DPD_OFDM

Where To Find This Example

AWR Version 15

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AWR Version 14

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Design Notes

Digital Pre-Distortion Test Bench

This example illustrates the use of Digital Pre-Distortion to linearize a device operating near its compression level. The DPD block offers several classic algorithms such as Memory Polynomials, Dynamic Deviation Reduction of 2-nd Order, Generalized Memory Polynomials and Look-up Table based.

The project shows an OFDM signal configured to simulate multi-user type operation. The signal is fed to a driver amp and then into a power amplifier implemented as a circuit schematic in MWO. The DPD uses a feedback signal from the device output which, along with the source signal, is used for initial calculations of the selected algorithm and then for incremental updates. The block offers various solvers that can be used for the initial DPD setup. Please notice that no delay is needed in the feedback path since the DPD block internally takes care of the loop delay at node 2.

Results compare device performance with and without the DPD, showing improvements in spectral regrowth, IQ constellation distortion and CCDF.

Further information can be found in the DPD element help.

System Diagram - DPD Test Bench

Graph - CCDF

Graph - PA TX Spectrum

Graph - Receiver IQ