Abstract: An adaptive predistorter system receives and predistorts an input signal so as to linearize the output signal of a nonlinear high power amplifier amplifying the predistorted input signal using closed-loop feedback of the output signal in complex form at baseband so as to adaptively change the amount of the predistortion of the input signal in the presence of high power amplifier changing characteristics.

Abstract: An adaptive predistorter system receives and predistorts an input signal so as to linearize the output signal of a nonlinear high power amplifier amplifying the predistorted input signal using closed-loop feedback of the output signal in complex form at baseband so as to adaptively change the amount of the predistortion of the input signal in the presence of high power amplifier changing characteristics.

Abstract: A predistortion method uses an extended Saleh model for linearizing the output of nonlinear high power amplifiers having inherent amplitude modulation to amplitude modulation distortion, and inherent amplitude modulation to phase modulation distortion, during conversions of an input signal to an output signal. A complex baseband linearizer provides predistortion at baseband for reducing spectral regrowth and improves bit error performance. The predistortion effects are matched to the amplifier distortions to cancel out the distortions to provide linearized conversions. The extended Saleh model provides a general solution using selected coefficients matched to distortion effects of a particular amplifier.

Abstract: A predistortion method use a modified linear-log model for linearizing the output of nonlinear high power amplifiers having inherent amplitude modulation to amplitude modulation distortion, and inherent amplitude modulation to phase modulation distortion, during conversions of an input signal to an output signal. A complex baseband linearizer provides predistortion at baseband for reducing spectral regrowth and improves bit error performance. The predistortion effects are matched to the amplifier distortions to cancel out the distortions to provide linearized conversions. The modified linear-log model is used to reduce the clipping effects through the peak operating point for a specified output power loss with minimum distortion.

Abstract: A compound of Formula I: ##STR1## wherein: Ar represents a polynuclear carboxyclic or heterocyclic fused ring system having at least one carbocylic or heterocyclic ring of aromatic character, the polynuclear ring system optionally carrying one or more of the substituents halogen, C.sub.1 -C.sub.6 alkyl --CF.sub.3, or --OCF.sub.y H.sub.3-y, wherein y is 0-3;n is 0 or 1 and m is 1-11Z represents a group of Formula: ##STR2## wherein: R.sub.A and R.sub.B which may be identical or different each represent hydrogen or methyl;R.sub.C represents methyl;R.sub.D represents methyl, ethyl, n-propyl, isopropyl, t-butyl, or vinyl; andR.sub.E represents hydrogen or methyl or wherein:R.sub.C and R.sub.D together with C.sub..beta. form a cyclopropane or a cyclobutane ring or goether form a methylene group (.dbd.CH.sub.2) or wherein:R.sub.A and R.sub.B together with C.sub..alpha. and C.sub..beta. form a cyclobutane ring.