A Universal Biological Interval Timer
W. Morton Caldwell · IEEE Transactions on Biomedical Engineering · 1971
A circuit for the measurement of biological time intervals from 0.1 ms to 10 s is described. This device accepts biopotentials, stimuli, or transducer signals to produce an instantaneous dc voltage readout proportional to the time between two successive input signals. Digital preconditioning and analog integration are used to simplify the design.