Abstract: This paper studies how to analyze a weakly nonlinear circuit using Volterra series, make a nonlinear Volterra model of a high-frequency transistor, and calculate the third order intermodulation in a Beeper high-frequency amplifier. This way can be used in designing other weakly nonlinear circuits in order to have highly linear high frequency amplifier.

Key words: Volterra series, high-frequency transistor, the third order intermodulation distortion, Beeper