Hi,

 Well, that was the data I was able to find (and I referred to TvBs
 page where I found it). If you have more accurate data, please share
 so we can get the numbers right.

 The Z3801A will do a least square estimate of frequency error and then
 translate that into an initial DAC setting assuming it knows the EFC
 sensitivity, and the loop will work out the rest from there

 Cheers,
 Magnus


 On 12/29/2016 12:32 AM, Bob Camp wrote:

     Hi

     Ummm ….. errrrr ….

     The 10811 that is used in the Z3801 has a *larger* electrical
     tuning range than the standard
     10811 not a smaller one. It’s tuning range and the TBolt OCXO’s
     tuning range are
     very similar.

     Bob

         On Dec 28, 2016, at 6:22 PM, Magnus Danielson
         <magnus@rubidium.dyndns.org
         <mailto:magnus@rubidium.dyndns.org>> wrote:

         Paul,

         We just want to help you with that curiosity, it sounds like
         a fun little project. :)

         The FRS-C [1] has a range of +/- 1E-9 over 0-5V, so EFC
         sensitivity is 4E-10/V.

         The Z3801A has a range of 5.20E-10 [2] over -5V to +5V [3],
         so EFC sensitivity is 5.2E-11/V.

         So, it looks like you need to have a gain of 8 and raise the
         EFC 2.5 V.

         Cheers,
         Magnus

         [1] http://www.to-way.com/tf/frs.pdf
         <http://www.to-way.com/tf/frs.pdf>

         [2] http://www.leapsecond.com/pages/z3801a-efc/
         <http://www.leapsecond.com/pages/z3801a-efc/>

         [3] http://www.realhamradio.com/joe-geller.htm
         <http://www.realhamradio.com/joe-geller.htm>

         On 12/28/2016 11:42 PM, paul swed wrote:

             Magnus and Bob,
             Thank you for your response. As far as the original HO
             10811 oscillator
             goes there is some well written details on it behavior
             and sensitivity. It
             was not the same as a standard 10811. A far smaller
             range as I recall. But
             the data is there.
             Its funny on the RB I have the EFC range from the spec
             sheet. It really
             tunes from 0-5V. But I find it interesting that the best
             alignment with
             other references is sub 1V. Its an old FRS C and I have
             others that may
             present a more centered range.

             I'll have to compare the detials that I have on the
             10811 and FRS C. But I
             actually pulled out a 100:1 antenuator I was using on
             the Piezo crystal
             that indeed does lock.

             Goal in all of this is nothing special simply curiosity.
             Thanks again. When I have some real numbers to share I

             On Tue, Dec 27, 2016 at 10:26 PM, Bob Camp
             <kb8tq@n1k.org <mailto:kb8tq@n1k.org>> wrote:

                 Hi

                 The loop gain (as Magnus mentions) needs to be
                 “correct” for the Rb. Since
                 the firmware was written for an OCXO with a PPM(ish)
                 trim range, tacking it
                 on to a PPB(ish) Rb will require everything to scale
                 by 1000:1. That’s 10
                 bits.
                 You may (or may not) have enough resolution in the
                 math to handle that wide
                 a range of gains.

                 If it really locks, the next challenge is to get it
                 to run out to ~ 4 days
                 or more on
                 the loop. Again, the firmware may or may not be able
                 to do this. Unless it
                 does,
                 the Rb really will not lock as well as it could.

                 With the Rb correctly locked, you still have the
                 issue that the Rb is a
                 2x10^-11
                 device (ADEV) at 1 second and the OCXO probably is
                 2x10^-12 (or better).
                 For
                 driving a counter with a normal gate, the Rb may not
                 show much (if any)
                 improvement.
                 There is the slight chance the ADEV will get the
                 firmware confused…..

                 Since the firmware source is running around
                 somewhere, you *could* dig into
                 all of this wonderful stuff :)

                 Bob


                     On Dec 27, 2016, at 8:33 PM, paul swed
                     <paulswedb@gmail.com
                     <mailto:paulswedb@gmail.com>> wrote:

                     OK so could not resist. The replacement of the
                     HP 10811 with a PIEZO ocxo
                     went very well. So in for a penny in for a
                     pound. Why not an RB. Having a
                     few around. Choice efratom FRS-c. Lot of thought
                     went into this choice.

                 Not

                     really it was there. It has a inverse frequency
                     to EFC voltage just like
                     the piezo and opposite the HP 10811.
                     Well it connects runs and locks using the simple
                     1 opamp level ofset and
                     and phase inverter.
                     But locked is a funny comment. According to
                     HPsatstat and LH. Its pll is
                     locked. But both scope and the LH graph shows a
                     very slow frequency drift
                     that with the offset I can make positive or
                     negative. A cycle at 10 ns
                     takes quite some time about an hour compared to
                     a TBolt and another non
                     modified Z3801. At this level of resolution some
                     things start to become
                     questionable.

                     I almost wonder if the modified z3801 under some
                     level of drift assumes
                     everything is locked and fine. Can it be pushed
                     beyond expectations. I
                     suspect it can.
                     Anyhow as I say a bit of GPSDO fun.
                     Regards
                     Paul
                     WB8TSL
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                     time-nuts mailing list -- time-nuts@febo.com
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Magnus Good afternoon. I am having a hard time following this. Conflicting data I believe.. Using the FRS-C because its the clearest. On page 3-14 it says +/- 1E-9 for 5V (5V is later in the book) Wouldn't that be 2E-9th for 5V? The 10811 is far more difficult to pin down as several articles from TVB and others say the 10811 actually has a wider control range then the standard. Something like 10 Hz over 10V. Traditional is 1 Hz over 10 V. But as I say seems to be different answers depending on what you read. When these details are settled you then came up with the need for a gain of 8. Did you use a rule of thumb? Thanks Paul WB8TSL On Fri, Dec 30, 2016 at 9:06 AM, Magnus Danielson <magnus@rubidium.se> wrote: > I think the numbers given for 10811 sensitivity was grossly incorrect from > the source I had, so it should be +/- 1E-6 for +/- 5V, thus giving 2E-6 > over 10V thus giving a sensitivity of 2E-7/V. Compare to 4E-10/V fro the > FRS-C and just redo the work. > > I thought the numbers where funny but too tired to do extensive digging, > but I just wanted to show the general idea. > > Cheers, > Magnus > > > On 12/30/2016 04:05 AM, paul swed wrote: > >> Been interesting. >> Did increase the gain to 8 and remove the attenuation 10:1 needed for >> the piezo ocxo. Not sure I would say the system locks but it certainly >> slows the drift down to 10ns/30 minutes. I also added an offset after >> the amplifier. This allowed the Z3801 EFC to set its range more towards >> 50%. >> Though the FRS manual says the range is 0-5V for EFC the FRS is clearly >> offset with age to the +1.7V for center. (The other FRS was +.6V) >> >> Its interesting to see at the startup of the Z3801 the EFC range in the >> RB. Nice steps down towards a fairly low angle line according to Lady >> Heather. >> >> Have had to stop the experimentation late today to give a hand to a >> fellow on a HP 70-110GHz signal source. Till today I was a 10 GHz sort >> of guy. >> Regards >> Paul >> WB8TSL >> >> >> >> On Wed, Dec 28, 2016 at 6:51 PM, Magnus Danielson >> <magnus@rubidium.dyndns.org <mailto:magnus@rubidium.dyndns.org>> wrote: >> >> Hi, >> >> Well, that was the data I was able to find (and I referred to TvBs >> page where I found it). If you have more accurate data, please share >> so we can get the numbers right. >> >> The Z3801A will do a least square estimate of frequency error and then >> translate that into an initial DAC setting assuming it knows the EFC >> sensitivity, and the loop will work out the rest from there >> (hopefully). >> Getting EFC in the right neighborhood is probably wise for this >> reason. >> >> Cheers, >> Magnus >> >> >> On 12/29/2016 12:32 AM, Bob Camp wrote: >> >> Hi >> >> Ummm ….. errrrr …. >> >> The 10811 that is used in the Z3801 has a *larger* electrical >> tuning range than the standard >> 10811 not a smaller one. It’s tuning range and the TBolt OCXO’s >> tuning range are >> very similar. >> >> Bob >> >> On Dec 28, 2016, at 6:22 PM, Magnus Danielson >> <magnus@rubidium.dyndns.org >> <mailto:magnus@rubidium.dyndns.org>> wrote: >> >> Paul, >> >> We just want to help you with that curiosity, it sounds like >> a fun little project. :) >> >> The FRS-C [1] has a range of +/- 1E-9 over 0-5V, so EFC >> sensitivity is 4E-10/V. >> >> The Z3801A has a range of 5.20E-10 [2] over -5V to +5V [3], >> so EFC sensitivity is 5.2E-11/V. >> >> So, it looks like you need to have a gain of 8 and raise the >> EFC 2.5 V. >> >> Cheers, >> Magnus >> >> [1] http://www.to-way.com/tf/frs.pdf >> <http://www.to-way.com/tf/frs.pdf> >> >> [2] http://www.leapsecond.com/pages/z3801a-efc/ >> <http://www.leapsecond.com/pages/z3801a-efc/> >> >> [3] http://www.realhamradio.com/joe-geller.htm >> <http://www.realhamradio.com/joe-geller.htm> >> >> On 12/28/2016 11:42 PM, paul swed wrote: >> >> Magnus and Bob, >> Thank you for your response. As far as the original HO >> 10811 oscillator >> goes there is some well written details on it behavior >> and sensitivity. It >> was not the same as a standard 10811. A far smaller >> range as I recall. But >> the data is there. >> Its funny on the RB I have the EFC range from the spec >> sheet. It really >> tunes from 0-5V. But I find it interesting that the best >> alignment with >> other references is sub 1V. Its an old FRS C and I have >> others that may >> present a more centered range. >> >> I'll have to compare the detials that I have on the >> 10811 and FRS C. But I >> actually pulled out a 100:1 antenuator I was using on >> the Piezo crystal >> that indeed does lock. >> >> Goal in all of this is nothing special simply curiosity. >> Thanks again. When I have some real numbers to share I >> will. >> Regards >> Paul >> WB8TSL >> >> On Tue, Dec 27, 2016 at 10:26 PM, Bob Camp >> <kb8tq@n1k.org <mailto:kb8tq@n1k.org>> wrote: >> >> Hi >> >> The loop gain (as Magnus mentions) needs to be >> “correct” for the Rb. Since >> the firmware was written for an OCXO with a PPM(ish) >> trim range, tacking it >> on to a PPB(ish) Rb will require everything to scale >> by 1000:1. That’s 10 >> bits. >> You may (or may not) have enough resolution in the >> math to handle that wide >> a range of gains. >> >> If it really locks, the next challenge is to get it >> to run out to ~ 4 days >> or more on >> the loop. Again, the firmware may or may not be able >> to do this. Unless it >> does, >> the Rb really will not lock as well as it could. >> >> With the Rb correctly locked, you still have the >> issue that the Rb is a >> 2x10^-11 >> device (ADEV) at 1 second and the OCXO probably is >> 2x10^-12 (or better). >> For >> driving a counter with a normal gate, the Rb may not >> show much (if any) >> improvement. >> There is the slight chance the ADEV will get the >> firmware confused….. >> >> Since the firmware source is running around >> somewhere, you *could* dig into >> all of this wonderful stuff :) >> >> Bob >> >> >> On Dec 27, 2016, at 8:33 PM, paul swed >> <paulswedb@gmail.com >> <mailto:paulswedb@gmail.com>> wrote: >> >> OK so could not resist. The replacement of the >> HP 10811 with a PIEZO ocxo >> went very well. So in for a penny in for a >> pound. Why not an RB. Having a >> few around. Choice efratom FRS-c. Lot of thought >> went into this choice. >> >> Not >> >> really it was there. It has a inverse frequency >> to EFC voltage just like >> the piezo and opposite the HP 10811. >> Well it connects runs and locks using the simple >> 1 opamp level ofset and >> and phase inverter. >> But locked is a funny comment. According to >> HPsatstat and LH. Its pll is >> locked. But both scope and the LH graph shows a >> very slow frequency drift >> that with the offset I can make positive or >> negative. A cycle at 10 ns >> takes quite some time about an hour compared to >> a TBolt and another non >> modified Z3801. At this level of resolution some >> things start to become >> questionable. >> >> I almost wonder if the modified z3801 under some >> level of drift assumes >> everything is locked and fine. Can it be pushed >> beyond expectations. I >> suspect it can. >> Anyhow as I say a bit of GPSDO fun. >> Regards >> Paul >> WB8TSL >> _______________________________________________ >> time-nuts mailing list -- time-nuts@febo.com >> <mailto:time-nuts@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@febo.com >> <mailto:time-nuts@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@febo.com >> <mailto:time-nuts@febo.com> >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> <https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts> >> and follow the instructions there. >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts@febo.com >> <mailto:time-nuts@febo.com> >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> <https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts> >> and follow the instructions there. >> >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts@febo.com >> <mailto:time-nuts@febo.com> >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> <https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts> >> and follow the instructions there. >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts@febo.com <mailto: >> time-nuts@febo.com> >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> <https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts> >> and follow the instructions there. >> >> >>

paul wrote: > The 10811 is far more difficult to pin down as several articles from TVB > and others say the 10811 actually has a wider control range then the > standard. Something like 10 Hz over 10V. Traditional is 1 Hz over 10 V. But > as I say seems to be different answers depending on what you read. HP made lots of different sub-models of the 10811. According to the specs, they all had EFC sensitivities of either "at least" +/- 1Hz or "at least" +/- 2.5Hz for the -5v to +5v EFC range. The most commonly-encountered sub-models are specified as "at least" +/- 1Hz. However, the HP spec for the EFC range of the 10811-60158, which was used in the Z3801, is (quoting directly here) "> ± 2.0x10-7 (± 2.5 Hz) for control range of -5V to +5V". (Note that 2e-7 of 10MHz is 2Hz, not 2.5Hz, so there is some internal inconsistency in the spec.) So, the spec says to expect "at least" 4 or 5Hz (total, or +/- 2 to 2.5Hz) for the 10v control range (or, "at least" 0.4 to 0.5 Hz/V). I don't believe I've measured one that went 10Hz (total, or +/- 5Hz), but I have not taken careful measurements of the EFC tuning rates of many 10811-60158s. I certainly wouldn't be shocked to find examples with 10Hz EFC ranges (1Hz/V), based on the published spec. Best regards, Charles