Re: [time-nuts] Using commercial video amplifier for 10MHz clock distribution.

[tim...@timeok.it]

   Charles wrote:
   >Well, there is a distinct difference between DAs that use a single
   amplifier (discrete or integrated) to drive each output channel (as your
   design does), and DAs that drive multiple outputs from each amplifier
   using build-out resistors. In the case of the Extron integrated circuit
   DAs using CLS409 opamps, the isolation is 30dB between outputs fed from
   one amplifier, and >90dB between outputs fed from different amplifiers
   (see my document detailing recommended modifications to the Extron DAs,
   downloadable from):
   

   So, simply by using only some of the outputs of an Extron IC-based DA,
   one gets isolation roughly equal to your design.


   < The solution I proposed is a 107dB channnel to channel isolation (gain set 
+3dB).



> One advantage of the IC design is considerably lower distortion -- the
   harmonics are all below -65dBc at 10MHz, +16dBm output, compared to
   -45dBc at +13dBm for your design (per your table). Further, the
   distortion products of the IC design are essentially all odd-order
   harmonics, while your design shows predominant even-order harmonics.

   < The CLC409 datasheet show all the test response up to +12dBm (around 1Vpp 
on 75/50Ohm load)
see: pdf.datasheetcatalog.com/datasheet/nationalsemiconductor/DS012748.PDF

   I agree that harmonic distortion is an important factor to keep in mind 
however -45dBc is a very interesting value considering the market alternatives. 
In my document I have enclosed on page 10 a little research I did online on 
similar products and as you can see the -45 are positioned at a decidedly 
higher level than other commercial solutions
   see:
   
http://www.timeok.it/wp-content/uploads/2015/08/Frequency-Distribution-Design-Basic-Module-v-4.1.pdf

   An extremely important factor not to be overlooked is the maximum output 
power / level of the amplifier. Measurement systems such as the HP3048A for 
phase noise measurement use mixers that require minimum signal levels of + 
15dBm at higher PO1 and the CLC409 will never meet these requirements.


   >In your modification document: Residual phase noise of <-165dBc at 10 MHz


The Extron is a very nice solution, certainly of modest price, but we must 
consider * * * the low separation between the output channels.

   Well, there is a distinct difference between DAs that use a single
   amplifier (discrete or integrated) to drive each output channel (as your
   design does), and DAs that drive multiple outputs from each amplifier
   using build-out resistors. In the case of the Extron integrated circuit
   DAs using CLS409 opamps, the isolation is 30dB between outputs fed from
   one amplifier, and >90dB between outputs fed from different amplifiers
   (see my document detailing recommended modifications to the Extron DAs,
   downloadable from):

   


   So, simply by using only some of the outputs of an Extron IC-based DA,
   one gets isolation roughly equal to your design. Of course, one could
   easily build a one-output-per-amplifier DA using the Extron circuit
   (with LMH6702 or other suitable opamps) to have a DA with ~100 dB of
   isolation between all outputs (the exact isolation will be dependent
   upon the layout, just as it is with your design).

   One advantage of the IC design is considerably lower distortion -- the
   harmonics are all below -65dBc at 10MHz, +16dBm output, compared to
   -45dBc at +13dBm for your design (per your table). Further, the
   distortion products of the IC design are essentially all odd-order
   harmonics, while your design shows predominant even-order harmonics.

   Odd-order harmonics are symmetrical, so they do not generate additional
   amplitude-to-phase modulation when the output feeds a squarer/zero-cross
   detector. Even-order harmonics, conversely, *DO* generate additional
   amplitude-to-phase modulation when the output feeds a squarer/zero-cross
   detector. This is very important because the vast majority of
   measurement equipment likely to be fed by a DA/iso amp feeds its inputs
   directly to a ZCD. See reference in next paragraph.

   We have, in the past, disagreed about the importance of low distortion
   in DA/iso amplifiers, but I have satisfied myself that a timing DA/iso
   amp should have, at a bare minimum, -65dBc harmonic suppression. For
   just one reason, see the NIST publication, "The Effect of Harmonic
   Distortion on Phase errors in Frequency Distribution and Synthesis"
   (Walls and Ascarrunz), available at:

   


   Best regards,

   Charles



   

Re: [time-nuts] Ancient HP 5065A on ebay

[tim...@timeok.it]

   It must be very old, had I ever seen an HP5065A with three positions of the 
Function Switch (Adj Mag Field)

   Luciano


   Da "time-nuts" time-nuts-boun...@lists.febo.com
   A time-nuts@lists.febo.com
   Cc
   Data Mon, 21 Oct 2019 08:59:34 -0700
   Oggetto [time-nuts] Ancient HP 5065A on ebay
   There is an 5065A on Ebay that has the earliest SN I have ever seen.

   808-00031 or maybe 00051?

   Maybe the first one sold?

   If the lamp oven has not fried it might be a fun project.

   It has the Patek analog clock.

   Cheers,

   Corby


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Re: [time-nuts] Using commercial video amplifier for 10MHz clock distribution.

[tim...@timeok.it]

   Hi,

   A premise must be made to define the performance of these DAs as EXTRON can 
be compared to those built for the distribution of reference frequencies.
   The Extron is a very nice solution, certainly of modest price, but we must 
consider that its performances are limited. This especially if we talk about 
saturation levels but much more important is the low separation between the 
output channels. These two factors can be negligible if the required 
level/stability is good but not excellent, in fact by disconnecting a load or 
simply changing the length of a coax connection on a channel almost certainly a 
change in level / phase will occur in the adjacent output.

   If anyone is interested, you will find my solution here:

   
http://www.timeok.it/wp-content/uploads/2015/08/Frequency-Distribution-Design-Basic-Module-v-4.1.pdf

   Using it as a buffer for the low phase noise HP 10811-60109 and BVA 8600 
there is no deterioration of the phase / noise floor.

   I ordered some new PCBs related to the buffer only. If anyone is interested 
let me know off list.

   Luciano

   tim...@timeok.it


   Da "time-nuts" time-nuts-boun...@lists.febo.com
   A "Discussion of precise time and frequency measurement" 
time-nuts@lists.febo.com
   Cc
   Data Sat, 19 Oct 2019 08:30:02 +
   Oggetto Re: [time-nuts] Using commercial video amplifier for 10MHz clock 
distribution.
   There is a schematic here on the Extron uploaded by a TN member. The 
schematic for the Extron looks looks dead simple that one could really just 
make a simple 3 channel with the included mods in the writeup, only problem is 
I don't see a source for a CLC409 any longer, and I don't have the experience 
or knowledge to use a substitute ADA800x ??

   
<http://www.ko4bb.com/getsimple/index.php?id=download=02_GPS_Timing/Extron_ADA_6_modifications_for_use_as_10MHz_distribution_amp_STEINMETZ.pdf>

   -=Bryan=-

   
   From: time-nuts  on behalf of ed breya 

   Sent: October 18, 2019 1:39 PM
   To: time-nuts@lists.febo.com 
   Subject: Re: [time-nuts] Using commercial video amplifier for 10MHz clock 
distribution.

   I have a Hitachi VD-1000 video distribution unit that's been sitting
   unused for years, waiting until I finally get around to making it into a
   reference unit. I just dug it out and looked inside. It is full of RCA
   jack cables for jumping the signals around in different ways. I
   apparently had changed things around already, to make one section into a
   15-output distributor. I have forgotten all about it long ago, so now
   it's just a dizzying array of cabling. I must have made notes somewhere,
   that I'll have to find for when I eventually (probably fairly soon) do
   the proper conversion.

   It uses CLC404 amplifiers, which appear to be older and a little noisier
   than the CLC409, but should be OK for this. Unfortunately, it uses a
   small switching supply, which I dislike for things like this, so
   ultimately will make a linear one for it.

   This thing has 40 BNC connectors on the back, which would allow for lots
   of I/O and branching combinations. This is likely way more than I'll
   ever need, so the "new" plan is to incorporate some improvements,
   considering what I recently learned during my work on the frequency
   multiplier project. I'll be reducing the total fanout, and changing some
   of the outputs to have fully-floating transformer coupling, to reduce
   ground loop effects in high sensitivity applications, and also
   independent volume controls for some. I may do the same on the source
   inputs too. I don't know how many of each thing yet, but definitely
   some. In any of the BNC spots, I can easily put an isolating type BNC,
   or a volume control pot. The front panel is mostly blank, so there's
   lots of room for even more stuff there. I just have to be careful to not
   get carried away and make it too wonderful and complicated and never
   finished.

   I also have an Efratom something-something distribution rack with five
   "MBF" modules that have four outputs each. They should pretty good too,
   but unfortunately it's all for 5 MHz only - there's low- or band-pass
   filtering built into each channel, so needs reverse engineering and mods
   for 10 MHz. I vaguely recall looking for info on this about a year ago,
   and stumbled upon an old time nuts thread. Someone (maybe Chuck Harris?)
   had reported successful mods for 10 MHz on these, but there were no
   links to any info about it. So Chuck, if you see this, and it was you,
   or anyone else, I'd sure appreciate this info. If it was just my
   imagination, then never mind.

   Ed

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Re: [time-nuts] A simple sampling DMTD

[tim...@timeok.it]

   Hi Jan,

   this is precisely the instrument that is lacking at a hobbyist price.

   It would be excellent to have the possibility of measuring phase noise.

   Can you anticipate the features of the Sampling DMTD?

   Can it be used with Timelab?

   We are waiting for your new ones.

   Luciano


   Da "time-nuts" time-nuts-boun...@lists.febo.com
   A "Discussion of precise time and frequency measurement" 
time-nuts@lists.febo.com
   Cc
   Data Sat, 14 Sep 2019 14:25:48 +0200
   Oggetto Re: [time-nuts] A simple sampling DMTD
   Update: I have finished routing the board (placement diagram at
   http://www.lartmaker.nl/time-nuts/DMTD%20rev1.00%20assembly.pdf ) and
   ordered a few prototype PCBs.

   After the earlier discussions on the list I've grown sufficiently concerned
   about the impact of 1/f converter noise that I have added headers to the
   board to allow me to replace the D-flipflop sampler with an FPGA-based I/Q
   downconverter. While the main PCBs are in production I'll draw a simple
   daughterboard with dual ice40 UltraPlus FPGAs, If the FPGA solution turns
   out to be necessary (or a noticeable improvement), I'll redraw the main PCB.

   To be continued,

   JDB.

   On Sun, Sep 1, 2019 at 2:09 AM Jan-Derk Bakker  wrote:

   > Dear all,
   >
   > I've been working on a design for a (relatively) simple, standalone
   > sampling DMTD. Very rough preliminary schematics can be found at
   > http://www.lartmaker.nl/time-nuts/DMTD_rev0.99.pdf .
   >
   > Design goals are:
   > - ps-level accuracy
   > - comparison of frequencies between at least 10 and 50MHz, preferably
   > between 1 and 100MHz
   > - comparison of (selected) different frequencies (in my case: 10MHz vs
   > 50MHz)
   > - standalone operation, field-portable
   > - option for raw data sampling / (post)processing on a PC
   > - option for generating a tuning voltage to lock the measured oscillator
   > to the reference, so the DMTD can act as a PLL in phase noise test setups
   >
   > Context: you may remember that a year or two ago I posted to time-nuts
   > about a GPSDO-design geared for mobile applications, which I was working on
   > for an SDR-platform my students are working with. This SDR-platform has now
   > grown to include a 100-channel phased array receiver. To validate the
   > reference clock distribution in this array (amongst other things) I would
   > like to have a DMTD. As the commercial offerings are outside the budget of
   > our lab, I was planning to roll my own.
   >
   > The core of the system is a transformer-coupled LTC2140-14 dual 14-bit
   > ADC, sampling at an offset frequency of nominally 10MHz+10Hz generated by a
   > VCTCXO (with an option for an OCXO). The ADC was chosen for its large input
   > bandwidth and small aperture jitter. Simulations of a simple software ZCD
   > consisting of a digital filter and least-squares fitting showed that
   > 100ksps would be more than enough to get the desired accuracy. As the ADC
   > design is unable to achieve sample rates lower than 1MSPS, D-flipflops are
   > used to decimate the samples. These DFFs are also used to multiplex the
   > 2x14-bit samples to an 8-bit data bus going into one of the GPIO-ports of
   > an XMega. The XMega runs the ZCD, and generates a tuning voltage for the
   > offset oscillator. Communication to a logging PC is done with a
   > galvanically isolated FT2232H, which has both an ASCII COM-port for the ZCD
   > data and a control interface and an asynchronous FIFO to transfer raw
   > samples. System power comes from the isolated USB bus or a barrel jack; BOM
   > cost in qty10+ is around 100US$.
   >
   > (The DMTD has a few more power rails than I would have liked. Originally I
   > had planned to use the LTC2295 and have a 3v3-only system, but after
   > re-reading the NIST paper on SDR-as-a-DMTD I concluded that the single
   > clocking path of the 2140 would likely have better aperture jitter
   > correlation between the channels. As a 1.8V/10MHz XMega would only be
   > borderline able to handle the computations, I ended up with this design.
   > LVC logic is used to go from 3.3V->1.8V, LV1T translators for the opposite
   > direction.)
   >
   > Design decisions and/or non-goals:
   > - I considered putting a small FPGA (specifically a Lattice ice40
   > UltraPlus) between the ADC and the processor. This was rejected because the
   > performance of the decimator appeared to be sufficient, and I wasn't
   > certain that I could get DDR mode + a CORDIC working in this FPGA.
   > - Especially when I found the necessity to move part of the system to 1.8V
   > I considered moving to an ARM. I stuck with the XMega as performance was
   > sufficient, and I am very familiar with both the CPU and the peripherals
   > (particularly time-stamping counters and the Event system) that would ease
   > the ZCD implementation and issues like synchronization between processor
   > and sampling system.
   > - I looked into 

Re: [time-nuts] Hp10811 parts ref

[tim...@timeok.it]

   Gilles,

   what manual you refer? (Part number)

   Heating transistor are NPN.TO220 similar to TIP120

   Driver is Q6 and NPN similar to 2N3904

   U1 is LM2904N

   U3 is uA208M

   Luciano


   Da "time-nuts" time-nuts-boun...@lists.febo.com
   A time-nuts@lists.febo.com
   Cc
   Data Tue, 10 Sep 2019 17:54:17 +0200
   Oggetto [time-nuts] Hp10811 parts ref
   Dear list,
   Looking forward to apply the oven configuration of the 10811 oven oscillator 
- that is working so well - could you please help me identifying the 
appropriate references for the active parts :
   Q7 and Q8 heating darligntons PNP
   Q4 driving transistor PNP
   U1 and U3 op amps
   From the schematic on fig 8-15 on page 64 of the HP manual.

   Thx very much,
   Gilles.

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Re: [time-nuts] A comparison of the TAPR-TICC and BG7TBL FA1

[tim...@timeok.it]

   Hi Mark,

   the tests you did are between two different sources, so it is not a test 
that can determine the noise floor of the instruments under test.
   I understand that it is still a comparison on the field between the two 
measuring instruments,
   however I think it is interesting to have the noise floor of the test set 
because it is a reference absolute value.

   I enclose a plot I made about the n.f. of the TICC to which I inserted a 
10MHz in the reference channel and in the measurement channel the same signal,

   divided up to 1PPS in the measurement channel.

   I believe that this is the only way to measure the noise floor.

   best regards,

   Luciano


   Da "time-nuts" time-nuts-boun...@lists.febo.com
   A "time-nuts@lists.febo.com" time-nuts@lists.febo.com
   Cc
   Data Fri, 6 Sep 2019 20:05:57 +
   Oggetto [time-nuts] A comparison of the TAPR-TICC and BG7TBL FA1
   I did a comparison of the performance of the TAPR-TICC/TADD2-Mini divider 
and the BG7TBL FA1 frequency analyzer performance. The reference clock for both 
devices was a 5071A cesium. The device being tested was a Nortel NTPX GPSDO 10 
MHz output. Attached are screen dumps of the two Lady Heather runs.

   The noisy orange plot in the TICC run is the measured frequency offset from 
10 MHz. The noisy blue plot in the FA1 run is the measured frequency offset 
from 10 MHz. (Note the scale factor differences) Looking at the SPAN value (the 
difference between the max and min frequency measurements) shows that the FA1 
noise level is around 4 times higher than the TICC. The FA1 ADEV measurements 
are around 3 time higher. The FA1 may be better than the TICC at lower (<50 
second) tau, but I have no way to verify that. The FA1 screen dump includes a 
histogram of the frequency measurements.

   issue with the FA1 is that it seems to have an inherent frequency 
measurement bias of around -0.0002 Hz. See the "avg#" value in the lower left 
corner of the plot. I get nearly the same bias values when measuring 1, 5, and 
10 MHz signals. (I added a setting in Lady Heather to specify a measurment bias 
correction value). It is interesting that the same -0.0002 Hz bias was present 
in the original BG7TBL GPSDO.

   TAPR TICC pros:
   high performance
   lots of measurement and configuration options
   open source design

   TAPR TICC cons:
   more expensive
   requires external dividers to measure frequency (and a second power supply)
   no case

   FA1 pros:
   inexpensive (around $100), decent bang for the buck
   no frequency divider needed, 1 .. 80 MHz range
   very simple operation (no configuration needed)
   nice small unit with an extruded metal case.

   FA1 cons:
   measures frequency (no way to test 1PPS signals)
   around 3X-4x less performance than the TAPR TICC.
   closed source "black box"
   inherent minor frequency measurement offset

   Lately BG7TBL has released the FA2. This appears to be similar to the FA1, 
but it has some VERY nice features including a basic 1 Hz .. 200 MHz range plus 
a 30:1 pre-scaler allowing measurements to 6 GHz. It as an LCD display, an 
internal (adjustable) OCXO and external freq ref input, reference output, 
selectable 0.1/1/10 second timebase. Costs around $120 (with power supply) If 
the FA2 measurement performance matches the FA1, it would be greatly preferable 
over the FA1. I have an FA2 the way.
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[time-nuts] Low pn integrated frequency multiplier/PLL

[tim...@timeok.it]

   Hi,

   I was wondering, and I do it to you too, if this Texas Instruments  device 
could be used to build a
   frequency difference meter with high precision features.

   http://www.ti.com/lit/ds/symlink/lmx2594.pdf

   http://www.ti.com/lit/ug/tidud10a/tidud10a.pdf

   Thanks,

   Luciano

   www.timeok.it
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Re: [time-nuts] FSA3011 Frequency Stability Analyzer, HP 8405A or TAPR TIC

[tim...@timeok.it]

   Hi Perrier,

   The HP8405A is an analog vector analyzer that allows you to make phase 
measurements like the oscilloscope with Lissajous shapes. This method is the 
simplest one but allows quite approximate measurements and does not give you a 
complete view of stability (Allan Deviation).

   The TICC and the FSA3011 are more advanced systems that both require a 
laptop and a TIMELAB sw (free) but give you a complete view of the stability 
parameters both in the short and long term.

   To use TICC you need an additional 10/5 MHz to 1PPS divider like the TADD-2, 
mini PPS divider.

   https://tapr.org/kits_t2-mini.html

   The TICC is in the order of 205 $ the FSA3011 is around 470 $.

   The performance difference seem to be the Test Set noise floor. The FSA3011 
seem to be ten time better but I am not sure, for this reason I am asking more 
info about this new unit.

   Luciano

   www.timeok.it


   Da "time-nuts" time-nuts-boun...@lists.febo.com
   A time-nuts@lists.febo.com
   Cc "Perry Sandeen" sandee...@yahoo.com
   Data Tue, 30 Jul 2019 06:04:34 + (UTC)
   Oggetto [time-nuts] FSA3011 Frequency Stability Analyzer, HP 8405A or TAPR 
TIC
   Yo Bubba Dudes!,
   I've been following the discussion of the FSA3011 with great interest.
   Now I'm not in the upper levels of TN esoteric knowledge or have a burning 
desire to ever get there.   After seeing some small reference somewhere I 
looked at the HP 8405A on ebay and the price range seemed comparable to the 
FSA3011. Now the HP 8405 is a huge beast but i was thinking that it might be 
easier for me to use.  I'm interested in just 5 and 10 MHz oscillator 
comparison.  I know nothing about computer programs or writing any code.
   I also looked at the TAPR TIC.
   So my conclusion are:
   The FSA3011 may be technically the best BUT it seems to be having some 
teething problems and I don't really know about what programs it runs or needs.
   The HP 8405A is a big beast, but it maybe simpler for me to run and get the 
results I want which is stopping around 10 to ^12th. But I may have to watch it 
for a long time.
   The TAPR TIC is small (needed) cheaper (also a plus) and seems to run 
available software. but needs a dedicated laptop, which is not a real problem. 
I also have several extra HP 18011's available.

   Your opinions are gratefully solicited,
   Regards,
   Perrier

   Perrier

   If I can just download programs AFAIK I could use the TAPR TIC as I have a 
spare laptop that I could dedicate for its use.  The two advantaages
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Re: [time-nuts] FSA3011 Frequency Stability Analyzer

[tim...@timeok.it]

   Hal,

   I thank you for the answer, but I'm not a scientist like many of you
   but just an amateur so I'm not able to do what you suggest.

   Unfortunately I need a plug and play tool without post processing.

   Luciano

   www.timeok.it


   Da "Hal Murray" hmur...@megapathdsl.net
   A tim...@timeok.it,"Discussion of precise time and frequency measurement" 
time-nuts@lists.febo.com
   Cc hmur...@megapathdsl.net
   Data Sat, 27 Jul 2019 01:26:39 -0700
   Oggetto Re: [time-nuts] FSA3011 Frequency Stability Analyzer

   tim...@timeok.it said:
   > Another question is whether in the case of the FSA3011 there is the
   > problem of the timewrap that would not allow
   > the long acquisitions.

   Wha's the problem? If it's just running out of high order bits in a counting
   register, I can fix that with a post-collecting pass.

   You could hack the collecting software to do it. In one sense, it's nice to
   keep the collecting software clean and simple and log exactly what goes in to
   it, but if you collect enough data, then the extra pass gets annoying enough
   that I would take the time to fix the collection step and double check things
   so I'm pretty sure it won't turn into a source of problems.



   --
   These are my opinions. I hate spam.
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Re: [time-nuts] FSA3011 Frequency Stability Analyzer

[tim...@timeok.it]

   Tom,

   A good test, even if not too numerical, could be ADEV between a good 
Rubidium like the HP5065A and another
   equal or better reference made both with the TICC and with the FSA3011.

   The comparison of the two graphs would give us a first visual answer about 
the differences.

   Another question is whether in the case of the FSA3011 there is the problem 
of the timewrap that would not allow
   the long acquisitions. Can you post a similar chart?

   Luciano


   Da "time-nuts" time-nuts-boun...@lists.febo.com
   A time-nuts@lists.febo.com
   Cc
   Data Fri, 26 Jul 2019 12:02:24 -0700
   Oggetto Re: [time-nuts] FSA3011 Frequency Stability Analyzer
   Yes, I'm evaluating a FSA3011 at the moment. It's a cute little unit.
   Documentation is sparse, the jpg plots are fuzzy, "customer" support is
   nil, but it works. My initial tests show it's ~4x worse than the data
   sheet claims but it turns out the unit is quite dependent on the rise
   time and power of the input signals so YMMV.

   With 10 MHz sine inputs from a tee the noise is about 3 ps @1 s. I'm
   checking different frequency and waveform combinations in an attempt to
   obtain the "<1 ps" value implied by the specs.

   The output is phase difference, about a second. Readings look like
   "0.0591884\n". Note that last digit is 1 fs, which is
   ridiculous. It's like marketing said, "let's make this go to 15". In
   fact 11 or 12 digits contain actual information. Then again the
   TAPR/TICC has a similar problem with excessive digits so who am I to
   talk. For the most part, fake digits don't hurt, but realize that
   spitting out 15 decimal places does not in any way imply the device can
   measure to that level.

   The block diagram says it's a dual-mixer. It follows a very minimalist
   design. Just two SMA inputs and a 115.2 kbaud serial-over-USB output. No
   switches, no modes, no input commands, no GUI; a couple of labeled LED's
   -- my kind of "do thing, do it well, and do it quietly" device.
   Startup time (power-up to first reading) is ~1 minute.

   Since it first appeared eBay there are now dozen(s) of clone
   [re]sellers, which often happens these days, especially from far east
   sellers.

   My current feeling is if it were half the price and if the documentation
   were better and if they added clean ZCD the inputs, they'd sell a lot
   of them. Right now, I think they're just reaching for a top price to see
   if it will sell. From the eBay history there have been a couple of
   sales in several months so that's their answer.

   I'll have more info as the evaluation tests continue.

   The sad thing to me is that for ten+ years I kept hoping someone time-nuts 
would make a similar turn-key phase comparator. A number of
   members have mentioned their dual-mixer prototypes but I've never seen
   anyone take it to the level where it's integrated into a
   working-out-of-the-box board or black box like this FSA. A ps-level
   1-100 MHz RF phase comparator would be (would have been) a perfect TAPR
   product. With TAPR, you get open source, good documentation, reliable
   and peer reviewed circuits, and superb support.

   /tvb


   7/26/2019 8:11 AM, tim...@timeok.it wrote:
   > > Hi, > > for some time now on ebay they have been selling the FSA3011
   > Frequency Stability Analyzer which would seem interesting as a fair >
   compromise between resolution and price. Some have been sold and I >
   would like to know if any of you have had the chance to try it and >
   therefore have an opinion on this instrument. > > Thanks, > > Luciano >
   > timeok ___ time-nuts >
   mailing list -- time-nuts@lists.febo.com To unsubscribe, go to >
   http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and >
   follow the instructions there. >

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Re: [time-nuts] Galileo service currently degraded

[tim...@timeok.it]

   Looking at the data it seems that GPS is the best system among the four, 
correct?

   Luciano


   Da "time-nuts" time-nuts-boun...@lists.febo.com
   A "Discussion of precise time and frequency measurement" 
time-nuts@lists.febo.com
   Cc
   Data Fri, 12 Jul 2019 18:29:10 -0400
   Oggetto Re: [time-nuts] Galileo service currently degraded
   I built this website as my senior design project last year, unfortunately
   there's no timing data (except for tdop) being logged but you can see the
   impact. Data is collected with four ublox m8n receivers, one per
   constellation.

   Galileo data from last 1 week:
   https://gnssperformancemonitor.com/viewdata.php?constellation=2×pan=1

   Kevin

   On Fri, Jul 12, 2019, 4:06 PM Hal Murray  wrote:

   >
   >
   > > Galileo service is currently degraded, see: https://www.gsc-europa.eu/
   > > notice-advisory-to-galileo-users-nagu-2019025
   >
   > Thanks.
   >
   > Is anybody monitoring a Galileo-only setup to see how far off the timing
   > drifts?
   >
   >
   > --
   > These are my opinions. I hate spam.
   >
   >
   >
   >
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   >
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Re: [time-nuts] Neat looking DMTD unit on eBay

[tim...@timeok.it]

   Hi Corby,

   Do you have some news?

   thankyou,

   Luciano


   Da "time-nuts" time-nuts-boun...@lists.febo.com
   A time-nuts@lists.febo.com
   Cc
   Data Mon, 22 Apr 2019 08:11:01 -0700
   Oggetto [time-nuts] Neat looking DMTD unit on eBay
   Hi,

   A friend directed me to this listing. Nice looking DMTD unit.
   Low power and compact!
   Has anyone played with one of these yet?

   https://www.ebay.ca/itm/123728915157?ul_noapp=true

   Cheers,

   Corby


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Re: [time-nuts] F9T Info

[tim...@timeok.it]

Hi Bob,
I would like to know if there is a program to communicate with the F9T.
If I understand the acquisitions you have made with the TICC, they include
a direct input from the 1PPS of the F9T and a PPS by dividing the 5MHz of the 
5065.
Is it correct?
Luciano


   Da "time-nuts" time-nuts-boun...@lists.febo.com
   A "Discussion of precise time and frequency measurement" 
time-nuts@lists.febo.com
   Cc
   Data Mon, 25 Mar 2019 22:21:43 -0400
   Oggetto [time-nuts] F9T Info
   Hi

   Looks like uBlox has released the basic info on the protocols and 
interfacing of the F9T.

   https://www.u-blox.com/en/product/zed-f9t-module#tab-documentation-resources

   There are still a few documents referenced in what they did release that 
have not yet
   popped up on the web site.

   Still looking for something past FW 2.00 …..

   Bob
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[time-nuts] Jackson Labs Phase Station

[tim...@timeok.it]

Hi all,
I have not found details about the new product of the Jackson Labs, the Phase 
Station.
The new driver is now added to the  V1.32 Beta version of Timelab.
It seems to be an alternative of Timepod.
Can anyone anticipate something?
Luciano
www.timeok.it
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Re: [time-nuts] Clock project request from IEEE

[tim...@timeok.it]

Hi,
This request interests me a lot because there is not a good technical product 
on the market.
I would like something similar to the model 6460 TRAK Systems but with more 
advanced features
such as a synchronization within 10nS with an external clock and a clock 
synchronization from
GPS using both the NMEA code using also a PPS input in order to eliminate the 
delay due to the
serial port communication.
Unfortunately I do not have the skills to participate in this project but I 
sincerely hope
that some brilliant mind among you can accommodate the request. Tom for example?
Luciano


   Da "time-nuts" time-nuts-boun...@lists.febo.com
   A "Discussion of precise time and frequency measurement" 
time-nuts@lists.febo.com
   Cc
   Data Fri, 22 Feb 2019 10:31:06 -0800
   Oggetto [time-nuts] Clock project request from IEEE
   I received the following email and permission to post it on time-nuts:

   > Hello,
   >
   > I am the executive editor of the IEEE's flagship magazine, IEEE Spectrum.
   > I recently acquired a TAPR "Pulse Puppy" and I am intrigued by the idea of
   > using it to build a very precise clock that I would share with Spectrum's 
readers.
   >
   > I would like to partner with an engineer with experience in digital 
clocks, who
   > would be credited as co-author on this project.
   >
   > Can you suggest someone who might be interested in this project? I would be
   > much obliged if you had some suggestions.
   >
   > Kind regards,
   > -Glenn

   Glenn's contact info is:

   > Glenn Zorpette
   > g.zorpe...@ieee.org

   You can just imagine all the many ways the project could head. Send Glenn a 
note if you want to help. Or post here if you have suggestions.

   Thanks,
   /tvb


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Re: [time-nuts] Good clean-up oscillators

[tim...@timeok.it]

   Magnus,
   here the list of the most interesting OCXO  with the phase noise as declared 
by the companies.
   Luciano
   http://www.timeok.it/wp-content/uploads/2015/08/ocxo-comparative-table1.pdf


   Da "time-nuts" time-nuts-boun...@lists.febo.com
   A "Discussion of precise time and frequency measurement" 
time-nuts@lists.febo.com
   Cc
   Data Wed, 23 Jan 2019 21:43:34 +0100
   Oggetto [time-nuts] Good clean-up oscillators
   Fellow time-nuts,

   While we often look at long-term stability, ADEV etc. we consider
   oscillators in their free-running properties. This is all fine and dany,
   but when we want to use an oscillator as a clean-up oscillator, the
   servo-loop with surpress much of the low-frequency/high-tau properties
   and replace that with that of the reference.

   Consider for instance that we have a LPRO rubidium and we want to use a
   clean-up oscillator to provide better phase-noise, what would be a good
   selection?

   While there is plenty of choices, it is a bit different from that which
   is relevant when considering it as a free-running oscillator. The white
   noise which dominated far-out would dominate, and only some of the
   flicker phase becomes relevant.

   I could easily get a OCXO of good quality, but really, what would be
   interesting choices? Have someone measured this enough to get a kind of
   rough idea at least?

   Cheers,
   Magnus


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Re: [time-nuts] Short term 10MHz source

[tim...@timeok.it]

   John,
   I suppose this and all my measurenents are made in time stamp mode.
   Thanks for the work you have done.
   Luciano


   Da "time-nuts" time-nuts-boun...@lists.febo.com
   A time-nuts@lists.febo.com
   Cc
   Data Tue, 8 Jan 2019 13:48:22 -0500
   Oggetto Re: [time-nuts] Short term 10MHz source
   Hi Luciano --

   Thanks for posting that. There's a subtle point about the noise floor
   that's forever been on my list of things to investigate: the noise floor
   should be lower in timestamp mode than in time interval (A->B) mode.

   That's because in timestamp mode there is jitter contribution only from
   a single measurement, whereas in time interval mode there is a
   measurement from each channel so you have two jitter components. So a
   guess is that the floor should be about sqrt(2) lower in timestamp mode.
   Someday I will test that theory.

   John
   
   On 1/8/19 12:38 PM, tim...@timeok.it wrote:
   >
   > .gif of the TICC noise floor.
   > Luciano
   >
   >
   > Da "time-nuts" time-nuts-boun...@lists.febo.com
   > A time-nuts@lists.febo.com
   > Cc
   > Data Tue, 8 Jan 2019 18:31:02 +0100
   > Oggetto Re: [time-nuts] Short term 10MHz source
   >
   > Hi Paul,
   > here the TICC noise floor.
   > Regarding the GPS/TICC versus a good Rubidium standard like the HP5065A , 
you cannot apreciate the Rubidium ADEV stability lower than 10Kseconds.
   > Luciano
   >
   >
   > Da "time-nuts" time-nuts-boun...@lists.febo.com
   > A "Discussion of precise time and frequency measurement" 
time-nuts@lists.febo.com
   > Cc
   > Data Sat, 5 Jan 2019 12:35:26 -
   > Oggetto Re: [time-nuts] Short term 10MHz source
   > Hi All sorry for a new be question but what is a TICC regards Paul B UK
   >
   > -Original Message-
   > From: time-nuts [mailto:time-nuts-boun...@lists.febo.com] On Behalf Of 
Chris
   > Burford
   > Sent: 02 January 2019 03:56
   > To: Time Nuts List
   > Subject: [time-nuts] Short term 10MHz source
   >
   > I have a situation in which I have access to a GPSDO 10MHz source but for
   > only about 10-12 hours at a time. My current residence does not allow a
   > permanent GPS antenna therefore I am limited in its use.
   >
   > I do realise that the long term stability of the GPSDO is somewhat superior
   > to a Rubidium source. I'm planning on using my TICC to validate both my
   > GPSDO and RFS. I'm aware that such a short "power on" period is somewhat
   > counterproductive but I have no other options. I'd like to know if a 6-8
   > hour window for the GPSDO is sufficient for use as a 10MHz source for the
   > TICC.
   >
   > I appreciate any and all comments.
   >
   > Regards, Chris
   > ___
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   >
   >
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   >
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Re: [time-nuts] Short term 10MHz source

[tim...@timeok.it]

   Hi Paul,
   here the TICC noise floor.
   Regarding the GPS/TICC versus a good Rubidium standard like the HP5065A , 
you cannot apreciate the Rubidium ADEV stability lower than 10Kseconds.
   Luciano


   Da "time-nuts" time-nuts-boun...@lists.febo.com
   A "Discussion of precise time and frequency measurement" 
time-nuts@lists.febo.com
   Cc
   Data Sat, 5 Jan 2019 12:35:26 -
   Oggetto Re: [time-nuts] Short term 10MHz source
   Hi All sorry for a new be question but what is a TICC regards Paul B UK

   -Original Message-
   From: time-nuts [mailto:time-nuts-boun...@lists.febo.com] On Behalf Of Chris
   Burford
   Sent: 02 January 2019 03:56
   To: Time Nuts List
   Subject: [time-nuts] Short term 10MHz source

   I have a situation in which I have access to a GPSDO 10MHz source but for
   only about 10-12 hours at a time. My current residence does not allow a
   permanent GPS antenna therefore I am limited in its use.

   I do realise that the long term stability of the GPSDO is somewhat superior
   to a Rubidium source. I'm planning on using my TICC to validate both my
   GPSDO and RFS. I'm aware that such a short "power on" period is somewhat
   counterproductive but I have no other options. I'd like to know if a 6-8
   hour window for the GPSDO is sufficient for use as a 10MHz source for the
   TICC.

   I appreciate any and all comments.

   Regards, Chris
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;
;Measurement log file C:\Users\Principale\Desktop\TICC noise floor.tim
;Written by TimeLab 1.31 (Beta) of Sep 19 2018 by John Miles, KE5FX 
(j...@miles.io)
;

STR 0x "Driver" Acquire from counter in Talk-Only mode ...
STR 0x7900 "Channel" Ch 0
STR 0xC800 "Time/Date" 11/03/2017 17:26:36
DBL 0xCD40 "MJD" 57823.68534292824
STR 0x0501 "Trace" TICC noise floor
STR 0x0A01 "Notes"
STR 0xE601 "Instrument" TICC
STR 0x "Port Configuration" baud=115200parity=N data=8 stop=1
S32 0x "Counter Connection Type" 5
STR 0xFA00 "Imported From"
DBL 0x32200041 "Sample Interval" 1.00
BLN 0x "Autosense Rate" False
DBL 0x1481 "Input Freq" 1
S32 0x5A00 "Bin Density" 29
S32 0x5F00 "Bin Threshold" 4
S32 0x5000 "Trace History" 1
DBL 0x3C001001 "Duration" 36
S32 0x "Duration Type" 5
S32 0x "Stop Condition" 0
S32 0x "Data Format" 0
STR 0x "Comment Prefix" #
STR 0x "Interface" COM6
STR 0x "Setup String"
S32 0x "Field #" 1
S32 0x "Stability Channel Count" 1
STR 0x "Stability Channel ID" chB
DBL 0x2D00 "Scale Factor" 1.0
BLN 0x "Phase" False
BLN 0x "Unwrapped Phase" False
BLN 0x "Frequency" False
BLN 0x "Frequency Difference" False
BLN 0x "Timestamp" True
S32 0x "EOS Character" 10
BLN 0x "HP 5313xA Mode" False
BLN 0x "Prologix Compatibility Mode" False
BLN 0x "Read Existing Data" False
S32 0x "Wrap Period" 0
S32 0x "Data Type" 3
BLN 0x "Unwrapped" True
S32 0x "Driver version" 112
DBL 0x "Rescale Factor" 1.0
DBL 0x "New t0" 1
STR 0xEB02 "Source A"
STR 0xEB02 "Source B"

TIC 3600
   0.E+000
   -4.5999648534689167E-011
   -3.9981351562801145E-012
   -3.6998404340238247E-011
   1.1002310174035300E-011
   -3.4997782449863741E-011
   2.190555389771E-011
   -9.6999741572290077E-011
   -4.3000270011361863E-011
   -4.7000625613691234E-011
   -1.0600054167753118E-010
   -9.2999385969960713E-011
   1.7999823853642738E-011
   -3.6999736607867817E-011
   -8.1991302636197361E-011
   2.2007284883329719E-011
   -9.0992102741438443E-011
   -2.5991653274104465E-011
   4.5005776883044752E-011
   -2.2993162929196842E-011
   1.0007994433181010E-011
   -2.6993518531526206E-011
   -7.5992545589542715E-011
   -4.7990056373237167E-011
   -3.9992897882257239E-011
   -7.9992901191872092E-011
   1.8005152924160939E-011
   -3.6994407537349610E-011
   2.0005330725325637E-011
   -9.6992636144932476E-011
   -9.1006313596153645E-011
   -1.0300738040314176E-010
   -9.9007024800812360E-011
   -3.5001335163542542E-011
   -4.5005776883044752E-011
   -4.6007642140466487E-011
   2.0996537841710960E-011
   -1.4100720591159188E-010
   -8.9002583081310149E-011
   -1.0300738040314176E-010
   -4.2007286538137123E-011
   -4.1005421280715382E-011
   -1.5000978237367243E-010
   -8.7005957993824255E-011
   -1.8005152924160939E-011
   -9.5006669198483060E-011
   -2.6005864128819680E-011
   -4.1005421280715382E-011
   -5.1009863000217560E-011
   

Re: [time-nuts] Comparing the performance of 17 different GPSDOs

[tim...@timeok.it]

   Hi Mark,
   good job.
   Have you made an analysis of the results and made some considerations about 
the parameters you have measured?
   Luciano


   Da "time-nuts" time-nuts-boun...@lists.febo.com
   A "time-nuts@lists.febo.com" time-nuts@lists.febo.com
   Cc
   Data Sun, 9 Dec 2018 05:10:17 +
   Oggetto [time-nuts] Comparing the performance of 17 different GPSDOs
   I recently completed some comparison tests of the PPS and 10 MHz outputs of 
17 different GPSDOs.

   The tests were done with a TAPR TICC time interval counter running in 
timestamp mode and the data was acquired and processed with Lady Heather. The 
TICC was clocked by a HP-5071A cesium beam oscillator with the high-performance 
tube. The TICC has a resolution of around 60 picoseconds.

   The PPS signal from the GPSDO was connected to channel A of the TICC (for 
those GPSDOs that have an easily accessible PPS signal). For receivers without 
a PPS signal available, Heather shows ADEV, HDEV, MDEV, and TDEV data for the 
10 MHz signal. For receivers with a PPS, ADEV is shown for the 1PPS and 10 MHz 
signals.

   The GPSDO output frequency (10 MHZ) was connected to channel B of the TICC 
through a TAPR TADD-2 Mini divider to get a 1 Hz output.

   Note that PPS and 10 MHz plots have a display averaging filter applied. 
Without this filter the plots mostly show noisy "grass" and not any interesting 
details. A side effect of the display filter is to reduce the "span" 
(difference between the max and min values seen) of the plot data. Typically 
the unfiltered spans are around twice the value shown in the plot header, but 
for a couple of receivers it is up to a 10x reduction of the raw span.

   Each GPSDO was allowed to warm up for at least 24 hours, or longer... until 
the DAC output voltage slope leveled off.

   The GPSDO antenna was a L1/L2/GPS/GLONASS/BEIDOU antenna from China. With a 
L1/L2 survey receiver this antenna produces location error ellipse in the 
5-10mm range. It is mounted on a 1 meter tripod and fed into an 8-way amplified 
L1/L2/Glonass/Beidou splitter. The antenna is in a rather horrible location for 
multi-path and sky view. Lots of tall trees and a 2 story stucco-over-wire mesh 
house.

   
http://www.eevblog.com/forum/metrology/comparing-the-performance-of-17-different-gpsdos/msg2025295/#msg2025295
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Re: [time-nuts] RF isolation requirements for multiple GPS receivers

[tim...@timeok.it]

   Dana,
   As described in the following HP GPS splitter the isolation is  > 40dB.
   https://www.febo.com/time-freq/gps/hp58516a/HP_58516A.pdf
   I use one of these 8-channel splitters.
   I had a bad experience using a passive splitter of the minicircuits in the 
10MHz distribution in my lab.
   An instrument that accidentally generated instead of receiving the reference 
disturbed all other related instruments.
   In this case, an isolation of 25-30dB proved to be insufficient.
   Therefore, I recommend using a GPS splitter with active components such as 
the classic HP models and other brands.
   Luciano
   www.timeok.it


   Da "time-nuts" time-nuts-boun...@lists.febo.com
   A "Discussion of precise time and frequency measurement" 
time-nuts@lists.febo.com
   Cc
   Data Tue, 27 Nov 2018 07:44:23 -0600
   Oggetto [time-nuts] RF isolation requirements for multiple GPS receivers
   I want to run about 4 separate GPS units of disparate
   manufacture from a single antenna. My plan is to
   provide power for the antenna via a bias tee (power
   inserter) at the bottom end of the antenna's cable, then
   use an isolating splitter on the receiver side of the bias
   tee to split to the various receivers.

   My question is: how much isolation between receivers
   is likely to be necessary? Real life splitters are only
   so-so in isolation performance (15-25 dB), and may
   e significantly worse if the antenna's LNA's output is
   a poor match. So I'm wondering if I'm going to need
   more amplifiers in the splitter's outputs just for the sake
   of adequate isolation between the GPS receivers.

   Thanks,

   Dana K8YUM
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   and follow the instructions there.
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[time-nuts] Looking for AN/URQ-23 FE-150A

[tim...@timeok.it]

   Hi,
   I'm looking for an AN / URQ-23  also called the FE-150A made by Frequency 
Electronics.
   If you have one to sell please contact me off line:
   tim...@timeok.it
   thankyou ,
   Luciano
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Re: [time-nuts] Oscilloquartz 8600...

[tim...@timeok.it]

   Hi,
   the BVA has a very small frequency calibration range.
   I have solved this analogous problem on two 1000B by replacing the fixed 
capacitor which determines the base frequency of the resonance inside the 
oscillator.
   I think it's the only way to solve the problem.
   There are no wiring diagrams but with a little patience you can identify the 
capacitor and increase or decrease its value.
   cheers
   Luciano


   Da "time-nuts" time-nuts-boun...@lists.febo.com
   A time-nuts@lists.febo.com
   Cc mag...@rubidium.se
   Data Tue, 30 Oct 2018 22:40:07 +0100
   Oggetto Re: [time-nuts] Oscilloquartz 8600...
   Hej Ulf,

   On 10/30/18 10:18 PM, Ulf Kylenfall via time-nuts wrote:
   >
   > Regarding the Oscilloquartz 8600-3 that was 1 Hz off the frequency...
   > I have received information off the listthat I think will be helpful.
   > I will give it another try.

   One of mine is off in similar sense. It can't be tuned to be sharp on 5
   MHz anymore. The way that I use my main pair is as phase-noise reference
   for the TimePod.

   But, I'd love if I could tweak it back.

   Cheers,
   Magnus

   > Cheers
   > Ulf KylenfallSM6GXV
   >
   >
   >
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   > and follow the instructions there.
   >

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Re: [time-nuts] RF Isolation Amplifier ...

[tim...@timeok.it]

   Hi Corby,
   see: 
http://www.timeok.it/wp-content/uploads/2015/08/Frequency-Distribution-Design-Basic-Module-v-4.1.pdf
   Luciano


   Da "time-nuts" time-nuts-boun...@lists.febo.com
   A time-nuts@lists.febo.com
   Cc
   Data Mon, 15 Oct 2018 10:38:21 -0700
   Oggetto [time-nuts] RF Isolation Amplifier ...
   Thanks for the inputs.

   Attached is the blurb from the manual on the 5Mhz isolation amps.

   I don't want to redesign as the 3 amps are matched for delay and temp and
   run at 45 degrees C.

   I'll check the output of the amp with a spec-A and select the capacitor
   as appropriate.

   Cheers,

   Corby
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