A prototype filter design for cosine modulated transmultiplexer using weighted constrained least squares technique

Abstract

In this paper, an efficient design method of nearly perfect reconstruction cosine modulated transmultiplexer (CM TMUX) system is presented for the prescribed stop band attenuation (As), pass band attenuation (Ap), and channel overlapping or roll off factor (RF). The weighted constrained least squares (WCLS) technique is used for the design of a prototype filter in CM TMUX system. In the proposed algorithm, 3dB cut-off frequency (ωc) is iteratively adjusted, so that the magnitude of inter-channel interference or inter-carrier interference (ICI) can be minimized. Performance of the proposed algorithm has been measured in terms of ICI, inter-symbol interference (ISI), signal to inter-channel interference ratio (SICI), signal to inter-symbol interference ratio (SISI), and signal to total interference in the kth channel ratio (SIk). Several examples are presented to illustrate the key advantageous features of the proposed technique over other existing techniques.