Issue No.01 - January (1968 vol.17)
J. P. Seddon , Systems Engineering, International Business Machines, Winnipeg, Canada.
A dual classification of variable delays 1) by their explicit dependence on time or through a state variable and 2) through their origins as ``pipe'' or ``nonpipe'' problems is presented. Techniques of simulation through standard analog components and, more particularly, transport devices are analyzed and further classification made of the latter to distinguish those suitable for state-variable delay systems from those that are not. The construction and testing of a simple variable delay are described. An application to a system in which the delay is a sinusoidal function of time is discussed in detail. A theory is presented that predicts what frequencies will be present in the output of such a device when excited by a sinusoid of commensurate frequency; experimental results corroborating this are presented. A scheme for converting a problem with variable delay to one with fixed delay is further analyzed and its range of application delimited. Conclusions include a discussion of the best type of simulator to be used for variable delay problems.
J. P. Seddon, "The Simulation of Variable Delay", IEEE Transactions on Computers, vol.17, no. 1, pp. 89-94, January 1968, doi:10.1109/TC.1968.5008879