A Power Series Expansion Approach to Evaluate Modulation Transfer Noise Effects from Digital Carriers to FDM/FM Carriers in Memoryless Nonlinear Devices

This paper presents a power series expansion approach for evaluating modulation transfer noise effects from digital carriers (continuous or bursty) to FDM/FM carriers in a common memoryless nonlinear amplifier. The method allows for a complete characterization and assessment of this type of transmission impairment and its effects in satellite communications systems. The baseband modulation transfer noise in the FM carriers caused by the random envelope fluctuations due to filtering of PSK pulses and/or by the on-off bursting of the digital carriers can be calculated. Illustrative numerical results indicate that the mixed PSK-FM mode of operation in satellite transponders should be employed with great care since a number of 4 kHz channels in the basebands of the FM carriers may receive prohibitive interference.