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 on the Texas Instruments TDC7200 time-to-data-converter chip. The
one-second noise ADEV is about 7x10e-11, not much worse than the 5370,
but here's the trick: the TICC is an Arduino shield (mounting on a Mega
2560 controller) that weighs only 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 one 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 one 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 on 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
Hi
Cool !!!
Bob
On Nov 23, 2016, at 10:48 AM, John Ackermann N8UR jra@febo.com wrote:
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 on the Texas Instruments TDC7200 time-to-data-converter chip. The one-second noise ADEV is about 7x10e-11, not much worse than the 5370, but here's the trick: the TICC is an Arduino shield (mounting on a Mega 2560 controller) that weighs only 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 one 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 one 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 on 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
<TICC_rev_c_photo_small.jpg><ticc_rev_c-perf_test_adev.png>_______________________________________________
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That TI TDC7200 really is a nice part.
Neat project! Will buy . Two thumbs up.
On Wed, Nov 23, 2016 at 7:48 AM, John Ackermann N8UR jra@febo.com wrote:
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
on the Texas Instruments TDC7200 time-to-data-converter chip. The
one-second noise ADEV is about 7x10e-11, not much worse than the 5370, but
here's the trick: the TICC is an Arduino shield (mounting on a Mega 2560
controller) that weighs only 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 one 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 one 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 on 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
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Fantastic John - well done! Yes, I'll definitely put an order in as soon
as possible.
Regards,
Peter (G8ZZR, London)
Nice work!
On the website in the introduction you mention 22ps single-shot
time-stamping on the 5370A/B.
I think it's well established that the 53230A does about 11-12 ps for
time-intervals, which corresponds to about 9 ps single-channel. see for
example:
http://www.anderswallin.net/wp-content/uploads/2015/04/53230A_PPS_skew.png
Anders
On Wed, Nov 23, 2016 at 11:13 PM, Peter Vince petervince1952@gmail.com
wrote:
Fantastic John - well done! Yes, I'll definitely put an order in as soon
as possible.
Regards,
Peter (G8ZZR, London)
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.
On Wed, Nov 23, 2016 at 10:48 AM, John Ackermann N8UR jra@febo.com wrote:
The TICC is implemented as a two-channel timestamping counter. That means
it can measure one 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 one 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.)
Very exciting, I will definitely be wanting one :)
There's almost a way to do the coarse timer counting with almost no
CPU overhead, but unfortunately the Arduino folks were terribly
inconsistent about which timer signals they decided to assign to
Arduino pins. Of the six external clocks for timers, they brought out
two (T0 and T5), and of the four input captures, they brought out two
(ICP4 and ICP5). If they had brought out T4 then with a little bit of
timer configuration you could use COARSE to clock TIMER4 and TIMER5 in
lockstep, run STOP_A and STOP_B to ICP4 and ICP5, and instead of
interrupting at 10kHz to increment PICcount, you would only have to
interrupt every 6.5536 seconds to increment the upper bits. Plus
handling the actual events of course. I find that very appealing, but
unfortunately, T4 is out of reach of a shield.
Andrew
1-2ps rms single shot noise timestamping is feasible with embedded (occurs as part of the interpolation process) interpolator calibration. Only calibration of the differential delay between channels is required, as is required by all such instruments.
However the cost for such a timestamping counter is somewhat higher than for John's timestamping counter, but about a couple of orders of magnitude less than the final list price of a 5370B.
Bruce
On Thursday, 24 November 2016 9:01 PM, Anders Wallin <anders.e.e.wallin@gmail.com> wrote:
Nice work!
On the website in the introduction you mention 22ps single-shot
time-stamping on the 5370A/B.
I think it's well established that the 53230A does about 11-12 ps for
time-intervals, which corresponds to about 9 ps single-channel. see for
example:
http://www.anderswallin.net/wp-content/uploads/2015/04/53230A_PPS_skew.png
Anders
On Wed, Nov 23, 2016 at 11:13 PM, Peter Vince petervince1952@gmail.com
wrote:
Fantastic John - well done! Yes, I'll definitely put an order in as soon
as possible.
Regards,
Peter (G8ZZR, London)
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/
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and follow the instructions there.
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and follow the instructions there.
Hi Anders --
Thanks, and thanks for the info on the 53230A. I have not used one of
those myself but the data sheet lists 20ps single-shot.
Also I should note that the TICC does not compete with counters like the
53230A for high speed measurement, or frequency counting. It does far
fewer measurements per second than the high-end counters -- my design
criteria was for use in PPS measuring system.
With the current software, the actual measurement processing time is
about 1 millisecond; we may be able to optimize a hundred or two
microseconds from that as the code currently has more 64 bit operations
than are necessary, and there are other things that can surely be tweaked.
The killer is the serial output via USB. It can take up to 10 ms to
output 20 characters, and that's what really limits the measurement
rate. I'm pretty sure this can be improved (one idea is to buffer
results to reduce USB packetization delays), but there's other
functionality that I need to finish first.
BTW -- the software is open source and on github at
https://github.com/TAPR/TICC , so I welcome anyone who wants to work on
it. Bug fixes are gladly accepted, and if you're looking for work to
do, I could use a volunteer to work on a couple of areas, most
critically finishing a UI that will allow the user to set operating
parameters.
John
On 11/24/2016 02:40 AM, Anders Wallin wrote:
Nice work!
On the website in the introduction you mention 22ps single-shot
time-stamping on the 5370A/B.
I think it's well established that the 53230A does about 11-12 ps for
time-intervals, which corresponds to about 9 ps single-channel. see for
example:
http://www.anderswallin.net/wp-content/uploads/2015/04/53230A_PPS_skew.png
Anders
On Wed, Nov 23, 2016 at 11:13 PM, Peter Vince petervince1952@gmail.com
wrote:
Fantastic John - well done! Yes, I'll definitely put an order in as soon
as possible.
Regards,
Peter (G8ZZR, London)
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.
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and follow the instructions there.
Thanks, Andrew. Yes, it is weird how the Arduino folks choose what
capabilities to expose on the board. From some testing I did, it seems
that the Arduino handles the 100 kHz interrupt rate without too much
strain -- it became a bigger issue at 250 kHz or above -- but the timers
would have been a more elegant approach if they had been available.
John
On 11/24/2016 02:49 AM, Andrew Rodland wrote:
On Wed, Nov 23, 2016 at 10:48 AM, John Ackermann N8UR jra@febo.com wrote:
The TICC is implemented as a two-channel timestamping counter. That means
it can measure one 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 one 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.)
Very exciting, I will definitely be wanting one :)
There's almost a way to do the coarse timer counting with almost no
CPU overhead, but unfortunately the Arduino folks were terribly
inconsistent about which timer signals they decided to assign to
Arduino pins. Of the six external clocks for timers, they brought out
two (T0 and T5), and of the four input captures, they brought out two
(ICP4 and ICP5). If they had brought out T4 then with a little bit of
timer configuration you could use COARSE to clock TIMER4 and TIMER5 in
lockstep, run STOP_A and STOP_B to ICP4 and ICP5, and instead of
interrupting at 10kHz to increment PICcount, you would only have to
interrupt every 6.5536 seconds to increment the upper bits. Plus
handling the actual events of course. I find that very appealing, but
unfortunately, T4 is out of reach of a shield.
Andrew
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John
There is an application note or similar on the 53230A that indicates that
the single shot noise for time interval measurement is typically about 13ps
or so.
Bruce
On Thursday, November 24, 2016 09:43:54 AM John Ackermann N8UR
wrote:
Hi Anders --
Thanks, and thanks for the info on the 53230A. I have not used one of
those myself but the data sheet lists 20ps single-shot.
Also I should note that the TICC does not compete with counters like the
53230A for high speed measurement, or frequency counting. It does far
fewer measurements per second than the high-end counters -- my
design
criteria was for use in PPS measuring system.
With the current software, the actual measurement processing time is
about 1 millisecond; we may be able to optimize a hundred or two
microseconds from that as the code currently has more 64 bit
operations
than are necessary, and there are other things that can surely be
tweaked.
The killer is the serial output via USB. It can take up to 10 ms to
output 20 characters, and that's what really limits the measurement
rate. I'm pretty sure this can be improved (one idea is to buffer
results to reduce USB packetization delays), but there's other
functionality that I need to finish first.
BTW -- the software is open source and on github at
https://github.com/TAPR/TICC , so I welcome anyone who wants to work
on
it. Bug fixes are gladly accepted, and if you're looking for work to
do, I could use a volunteer to work on a couple of areas, most
critically finishing a UI that will allow the user to set operating
parameters.
John
On 11/24/2016 02:40 AM, Anders Wallin wrote:
Nice work!
On the website in the introduction you mention 22ps single-shot
time-stamping on the 5370A/B.
I think it's well established that the 53230A does about 11-12 ps for
time-intervals, which corresponds to about 9 ps single-channel. see
for
example:
http://www.anderswallin.net/wp-content/uploads/2015/04/53230A_PPS_skew.png
Anders
On Wed, Nov 23, 2016 at 11:13 PM, Peter Vince
wrote:
Fantastic John - well done! Yes, I'll definitely put an order in as soon
as possible.
Regards,
Peter (G8ZZR, London)
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.
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