Low-pass Approximations to a Time-delay Characteristic!

Some shortcomings of the Padé approximation to a time-delay characteristic are outlined. Optimum transfer functions, based on a minimum mean square error criterion, are derived which permit the use of extremely simple circuitry for their implementation, to give with less circuitry a bettor delay approximation than can be achieved by the more complex circuit for a Padé characteristic. Appropriate practical circuits are given, and relevant comparisons are made.