Implementation of dual-channel receiver suitable for 3G power amplifiers characterization in RF/Digital predistortion systems

This paper proposes a dual-channel receiver, which consists of a frequency downconverter, analog to digital converter and digital demodulator, suitable for 3G power amplifiers characterization and digital predistortion. The active mixer based frequency downconverter is designed with a flexible and balanced architecture, which can provide superior performance including low intermodulation distortion, low noise figure, high conversion gain, and low LO drive level. The digital demodulator, implemented in an Altera field programmable gate array, provides wide bandwidth, great flexibility and high performance due to bit precision resolution. The validation of the dual receiver was carried out using WCDMA signals. Measurement results with WCDMA signal centered at 1960 MHz show approximately 55 dBc adjacent channel power ratio in the demodulated spectrum.