Question

Choose the correct statement:
A. In amplitude modulation, the amplitude of the high-frequency carrier wave is varied in proportion to the amplitude of the audio signal.
B. In amplitude modulation, the frequency of the high-frequency carrier wave is made constant.
C. In frequency modulation, the amplitude of the low-frequency carrier is made to vary in proportion to the amplitude of the audio signal
D. None of the above

Answer 1

Hint: Modulation is the process of varying some of the characteristics of a carrier wave to achieve the required output. Amplitude modulation and frequency modulation are two methods for the modulation of signals. These methods are used to achieve or decode the required message from the scripted signal.

Complete answer:
A modulating signal is information or message that has to be transmitted after being converted into an electronic signal.
In amplitude modulation, the amplitude (signal strength) of the carrier wave is varied in proportion to the amplitude of the message signal, such as an audio signal. This modulation technique is most commonly used for transmitting messages with a radio carrier wave in electronic communication.
On the other hand, in frequency modulation, the frequency of the carrier wave is altered in accordance with the frequency of the modulating signal (message signal, audio signal). In the case of frequency modulation, the amplitude of the modulated signal is kept or it remains constant. In frequency, there is less interference and noise.

So, the correct answer is “Option A”.

Note:
Amplitude modulation (AM) was the earliest modulation method that is used for transmitting audio in radio broadcasting. It was developed during the first quarter of the 20th century starting from Roberto Landell de Moure and Reginald Fessenden’s radiotelephone experiments in 1900. Frequency modulation (FM) is widely used for FM radio broadcasting, telemetry, radar, seismic prospecting, two-way switching systems, magnetic tape-recording systems, sound synthesis, and some video-transmission systems.