Re: [time-nuts] Z3805 two frequency maxima
As far as I can see the PLL loop filter (SR620) has a corner frequency of about 33Hz. My HP counter 5385A has simply a switch to toggle between the external source and the internal osc. Am 18.11.2012 22:45, schrieb Bob Camp: Hi Most modern counters have an internal oscillator that they lock up to the external reference. The PLL bandwidth is (hopefully) chosen to optimize the noise contribution of the internal oscillator (quiet broad band) and the external reference (quiet close in). It will reject anything MHz away from the reference. Even if the reference signal is used directly, it would only be a problem if divided by an odd number. Even number division will wipe out the jitter. The most likely gate times are all a power of 10, so the division should always be even in a counter. Bottom line - you are unlikely to run into trouble using 10 MHz out of a Z3805 as reference signal. Crazy stuff…. Bob On Nov 18, 2012, at 4:35 PM, Volker Esper wrote: ...A PLL multiplier will (likely) also ignore the sub-harmonic, the jitter will not show up if you use the 10 MHz as a counter timebase in a HP counter... Yes, I wondered what the histogram would show when using the 2-maxima-Z3805 signal as a reference for the SR620 counter. Would the PLL filter it or would I get a mixer-like result with two maxima in the histogram? I applied the Z3805 to the reference input and the SMX signal generator to the counter input. The histogram looked equal to that I got when using the internal oscillator of the counter for reference. That obviously confirms Bob's statement. Volker Am 18.11.2012 21:23, schrieb Bob Camp: Hi This is one of those interesting areas where a broadband measurement (like a counter) and a narrowband measurement (like a DMTD) will give very different results. The counter will see the sub-harmonic, and call it jitter. It can show up in an ADEV calculation. A DMTD will ignore the sub-harmonic, and show no added jitter. With a DMTD, the ADEV will look fine. A PLL multiplier will (likely) also ignore the sub-harmonic, the jitter will not show up if you use the 10 MHz as a counter timebase in a HP counter. Which one's right / does it matter - as always, that depends on what you are trying to do with the signal. Bob On Nov 18, 2012, at 1:26 PM, Volker Esper wrote: @Azelio: Yes, (like Bob told) it's the phase lock, that locks the two maxima. Actually the counter is able to look between the 60ps spaced towers, have a look at the pictures in the first mail of this thread. However, there is a smallest time value the counter can determine, but it is much smaller than 60ps. Volker Am 18.11.2012 17:11, schrieb Bob Camp: Hi The 5 MHz and 10 MHz are "locked together" by the multiplier. Their relative phase is fixed. The 5 MHz component is not free to wander independently relative to the 10 MHz. Since it's a doubler, you get a two peak plot. If it was a X3 you would get three peaks. It really only makes sense if you look at it on a scope. Of course at 60 ps, it would have to be a mighty good scope. Much easier to see when the sub-harmonic is a bit stronger... Bob On Nov 18, 2012, at 9:53 AM, Azelio Borianiwrote: Interesting this, but why exactly 60pS? I would expect also something in-between. That is, to have the 5MHz energy 64dB below, in my opinion nothing prevents to have the edge to wander not only at 60pS but continuously between 0 and 60pS. Maybe the SR620, being a 25pS resolution counter, simply doesn't see what's going on in-between and the resulting histogram looks that way. On Sun, Nov 18, 2012 at 3:51 AM, Bob Campwrote: Hi A little more detail: What's going on is more clear if you trigger a scope on the positive edge of the 5 MHz and look at the 10 MHz. With an ideal multiplier, both the positive and negative edges of the 5 MHz should line up exactly with a positive edge of the 10 MHz. In reality, negative edge (the one not triggered) does not quite line up. It's a bit ahead (or behind) the ideal location. Since it's a small angle, the delta in phase and delta in amplitude both follow the same basic law. Bob On Nov 17, 2012, at 9:36 PM, Bob Campwrote: Hi Just good old Fourier series. Bob On Nov 17, 2012, at 9:12 PM, Volker Esperwrote: I'm impressed - but what law is behind this? Am 17.11.2012 21:26, schrieb Bob Camp: Hi 60 db isn't to bad a number. More or less: 100 ns -> 100 ps is 1000:1. 20 log of that is 60 db. 100 ps to 60 ps is about 4.4 db. That would sum up to -64.4 dbc. The main gotcha is that you *might* also have some 15 MHz (and higher) energy in the signal as well. Also phase gets into the calculation. Still, pretty close. Bob On Nov 17, 2012, at 12:50 PM, Volker Esper wrote: So let's have a look into the machine... and what do we see? There's a nice little Symmetrcom oven, with the sign reading "5.000 MHz" - bingo! May be there's a time saving way to determine the energie of
Re: [time-nuts] Z3805 two frequency maxima
Hi Most modern counters have an internal oscillator that they lock up to the external reference. The PLL bandwidth is (hopefully) chosen to optimize the noise contribution of the internal oscillator (quiet broad band) and the external reference (quiet close in). It will reject anything MHz away from the reference. Even if the reference signal is used directly, it would only be a problem if divided by an odd number. Even number division will wipe out the jitter. The most likely gate times are all a power of 10, so the division should always be even in a counter. Bottom line - you are unlikely to run into trouble using 10 MHz out of a Z3805 as reference signal. Crazy stuff…. Bob On Nov 18, 2012, at 4:35 PM, Volker Esper wrote: > > > ...A PLL multiplier will (likely) also ignore the sub-harmonic, the > > jitter will not show up if you use the 10 MHz as a counter timebase > > in a HP counter... > > > Yes, I wondered what the histogram would show when using the 2-maxima-Z3805 > signal as a reference for the SR620 counter. Would the PLL filter it or would > I get a mixer-like result with two maxima in the histogram? > > I applied the Z3805 to the reference input and the SMX signal generator to > the counter input. The histogram looked equal to that I got when using the > internal oscillator of the counter for reference. > > That obviously confirms Bob's statement. > > Volker > > > > Am 18.11.2012 21:23, schrieb Bob Camp: >> Hi >> >> This is one of those interesting areas where a broadband measurement (like a >> counter) and a narrowband measurement (like a DMTD) will give very different >> results. The counter will see the sub-harmonic, and call it jitter. It can >> show up in an ADEV calculation. A DMTD will ignore the sub-harmonic, and >> show no added jitter. With a DMTD, the ADEV will look fine. A PLL multiplier >> will (likely) also ignore the sub-harmonic, the jitter will not show up if >> you use the 10 MHz as a counter timebase in a HP counter. >> >> Which one's right / does it matter - as always, that depends on what you are >> trying to do with the signal. >> >> Bob >> >> On Nov 18, 2012, at 1:26 PM, Volker Esper wrote: >> >>> >>> @Azelio: Yes, (like Bob told) it's the phase lock, that locks the two >>> maxima. Actually the counter is able to look between the 60ps spaced >>> towers, have a look at the pictures in the first mail of this thread. >>> However, there is a smallest time value the counter can determine, but it >>> is much smaller than 60ps. >>> >>> Volker >>> >>> >>> >>> Am 18.11.2012 17:11, schrieb Bob Camp: Hi The 5 MHz and 10 MHz are "locked together" by the multiplier. Their relative phase is fixed. The 5 MHz component is not free to wander independently relative to the 10 MHz. Since it's a doubler, you get a two peak plot. If it was a X3 you would get three peaks. It really only makes sense if you look at it on a scope. Of course at 60 ps, it would have to be a mighty good scope. Much easier to see when the sub-harmonic is a bit stronger... Bob On Nov 18, 2012, at 9:53 AM, Azelio Boriani wrote: > Interesting this, but why exactly 60pS? I would expect also something > in-between. That is, to have the 5MHz energy 64dB below, in my opinion > nothing prevents to have the edge to wander not only at 60pS but > continuously between 0 and 60pS. Maybe the SR620, being a 25pS resolution > counter, simply doesn't see what's going on in-between and the resulting > histogram looks that way. > > On Sun, Nov 18, 2012 at 3:51 AM, Bob Camp wrote: > >> Hi >> >> A little more detail: >> >> What's going on is more clear if you trigger a scope on the positive edge >> of the 5 MHz and look at the 10 MHz. With an ideal multiplier, both the >> positive and negative edges of the 5 MHz should line up exactly with a >> positive edge of the 10 MHz. In reality, negative edge (the one not >> triggered) does not quite line up. It's a bit ahead (or behind) the ideal >> location. Since it's a small angle, the delta in phase and delta in >> amplitude both follow the same basic law. >> >> Bob >> >> >> On Nov 17, 2012, at 9:36 PM, Bob Camp wrote: >> >>> Hi >>> >>> Just good old Fourier series. >>> >>> Bob >>> >>> On Nov 17, 2012, at 9:12 PM, Volker Esper wrote: >>> I'm impressed - but what law is behind this? Am 17.11.2012 21:26, schrieb Bob Camp: > Hi > > 60 db isn't to bad a number. More or less: > > 100 ns ->100 ps is 1000:1. 20 log of that is 60 db. 100 ps to 60 > ps >> is about 4.4 db. That would sum up to -64.4 dbc. The main gotcha is that >> you *might* also have some 15 MHz (and higher) energy in the signal as >>
Re: [time-nuts] Z3805 two frequency maxima
> ...A PLL multiplier will (likely) also ignore the sub-harmonic, the > jitter will not show up if you use the 10 MHz as a counter timebase > in a HP counter... Yes, I wondered what the histogram would show when using the 2-maxima-Z3805 signal as a reference for the SR620 counter. Would the PLL filter it or would I get a mixer-like result with two maxima in the histogram? I applied the Z3805 to the reference input and the SMX signal generator to the counter input. The histogram looked equal to that I got when using the internal oscillator of the counter for reference. That obviously confirms Bob's statement. Volker Am 18.11.2012 21:23, schrieb Bob Camp: Hi This is one of those interesting areas where a broadband measurement (like a counter) and a narrowband measurement (like a DMTD) will give very different results. The counter will see the sub-harmonic, and call it jitter. It can show up in an ADEV calculation. A DMTD will ignore the sub-harmonic, and show no added jitter. With a DMTD, the ADEV will look fine. A PLL multiplier will (likely) also ignore the sub-harmonic, the jitter will not show up if you use the 10 MHz as a counter timebase in a HP counter. Which one's right / does it matter - as always, that depends on what you are trying to do with the signal. Bob On Nov 18, 2012, at 1:26 PM, Volker Esper wrote: @Azelio: Yes, (like Bob told) it's the phase lock, that locks the two maxima. Actually the counter is able to look between the 60ps spaced towers, have a look at the pictures in the first mail of this thread. However, there is a smallest time value the counter can determine, but it is much smaller than 60ps. Volker Am 18.11.2012 17:11, schrieb Bob Camp: Hi The 5 MHz and 10 MHz are "locked together" by the multiplier. Their relative phase is fixed. The 5 MHz component is not free to wander independently relative to the 10 MHz. Since it's a doubler, you get a two peak plot. If it was a X3 you would get three peaks. It really only makes sense if you look at it on a scope. Of course at 60 ps, it would have to be a mighty good scope. Much easier to see when the sub-harmonic is a bit stronger... Bob On Nov 18, 2012, at 9:53 AM, Azelio Boriani wrote: Interesting this, but why exactly 60pS? I would expect also something in-between. That is, to have the 5MHz energy 64dB below, in my opinion nothing prevents to have the edge to wander not only at 60pS but continuously between 0 and 60pS. Maybe the SR620, being a 25pS resolution counter, simply doesn't see what's going on in-between and the resulting histogram looks that way. On Sun, Nov 18, 2012 at 3:51 AM, Bob Camp wrote: Hi A little more detail: What's going on is more clear if you trigger a scope on the positive edge of the 5 MHz and look at the 10 MHz. With an ideal multiplier, both the positive and negative edges of the 5 MHz should line up exactly with a positive edge of the 10 MHz. In reality, negative edge (the one not triggered) does not quite line up. It's a bit ahead (or behind) the ideal location. Since it's a small angle, the delta in phase and delta in amplitude both follow the same basic law. Bob On Nov 17, 2012, at 9:36 PM, Bob Camp wrote: Hi Just good old Fourier series. Bob On Nov 17, 2012, at 9:12 PM, Volker Esper wrote: I'm impressed - but what law is behind this? Am 17.11.2012 21:26, schrieb Bob Camp: Hi 60 db isn't to bad a number. More or less: 100 ns ->100 ps is 1000:1. 20 log of that is 60 db. 100 ps to 60 ps is about 4.4 db. That would sum up to -64.4 dbc. The main gotcha is that you *might* also have some 15 MHz (and higher) energy in the signal as well. Also phase gets into the calculation. Still, pretty close. Bob On Nov 17, 2012, at 12:50 PM, Volker Esperwrote: So let's have a look into the machine... and what do we see? There's a nice little Symmetrcom oven, with the sign reading "5.000 MHz" - bingo! May be there's a time saving way to determine the energie of the sub harmonic: using my spectrum analyzer. It tells me, that there's a 5 MHz subharmonic at the level of -62dBc. How would you have calculated the energy? What would be your ansatz? Thanks so far Volker Am 17.11.2012 17:55, schrieb Bob Camp: Hi That's what you get if you have "sub harmonic" energy in the output of your OCXO. I'd bet you a warm glass of beer that you have a 5 MHz / doubled to 10 MHz MTI OCXO in your Z3805. If you have a lot of time on your hands, you can calculate the likely level of the energy from the amount of jitter (spacing between the two peaks) you get. Bob On Nov 17, 2012, at 11:41 AM, Volker Esper wrote: Hi, while playing with my recently aquired TIC (SR620) and measuring the period time of some oscillators I discovered something I hadn't expect at all: The output of my GPSDO (Z3805) writes two maxima in the period histogram (at a spacing of 60ps). I didn't believe that result and assumed an inherent error in my meas
Re: [time-nuts] Z3805 two frequency maxima
Hi This is one of those interesting areas where a broadband measurement (like a counter) and a narrowband measurement (like a DMTD) will give very different results. The counter will see the sub-harmonic, and call it jitter. It can show up in an ADEV calculation. A DMTD will ignore the sub-harmonic, and show no added jitter. With a DMTD, the ADEV will look fine. A PLL multiplier will (likely) also ignore the sub-harmonic, the jitter will not show up if you use the 10 MHz as a counter timebase in a HP counter. Which one's right / does it matter - as always, that depends on what you are trying to do with the signal. Bob On Nov 18, 2012, at 1:26 PM, Volker Esper wrote: > > @Azelio: Yes, (like Bob told) it's the phase lock, that locks the two maxima. > Actually the counter is able to look between the 60ps spaced towers, have a > look at the pictures in the first mail of this thread. However, there is a > smallest time value the counter can determine, but it is much smaller than > 60ps. > > Volker > > > > Am 18.11.2012 17:11, schrieb Bob Camp: >> Hi >> >> The 5 MHz and 10 MHz are "locked together" by the multiplier. Their relative >> phase is fixed. The 5 MHz component is not free to wander independently >> relative to the 10 MHz. Since it's a doubler, you get a two peak plot. If >> it was a X3 you would get three peaks. It really only makes sense if you >> look at it on a scope. Of course at 60 ps, it would have to be a mighty good >> scope. Much easier to see when the sub-harmonic is a bit stronger... >> >> Bob >> >> On Nov 18, 2012, at 9:53 AM, Azelio Boriani wrote: >> >>> Interesting this, but why exactly 60pS? I would expect also something >>> in-between. That is, to have the 5MHz energy 64dB below, in my opinion >>> nothing prevents to have the edge to wander not only at 60pS but >>> continuously between 0 and 60pS. Maybe the SR620, being a 25pS resolution >>> counter, simply doesn't see what's going on in-between and the resulting >>> histogram looks that way. >>> >>> On Sun, Nov 18, 2012 at 3:51 AM, Bob Camp wrote: >>> Hi A little more detail: What's going on is more clear if you trigger a scope on the positive edge of the 5 MHz and look at the 10 MHz. With an ideal multiplier, both the positive and negative edges of the 5 MHz should line up exactly with a positive edge of the 10 MHz. In reality, negative edge (the one not triggered) does not quite line up. It's a bit ahead (or behind) the ideal location. Since it's a small angle, the delta in phase and delta in amplitude both follow the same basic law. Bob On Nov 17, 2012, at 9:36 PM, Bob Camp wrote: > Hi > > Just good old Fourier series. > > Bob > > On Nov 17, 2012, at 9:12 PM, Volker Esper wrote: > >> >> I'm impressed - but what law is behind this? >> >> >> Am 17.11.2012 21:26, schrieb Bob Camp: >>> Hi >>> >>> 60 db isn't to bad a number. More or less: >>> >>> 100 ns -> 100 ps is 1000:1. 20 log of that is 60 db. 100 ps to 60 ps is about 4.4 db. That would sum up to -64.4 dbc. The main gotcha is that you *might* also have some 15 MHz (and higher) energy in the signal as well. Also phase gets into the calculation. Still, pretty close. >>> >>> Bob >>> >>> On Nov 17, 2012, at 12:50 PM, Volker Esper wrote: >>> So let's have a look into the machine... and what do we see? There's a nice little Symmetrcom oven, with the sign reading "5.000 MHz" - bingo! May be there's a time saving way to determine the energie of the sub harmonic: using my spectrum analyzer. It tells me, that there's a 5 MHz subharmonic at the level of -62dBc. How would you have calculated the energy? What would be your ansatz? Thanks so far Volker Am 17.11.2012 17:55, schrieb Bob Camp: > Hi > > That's what you get if you have "sub harmonic" energy in the output of your OCXO. I'd bet you a warm glass of beer that you have a 5 MHz / doubled to 10 MHz MTI OCXO in your Z3805. If you have a lot of time on your hands, you can calculate the likely level of the energy from the amount of jitter (spacing between the two peaks) you get. > > Bob > > On Nov 17, 2012, at 11:41 AM, Volker Esper wrote: > >> Hi, >> >> while playing with my recently aquired TIC (SR620) and measuring the period time of some oscillators I discovered something I hadn't expect at all: >> >> The output of my GPSDO (Z3805) writes two maxima in the period histogram (at a spacing of 60ps). >> >> I didn't believe that result and assumed an inherent error in my measuring setup
Re: [time-nuts] Warning if buying from directly from Agilent via eBay with Paypal.
On 16/11/12 23:48, J. Forster wrote: PayPal is pretty much a law unto itself. Basically, if you choose to become involved with them, it's their bat, ball, glove, and ballpark. Your only real alternative is to play another game. Unfortunately, the younger generation of eBay sellers is convinced that PayPal and plastic is the only trustworthy way of doing business. I am somewhat pissed because I just lost out on an eBay item, not to another bidder as there was no one else, but to a PayPal only lockout. I think most sellers would drop Paypal like a hot stone if they could. For the most part ebay insist that you offer Paypal above anything else. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Z3805 two frequency maxima
@Azelio: Yes, (like Bob told) it's the phase lock, that locks the two maxima. Actually the counter is able to look between the 60ps spaced towers, have a look at the pictures in the first mail of this thread. However, there is a smallest time value the counter can determine, but it is much smaller than 60ps. Volker Am 18.11.2012 17:11, schrieb Bob Camp: Hi The 5 MHz and 10 MHz are "locked together" by the multiplier. Their relative phase is fixed. The 5 MHz component is not free to wander independently relative to the 10 MHz. Since it's a doubler, you get a two peak plot. If it was a X3 you would get three peaks. It really only makes sense if you look at it on a scope. Of course at 60 ps, it would have to be a mighty good scope. Much easier to see when the sub-harmonic is a bit stronger... Bob On Nov 18, 2012, at 9:53 AM, Azelio Boriani wrote: Interesting this, but why exactly 60pS? I would expect also something in-between. That is, to have the 5MHz energy 64dB below, in my opinion nothing prevents to have the edge to wander not only at 60pS but continuously between 0 and 60pS. Maybe the SR620, being a 25pS resolution counter, simply doesn't see what's going on in-between and the resulting histogram looks that way. On Sun, Nov 18, 2012 at 3:51 AM, Bob Camp wrote: Hi A little more detail: What's going on is more clear if you trigger a scope on the positive edge of the 5 MHz and look at the 10 MHz. With an ideal multiplier, both the positive and negative edges of the 5 MHz should line up exactly with a positive edge of the 10 MHz. In reality, negative edge (the one not triggered) does not quite line up. It's a bit ahead (or behind) the ideal location. Since it's a small angle, the delta in phase and delta in amplitude both follow the same basic law. Bob On Nov 17, 2012, at 9:36 PM, Bob Camp wrote: Hi Just good old Fourier series. Bob On Nov 17, 2012, at 9:12 PM, Volker Esper wrote: I'm impressed - but what law is behind this? Am 17.11.2012 21:26, schrieb Bob Camp: Hi 60 db isn't to bad a number. More or less: 100 ns -> 100 ps is 1000:1. 20 log of that is 60 db. 100 ps to 60 ps is about 4.4 db. That would sum up to -64.4 dbc. The main gotcha is that you *might* also have some 15 MHz (and higher) energy in the signal as well. Also phase gets into the calculation. Still, pretty close. Bob On Nov 17, 2012, at 12:50 PM, Volker Esper wrote: So let's have a look into the machine... and what do we see? There's a nice little Symmetrcom oven, with the sign reading "5.000 MHz" - bingo! May be there's a time saving way to determine the energie of the sub harmonic: using my spectrum analyzer. It tells me, that there's a 5 MHz subharmonic at the level of -62dBc. How would you have calculated the energy? What would be your ansatz? Thanks so far Volker Am 17.11.2012 17:55, schrieb Bob Camp: Hi That's what you get if you have "sub harmonic" energy in the output of your OCXO. I'd bet you a warm glass of beer that you have a 5 MHz / doubled to 10 MHz MTI OCXO in your Z3805. If you have a lot of time on your hands, you can calculate the likely level of the energy from the amount of jitter (spacing between the two peaks) you get. Bob On Nov 17, 2012, at 11:41 AM, Volker Esper wrote: Hi, while playing with my recently aquired TIC (SR620) and measuring the period time of some oscillators I discovered something I hadn't expect at all: The output of my GPSDO (Z3805) writes two maxima in the period histogram (at a spacing of 60ps). I didn't believe that result and assumed an inherent error in my measuring setup or the counter itself. So I plugged another oscillator, the reference TCXO of my signal generator (R&S SMX), and that result made me happy and uneasy at once: The TCXO hat only one maximum. I havn't calculated the ADEV curve, yet. See pictures. Why does my GPSDO produce such a weird result? Cheers Volker - DF9PL ___ time-nuts mailing list -- 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 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 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 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 To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow
Re: [time-nuts] Wavecrest DTS 2077 Service Manual?
>I've never been confronted with such a poor customer sevice > attitude before. Have you bought an instrument as complex as at DTS 207x recently ? >From the mid 90's this has become the norm even with companies that were bastions of the quality of their service manuals such as Tek and Agilent (HP) The first move was to charge for the service manual, then component level service documentation CLIPs became available at a high price, then what you have today even internal customers can not get CLIPS. -pete On Sun, Nov 18, 2012 at 8:37 AM, Adrian wrote: > In the meantime I heard that Wavecrest is not distributing service manuals. > All repair is depot.repair. > > This makes me considering if I should take the chance on a second unit, > hoping to get one working out of two, or simply to give up and accept that > these boxes are only intended to be used as door stops of land fill once > defective... I've never been confronted with such a poor customer sevice > attitude before. > > Nevertheless... is there anyone who has acquired some experience with the > DTS-series innards who would be willing to share his knowledge? > > Adrian > > > Adrian schrieb: > >> Anyone have a Wavecrest DTS 2075/77/79 service manual? >> >> I've recently got a DTS 2077 that however turned out to be defective. >> There was a power supply failure that I could fix, but there is still a >> power-up selftest error message and calibratin fails. >> >> Adrian >> >> ___ >> time-nuts mailing list -- 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 > 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 To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Wavecrest DTS 2077 Service Manual?
In the meantime I heard that Wavecrest is not distributing service manuals. All repair is depot.repair. This makes me considering if I should take the chance on a second unit, hoping to get one working out of two, or simply to give up and accept that these boxes are only intended to be used as door stops of land fill once defective... I've never been confronted with such a poor customer sevice attitude before. Nevertheless... is there anyone who has acquired some experience with the DTS-series innards who would be willing to share his knowledge? Adrian Adrian schrieb: Anyone have a Wavecrest DTS 2075/77/79 service manual? I've recently got a DTS 2077 that however turned out to be defective. There was a power supply failure that I could fix, but there is still a power-up selftest error message and calibratin fails. Adrian ___ time-nuts mailing list -- 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 To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Recommended parameters for Timelab ADEV analysis
Hi Magnus, when I noticed the difference between frequency and time interval mode on my 53131A, I compared some sources in both modes. There was little difference between both modes where the signal was above the TI mode noise floor. Below that t-range (that is, below the point where in TI mode the signal is buried by the 1/f slope noise floor), the frequency mode showed significantly lower values, but I had nothing at hands to compare them with. At least they looked plausible. In the meantime I could replace the 53131A with a Quartzlock A7 / HP 5370B combination. You might understand that I was no longer motivated to investigate further, especially because the '131 showed much less 'improvement' as a '132 which I saw a plot of but don't have access to. Cheers, Adrian Magnus Danielson schrieb: Adrian, On 15/11/12 03:59, Adrian wrote: Hi Edgardo, however, the 53132A is considerably more sensitive in frequency mode as we have recently discovered. I saw an astoundingly low ADEV noise floor of some 6E-13 at t=10 sec as opposed to only 2.5E-11 in TI mode. I don't have a 53132A, only a 53131A that I don't use anymore for ADEV, so I can't be more specific. No. The filtering that the 53132A does on frequency data does not make it more sensitive in the ADEV context, it pre-filters the data to improve frequency reading, yes, but that pre filtering cause bias in the ADEV measurement and when you compensate for that bias you are back where you started. We have been over this many times in the history of the list, there is papers explaining it, so let's not again spread this misconception. The 53132A is still just a 150 ps resolution counter, which forms the 1/f limit slope on the ADEV plot (1/f^2 power slope). Doing a ADEV with the 53132A frequency mode gives you the stability measure of that measurement mode, true, the trouble is that the filtering will also applied to the source, so we do not get closer to the source while we see an lower value in the plot and fools ourselves that we got closer. The only thing we have achieved is a lower value, but the relative distance between source and counter noise limit remains the same. The improvement you may do is to combat trigger jitter, so squaring the signal up could get you a bit closer to the counters abilities. If you want to break the trigger jitter and resolution noise limit of the pure counter, besides squaring up you got to look into mixer enhancements, and you end up doing the Dual Mixer Time Difference (DMTD) game, but filterings such as that in the 53132A isn't it. This filtering, which also applies to the later Pendulum counters such as CNT-90, isn't a bad thing when you want to provide a higher frequency resolution while still maintaining relatively high reporting rate. It's actually a very good method. It's just that you don't get "pure" ADEV that way, and we already have a systematic method of doing something similar called the modified Allan Deviation (MDEV) which actually builds on such filtering, but applied in a more systematic way. The MDEV has known different behaviour to the noises compared to ADEV, and this fact is used to separate noise-variants better. Dr. Allan even is eager to point out that MDEV is actually fixing what is broken with ADEV, and we should be using MDEV. I tend to agree. This type of prefiltering of 53132A frequency readings will not improve MDEV measures either. So, that is the wrong tool for improving our measures. The only thing is that it for most of the quality stuff we measure won't do much harm, since it only dominates the part of the curve where we are we are usually counter limited, so we just got another shape of that, but it adds nothing and we gain nothing. Hence, it's not helping us one bit. Only subtle benefit would be that auto-scaling could work a little better, but I doubt it's a strong enough reason. Please enlight me if I missed something important. Cheers, Magnus ___ time-nuts mailing list -- 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 To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Wanted - AN/URQ-10 manual
Goodness FORTH and a R1051. Who would have thought. I am a big fan of forth also. Loved the way you could extend the dictionary. Plus it ran like a bat out of heck fast. Like you I went through ETA school as the second class to be trained on the 1051. At $27,000 each did not think I would ever own one. I do have a operational 1051 purchased many years after leaving the service from Fair Radio and a RT-918 all operational. Though the RT918 was a serious $25 basket case from the air force. DDS for the 1051. I have often thought about that. Today they are so cheap that you could build a composite unit or 3 or so separate ones for the translatersyn. What will drive me to do that is the pesky aging crystals that I have already had to deal with on the RT918. To keep this in a time-nuts spirit, they all run on the RB reference or the GPS reference. See back to time-nuts. Regards Paul WB8TSL On Sun, Nov 18, 2012 at 3:32 AM, DaveH wrote: > Another FORTH fan here. > > Originally written to control radio telescopes -- hardware was changing all > the time so the language was by definition designed to be extensible. Want > to add a function? Define it, give it a name and bingo... > > Sometimes less __IS__ Moore. > > > > > -Original Message- > > From: time-nuts-boun...@febo.com > > [mailto:time-nuts-boun...@febo.com] On Behalf Of Don Latham > > Sent: Saturday, November 17, 2012 23:19 > > To: M. Simon; Discussion of precise time and frequency measurement > > Subject: Re: [time-nuts] Wanted - AN/URQ-10 manual > > > > Forth forever!!! > > Don L > > M. Simon > > > Can't help you with the manual but I just wanted to say > > that the 1051 > > > was one of my favorites. Loved the PLLs. I worked on an upgrade for > > > Stewart Warner back in the early 80s. As part of a > > prototype I put two > > > Z-80 systems in the space between the front panel and the main gear. > > > Part of its purpose was to interface to the 1553 bus. I > > also implemented > > > a DDS in TTL for fine tuning. I still like tube front ends for mil > > > radios for ruggedness. But you can't sell it because of > > wear out issues. > > > > > > > > > The Navy didn't buy in to the prototype. Collins beat us. > > The code for > > > the processors was written in Forth. The Navy "code > > inspector" said it > > > was some of the best written code he had seen in several > > years. We also > > > could complete a design cycle - including code - in a > > month. The Collins > > > boys had a team 10X as large as ours (we had 3). And it took them 6 > > > months to complete a design cycle using "C". I was project > > manager and > > > lead engineer. I was mostly hardware but I did some > > software and rode > > > heard on the coders. Forth was my idea. > > > > > > > > > I also put a Z-80 inside the companion 1KW transmitter. The > > RF inside > > > the transmitter was a few volts per inch. I used a sealed > > box and a lot > > > of feed through filters. It worked the first time. > > > > > > I also worked with the gear in Navy ETA school. And went on > > to become a > > > Nuke so I didn't see that radio gear again until about 15 > > years later. > > > > > > > > > Simon > > > > > > > > > Engineering is the art of making what you want from what > > you can get at > > > a profit. > > > ___ > > > time-nuts mailing list -- time-nuts@febo.com > > > To unsubscribe, go to > > > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > > and follow the instructions there. > > > > > > > > > > > > -- > > "Neither the voice of authority nor the weight of reason and argument > > are as significant as experiment, for thence comes quiet to the mind." > > De Erroribus Medicorum, R. Bacon, 13th century. > > "If you don't know what it is, don't poke it." > > Ghost in the Shell > > > > > > Dr. Don Latham AJ7LL > > Six Mile Systems LLP > > 17850 Six Mile Road > > POB 134 > > Huson, MT, 59846 > > VOX 406-626-4304 > > www.lightningforensics.com > > www.sixmilesystems.com > > > > > > > > ___ > > time-nuts mailing list -- 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 > 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 To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Z3805 two frequency maxima
Hi The 5 MHz and 10 MHz are "locked together" by the multiplier. Their relative phase is fixed. The 5 MHz component is not free to wander independently relative to the 10 MHz. Since it's a doubler, you get a two peak plot. If it was a X3 you would get three peaks. It really only makes sense if you look at it on a scope. Of course at 60 ps, it would have to be a mighty good scope. Much easier to see when the sub-harmonic is a bit stronger... Bob On Nov 18, 2012, at 9:53 AM, Azelio Boriani wrote: > Interesting this, but why exactly 60pS? I would expect also something > in-between. That is, to have the 5MHz energy 64dB below, in my opinion > nothing prevents to have the edge to wander not only at 60pS but > continuously between 0 and 60pS. Maybe the SR620, being a 25pS resolution > counter, simply doesn't see what's going on in-between and the resulting > histogram looks that way. > > On Sun, Nov 18, 2012 at 3:51 AM, Bob Camp wrote: > >> Hi >> >> A little more detail: >> >> What's going on is more clear if you trigger a scope on the positive edge >> of the 5 MHz and look at the 10 MHz. With an ideal multiplier, both the >> positive and negative edges of the 5 MHz should line up exactly with a >> positive edge of the 10 MHz. In reality, negative edge (the one not >> triggered) does not quite line up. It's a bit ahead (or behind) the ideal >> location. Since it's a small angle, the delta in phase and delta in >> amplitude both follow the same basic law. >> >> Bob >> >> >> On Nov 17, 2012, at 9:36 PM, Bob Camp wrote: >> >>> Hi >>> >>> Just good old Fourier series. >>> >>> Bob >>> >>> On Nov 17, 2012, at 9:12 PM, Volker Esper wrote: >>> I'm impressed - but what law is behind this? Am 17.11.2012 21:26, schrieb Bob Camp: > Hi > > 60 db isn't to bad a number. More or less: > > 100 ns -> 100 ps is 1000:1. 20 log of that is 60 db. 100 ps to 60 ps >> is about 4.4 db. That would sum up to -64.4 dbc. The main gotcha is that >> you *might* also have some 15 MHz (and higher) energy in the signal as >> well. Also phase gets into the calculation. Still, pretty close. > > Bob > > On Nov 17, 2012, at 12:50 PM, Volker Esper wrote: > >> >> So let's have a look into the machine... and what do we see? There's >> a nice little Symmetrcom oven, with the sign reading "5.000 MHz" - bingo! >> >> May be there's a time saving way to determine the energie of the sub >> harmonic: using my spectrum analyzer. It tells me, that there's a 5 MHz >> subharmonic at the level of -62dBc. >> >> How would you have calculated the energy? What would be your ansatz? >> >> Thanks so far >> >> Volker >> >> >> Am 17.11.2012 17:55, schrieb Bob Camp: >>> Hi >>> >>> That's what you get if you have "sub harmonic" energy in the output >> of your OCXO. I'd bet you a warm glass of beer that you have a 5 MHz / >> doubled to 10 MHz MTI OCXO in your Z3805. If you have a lot of time on >> your hands, you can calculate the likely level of the energy from the >> amount of jitter (spacing between the two peaks) you get. >>> >>> Bob >>> >>> On Nov 17, 2012, at 11:41 AM, Volker Esper >> wrote: >>> Hi, while playing with my recently aquired TIC (SR620) and measuring >> the period time of some oscillators I discovered something I hadn't expect >> at all: The output of my GPSDO (Z3805) writes two maxima in the period >> histogram (at a spacing of 60ps). I didn't believe that result and assumed an inherent error in my >> measuring setup or the counter itself. So I plugged another oscillator, the reference TCXO of my signal >> generator (R&S SMX), and that result made me happy and uneasy at once: The >> TCXO hat only one maximum. I havn't calculated the ADEV curve, yet. See pictures. Why does my GPSDO produce such a weird result? Cheers Volker - DF9PL >> ___ time-nuts mailing list -- 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 >>> 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 >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. > > > ___ > time-nuts
Re: [time-nuts] Z3805 two frequency maxima
Interesting this, but why exactly 60pS? I would expect also something in-between. That is, to have the 5MHz energy 64dB below, in my opinion nothing prevents to have the edge to wander not only at 60pS but continuously between 0 and 60pS. Maybe the SR620, being a 25pS resolution counter, simply doesn't see what's going on in-between and the resulting histogram looks that way. On Sun, Nov 18, 2012 at 3:51 AM, Bob Camp wrote: > Hi > > A little more detail: > > What's going on is more clear if you trigger a scope on the positive edge > of the 5 MHz and look at the 10 MHz. With an ideal multiplier, both the > positive and negative edges of the 5 MHz should line up exactly with a > positive edge of the 10 MHz. In reality, negative edge (the one not > triggered) does not quite line up. It's a bit ahead (or behind) the ideal > location. Since it's a small angle, the delta in phase and delta in > amplitude both follow the same basic law. > > Bob > > > On Nov 17, 2012, at 9:36 PM, Bob Camp wrote: > > > Hi > > > > Just good old Fourier series. > > > > Bob > > > > On Nov 17, 2012, at 9:12 PM, Volker Esper wrote: > > > >> > >> I'm impressed - but what law is behind this? > >> > >> > >> Am 17.11.2012 21:26, schrieb Bob Camp: > >>> Hi > >>> > >>> 60 db isn't to bad a number. More or less: > >>> > >>> 100 ns -> 100 ps is 1000:1. 20 log of that is 60 db. 100 ps to 60 ps > is about 4.4 db. That would sum up to -64.4 dbc. The main gotcha is that > you *might* also have some 15 MHz (and higher) energy in the signal as > well. Also phase gets into the calculation. Still, pretty close. > >>> > >>> Bob > >>> > >>> On Nov 17, 2012, at 12:50 PM, Volker Esper wrote: > >>> > > So let's have a look into the machine... and what do we see? There's > a nice little Symmetrcom oven, with the sign reading "5.000 MHz" - bingo! > > May be there's a time saving way to determine the energie of the sub > harmonic: using my spectrum analyzer. It tells me, that there's a 5 MHz > subharmonic at the level of -62dBc. > > How would you have calculated the energy? What would be your ansatz? > > Thanks so far > > Volker > > > Am 17.11.2012 17:55, schrieb Bob Camp: > > Hi > > > > That's what you get if you have "sub harmonic" energy in the output > of your OCXO. I'd bet you a warm glass of beer that you have a 5 MHz / > doubled to 10 MHz MTI OCXO in your Z3805. If you have a lot of time on > your hands, you can calculate the likely level of the energy from the > amount of jitter (spacing between the two peaks) you get. > > > > Bob > > > > On Nov 17, 2012, at 11:41 AM, Volker Esper > wrote: > > > >> Hi, > >> > >> while playing with my recently aquired TIC (SR620) and measuring > the period time of some oscillators I discovered something I hadn't expect > at all: > >> > >> The output of my GPSDO (Z3805) writes two maxima in the period > histogram (at a spacing of 60ps). > >> > >> I didn't believe that result and assumed an inherent error in my > measuring setup or the counter itself. > >> > >> So I plugged another oscillator, the reference TCXO of my signal > generator (R&S SMX), and that result made me happy and uneasy at once: The > TCXO hat only one maximum. > >> > >> I havn't calculated the ADEV curve, yet. > >> > >> See pictures. > >> > >> Why does my GPSDO produce such a weird result? > >> > >> Cheers > >> > >> Volker - DF9PL > >> > ___ > >> time-nuts mailing list -- 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 > > 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 > 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 > >>> 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 > >> 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 > > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > a
Re: [time-nuts] Recommended parameters for Timelab ADEV analysis
Adrian, On 15/11/12 03:59, Adrian wrote: Hi Edgardo, however, the 53132A is considerably more sensitive in frequency mode as we have recently discovered. I saw an astoundingly low ADEV noise floor of some 6E-13 at t=10 sec as opposed to only 2.5E-11 in TI mode. I don't have a 53132A, only a 53131A that I don't use anymore for ADEV, so I can't be more specific. No. The filtering that the 53132A does on frequency data does not make it more sensitive in the ADEV context, it pre-filters the data to improve frequency reading, yes, but that pre filtering cause bias in the ADEV measurement and when you compensate for that bias you are back where you started. We have been over this many times in the history of the list, there is papers explaining it, so let's not again spread this misconception. The 53132A is still just a 150 ps resolution counter, which forms the 1/f limit slope on the ADEV plot (1/f^2 power slope). Doing a ADEV with the 53132A frequency mode gives you the stability measure of that measurement mode, true, the trouble is that the filtering will also applied to the source, so we do not get closer to the source while we see an lower value in the plot and fools ourselves that we got closer. The only thing we have achieved is a lower value, but the relative distance between source and counter noise limit remains the same. The improvement you may do is to combat trigger jitter, so squaring the signal up could get you a bit closer to the counters abilities. If you want to break the trigger jitter and resolution noise limit of the pure counter, besides squaring up you got to look into mixer enhancements, and you end up doing the Dual Mixer Time Difference (DMTD) game, but filterings such as that in the 53132A isn't it. This filtering, which also applies to the later Pendulum counters such as CNT-90, isn't a bad thing when you want to provide a higher frequency resolution while still maintaining relatively high reporting rate. It's actually a very good method. It's just that you don't get "pure" ADEV that way, and we already have a systematic method of doing something similar called the modified Allan Deviation (MDEV) which actually builds on such filtering, but applied in a more systematic way. The MDEV has known different behaviour to the noises compared to ADEV, and this fact is used to separate noise-variants better. Dr. Allan even is eager to point out that MDEV is actually fixing what is broken with ADEV, and we should be using MDEV. I tend to agree. This type of prefiltering of 53132A frequency readings will not improve MDEV measures either. So, that is the wrong tool for improving our measures. The only thing is that it for most of the quality stuff we measure won't do much harm, since it only dominates the part of the curve where we are we are usually counter limited, so we just got another shape of that, but it adds nothing and we gain nothing. Hence, it's not helping us one bit. Only subtle benefit would be that auto-scaling could work a little better, but I doubt it's a strong enough reason. Please enlight me if I missed something important. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Wanted - AN/URQ-10 manual
Another FORTH fan here. Originally written to control radio telescopes -- hardware was changing all the time so the language was by definition designed to be extensible. Want to add a function? Define it, give it a name and bingo... Sometimes less __IS__ Moore. > -Original Message- > From: time-nuts-boun...@febo.com > [mailto:time-nuts-boun...@febo.com] On Behalf Of Don Latham > Sent: Saturday, November 17, 2012 23:19 > To: M. Simon; Discussion of precise time and frequency measurement > Subject: Re: [time-nuts] Wanted - AN/URQ-10 manual > > Forth forever!!! > Don L > M. Simon > > Can't help you with the manual but I just wanted to say > that the 1051 > > was one of my favorites. Loved the PLLs. I worked on an upgrade for > > Stewart Warner back in the early 80s. As part of a > prototype I put two > > Z-80 systems in the space between the front panel and the main gear. > > Part of its purpose was to interface to the 1553 bus. I > also implemented > > a DDS in TTL for fine tuning. I still like tube front ends for mil > > radios for ruggedness. But you can't sell it because of > wear out issues. > > > > > > The Navy didn't buy in to the prototype. Collins beat us. > The code for > > the processors was written in Forth. The Navy "code > inspector" said it > > was some of the best written code he had seen in several > years. We also > > could complete a design cycle - including code - in a > month. The Collins > > boys had a team 10X as large as ours (we had 3). And it took them 6 > > months to complete a design cycle using "C". I was project > manager and > > lead engineer. I was mostly hardware but I did some > software and rode > > heard on the coders. Forth was my idea. > > > > > > I also put a Z-80 inside the companion 1KW transmitter. The > RF inside > > the transmitter was a few volts per inch. I used a sealed > box and a lot > > of feed through filters. It worked the first time. > > > > I also worked with the gear in Navy ETA school. And went on > to become a > > Nuke so I didn't see that radio gear again until about 15 > years later. > > > > > > Simon > > > > > > Engineering is the art of making what you want from what > you can get at > > a profit. > > ___ > > time-nuts mailing list -- time-nuts@febo.com > > To unsubscribe, go to > > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > and follow the instructions there. > > > > > > > -- > "Neither the voice of authority nor the weight of reason and argument > are as significant as experiment, for thence comes quiet to the mind." > De Erroribus Medicorum, R. Bacon, 13th century. > "If you don't know what it is, don't poke it." > Ghost in the Shell > > > Dr. Don Latham AJ7LL > Six Mile Systems LLP > 17850 Six Mile Road > POB 134 > Huson, MT, 59846 > VOX 406-626-4304 > www.lightningforensics.com > www.sixmilesystems.com > > > > ___ > time-nuts mailing list -- 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 To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
