Free running time to digital converter with 1 nanosecond resolution

A description is given of a number of time-to-digital converters (TDCs) that have been built with 1-ns resolution. They can run for long times and be used with triggers that arrive immediately or several microseconds after the event of interest. The TDCs are very linear, with a standard deviation of less than 0.53 ns. The discussion covers the timing method, tolerances, multiplexing, Fastbus implementation, the clock-clear board, fabrication, and performance.<
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