ARRL Technician Practice Exam

What is the purpose of an audio frequency oscillator in amateur radio transmission?

1. To generate radio frequency signals

2. To modulate audio signals with RF

3. To amplify incoming signals

4. To filter unwanted noise

The correct answer is: To modulate audio signals with RF

The purpose of an audio frequency oscillator in amateur radio transmission is to modulate audio signals with radio frequency (RF). This process involves taking the audio signals, which are often within the frequency range audible to the human ear, and combining them with a higher frequency carrier wave. The oscillator creates the necessary audio tones that can be applied to the RF signal, enabling the transmission of voice or other audio information over long distances. When transmitting, the audio frequency oscillator generates the specific audio tones that correspond to the sounds being transmitted, such as speech or music. This modulation allows the information to be carried effectively on the RF waves, making it possible for receivers to demodulate the signal and reproduce the original audio. The other options, while related to radio operation, do not accurately describe the specific function of an audio frequency oscillator. Generating radio frequency signals pertains more to RF oscillators, amplifying signals is the role of amplifiers, and filtering unwanted noise is handled by filters within the receiver or transmitter design.