Quiz In Communication System

The total power of an amplitude modulated wave is equal to 1.5 times the power of the carrier wave because in amplitude modulation, the power of the modulated wave is a combination of the power of the carrier wave and the power of the sidebands. The sidebands carry information and contribute to the overall power of the modulated wave. Therefore, the total power is greater than just the power of the carrier wave alone. In this case, it is 1.5 times the carrier wave power.

Modulation refers to the process of varying certain characteristics (such as amplitude, frequency, and phase) of a carrier wave in accordance with a modulating wave. This technique is commonly used in telecommunications to transmit information over long distances. By modulating the carrier wave, the original signal can be efficiently transmitted and then demodulated at the receiving end to retrieve the original information. Multiplexing and demultiplexing, on the other hand, refer to the techniques of combining and separating multiple signals, respectively, for efficient transmission over a single communication channel.

Phase modulation is a modulation technique where the phase of the carrier signal is varied according to the amplitude of the message signal. This means that the carrier signal's phase is shifted in response to changes in the amplitude of the message signal. Phase modulation is commonly used in telecommunications and is known for its ability to provide high-quality signal transmission, as it is less susceptible to noise and interference compared to other modulation techniques.

The modulation index refers to the ratio between the modulating signal voltage and the carrier voltage in amplitude modulation. It determines the extent to which the carrier signal is varied by the modulating signal, and is a crucial parameter in determining the level of modulation in the signal. A higher modulation index implies a higher level of modulation, while a lower modulation index indicates a lower level of modulation. Therefore, the modulation index accurately describes the relationship between the modulating signal voltage and the carrier voltage in amplitude modulation.

Frequency modulation and phase modulation are the two most important classes of angle modulation. Angle modulation is a technique used in communication systems to encode information onto a carrier wave. Frequency modulation (FM) varies the frequency of the carrier wave according to the amplitude of the modulating signal, while phase modulation (PM) varies the phase of the carrier wave. Both FM and PM are widely used in various applications, including radio broadcasting, satellite communication, and digital communication systems.

A transmitter is the equipment that converts physical messages, such as sound, words, pictures, etc., into corresponding electrical signals. This device is responsible for transmitting the electrical signals to a receiver or through a channel for further processing or communication.

A receiver is the equipment that converts an electrical signal back into the physical message. It is responsible for receiving the transmitted signal and decoding it to retrieve the original message. The receiver plays a crucial role in communication systems as it allows the recipient to understand and interpret the information being transmitted. Without a receiver, the transmitted signal would remain in its electrical form and would not be accessible or understandable to the recipient.

In frequency modulation, all of the above statements are correct. The amplitude of the carrier remains the same, meaning it does not change. The frequency of the carrier varies in accordance with the modulating signal, which means that the frequency of the carrier wave is modified based on the input signal. Lastly, the phase of the carrier remains the same, indicating that the phase shift of the carrier wave remains constant.

In PM (Phase Modulation), the information is transmitted by changing the phase of the carrier signal. This means that the phase of the carrier wave is modified in accordance with the input signal. By altering the phase, the information can be encoded and transmitted. Unlike frequency modulation (FM) or amplitude modulation (AM), PM focuses solely on changing the phase of the carrier wave to transmit data.

In a communication system, noise is most likely to affect the signal in the channel. The channel refers to the medium through which the signal is transmitted, such as a wire, cable, or airwaves. Noise can be introduced into the signal during transmission through various factors like interference, distortion, or attenuation. These factors can disrupt the integrity of the signal, leading to errors or degradation in the received information. Therefore, the channel is the most susceptible point where noise can impact the signal in a communication system.