Analog and digital-multistage time-averaging filters

In time measurements involved in the detection of elementary particles using large counters, the time uncertainty introduced by the finite propagation velocity of the produced signal may be significant compared to the desired time resolution. A method, the essential ingredients of which are the time properties of delay lines and AND and OR logic gates, is introduced to reduce the effect. The basic circuit is described, and then the synthesis of time averaging filters, a four stage filter (implementation and testing), experimental results, and future applications are discussed. The problem of precise timing with a counter of large dimensions can also be solved by means of an analog method; the principle involved, implementation, testing, and time resolution and deadtime are considered.