[time-nuts] New Timestamping / Time Interval Counter: the TICC

Bob Camp kb8tq at n1k.org
Wed Nov 23 13:10:42 EST 2016


Hi

Cool !!!

Bob

> On Nov 23, 2016, at 10:48 AM, John Ackermann N8UR <jra at 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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