Iterative Direct DPD

Digital pre-distortion (DPD) is a common method to linearize the output signal of a power amplifier (PA), which is being operated in its non-linear operating range.

Most PAs operate in their non-linear range for efficiency reasons. The drawback of higher efficiency is the non-linear operating range. In order to maintain signal quality, many transmitters employ DPD. Implementing real-time DPD in a transmitter is a challenging task and often ends in PA models, which are specific to the signal transmitted.

Even though these complex models are required for transmitter development, they are not needed during PA verification and development.

This article describes an approach to generate a pre-distorted signal based on a hard-clipper. The resulting waveform pushes the output of the DUT as close to the hard-clipper as possible.

Due to the waveform approach, the algorithm compensates all memory effects.