Root locus method of pulse transfer function for sampled-data control systems

The pulse transfer function is a powerful tool for analysis and synthesis of sampled-data systems. The author has extended the root-locus method to the region of the pulse transfer function so that we can analyze and synthesize the sampled-data systems by the analogous method for the continuous-data systems. The results are as follows: the rules by which the root loci of the pulse transfer function can be plotted are identical to those of the continuous-data systems. The conditions for absolute and relative stabilities for the sampled-data systems on the plane are conformal to those for the continuous-data systems on the plane. Existence of a finite settling time in a sampled-data control system has been pointed out by the root-locus method.