Implementation of energy-saving compressor for AM broadcast transmitters using FPGA

The radio terrestrial AM sound broadcasting in the frequency bands up to 30 MHz is the oldest radio service which originates in the beginning of the last century. It still plays a major role in the large coverage audio broadcasting services mainly in the segment of high power broadcasting transmitters. The main disadvantage of large power double-sideband AM transmitters is a poor efficiency. In this paper we present fully-digital implementation of energy-saving compressor for AM transmitters using FPGA. First, the general theory of energy-saving techniques is discussed which results in the design of parameterized VHDL module aimed at FPGA with a multiply-accumulate cores. The module is supposed to feed the digital AM modulator based on the Pulse Step Modulation (PSM), Pulse Duration/Width Modulation (PDM, PWM), and similar modern modulation techniques. Finally, we conclude with the module operation and performance description.