A Linear and Efficient RF Amplifier Architecture for Modern Wireless Applications
When composing signal components from a complex baseband input signal in the digital domain, the spectral bandwidth of signal components is ultimately determined by the sample rate and the bandwidth of reconstruction filters. This finite bandwidth, together with a finite sample rate, introduces a variation in the envelope of a signal component. A detailed analysis of the effect of signal reconstruction and sample rate on the envelope of the signal components, and further, the effect of this envelope variation on highly nonlinear amplifiers, is presented, and a new method that minimizes the envelope variation and bandwidth of the signal components, named differential LINC (DLINC), is demonstrated. It is also shown that further improvement in the overall system linearity and efficiency can be achieved by applying the envelope elimination and restoration (EER) technique to the nonlinear gain blocks that amplify the signal components. An entirely new amplifier architecture, named efficient differential LINC (EDLINC), that provides high linearity and optimal system efficiency simultaneously, is presented. Combining the advantages of DLINC and EER, EDLINC allows optimal signal component separation for a given linear dynamic range of the amplifier modules employed in the system.
University of Illinois - Urbana-Champaign
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University of Illinois at Urbana-Champaign