CRITERIA FOR STABILITY OF ZEROS OF SAMPLED SYSTEMS

Simplified forms of criteria are presented for ensuring that all zeros of a discrete system are stable when a continuous-time and strictly p roper plant is discretised by the use of a sampler and a zero-order ho lder. The Nyquist algorithm proposed by Fu and Dumont has been improve d in the sense that a point of the Nyquist curve is obtained analytica lly. When a lowpass system is sampled, analytical forms of criteria wi thout drawing the Nyquist curves have been also shown.