Patent ID: 9712193
Date: 2017-07-18
CPC Classifications: H03F,H04B

Claim:
1. A method executed at a digital predistortion (DPD) coefficient finder of an amplifier module in a cable network, the method comprising: receiving a first signal and a second signal at the DPD coefficient finder, wherein the second signal comprises a transformation of the first signal including distortions due to channel effects and distortions due to amplifier nonlinearity, the first signal being transformed into the second signal after being passed in sequence through a pre-network circuit, an amplifier, and a post-network circuit, wherein the pre-network circuit and the post-network circuit introduce the distortions due to channel effects and the amplifier introduces the distortions due to amplifier nonlinearity; synchronizing the first signal and the second signal, wherein the synchronizing removes the channel effects of the pre-network circuit and the post-network circuit from the second signal, wherein the synchronizing comprises finding a vector w representative of a combination of the channel effects; computing a first vector representing an inverse of the nonlinearity of the amplifier based on the vector w; computing a second vector representing an inverse of the channel effects of the pre-network circuit based on the first vector; and providing DPD coefficients to a DPD actuator in the amplifier module, wherein the DPD coefficients comprise the first vector and the second vector, wherein the DPD actuator predistorts an input signal to the amplifier module with the DPD coefficients, wherein an output signal from the amplifier module retains linearity relative to the input signal.