An equal-ripple pulse frequency modulator in control systems

The design of an equal-ripple modulator for regulator systems with type o plants is presented in this paper. The goal of this design is to produce an equal-ripple steady-state response. To conserve the control effort, rids modulator drives the system output towards the desired level and lets it relax naturally to the zero-state. A number of systems using this modulator were simulated on a digital computer and the results are presented. It can be seen from these results, that the modulator achieves an equal.ripple steady-state response regardless of system parameter values. To employ the modulator in a control system requires only a noncritical choice of the pulse height and width. Large pulse sizes will decrease the transient rise time but will increase the magnitude of the steady-state error. As the modulator threshold level is obtained recursively from information gained from the system error, it possesses "adaptive" qualities. Therefore, it particularly recommends itself to situations in which system parameter variations are expectecd.