Pre-distortion-compensated up-converting OFDM power amplifier of 2W at 7GHz for digital TV broadcasting service

Abstract

The linear- and temperature-compensated negative feedback loop of the GaAs FET SHF power amplifier operating at 7GHz greatly improved the non-linear distortion as well as the improved thermal stability in this class-A amplifier when used in the up-converting amplifier with an IF(37.5MHz) input port at -40dBm. The inter-modulation to the third harmonic frequency for the OFDM TV signals was improved by a factor of 15dB, and the equivalent CNR was improved by a factor of 9.6dB at 7GHz. The result was satisfactory. This up-converting amplifier of new type was designed to be employed in the OFDM digital TV broadcasting facilities for new terrestrial digital TV broadcasting service at 7GHz. It will be useful also for the wireless communication facilities.