Intermodulation Noise of FDM-FM Communications Through a Hard Limiter

When the multiple signals of FDM-FM communications are passed through a hard limiter, intermodulation products are generated which cause baseband noise. A technique is presented, implemented by a computer program, of explicitly determining this baseband noise as a function of the system parameters of frequency ratio, frequency deviation, and carrier magnitudes. Results are presented as a function of the system parameters using four carriers which are each modulated by four voice channels. The technique presented permits the minimization of the intermodulation baseband noise without the cost of system simulation.