Research in Motion Corporation

Blackberry Corporation

Nortel Networks Corporation

Dorian Davies

Graham Dolman

Coefficients of a pre-distorter are determined for distortion correction of a signal amplified by a radio frequency amplifier by sampling the signal at the pre-distorter input to generate a plurality of input samples and sampling the signal at the amplifier output to generate a plurality of output samples, each of the output samples corresponding to one of the input samples, calculating a figure of merit for one or more of the input samples on the basis of the one or more input samples, selectively updating a previously selected set of input samples with the one or more input samples on the basis of the calculated figure of merit, whereby to generate an updated selected set and determining the coefficients of the pre-distorter on the basis of the input samples in the updated selected set and the corresponding output samples.

Pre-distortion for a radio frequency power amplifier

Coefficients of a pre-distorter are determined for correction of distortion of a signal amplified by a radio frequency amplifier by sampling the signal at the pre-distorter input to generate a plurality of input samples and sampling the signal at the amplifier output to generate a plurality of output samples, each of the output samples corresponding to one of the input samples, calculating a figure of merit for one or more of the input samples on the basis of the one or more of the input samples, selectively updating a previously selected set of input samples with said one or more input samples on the basis of the calculated figure of merit, whereby to generate an updated selected set and determining the coefficients of the pre-distorter on the basis of the input samples in the updated selected set and the corresponding output samples.

A modulated power supply comprises first and second coding units. The second coding unit is responsive to a feed-forward error signal representing the error between the coded output of the first coding unit and an input modulating signal. The second coding unit codes for the more limited range of the error signal, thereby improving resolution. The first coding unit can comprise M coding units arranged in parallel with one another. The M coding units are operated in a manner which increases the apparent number of quantisation levels. This is achieved by feeding a modified version of the input modulating signal to each of the M coding units or by offsetting by quantisation grids of the M coding units. The improvements are particularly useful for improving performance where the input modulating signal has a wide bandwidth.

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Bishops Stortford, United Kingdom

Dorian Davies