Patent ID: 7330073
Filing Date: 2008-02-12
Classification: H03F

Abstract:
1. A method of determining predistortion that will compensate for distortion introduced by a power amplifier circuit, the method comprising: applying a time-varying reference signal to the power amplifier circuit, wherein at each moment the time-varying reference signal has a reference amplitude and a reference phase; measuring a corresponding output signal supplied by the power amplifier circuit, wherein at each moment the output signal has a measured amplitude and a measured phase; determining amplitude predistortion by comparing the reference amplitude with the measured amplitude; determining phase predistortion by comparing the reference phase with the measured phase; and determining a relationship between the phase predistortion and the reference amplitude such that, for any value of the reference amplitude, a corresponding value of the phase predistortion is identified, wherein: the amplitude predistortion is associated with a range of measured amplitude values; and the method further comprises extracting representative points from the amplitude predistortion by performing: