METHOD AND APPARATUS FOR INTERMODULATION NOISE SUPPRESSION IN RF POWER AMPLIFIERS

摘要

An apparatus and method for suppressing intermodulation noise in a radio frequency power amplifier (PA<1>). Intermodulation noise suppression is achieved by use of an amplitude limiter (AL<1>) connected to the signal source and a shaping filter (SF<1>) connected between the amplitude limiter (AL<1>) and the power amplifier (PA<1>). The shaping filter (SF<1>) may be a band-stop notch filter which attenuates intermodulation noise in a selected radio band or a bandpass filter which attenuates all out-of-band intermodulation noise. The intermodulation noise suppression of this invention causes the signal entering the power amplifier to be characterized by (1) a low peak-to-average envelope distribution and (2) low spectral content in the radio frequency bands to be protected.