Application of classical cosine series window functions to fullresponse signaling offset quadrature binary modulation systems

It is proposed that classical cosine series window functions be applied to finite symbol duration quadrature binary modulation systems as pulse shapes in the interest of increasing the spectral confinement of the resulting modulated signals. The respective modulation systems are analyzed in terms of modulated signal envelope uniformity, spectral confinement, and bit error rate in the presence of white Gaussian noise with varying degrees of modulated signal amplitude compression. Even in the presence of moderate modulated signal compression, classical cosine series window function pulse shapes offer spectral confinement for quadrature binary modulation systems that is equal to or better than that provided by the conventional pulse shapes corresponding to QPSK, MSK, SFSK, and DSFSK. It is shown that moderate levels of modulated signal compression have negligible effects on the system bit error rate. A system implementation using the sum of FSK modulated signal components to achieve spectral confinement based on the classical cosine series window functions is presented