Ham Amateur Radio Technician Practice Exam 2026 – The Complete All-in-One Guide to Exam Success

The correct answer is amplitude modulation. In amplitude modulation (AM), the amplitude, or power level, of the carrier wave is varied in accordance with the instantaneous amplitude of the modulating signal. This means that when the audio signal (or any other information signal) is at a higher level, the amplitude of the RF signal increases, resulting in a higher power level. Conversely, when the information signal is at a lower level, the amplitude of the RF signal decreases, leading to a lower power level.

This variation in power is critical in the transmission of audio signals, as it contains the information that the receiver will decode. Amplitude modulation is commonly used in AM radio broadcasting, where it allows for the transmission of audio signals over long distances.

The other modulation types operate differently: frequency modulation (FM) varies the frequency of the carrier signal, while phase modulation varies the phase angle of the carrier signal. Pulsed modulation typically refers to a signal that has been changed to a series of pulses for transmission, which does not focus on varying the instantaneous power level in the same manner as amplitude modulation does.