Cosine series design of [-2T,2T] symbol shapes for spectrally efficient quadrature binary modulation systems

This paper evaluates the performance of partial response quadrature modulation techniques using symbol shapes based on the cosine series functions design approach. The baseband quadrature modulation symbol is allowed to spill outside the interval [-T,T] to the interval [-2T,2T]. Spectral efficiency, envelope uniformity, intersymbol interference and probability of error are the performance parameters of interest. Linear and hard-limiting channels are considered. Resulting performance is compared to that of quasi-bandlimited (QBL) signaling introduced by Amoroso (1979) and quadrature overlapped raised cosine (QORC) modulation introduced by Austin and Chang (1981). A simple modulator implementation for a synthesized symbol shape which resembles n=3 QBL is also presented.<>