Parallel data processing in a 3-channel integrated time-interval counter

In this paper, we discuss an issue of parallel data processing in multichannel time interval counters (TICs). Particularly we analyze this problem within the framework of a 3-channel TIC developed for the international project Legal Time Distribution System (LTDS). The TIC provides the high measurement precision (< 15 ps) and wide range (> 1s) that are obtained by combining reference clock period counting with in-period interpolation. A measurement process consists of three main stages: (1) events registration, (2) data processing and (3) data transfer. In the event registration stage all input events are identified and registered with related unique timestamps based on a consistent time scale. To achieve high measurement precision, the stream of timestamps is then processed using actual transfer characteristics of the TIC and offset values of all measurement channels. We describe the concept of parallel data processing and its implementation in a Spartan-6 FPGA device (XC6SLX75, Xilinx).