This paper presents a standard H<sup>∞</sup> controller design for singularly perturbed systems with frequency domain by unified approach using the delta operators. Decomposition of the singularly perturbed systems into the fast and slow subsystems is shown. And the delta operator approach is implemented to improve a finite word-length (FWL) characteristics. The delta operator systems have the better FWL characteristics over the shift operator systems. The result is shown in the example.
