Re: [time-nuts] New Timestamping / Time Interval Counter: the TICC
Hi At least in my “unconstrained by reality” state, my thought is that the “sync” PPS signal is there all the time. You are as much doing a phase lock as a sync. The “PLL” only has a phase resolution of 100 ns so once it’s running, not much happens. Yes, this might get you into all sorts of issues like some D-FF’s for early / late detection. Things are getting more complex …… Bob > On Nov 27, 2016, at 7:18 PM, John Ackermann N8UR wrote: > > Hi Bob -- > > It's certainly possible to synchronize the TICC timescale epoch to an > external pulse at startup. The external sync pulse would have to > simultaneously reset (a) the picDIV and (b) the coarse (100us) counter in the > Arduino. The signals to do that are available, so it's a worthwhile > experiment. > > I have to think through whether there are any other gotchas but I'm pretty > sure that you would not get closer than a few hundred nanoseconds given how > closely the picDIV can sync -- I think Tom specifies that it's within 4 > clocks, or 400 ns. > > (Now, syncing two TICCs to each other is a different matter because there we > one unit is master and provides the coarse clock directly to the slave; if > both units are run from the same 10 MHz clock they should align within one 10 > MHz tick.) > > John > > > On 11/27/2016 12:26 PM, Bob Camp wrote: >> Hi >> >> Ok, so the guess was fairly close :) >> >> How about a connector to allow an external PPS to reset the internal 10 MHz >> divider? That way all >> the data is “in syncâ€� with the house standard. If I want to know that my >> GPSDO is +32.751 ns off from >> the house standard, I just look at the data on a terminal program … >> >> Or am I missing something really obvious (again)? >> >> Bob >> >>> On Nov 27, 2016, at 10:04 AM, John Ackermann N8UR wrote: >>> >>> Good guess. The 10 MHz reference drives all the logic on the board, and >>> particularly the counter that maintains a local timescale in 100us >>> increments; the TDC7200 interpolates between the 100us ticks to stamp >>> incoming events on channel A and/or B with picosecond precision. The >>> stamps on both channels are referenced to the same local timescale. >>> >>> Therefore, you can do a measurement of a PPS source against the 10 MHz >>> reference and the resulting timestamp output can be processed by TimeLab or >>> whatever into stability data (the requirement being that the software knows >>> how to deal with timestamps that increment by the nominal measurement rate, >>> e.g., 1 second per measurement for PPS data). >>> >>> So with PPS from GPSDO "A" on channel A the timestamp output after >>> unwrapping will show the phase of A vs. 10 MHz. >>> >>> You can add PPS from GPSDO "B" on channel B and the TICC will also output >>> timestamps of B vs. the 10 MHz source. >>> >>> If you want, you can subtract A from B to get the time interval between the >>> two GPSDO, since both timestamp measurements are against a common >>> timescale. The TICC has a mode to output the (B-A) difference, so it can >>> act as either a traditional time interval counter, or as a two-channel >>> timestamping counter. >>> >>> And as noted in my other message to Luciano, the TICC can also output both >>> timestamp and time interval data simultaneously to allow three-corner-hat >>> measurements of (A-C, B-C, B-A) where C is the 10 MHz reference. >>> >>> John >>> >>> >>> On 11/27/2016 09:24 AM, Bob Camp wrote: Hi Without doing a bunch of actual *work* I’m not sure what is inside the guts of the board. Being lazy I’ll just guess …. There appears to be a 10 MHz time base input and a pair of measurement inputs. In a lot us will be comparing to a “house standard�. That standard has a pps output that is related directly to the 10 MHz reference. If I can uniquely identify one edge (out of 10 million edges) as the right edge, I can use the 10 MHz as my pps reference. Put another way, I don’t really need to measure a pps input from the house standard if I’m already locked up in phase to the 10 MHz. All I need to do is to tag an edge / reset a counter. The advantage of this is that I may not need another fancy TDC chip to set up the reference. I can use *both* inputs for DUT’s rather than using one as a reference. Part of the reason I’m guessing this would work is the claim that boards can be stacked for multiple input setups …. Bob > On Nov 27, 2016, at 7:36 AM, timeok wrote: > > > Hi John, > I have planned to buy two TICC. > An interesting feature would be to be able to do two simultaneous > acquisitions, > and Timelab as real time display,using the two indipendent input channels > and the 10Mhz clock as single reference. > Luciano > www.time
Re: [time-nuts] New Timestamping / Time Interval Counter: the TICC
John, The PD15 divider that you're using will sync to within 1 PIC instruction. That's sounds good, but the TICC reads down to picoseconds so the 400 ns PIC granularity will look pretty high. There is another solution. And that is not to sync the h/w or s/w counters at all. You just let them free-run. But you allow a sync mode where the user places a known UTC 1PPS in chA or chB and then the Arduino takes a reading. That number is then stored and subtracted from all subsequent readings that the Arduino outputs. It's better than a h/w sync because it allows you to sync to the ps level. And it also takes into account any propagation delays on your board, connector and cables. /tvb - Original Message - From: "John Ackermann N8UR" To: Sent: Sunday, November 27, 2016 4:18 PM Subject: Re: [time-nuts] New Timestamping / Time Interval Counter: the TICC Hi Bob -- It's certainly possible to synchronize the TICC timescale epoch to an external pulse at startup. The external sync pulse would have to simultaneously reset (a) the picDIV and (b) the coarse (100us) counter in the Arduino. The signals to do that are available, so it's a worthwhile experiment. I have to think through whether there are any other gotchas but I'm pretty sure that you would not get closer than a few hundred nanoseconds given how closely the picDIV can sync -- I think Tom specifies that it's within 4 clocks, or 400 ns. (Now, syncing two TICCs to each other is a different matter because there we one unit is master and provides the coarse clock directly to the slave; if both units are run from the same 10 MHz clock they should align within one 10 MHz tick.) John On 11/27/2016 12:26 PM, Bob Camp wrote: > Hi > > Ok, so the guess was fairly close :) > > How about a connector to allow an external PPS to reset the internal 10 MHz > divider? That way all > the data is “in sync� with the house standard. If I want to know that my > GPSDO is +32.751 ns off from > the house standard, I just look at the data on a terminal program … > > Or am I missing something really obvious (again)? > > Bob > >> On Nov 27, 2016, at 10:04 AM, John Ackermann N8UR wrote: >> >> Good guess. The 10 MHz reference drives all the logic on the board, and >> particularly the counter that maintains a local timescale in 100us >> increments; the TDC7200 interpolates between the 100us ticks to stamp >> incoming events on channel A and/or B with picosecond precision. The stamps >> on both channels are referenced to the same local timescale. >> >> Therefore, you can do a measurement of a PPS source against the 10 MHz >> reference and the resulting timestamp output can be processed by TimeLab or >> whatever into stability data (the requirement being that the software knows >> how to deal with timestamps that increment by the nominal measurement rate, >> e.g., 1 second per measurement for PPS data). >> >> So with PPS from GPSDO "A" on channel A the timestamp output after >> unwrapping will show the phase of A vs. 10 MHz. >> >> You can add PPS from GPSDO "B" on channel B and the TICC will also output >> timestamps of B vs. the 10 MHz source. >> >> If you want, you can subtract A from B to get the time interval between the >> two GPSDO, since both timestamp measurements are against a common timescale. >> The TICC has a mode to output the (B-A) difference, so it can act as either >> a traditional time interval counter, or as a two-channel timestamping >> counter. >> >> And as noted in my other message to Luciano, the TICC can also output both >> timestamp and time interval data simultaneously to allow three-corner-hat >> measurements of (A-C, B-C, B-A) where C is the 10 MHz reference. >> >> John >> >> >> On 11/27/2016 09:24 AM, Bob Camp wrote: >>> Hi >>> >>> Without doing a bunch of actual *work* I’m not sure what is inside >>> the guts of the board. Being >>> lazy I’ll just guess …. >>> >>> There appears to be a 10 MHz time base input and a pair of measurement >>> inputs. In a lot us will >>> be comparing to a “house standardâ€�. That standard has a pps >>> output that is related directly to >>> the 10 MHz reference. If I can uniquely identify one edge (out of 10 >>> million edges) as the right >>> edge, I can use the 10 MHz as my pps reference. Put another way, I >>> don’t really need to measure >>> a pps input from the house standard if I’m already locked up in >>> phase to the 10 MHz. All I need to >>> do is to tag an edge / reset a counter. >>> >>> The advantage of this is that I may not need another fancy TDC chip to set >>> up the reference. I can >>> use *both* inputs for DUT’s rather than using one as a reference. >>> >>> Part of the reason I’m guessing this would work is the claim that >>> boards can be stacked for multiple >>> input setups …. >>> >>> Bob >>> On Nov 27, 2016, at 7:36 AM, timeok wrote: Hi John, >>
Re: [time-nuts] New Timestamping / Time Interval Counter: the TICC
Hi Bob -- It's certainly possible to synchronize the TICC timescale epoch to an external pulse at startup. The external sync pulse would have to simultaneously reset (a) the picDIV and (b) the coarse (100us) counter in the Arduino. The signals to do that are available, so it's a worthwhile experiment. I have to think through whether there are any other gotchas but I'm pretty sure that you would not get closer than a few hundred nanoseconds given how closely the picDIV can sync -- I think Tom specifies that it's within 4 clocks, or 400 ns. (Now, syncing two TICCs to each other is a different matter because there we one unit is master and provides the coarse clock directly to the slave; if both units are run from the same 10 MHz clock they should align within one 10 MHz tick.) John On 11/27/2016 12:26 PM, Bob Camp wrote: Hi Ok, so the guess was fairly close :) How about a connector to allow an external PPS to reset the internal 10 MHz divider? That way all the data is “in sync� with the house standard. If I want to know that my GPSDO is +32.751 ns off from the house standard, I just look at the data on a terminal program … Or am I missing something really obvious (again)? Bob On Nov 27, 2016, at 10:04 AM, John Ackermann N8UR wrote: Good guess. The 10 MHz reference drives all the logic on the board, and particularly the counter that maintains a local timescale in 100us increments; the TDC7200 interpolates between the 100us ticks to stamp incoming events on channel A and/or B with picosecond precision. The stamps on both channels are referenced to the same local timescale. Therefore, you can do a measurement of a PPS source against the 10 MHz reference and the resulting timestamp output can be processed by TimeLab or whatever into stability data (the requirement being that the software knows how to deal with timestamps that increment by the nominal measurement rate, e.g., 1 second per measurement for PPS data). So with PPS from GPSDO "A" on channel A the timestamp output after unwrapping will show the phase of A vs. 10 MHz. You can add PPS from GPSDO "B" on channel B and the TICC will also output timestamps of B vs. the 10 MHz source. If you want, you can subtract A from B to get the time interval between the two GPSDO, since both timestamp measurements are against a common timescale. The TICC has a mode to output the (B-A) difference, so it can act as either a traditional time interval counter, or as a two-channel timestamping counter. And as noted in my other message to Luciano, the TICC can also output both timestamp and time interval data simultaneously to allow three-corner-hat measurements of (A-C, B-C, B-A) where C is the 10 MHz reference. John On 11/27/2016 09:24 AM, Bob Camp wrote: Hi Without doing a bunch of actual *work* I’m not sure what is inside the guts of the board. Being lazy I’ll just guess …. There appears to be a 10 MHz time base input and a pair of measurement inputs. In a lot us will be comparing to a “house standardâ€�. That standard has a pps output that is related directly to the 10 MHz reference. If I can uniquely identify one edge (out of 10 million edges) as the right edge, I can use the 10 MHz as my pps reference. Put another way, I don’t really need to measure a pps input from the house standard if I’m already locked up in phase to the 10 MHz. All I need to do is to tag an edge / reset a counter. The advantage of this is that I may not need another fancy TDC chip to set up the reference. I can use *both* inputs for DUT’s rather than using one as a reference. Part of the reason I’m guessing this would work is the claim that boards can be stacked for multiple input setups …. Bob On Nov 27, 2016, at 7:36 AM, timeok wrote: Hi John, I have planned to buy two TICC. An interesting feature would be to be able to do two simultaneous acquisitions, and Timelab as real time display,using the two indipendent input channels and the 10Mhz clock as single reference. Luciano www.timeok.it From "time-nuts" time-nuts-boun...@febo.com To "Discussion of precise time and frequency measurement" time-nuts@febo.com Cc Date Wed, 23 Nov 2016 10:48:57 -0500 Subject [time-nuts] New Timestamping / Time Interval Counter: the TICC Counters with resolution below 1 nanosecond are difficult. They require either outrageous clock speeds, or interpolators that are typically a bunch of analog components mixed with black magic and stirred by frequent calibration. The very best single-shot resolution that's been commercially available is 22 picoseconds in the HP 5370A/B, with jitter somewhat more than that. My 5370B has an one-second noise ADEV of about 4x10e-11. With the help of some very talented friends, I've been working on a new counter called the "TICC" with <60ps resolution and similar jitter, based the Texas
[time-nuts] FS: HP Z3801A
I'm selling my remaining Z3801A. Months ago, I replaced the original GPS module with a more sensitive Oncore VP. At that time, I also replaced several suspect capacitors on the DC-DC converter board. Everything has been 100% since. The RS-232 mod was done long ago. A serial cable and a 24 VDC power supply is included. I will also include a spare Oncore VP module for free. Asking $300 plus shipping/insurance. I also have an HP 58516A 4-way GPS splitter that I will include for $50 more. Joe Gray W5JG ___ 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] New Timestamping / Time Interval Counter: the TICC
Hi Ok, so the guess was fairly close :) How about a connector to allow an external PPS to reset the internal 10 MHz divider? That way all the data is “in sync” with the house standard. If I want to know that my GPSDO is +32.751 ns off from the house standard, I just look at the data on a terminal program … Or am I missing something really obvious (again)? Bob > On Nov 27, 2016, at 10:04 AM, John Ackermann N8UR wrote: > > Good guess. The 10 MHz reference drives all the logic on the board, and > particularly the counter that maintains a local timescale in 100us > increments; the TDC7200 interpolates between the 100us ticks to stamp > incoming events on channel A and/or B with picosecond precision. The stamps > on both channels are referenced to the same local timescale. > > Therefore, you can do a measurement of a PPS source against the 10 MHz > reference and the resulting timestamp output can be processed by TimeLab or > whatever into stability data (the requirement being that the software knows > how to deal with timestamps that increment by the nominal measurement rate, > e.g., 1 second per measurement for PPS data). > > So with PPS from GPSDO "A" on channel A the timestamp output after unwrapping > will show the phase of A vs. 10 MHz. > > You can add PPS from GPSDO "B" on channel B and the TICC will also output > timestamps of B vs. the 10 MHz source. > > If you want, you can subtract A from B to get the time interval between the > two GPSDO, since both timestamp measurements are against a common timescale. > The TICC has a mode to output the (B-A) difference, so it can act as either a > traditional time interval counter, or as a two-channel timestamping counter. > > And as noted in my other message to Luciano, the TICC can also output both > timestamp and time interval data simultaneously to allow three-corner-hat > measurements of (A-C, B-C, B-A) where C is the 10 MHz reference. > > John > > > On 11/27/2016 09:24 AM, Bob Camp wrote: >> Hi >> >> Without doing a bunch of actual *work* I’m not sure what is inside the >> guts of the board. Being >> lazy I’ll just guess …. >> >> There appears to be a 10 MHz time base input and a pair of measurement >> inputs. In a lot us will >> be comparing to a “house standardâ€�. That standard has a pps output that >> is related directly to >> the 10 MHz reference. If I can uniquely identify one edge (out of 10 million >> edges) as the right >> edge, I can use the 10 MHz as my pps reference. Put another way, I don’t >> really need to measure >> a pps input from the house standard if I’m already locked up in phase to >> the 10 MHz. All I need to >> do is to tag an edge / reset a counter. >> >> The advantage of this is that I may not need another fancy TDC chip to set >> up the reference. I can >> use *both* inputs for DUT’s rather than using one as a reference. >> >> Part of the reason I’m guessing this would work is the claim that boards >> can be stacked for multiple >> input setups …. >> >> Bob >> >>> On Nov 27, 2016, at 7:36 AM, timeok wrote: >>> >>> >>> Hi John, >>> I have planned to buy two TICC. >>> An interesting feature would be to be able to do two simultaneous >>> acquisitions, >>> and Timelab as real time display,using the two indipendent input channels >>> and the 10Mhz clock as single reference. >>> Luciano >>> www.timeok.it >>> >>> >>> From "time-nuts" time-nuts-boun...@febo.com >>> To "Discussion of precise time and frequency measurement" >>> time-nuts@febo.com >>> Cc >>> Date Wed, 23 Nov 2016 10:48:57 -0500 >>> Subject [time-nuts] New Timestamping / Time Interval Counter: the TICC >>> Counters with resolution below 1 nanosecond are difficult. They require >>> either outrageous clock speeds, or interpolators that are typically a >>> bunch of analog components mixed with black magic and stirred by >>> frequent calibration. The very best single-shot resolution that's been >>> commercially available is 22 picoseconds in the HP 5370A/B, with jitter >>> somewhat more than that. My 5370B has an one-second noise ADEV of about >>> 4x10e-11. >>> >>> With the help of some very talented friends, I've been working on a new >>> counter called the "TICC" with <60ps resolution and similar jitter, >>> based the Texas Instruments TDC7200 time-to-data-converter chip. The >>> noise ADEV is about 7x10e-11, not much worse than the 5370, >>> but here's the trick: the TICC is an Arduino shield (mounting a Mega >>> 2560 controller) that weighs a couple of ounces, requires *no* >>> calibration, and is powered from a USB cable! >>> >>> The TICC is implemented as a two-channel timestamping counter. That >>> means it can measure or two low-frequency (e.g., pulse-per-second) >>> inputs against an external 10 MHz reference, or it can do a traditional >>> time interval measurement of input against the other. It can also >>> measure period, ratio, or any oth
Re: [time-nuts] New Timestamping / Time Interval Counter: the TICC
Good guess. The 10 MHz reference drives all the logic on the board, and particularly the counter that maintains a local timescale in 100us increments; the TDC7200 interpolates between the 100us ticks to stamp incoming events on channel A and/or B with picosecond precision. The stamps on both channels are referenced to the same local timescale. Therefore, you can do a measurement of a PPS source against the 10 MHz reference and the resulting timestamp output can be processed by TimeLab or whatever into stability data (the requirement being that the software knows how to deal with timestamps that increment by the nominal measurement rate, e.g., 1 second per measurement for PPS data). So with PPS from GPSDO "A" on channel A the timestamp output after unwrapping will show the phase of A vs. 10 MHz. You can add PPS from GPSDO "B" on channel B and the TICC will also output timestamps of B vs. the 10 MHz source. If you want, you can subtract A from B to get the time interval between the two GPSDO, since both timestamp measurements are against a common timescale. The TICC has a mode to output the (B-A) difference, so it can act as either a traditional time interval counter, or as a two-channel timestamping counter. And as noted in my other message to Luciano, the TICC can also output both timestamp and time interval data simultaneously to allow three-corner-hat measurements of (A-C, B-C, B-A) where C is the 10 MHz reference. John On 11/27/2016 09:24 AM, Bob Camp wrote: Hi Without doing a bunch of actual *work* I’m not sure what is inside the guts of the board. Being lazy I’ll just guess …. There appears to be a 10 MHz time base input and a pair of measurement inputs. In a lot us will be comparing to a “house standard�. That standard has a pps output that is related directly to the 10 MHz reference. If I can uniquely identify one edge (out of 10 million edges) as the right edge, I can use the 10 MHz as my pps reference. Put another way, I don’t really need to measure a pps input from the house standard if I’m already locked up in phase to the 10 MHz. All I need to do is to tag an edge / reset a counter. The advantage of this is that I may not need another fancy TDC chip to set up the reference. I can use *both* inputs for DUT’s rather than using one as a reference. Part of the reason I’m guessing this would work is the claim that boards can be stacked for multiple input setups …. Bob On Nov 27, 2016, at 7:36 AM, timeok wrote: Hi John, I have planned to buy two TICC. An interesting feature would be to be able to do two simultaneous acquisitions, and Timelab as real time display,using the two indipendent input channels and the 10Mhz clock as single reference. Luciano www.timeok.it From "time-nuts" time-nuts-boun...@febo.com To "Discussion of precise time and frequency measurement" time-nuts@febo.com Cc Date Wed, 23 Nov 2016 10:48:57 -0500 Subject [time-nuts] New Timestamping / Time Interval Counter: the TICC Counters with resolution below 1 nanosecond are difficult. They require either outrageous clock speeds, or interpolators that are typically a bunch of analog components mixed with black magic and stirred by frequent calibration. The very best single-shot resolution that's been commercially available is 22 picoseconds in the HP 5370A/B, with jitter somewhat more than that. My 5370B has an one-second noise ADEV of about 4x10e-11. With the help of some very talented friends, I've been working on a new counter called the "TICC" with <60ps resolution and similar jitter, based the Texas Instruments TDC7200 time-to-data-converter chip. The noise ADEV is about 7x10e-11, not much worse than the 5370, but here's the trick: the TICC is an Arduino shield (mounting a Mega 2560 controller) that weighs a couple of ounces, requires *no* calibration, and is powered from a USB cable! The TICC is implemented as a two-channel timestamping counter. That means it can measure or two low-frequency (e.g., pulse-per-second) inputs against an external 10 MHz reference, or it can do a traditional time interval measurement of input against the other. It can also measure period, ratio, or any other function of two-channel timestamp data. (And by the way -- multiple TICCs can be connected to yield 4, 6, 8, or more synchronized channels, though we haven't tested this capability yet.) I've attached a picture of the TICC prototype as well as an ADEV plot of a 17+ day run of multiple measurements taken by two TICCs, and also showing the TICC noise floor. The good news behind that plot is that there are more than 6 million data points behind these results, and there was not a single glitch or significant outlier among them. There's more information available at http://febo.com/pages/TICC The software is open source (BSD license) and is available at https://gi
Re: [time-nuts] New Timestamping / Time Interval Counter: the TICC
Hi Luciano -- Glad to hear that! The capability you asked for already exists (great minds think alike...) In timestamp mode, the TICC will output the stamps for each channel independently, measured against the common 10 MHz reference. So if both channels are active, you'll see a bunch of lines something like: 1.234567891234 chA 1.234567892345 chB 2.234567890434 chA 2.234567892789 chB Recent beta versions of TimeLab can acquire multiple channels on a single serial port; there are a couple of magic setup commands in the "Acquire" dialog that will allow TimeLab to receive the above and display it as two separate traces. There is also a three-cornered-hat capability, though it's a bit of a hack. The TICC has a "TimeLab" mode which will output two timestamps as above, but in addition "chC" which is the time interval (B-A). Since TimeLab requires all the input signals to be in the same format, the chC output is munged into a fake timestamp like this (adding the integer part of chB to the B-A difference): 1.234567891234 chA 1.234567892345 chB 1. chC 2.234567890434 chA 2.234567892789 chB 2.2355 chC With both TICC and TimeLab configured this way, you can do three-cornered-hat measurements in real time, which is pretty cool. When I get a chance, I'll document the setup for this in the TICC operation manual. John On 11/27/2016 07:36 AM, timeok wrote: Hi John, I have planned to buy two TICC. An interesting feature would be to be able to do two simultaneous acquisitions, and Timelab as real time display,using the two indipendent input channels and the 10Mhz clock as single reference. Luciano www.timeok.it From "time-nuts" time-nuts-boun...@febo.com To "Discussion of precise time and frequency measurement" time-nuts@febo.com Cc Date Wed, 23 Nov 2016 10:48:57 -0500 Subject [time-nuts] New Timestamping / Time Interval Counter: the TICC Counters with resolution below 1 nanosecond are difficult. They require either outrageous clock speeds, or interpolators that are typically a bunch of analog components mixed with black magic and stirred by frequent calibration. The very best single-shot resolution that's been commercially available is 22 picoseconds in the HP 5370A/B, with jitter somewhat more than that. My 5370B has an one-second noise ADEV of about 4x10e-11. With the help of some very talented friends, I've been working on a new counter called the "TICC" with <60ps resolution and similar jitter, based the Texas Instruments TDC7200 time-to-data-converter chip. The noise ADEV is about 7x10e-11, not much worse than the 5370, but here's the trick: the TICC is an Arduino shield (mounting a Mega 2560 controller) that weighs a couple of ounces, requires *no* calibration, and is powered from a USB cable! The TICC is implemented as a two-channel timestamping counter. That means it can measure or two low-frequency (e.g., pulse-per-second) inputs against an external 10 MHz reference, or it can do a traditional time interval measurement of input against the other. It can also measure period, ratio, or any other function of two-channel timestamp data. (And by the way -- multiple TICCs can be connected to yield 4, 6, 8, or more synchronized channels, though we haven't tested this capability yet.) I've attached a picture of the TICC prototype as well as an ADEV plot of a 17+ day run of multiple measurements taken by two TICCs, and also showing the TICC noise floor. The good news behind that plot is that there are more than 6 million data points behind these results, and there was not a single glitch or significant outlier among them. There's more information available at http://febo.com/pages/TICC The software is open source (BSD license) and is available at https://github.com/TAPR/TICC -- the current version seems be reliable but there are still features to add and a *lot* of cleanup to do; it's currently ugly and very much a work in process. As always, I'll be making the TICC available through TAPR. We're still finalizing details, but we expect the price to be less than $200 for a turn-key system: TICC mounted an Arduino with software loaded and tested for basic functionality. We hope to ship the TICC by February. I'll post a note in a week or two with final price and ordering information. As a heads up, we will probably offer a small discount for pre-orders. TAPR is a shoestring non-profit group and the up-front cost to manufacture this unit will frankly be a challenge for us. Getting pre-orders will help our cash flow significantly, so we ask you to keep that in mind. John ___ 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 the
Re: [time-nuts] New Timestamping / Time Interval Counter: the TICC
Hi Without doing a bunch of actual *work* I’m not sure what is inside the guts of the board. Being lazy I’ll just guess …. There appears to be a 10 MHz time base input and a pair of measurement inputs. In a lot us will be comparing to a “house standard”. That standard has a pps output that is related directly to the 10 MHz reference. If I can uniquely identify one edge (out of 10 million edges) as the right edge, I can use the 10 MHz as my pps reference. Put another way, I don’t really need to measure a pps input from the house standard if I’m already locked up in phase to the 10 MHz. All I need to do is to tag an edge / reset a counter. The advantage of this is that I may not need another fancy TDC chip to set up the reference. I can use *both* inputs for DUT’s rather than using one as a reference. Part of the reason I’m guessing this would work is the claim that boards can be stacked for multiple input setups …. Bob > On Nov 27, 2016, at 7:36 AM, timeok wrote: > > > Hi John, > I have planned to buy two TICC. > An interesting feature would be to be able to do two simultaneous > acquisitions, > and Timelab as real time display,using the two indipendent input channels and > the 10Mhz clock as single reference. > Luciano > www.timeok.it > > > From "time-nuts" time-nuts-boun...@febo.com > To "Discussion of precise time and frequency measurement" time-nuts@febo.com > Cc > Date Wed, 23 Nov 2016 10:48:57 -0500 > Subject [time-nuts] New Timestamping / Time Interval Counter: the TICC > Counters with resolution below 1 nanosecond are difficult. They require > either outrageous clock speeds, or interpolators that are typically a > bunch of analog components mixed with black magic and stirred by > frequent calibration. The very best single-shot resolution that's been > commercially available is 22 picoseconds in the HP 5370A/B, with jitter > somewhat more than that. My 5370B has an one-second noise ADEV of about > 4x10e-11. > > With the help of some very talented friends, I've been working on a new > counter called the "TICC" with <60ps resolution and similar jitter, > based the Texas Instruments TDC7200 time-to-data-converter chip. The > noise ADEV is about 7x10e-11, not much worse than the 5370, > but here's the trick: the TICC is an Arduino shield (mounting a Mega > 2560 controller) that weighs a couple of ounces, requires *no* > calibration, and is powered from a USB cable! > > The TICC is implemented as a two-channel timestamping counter. That > means it can measure or two low-frequency (e.g., pulse-per-second) > inputs against an external 10 MHz reference, or it can do a traditional > time interval measurement of input against the other. It can also > measure period, ratio, or any other function of two-channel timestamp > data. (And by the way -- multiple TICCs can be connected to yield 4, 6, > 8, or more synchronized channels, though we haven't tested this > capability yet.) > > I've attached a picture of the TICC prototype as well as an ADEV plot of > a 17+ day run of multiple measurements taken by two TICCs, and also > showing the TICC noise floor. The good news behind that plot is that > there are more than 6 million data points behind these results, and > there was not a single glitch or significant outlier among them. > > There's more information available at http://febo.com/pages/TICC > > The software is open source (BSD license) and is available at > https://github.com/TAPR/TICC -- the current version seems be reliable > but there are still features to add and a *lot* of cleanup to do; it's > currently ugly and very much a work in process. > > As always, I'll be making the TICC available through TAPR. We're still > finalizing details, but we expect the price to be less than $200 for a > turn-key system: TICC mounted an Arduino with software loaded and > tested for basic functionality. We hope to ship the TICC by February. > > I'll post a note in a week or two with final price and ordering > information. As a heads up, we will probably offer a small discount for > pre-orders. TAPR is a shoestring non-profit group and the up-front cost > to manufacture this unit will frankly be a challenge for us. Getting > pre-orders will help our cash flow significantly, so we ask you to keep > that in mind. > > John > ___ > 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] Trimble 65256 OCXO
Hi Pin 5 is the EFC reference pin. It may (or may not) have a voltage on it. If there is a voltage on it, it’s a voltage that the original OEM customer found useful. It may (or may not) have a series resistor to match up with an OEM specified trim pot. Bob > On Nov 27, 2016, at 2:04 AM, Dave Brown wrote: > > This 10 MHz unit has a 5th pin that I can't find any documentation about. > There have been posts in the past that have also indicated its use is > unknown. Looking at the base, the four connections in the corners are known > quantities. (ground, EFC, 10 MHz out and + supply) No. 5 is midway along one > side. > I thought it may be a reference supply for the EFC pin- with a 12.03 volt > supply the unknown pin measures at 2.803 volts-which is usefully above the > required EFC voltage ( ~2.4 volts) to bring it on frequency. > But does anyone have some hard data on this 'unknown' pin? > DaveB, NZ > > > ___ > 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] UCCM arrived
Hi You have a system with cascaded gains and noise figures. The “front end” of the GPSDO is in the antenna. The cable is between the front end of the receiver and the rest of the “radio”. With a cascaded noise figure situation, as long as the noise figure of the first stage is low (it is) and the gain of the first stage is high (it is) and the noise of the next stage (in the GPSDO) isn’t awful (it’s not) there is no problem. The gain of the antenna is specified so you know what that is. If the cable loss is less than the gain by about 6 db, there is little impact. In this case “little” means that you can’t measure what the impact is. Since you have a 26 db antenna, the cable loss needs to be less than 20 db. If you can get it down to 16 db that would give you a bit of margin. Bob > On Nov 27, 2016, at 2:01 AM, David J Taylor > wrote: > > Hello to all, > > I connected the unit to a 11m of H-155 cable(assumed 4.79dB loss "worst case" > at 1.5GHz), thrown the GPS antenna on the balcony horizontally and this is > what I got: > [] > - Given the attenuation (less than 5 dB) do I really need to change the cable > for something better? > [] > Giuseppe Marullo > IW2JWW - JN45RQ > = > > Giuseppe, > > Most GPS antennas have an LNA built-in, making cable loss less significant. > Doesn't your antenna have that? > > 73, > David GM8ARV > -- > SatSignal Software - Quality software written to your requirements > Web: http://www.satsignal.eu > Email: david-tay...@blueyonder.co.uk > Twitter: @gm8arv > ___ > 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] New Timestamping / Time Interval Counter: the TICC
Hi John, I have planned to buy two TICC. An interesting feature would be to be able to do two simultaneous acquisitions, and Timelab as real time display,using the two indipendent input channels and the 10Mhz clock as single reference. Luciano www.timeok.it From "time-nuts" time-nuts-boun...@febo.com To "Discussion of precise time and frequency measurement" time-nuts@febo.com Cc Date Wed, 23 Nov 2016 10:48:57 -0500 Subject [time-nuts] New Timestamping / Time Interval Counter: the TICC Counters with resolution below 1 nanosecond are difficult. They require either outrageous clock speeds, or interpolators that are typically a bunch of analog components mixed with black magic and stirred by frequent calibration. The very best single-shot resolution that's been commercially available is 22 picoseconds in the HP 5370A/B, with jitter somewhat more than that. My 5370B has an one-second noise ADEV of about 4x10e-11. With the help of some very talented friends, I've been working on a new counter called the "TICC" with <60ps resolution and similar jitter, based the Texas Instruments TDC7200 time-to-data-converter chip. The noise ADEV is about 7x10e-11, not much worse than the 5370, but here's the trick: the TICC is an Arduino shield (mounting a Mega 2560 controller) that weighs a couple of ounces, requires *no* calibration, and is powered from a USB cable! The TICC is implemented as a two-channel timestamping counter. That means it can measure or two low-frequency (e.g., pulse-per-second) inputs against an external 10 MHz reference, or it can do a traditional time interval measurement of input against the other. It can also measure period, ratio, or any other function of two-channel timestamp data. (And by the way -- multiple TICCs can be connected to yield 4, 6, 8, or more synchronized channels, though we haven't tested this capability yet.) I've attached a picture of the TICC prototype as well as an ADEV plot of a 17+ day run of multiple measurements taken by two TICCs, and also showing the TICC noise floor. The good news behind that plot is that there are more than 6 million data points behind these results, and there was not a single glitch or significant outlier among them. There's more information available at http://febo.com/pages/TICC The software is open source (BSD license) and is available at https://github.com/TAPR/TICC -- the current version seems be reliable but there are still features to add and a *lot* of cleanup to do; it's currently ugly and very much a work in process. As always, I'll be making the TICC available through TAPR. We're still finalizing details, but we expect the price to be less than $200 for a turn-key system: TICC mounted an Arduino with software loaded and tested for basic functionality. We hope to ship the TICC by February. I'll post a note in a week or two with final price and ordering information. As a heads up, we will probably offer a small discount for pre-orders. TAPR is a shoestring non-profit group and the up-front cost to manufacture this unit will frankly be a challenge for us. Getting pre-orders will help our cash flow significantly, so we ask you to keep that in mind. John ___ 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] UCCM arrived
>Most GPS antennas have an LNA built-in, making cable loss less significant. >Doesn't your antenna have that? Sure, specs says: - Amplifier Gain: 26 dB +/- 3 dB - Maximum Noise Figure:≤ 2.5 dB @ +25°C including pre-selector I still have to search a command to check signal strength. >For a long term installation, an antenna location that will “see” more sat’s >is a really good idea. > >Bob Antenna was on the balcony at first floor (european, 2nd floor us) on the balcony, laid there horizontally. Frankly I was not even expecting it to work at all, LOL! With a ten feet mast I was able to get eight-nine satellites before having to disconnect it. A little higher and it should have a perfect sky clearance (a little bit more cable will be needed though, hence the question about length). Giuseppe Marullo IW2JWW - JN45RQ From: "time-nuts" time-nuts-boun...@febo.com To: time-nuts@febo.com Cc: Date: Sun, 27 Nov 2016 07:01:05 - Subject: Re: [time-nuts] UCCM arrived Hello to all, I connected the unit to a 11m of H-155 cable(assumed 4.79dB loss "worst case" at 1.5GHz), thrown the GPS antenna on the balcony horizontally and this is what I got: [] - Given the attenuation (less than 5 dB) do I really need to change the cable for something better? [] Giuseppe Marullo IW2JWW - JN45RQ = Giuseppe, Most GPS antennas have an LNA built-in, making cable loss less significant. Doesn't your antenna have that? 73, David GM8ARV -- SatSignal Software - Quality software written to your requirements Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk Twitter: @gm8arv ___ 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] Trimble 65256 OCXO
tract...@ihug.co.nz said: > I thought it may be a reference supply for the EFC pin- with a 12.03 volt > supply the unknown pin measures at 2.803 volts-which is usefully above the > required EFC voltage ( ~2.4 volts) to bring it on frequency. > But does anyone have some hard data on this 'unknown' pin? Is it input or output? What happens if you pull it to ground with a 10K or 1K resistor? Or measure the impedance when powered off. 2.8 volts seems a bit low to be a useful supply. -- These are my opinions. I hate spam. ___ 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.
