Ham Amateur Radio Technician Practice Exam 2026 - Free Technician Practice Questions and Study Guide

The process that changes the phase angle of an RF (radio frequency) signal to convey information is known as phase modulation. In phase modulation, the phase of the carrier wave is varied in accordance with the instantaneous amplitude of the modulating signal, effectively encoding information in the phase of the transmitted signal. This method allows for the transmission of data by altering the timing of the wave cycles rather than modifying the wave's amplitude or frequency.

Phase modulation is particularly effective and popular in various communication systems, as it can be more resilient to noise compared to other modulation methods. Changes in phase can carry significant amounts of information without requiring a large bandwidth increase, making it efficient for many applications.

In contrast, amplitude modulation involves changing the strength (amplitude) of the carrier wave to convey information, while frequency modulation varies the frequency of the carrier wave. Digital modulation represents a broad category that can include methods like phase shift keying, but it is not specific to modifying phase only. Understanding these distinctions highlights why phase modulation is the appropriate term for the process described in the question.