| 摘要 |
A transmitter comprising at least first and second phase related signal paths, respective frequency up-converters, a combiner for combining the output of the respective frequency up-converters and for supplying the combined signal to a power amplifier. A feedback loop is provided which has a coupler for deriving a portion of the power amplifier output signal and supplying it to first and second phase related feedback paths. Each of the feedback paths comprises frequency down-converters. The dc offset is measured at the respective inputs of the frequency up-converters when the feedback around the linearization loop is reduced to zero without altering the dc offsets produced at the outputs of the frequency down-converters. Subtractors subtract the measured dc offsets from the feedback loop error signals. |
