Multiple-signal intermodulation and stability considerations in the use of linear repeaters

Expressions are generated to determine the third- and fifth-order intermodulation levels associated with N channelized signals being amplified by a linear repeater. Under reasonably general assumptions, it is shown that out-of-band third-order intermodulation power is enhanced by a power ratio of N²-3N/2 or less. Fifth-order intermodulation is shown to be enhanced for multiple signals and is potentially a dominant source of interference. Expressions are also given that relate linear repeater stability requirements to frequency response flatness, a source of potential increased intermodulation and system degradation