Low Dead Time, Multi-hit FPGA-Based Time-to-Digital Converter

This paper presents improvements on a novel FPGA-based multi-hit time-to-digital converter (TDC) to measure time intervals with a resolution of 100ps and a variable dynamic range controlled by a binary coarse counter. We use a matrix topology to provide a two-level resolution, aiming to minimize the overall measurement time. The conventional dead time is eliminated by the continuous detection and processing of data by two delay matrices operating in parallel. A back-resetting scheme eliminates the erroneous multi-detection of an event along matrix tap lines. The circuit was tested on a XILINX SPARTAN-3 FPGA platform