Bandwidth-Conserving Independent Amplitude and Phase Modulation
B. F. Logan · Bell System Technical Journal · 1983
Given two baseband signals f(t) and g(t), suitably restricted in amplitude and bandlimited to [λ, μ] and [−μ, −λ], 00, i.e., that the baseband signals be bandpass, is not essential but it is a practical constraint in approximating the required operations. Also a modification is given for conserving bandwidth in case the signals f(t) and g(t) are of disparate bandwidths.