| 摘要 |
<p>A method is disclosed for obtaining high throughput linearity using a predistorter in front of RF power amplifier, for instance a multi-carrier power amplifier (MCPA) for a communications system. The present method has been designed to be carried out off-line to thereby save costs and components otherwise needed for a common art on-line feed back. In a first step calibration is performed by measuring spectrum by means of an off-line spectrum analysis of an output spectrum of the power amplifier and simultaneously applying a known input signal. As a next step digitized parameters characterizing the power amplifier are calculated in the frequency domain by comparing spectrum points between input spectrum and output spectrum. Thereafter calculated and weighted digitized parameters are transferred to a pre-distoring device. In a third step the known signal spectrum is transferred to the pre-distorting device feeding its output signal together with the original known signal spectrum to the power amplifier input thereby compensating for power amplifier non-linearity and minimizing inter-modulation products. Finally in a fourth step an uncompensated known input spectrum is compared with a corresponding compensated output spectrum of the power amplifier and repeating the steps of calibration calculation until a best optimization input signal to the power amplifier regading the inter-modulation products of the output signal has been achieved.</p> |
