| 摘要 |
An apparatus and method for generating an envelope predistorted radio frequency signal which avoids undesirable spurious emissions. A complex baseband signal, having an in-phase component I and a quadrature component Q, is sampled and filtered in a sampling circuit and filter circuit to obtain samples Ik of the in-phase component and samples Qk, the quadrature component. The magnitude xk of each sample pair is determined in a first calculation circuit. An amplitude and phase distortion factor Dk, based on scaled values of the archyperbolic tangent and the hyperbolic tangent of the baseband sample magnitude is determined in further calculation circuit and a multiplier. Each sample Ik of the in-phase component and Qk of the quadrature component is multiplied by the corresponding distortion factor Dk, and the resulting predistorted components combined and upconverted to provide a predistorted baseband signal which is amplified in a power amplifier having hyperbolic tangent distortion.
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