Question

For transmission of TV- signal, sound-part is
A. amplitude modulated
B. frequency modulated
C. phase modulated
D. pulse modulated

Answer 1

Hint: First, one must understand what is modulation and its purpose. Modulation is the procedure of changing the carrier signal by changing its properties. There are various modulations. Defining each of those will give us a good idea about what different modulations are and how they are used.

Complete answer:
Modulation is the process of varying the properties of a carrier signal and superimposing with a modulation signal, which carries the information. Modulation is of two types- Pulse modulation and Continuous Wave modulation.
In Pulse modulation, the signal is transmitted in a train of pulses. It is mostly used in digital audio applications like computers.
Continuous Wave modulation is further divided into Amplitude Modulation and Angle Modulation.
In amplitude modulation, the carrier signal amplitude is varied with respect to the modulating signal. AM signals travel very long distances, which leads to the accumulation of more noise. The AM Detectors are used to receive the transmitted signal very sensitive to noise. This leads to heavy noises in the received signal.
Angle Modulation of two types – Frequency Modulation and Phase Modulation. In frequency modulation, the carrier signal with high frequency is superimposed with the modulating signal. Frequency modulation is more preferred to amplitude modulation, which we are seeing these days in radios. One of the most important reasons is the improved signal to noise ratio compared to AM.
In phase, modulation is the phase of the carrier signal that is modulated to follow the amplitude of the modulation signal. Phase modulation is frequently utilized as a middle of the road step to accomplish frequency modulation.
As FM has more bandwidth, it has less noise and is used for transmitting the sound-part of TV.

So, the correct answer is “Option b”.

Note:
The video part of our TV is amplitude modulation, unlike the sound part. It is primarily because the sound noise is felt more than the video noise. Discussion of the modulation and its explanation is beyond this answer. So, we’ve kept it simple to understand the various modulations before answering the question.