IIR Ultra-Wideband Pulse Shaper Design

This paper introduces a new method to generate an ultra-wideband (UWB) pulse to fill up the Federal Communications Commission (FCC) mask. One way to generate the pulse is by summing a weighted delayed elementary waveform (e.g., a Gaussian monocycle pulse). This method can be reduced to an FIR filter design problem. In this paper, an IIR-like method is introduced. It generates the UWB pulse using the weighted sum of not only the delayed elementary waveform but also the feedback waveforms. Allpass decomposition and lattice structures are used to reduce the complexity of the implementation. Simulation shows that the IIR based method has higher filling efficiency than the FIR based method. Simulation also shows that the impulse response of the IIR shaper decays very fast. Therefore the expected long transient created by the IIR shaper is negligible.