This paper proposes a new s-z transform method to obtain a digital system simulating an analog system. The method is based on preserving the waveform response of the analog system for the digital system, and employs triangular pulse whose Fourier spectrum attenuates with high rate. This choice brings the desirable property of reduced effect of aliasing in the frequency response and error of the impulse response.
Several examples will be presented and describe that the new method is more useful than the conventional methods.