Lucent Technologies Inc.

Liang Hsu

Jaehyeong Kim

Kyriaki Konstantinou

A predistortion system compensates or equalizes the phase and/or amplitude response over frequency of at least a portion of a signal path prior to the distortion generating circuitry, such as an amplifier, and/or of at least a portion of a feedback path after the distortion generating circuitry. For example, in a power amplification system using predistortion, an equalizer on the signal path adjusts the phase and amplitude of a predistorted signal across frequency to compensate for the amplitude and phase response of circuitry on the signal path, such as the amplitude and phase response of analog filters in the up-conversion process. After amplification, an equalizer on a feedback path adjusts the phase and amplitude across frequency of the signal representing the output of the amplifier to compensate for the amplitude and phase response of circuitry, such as analog filters in the down-conversion process, on the feedback path. Thus, the distortions introduced onto the envelope of the predistorted signal on the signal path and onto the amplifier output signal on the feedback path can be reduced. As such, the distortion of an input used in the predistortion function determination is reduced, thereby enabling an improved characterization of the amplifier and/or an improved determination of the predistortion function.

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Liang Hsu