Venturing into the Walsh Domain with a Labview Based Communication Systems Toolkit

1. ABSTRACT In a recent publication, we reported on the utilization of a LabVIEW based Communication Systems Toolkit in the investigation of a novel idea for envelope detection of amplitude modulated (AM) signals (Wright, Tanyel 2005). In this paper, we will describe our efforts to develop the toolkit further and our investigations into the Walsh domain with the help of our latest developments. In communications theory, the Fourier Transform is the traditional frequency domain analysis tool and as such, the current toolkit is based exclusively on this technique. However, other transforms do exist and in the course of study, we became interested in the Walsh Transform. We developed virtual instruments (VIs) to compute the Walsh transform, generated the Walsh basis functions and modified LabVIEW’s natural ordered fast Walsh Transform (FWT) routine to provide Walsh ordered Walsh transforms. In this paper, we investigate the Walsh domain and compare it to the Fourier domain using these newly developed VIs. We demonstrate similarities and differences between FFT and FWT. We then propose a new arrangement of the FWT sequency plots that will correspond to the magnitude spectrum plots obtained by the FFT.