Bandwidth-constrained signal regulation

Abstract

Non-linear signal conditioning is provided by signal processing in at least 2 consecutive steps (10). In each step (10) an insertion source signal (41) is provided, which is treated non-linearly to fulfill certain restrictions in bandwidth and / or spectral mask. The insertion signal is combined with a main signal (21) using a reinsertion factor (k1-kn), as a correction of the main signal (21). The reinsertion factor of at least one step is larger than the reinsertion factor of a previous step. In particular embodiments, the reinsertion factor increases for each of the at least 2 steps. This principle can be applied to most non-linear signal processing, and for example in PAR reduction systems, dynamic drain bias PA systems, Doherty and Chireix PA systems and in Dynamic Gate Bias systems.

Description

technical field [0001] The present invention generally relates to methods and apparatus for non-linear signal conditioning of alternating signals, and in particular to such apparatus and methods where the signal must remain within bandwidth and / or spectral constraints. Background technique [0002] In many applications, typically in various communication systems and especially in multi-carrier and multi-user systems, there is a need for nonlinear correction of signals. In many cases, this non-linear correction must be kept within a certain bandwidth or within a certain spectral mask restriction. A typical example of this nonlinear correction is peak-to-average ratio (PAR) reduction, also known as decresting or clipping. PAR reduction improves power amplifier (PA) efficiency and average output power. The aim is to reduce the peak amplitude excursion of the output signal while keeping the spectral spread within given limits, such as spectral masking and adjacent channel powe...

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