CONTROL SYSTEM DESIGN ASPECTS OF DIGITAL TRANSDUCERS

The control system aspects of digital transducers, based upon the application of sigma-delta modulation to a closed-loop structure, is discussed. Such a system is a nonlinear, discrete data, control system and consequently is a challenging task for the design engineer. In this paper the authors consider the use of describing function techniques in the s and w-domains to predict limit cycling conditions and closed loop performance. Simple examples of an electric current transducer and an accelerometer are used to illustrate the approach.