TDC with High Measuring Rnge - Page 1
Forum section: electronics / general

author: Md_Aslam
author_rank: Contributor
timestamp: August 10, 2022, 06:49:22 am
content: I am trying to find some TDC(Time to Digital Converter) for measuring the delay of my two 1PPS signals. The delay may vary from some nanoseconds to some milliseconds, to be exact up to 900ms.I came across some TDC like "TDC7200 from TI" and "AS6500 from Sciosence", But the problem with this kind of TDC is that it has a maximum measuring range of 8ms and 13ms only, and I want such TDC which can measure delay up to 1s.So can anyone suggest to me the required TDC?PS: I am looking for a miniaturized system therefore the size of TDC will matter to me.

author: Echo88
author_rank: Frequent Contributor
timestamp: August 10, 2022, 12:42:05 pm
content: I cant recommend a direct TDC-IC, but this project might do what you want:https://github.com/TAPR/TICC

author: dietert1
author_rank: Super Contributor
timestamp: August 10, 2022, 01:55:24 pm
content: You might use a high resolution timer of a MSP430:https://www.ti.com/lit/an/slaa601/slaa601.pdfAt 256 MHz clock it should give you 4 nsec resolution. It's a 16-bit timer, so it needs overflow handling in firmware.Regards, Dieter

author: MegaVolt
author_rank: Frequent Contributor
timestamp: August 10, 2022, 02:18:53 pm
content: Quote from: Md_Aslam on August 10, 2022, 06:49:22 amWhat time frame do you need?Modern FPGAs will easily give you 1ns with any signal duration. If you need less than 1ns, they can also help, but it will be more difficult.

author: Marco
author_rank: Super Contributor
timestamp: August 10, 2022, 08:26:34 pm
content: Quote from: Echo88 on August 10, 2022, 12:42:05 pmI was going to suggest the method they used :QuoteI think he'd need two of them though, to be able to measure very short intervals. Still, it's an option.

author: David Hess
author_rank: Super Contributor
timestamp: August 11, 2022, 12:40:00 am
content: You did not say what resolution you require, but I assume it is 10s of nanoseconds or nanoseconds.That kind of resolution over such a long duration requires the TDC to be combined with a digital counter, so the digital counter returns coarse resolution and the TDC compares the counter clock to the triggers for fine resolution. An FPGA can do this. A microcontroller with built in timer/counter and charge time measurement unit might be able to do it.

author: Md_Aslam
author_rank: Contributor
timestamp: August 11, 2022, 04:35:24 am
content: Quote from: Echo88 on August 10, 2022, 12:42:05 pmThis Project is Excellent, But I am not able to see the maximum delay measuring range of this board. As for my project, I need some TDC(size should be as small as possible) with a measuring range of 1ns to 1s with a resolution between 20ps to 60ps.Also due to its size, I can only think about this product for my future projects.

author: Md_Aslam
author_rank: Contributor
timestamp: August 11, 2022, 04:42:11 am
content: Quote from: dietert1 on August 10, 2022, 01:55:24 pmCan I use it as a TIC to measure delay up to 1s with better accuracy?

author: Md_Aslam
author_rank: Contributor
timestamp: August 11, 2022, 04:49:23 am
content: Quote from: MegaVolt on August 10, 2022, 02:18:53 pmOk, If I won't be able to find any TDC IC which fulfills my requirements then I will definitely think about FPGA as a TIC.

author: Marco
author_rank: Super Contributor
timestamp: August 11, 2022, 06:21:33 am
content: AFAICS the TICC has essentially infinite upper limit for the interval measurement, I also missed that it already has two completely independent channels so it can measure down to 1 tick of its resolution too (60 ps).Will be hard to find a better solution for the price.

author: Md_Aslam
author_rank: Contributor
timestamp: August 11, 2022, 07:02:30 am
content: Quote from: Marco on August 11, 2022, 06:21:33 amThis Board comes as a shield of an Arduino Mega 2560, So is it possible to interface it with another microcontroller like STM32? Also, what is the meaning of infinite upper limit? The exact range value will help me.

author: Kleinstein
author_rank: Super Contributor
timestamp: August 11, 2022, 08:43:44 am
content: Quote from: Md_Aslam on August 11, 2022, 07:02:30 amThe project uses an TDC chip in combination with a µC for longer time intervals. The upper limit for the timing depends on the SW and can be very long (e.g. 32 bit with 10 MHz clock gives around 6 minutes. One can relatively easy extend on that if really needed.AFAIK some of PIC18 µCs include hardware for capacitive sensors that can be used also for anlog time interpolation with minimal external hwardware.

author: Md_Aslam
author_rank: Contributor
timestamp: August 12, 2022, 05:43:50 am
content: Quote from: Kleinstein on August 11, 2022, 08:43:44 amI have gone through the details and working of the TAPR TICC and I think this product will be suitable for my project.