A random pulse generator with variable mean rate

The paper describes the methods by which a random pulse train with predetermined statistical properties may be produced. It is required that the mean pulse rate shall be variable over a wide range and that the probability of a pulse occurring at any instant shall be independent of the previous history of the pulse train. This second condition is satisfied if the time of occurrence of the pulses obeys the Poisson distribution, and several methods of realizing this distribution are investigated. The most satisfactory practical means of obtaining the required pulse train is found to be the sampling of a random signal, an output pulse being given whenever the random signal exceeds a predetermined amplitude. The theoretical requirements are discussed and the circuit techniques presented. Automatic control of mean rate is incorporated in the device described.