A method for computing adjacent-channel spectral energy in cellular power amplifiers

The requirements for energy efficiency in cellular RF power amplifiers necessitate their operation in regions of significant nonlinear distortion, with a resultant regrowth of undesired adjacent-channel spectral products that must be maintained within specified limits. This paper presents a method for predicting adjacent-channel spectral regrowth based on single-tone distortion curves that are easily measured in the laboratory and readily simulated in SPICE. The method affords a practical approach to predicting adjacent-channel power that has proven very useful for designing power amplifiers for cellular service under the IS-54 standard.