Picosecond-precision multichannel autonomous time and frequency counter

Abstract

This paper presents the design, implementation, and test results of a multichannel time interval and frequency counter developed as a desktop instrument. The counter contains four main functional modules for (1) performing precise measurements, (2) controlling and fast data processing, (3) low-noise power suppling, and (4) supplying a stable reference clock (optional rubidium standard). A fundamental for the counter, the time interval measurement is based on time stamping combined with a period counting and in-period two-stage time interpolation that allows us to achieve wide measurement range (above 1 h), high precision (even better than 4.5 ps), and high measurement speed (up to 91.2 × 10 timestamps/s). The frequency is measured up to 3.0 GHz with the use of the reciprocal method. Wide functionality of the counter includes also the evaluation of frequency stability of clocks and oscillators (Allan deviation) and phase variation (time interval error, maximum time interval error, time deviation). The 8-channel measurement module is based on a field programmable gate array device, while the control unit involves a microcontroller with a high performance ARM-Cortex core. An efficient and user-friendly control of the counter is provided either locally, through the built-in keypad or/and color touch panel, or remotely, with the aid of USB, Ethernet, RS232C, or RS485 interfaces.

Bubble-Proof Algorithm for Wave Union TDCs

“…Two MSWU TDCs were implemented in a Xilinx Kintex-7 FPGA chip mounted in an MTC 108 multichannel time interval counter [22]. Each TDL consists of 200 carry chain multiplexers that ensure the fastest connection paths between subsequent elements in programmable logic blocks.…”

Traceable frequency measurements with counters

“…Basic features of the construction of and measurements with frequency counters can be found in the relevant literature, which includes textbooks [4,5], selected manufacturers' manuals which clearly collect the basic properties [6][7][8][9][10][11], and recent technical publications (see e.g. [12] or references given in the next lines). During the last decades, in various papers statistical properties of frequency counters were analyzed and methods of evaluation developed.…”

Gray-Code TDC with Improved Linearity and Scalability for LiDAR applications

“…The research on Time-to-Digital Converters (TDC) implemented in Field-Programmable Gate Arrays (FPGA) has gained increased relevance over the last few years [1], [2]. FPGA-based TDCs have been highly utilized in physics experiments [3]- [5] and metrology equipment [6]. The recent FPGA technology developments allowed these systems to achieve high resolutions and precision, capable of competing with the ones reported in Application Specific Integrated Circuits (ASIC) implementations [7]- [9].…”