[time-nuts] ocxo

Mon Nov 24 00:25:02 UTC 2014

Did we answer the q? about schematics?

All of SRS's products have their block diagram and parts list with a
detailed circuit description in their user manual.  Sneak preview: its all
resistors.

NS

On Sun, Nov 23, 2014 at 4:22 PM, Don Latham <djl at montana.com> wrote:

> 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
>
>
> _______________________________________________
> 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.
>