Transistorized Control System Analyser

ABSTRACT

Quite often it becomes necessary to know the transfer function of a control system for its analysis and improvement. One of the many methods of determining the transfer function experimentally is to plot the Bode Diagram for gain and phase curves of the system. From these diagrams, the transfer function is determined by standard procedure. The present paper describes one simple transistorized instrument by which such determination of the transfer function is possible. Gain and phase are determined by determining the Fourier expression for inphase and quadrature components of the a.c. signal output with respect to the reference input. The instrument consists of an oscillator of variable frequency ranging from 0·01 to 10 c/s. and a phase sensitive voltmeter by which the inphase and quadrature components are determined for different value of oscillator frequency. The oscillator and the different units of the phase sensitive voltmeter are described in the later sections. Finally the accuracy of the instrument is discussed.