This paper introduces a mathematical model for Pulse-Width Modulated Amplifier for DC Servo Motor. The
relationship between pulse-width modulated (PWM) signal and reference rotation speed is specified, and a general model
of motor represented by transfer function is also put forward. When the input signal changes, the rotation speed of the servo
motor will change accordingly. By changing zeros and poles, transient performance of this system is discussed in detail,
and optimal ranges of the parameters is recommended at the end of discussion.
