work.
>>>>>>>> Apparently a correct oscillator must be in place to use an external
>>>>>>>> source,
>>>>>>>> if
>>>>>>>> I read the manual right.
>>>>>>>>
>>>>>>>> 3) do we have a source for the schematics for the SR 620?
>>>>>>>>
>>>>>>>> The FTS 4060 is up, pumpin' and firmly locked. At least for now. That
>>>>>>>> dealer
>>>>>>>> was not lyin'
>>>>>>>>
>>>>>>>> Much thanks to all of you.
>>>>>>>> The adventure continues
>>>>>>>>
>>>>>>>>
>>>>>>>> --
>>>>>>>> "The power of accurate observation is commonly called cynicism by
>>>>>>>> those
>>>>>>>> who
>>>>>>>> have not got it."
>>>>>>>> -George Bernard Shaw
>>>>>>>>
>>>>>>>> Dr. Don Latham AJ7LL
>>>>>>>> Six Mile Systems LLC
>>>>>>>> 17850 Six Mile Road
>>>>>>>> Huson, MT, 59846
>>>>>>>> mail:  POBox 404
>>>>>>>> Frenchtown MT 59834-0404
>>>>>>>> VOX 406-626-4304
>>>>>>>> Skype: buffler2
>>>>>>>> www.lightningforensics.com
>>>>>>>> www.sixmilesystems.com
>>>>>>>>
>>>>>>>>
>>>>>>>> _______________________________________________
>>>>>>>> time-nuts mailing list -- time-nuts at febo.com
>>>>>>>> To unsubscribe, go to
>>>>>>>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>>>>>>>> and follow the instructions there.
>>>>>>>
>>>>>>> _______________________________________________
>>>>>>> time-nuts mailing list -- time-nuts at febo.com
>>>>>>> To unsubscribe, go to
>>>>>>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>>>>>>> and follow the instructions there.
>>>>>>>
>>>>>>>
>>>>>>
>>>>>>
>>>>>> --
>>>>>> "The power of accurate observation is commonly called cynicism by those
>>>>>> who
>>>>>> have not got it."
>>>>>> -George Bernard Shaw
>>>>>>
>>>>>> Dr. Don Latham AJ7LL
>>>>>> Six Mile Systems LLC
>>>>>> 17850 Six Mile Road
>>>>>> Huson, MT, 59846
>>>>>> mail:  POBox 404
>>>>>> Frenchtown MT 59834-0404
>>>>>> VOX 406-626-4304
>>>>>> Skype: buffler2
>>>>>> www.lightningforensics.com
>>>>>> www.sixmilesystems.com
>>>>>>
>>>>>>
>>>>>> _______________________________________________
>>>>>> time-nuts mailing list -- time-nuts at febo.com
>>>>>> To unsubscribe, go to
>>>>>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>>>>>> and follow the instructions there.
>>>>>
>>>>> _______________________________________________
>>>>> time-nuts mailing list -- time-nuts at febo.com
>>>>> To unsubscribe, go to
>>>>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>>>>> and follow the instructions there.
>>>>>
>>>>>
>>>>
>>>>
>>>> --
>>>> "The power of accurate observation is commonly called cynicism by those
>>>> who
>>>> have not got it."
>>>> -George Bernard Shaw
>>>>
>>>> Dr. Don Latham AJ7LL
>>>> Six Mile Systems LLC
>>>> 17850 Six Mile Road
>>>> Huson, MT, 59846
>>>> mail:  POBox 404
>>>> Frenchtown MT 59834-0404
>>>> VOX 406-626-4304
>>>> Skype: buffler2
>>>> www.lightningforensics.com
>>>> www.sixmilesystems.com
>>>>
>>>>
>>>> _______________________________________________
>>>> time-nuts mailing list -- time-nuts at febo.com
>>>> To unsubscribe, go to
>>>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>>>> and follow the instructions there.
>>>
>>> _______________________________________________
>>> time-nuts mailing list -- time-nuts at febo.com
>>> To unsubscribe, go to
>>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>>> and follow the instructions there.
>>>
>>>
>>
>>
>> --
>> "The power of accurate observation is commonly called cynicism by those who
>> have not got it."
>> -George Bernard Shaw
>>
>> Dr. Don Latham AJ7LL
>> Six Mile Systems LLC
>> 17850 Six Mile Road
>> Huson, MT, 59846
>> mail:  POBox 404
>> Frenchtown MT 59834-0404
>> VOX 406-626-4304
>> Skype: buffler2
>> www.lightningforensics.com
>> www.sixmilesystems.com
>>
>>
>> _______________________________________________
>> time-nuts mailing list -- time-nuts at febo.com
>> To unsubscribe, go to
>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>> and follow the instructions there.
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>
>


-- 
"The power of accurate observation is commonly called cynicism by those who
have not got it."
 -George Bernard Shaw

Dr. Don Latham AJ7LL
Six Mile Systems LLC
17850 Six Mile Road
Huson, MT, 59846
mail:  POBox 404
Frenchtown MT 59834-0404
VOX 406-626-4304
Skype: buffler2
www.lightningforensics.com
www.sixmilesystems.com




More information about the time-nuts mailing list