| 摘要 |
Various circuits and methods are provided for reducing the effects of differences between the amplification chains of a LINC amplifier or other transmission system. In a preferred embodiment, a LINC amplifier includes a signal component separator (11) which divides a transmit signal s(t) into multiple constant-amplitude, varying phase component signals PhA(t) and PhB(t). Each component signal is amplified (and in RF embodiments, upconverted) along a respective analog amplification chain or path, and the amplified component signals are combined by a signal combiner (25) to generate the transmission signal ks(t). The amplifiers (15, 16) provided along the analog paths are preferably non-linear. Prior to amplification, the component signals are digitally processed by respective compensation processors (21) to compensate for differences between the analog chains. The compensation processing applied along each path is specified by sets of compensation parameters which are generated and updated by a compensation estimator (28). The compensation estimator (28) preferably generates the parameters in a non-real-time mode by adaptively processing captured sequences of samples of the component signals PhA(t) and PhB(t) and of a downconverted version of the output signal ks(t). When no information signal is being transmitted, the signal component separator (11) preferably generates training signals that are used by the compensation estimator (28) to update the compensation parameters. The training signals are preferably maintained in antiphase so that they substantially cancel when combined by the signal combiner (25), so that unwanted emissions are reduced without the need for an antenna switch.
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