Analysis of errors in sampled-data feedback systems

The system error in sampled-data feedback systems resulting from the application of a test function is an important design parameter. The “system error” is defined as the difference between the actual output of the system and the desired output. There are two components which contribute to this error: one, called “organic error,” is brought about by the system energy storages, and the other, called “ripple,” is brought about by the sampling process. Formulation of the system error is obtained by the application of the Laplace and z-transformations. Both the system error time function in intersampling times and the rms system error are formulated in terms of the system parameters. Illustrative examples demonstrate the theory.