Linearity Nonlinearity high adjacent channel power as a result of spectral regrowth amplitude compression The PA characterization begins with two generic tests of nonlinearity based on unmodulated tones: intermodulation and compression. yielding a first-order estimate of the PA nonlinearity Figure 12.6.PA characterization by (a)two-tone test,(b)compression. [View full size imagel Full Power Level Full Power Level Ain,1dB 20logAin (b)Linearity Nonlinearity ◦ high adjacent channel power as a result of spectral regrowth ◦ amplitude compression The PA characterization begins with two generic tests of nonlinearity based on unmodulated tones: ◦ intermodulation and compression. ◦ yielding a first-order estimate of the PA nonlinearity