L-PSK - A new type of PSK modulation

The transients accompanying the phase changes of filtered PSK signals depend on the carrier phase values at which the phase shifts are forced. By a proper choice of such values, the amplitude fluctuations can be greatly reduced, and PSK signals with low AM component can be obtained. A QPSK modulator with a simple logic circuit to properly force the epochs of phase shifts has been designed and implemented. Its output signal has a very low AM component after undergoing bandpass filtering so that it is particularly suited to data transmission through nonlinear systems. This new type of PSK modulation has been called L-PSK modulation, being characterized by the logic choice of the epochs of the phase shifts.