Abstract: Complex additional feed-forward error sensor loops and error correction loops are replaced in a high-frequency multi-carrier signal amplifier system with simple signal predistortor structures. In addition, less costly error amplifiers are facilitated and system efficiency increased by the introduction of error predistortor structures.

Abstract: A replica of a microwave input signal is subtracted from an amplified version of the input signal produced by main power amplifiers (52a,52b) to produce an error signal corresponding to distortions introduced into the input signal by the power amplifiers (52a,52b). The error signal is amplified by an error amplifier (30), and subtracted from the amplified input signal to produce an output signal in which the distortions have been canceled. A bandpass filter (54) is provided immediately following the power amplifiers (52a,52b) to suppress or block intermodulation products generated in the power amplifiers (52a,52b) which are outside the bandwidth of the input signal and which could overload the error amplifier (30) to generate further distortion. A second filter (78) may be provided through which the replica signal passes to better match the replica signal to the amplified and filtered input signal.

Abstract: Microwave circuitry is disclosed for a distortion generating circuit. Input and output baluns are disposed on the tap surface of a substrate while secondary and primary conductors are respectively juxtaposed under these baluns. Four diodes connected in a star configuration are coupled between the primary and secondary conductors. The carrier signal may be fed into the input balun which is coupled to the secondary conductors and across the diode star configuration, generating intermodulation signals while suppressing the carrier signals. The intermodulation signal is coupled from the primary conductors to the output balun where it may be fed to a microwave amplifier to cancel intermodulation by-products thereof. A DC signal may be impressed across the diode star configuration to adjust the amplitude of the intermodulation signal generated by the diodes.