Envelope tracking using transient waveform switching shaping supply modulation

A novel supply modulation scheme for envelope tracking for a power amplifier in a transmitter is proposed, which follows a control principle that is fundamentally different from the existing ones. Instead of regulating the supply modulator's output in accordance with a given reference signal, the system utilizes a look-ahead window and synthesizes pulses for the supply modulator such that its output tracks the envelope of the radio frequency signal amplified by the power amplifier, while minimizing its switching rate. Simulation results for a 5MHz Long Term Evolution signal with 16 quadrature amplitude modulation indicates that the proposed technique provides very high average efficiency 84% while maintaining a very low ratio between the switching frequency and the envelope bandwidth. Copyright © 2013 John Wiley & Sons, Ltd.

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