The Study Of Digital Pre-distortion Platform Of Envelope Tracking Power Amplifier

With the society developing, the growth of information is extremely fast. People pay more attention on transferring data better and faster. To obtain higher transmission rate, high peak-average-ratio coding methods are developed. But high peak-average-ratio brings new challenge to the efficiency and linearity of power amplifier. To solve the efficiency and linearity problem of power amplifier, digital pre-distortion technology and envelope tracking power amplifier (ET) become very important.This thesis developed a digital pre-distortion platform for ET, including baseband and envelop signal processing. The system is zero-IF structure consists of transmitting link, receiving link, sample clock module, wideband local oscillator module, digital platform and MCU control module. The device selection and link budget simulation was completed based on the system design.The power supply, clock, register configuration, interface circuits within and among modules were designed based on the Kintex-7 FPGA platform and C8051F330 MCU control module. According to the signal integrity theory, the thesis completed the high speed signal routing and PCB grounding of the converters in transmitting and receiving link.The system measurement was completed at 2.1 GHz. For the transmitting link, using 16QAM and QPSK 25MHz to 50MHz bandwidth signal as the input, the EVM is better than 0.89% and 1.23%; bandwidth from 12.5MHz to 50MHz, the ACLR is better than-61.7dBc. For the receiving link, while single tone signal input ranging from 5MHz to 50MHz, the SFDR measured is better than 61dBc. Testing the transmit and receive chain with 10MHz to 50MHz bandwidth 16QAM signal, the EVM deteriorates less than 1.2%, the ACLR is better than-54.7dBc. The result measured indicates the system has excellent performance and achieves the expected goal.