What is the purpose of an RF power amplifier?

The purpose of an RF power amplifier is to increase the power level of RF signals. In communication systems, the transmission of radio frequency signals over distances often requires signals to be amplified to ensure that they can travel efficiently through the medium and reach their intended destination with sufficient strength. This amplification helps to counteract losses that can occur due to distance, obstacles, and other factors.

RF power amplifiers take low-level RF signals and boost their power to a level that can be effectively transmitted by antennas. This is critical in applications such as broadcasting, wireless communication, and radar systems, where maintaining signal integrity and strength is essential for reliable communication.

The other options do not align with the primary function of an RF power amplifier. Filtering unwanted frequencies pertains to removing or isolating specific frequency components, which is typically handled by filters, not amplifiers. Converting analog to digital signals relates to analog-to-digital converters, which are separate components used to digitize signals. Modulating carrier signals involves modifying a carrier wave with the information signal to be transmitted, which is done by modulator circuits, not power amplifiers. Thus, the correct answer emphasizes the amplifying role that is essential in RF signal propagation.