Predistortion System Implementation Based on Analog Neural Networks for Linearizing High Power Amplifiers Transfer Characteristics
In order to correct non-linearities due to High Power Amplifiers (HPA) operating near saturation in telecommunication transceivers, a new adaptive predistortion system based on analog Neural Networks (NNs) was developed. Based on size, consumption and bandwidth considerations, Multi-Layer Perceptron (MLP) type NNs were implemented in a 0.6 Î¼m CMOS ASIC. The NNs parameters are digitally updated with a computer, depending on simulation conditions (temperature drifts and ageing variations). The interface between the analog part and the software updating system is integrated in an analog-digital PCB including a FPGA, 6 analog-to-digital converters and 62 digital-to-analog converters.