# CBSE Class 12 Physics Notes Chapter 15 Communication Systems

According to the CBSE Syllabus 2023-24, this chapter has been removed from NCERT Class 12 Physics textbook.

## What Is Electronic Communication?

The faithful transformation of a message or information is known as electronic communication, which can be available in the form of electrical current or voltage travelling from one point to another.

### Basic Units of a Communication System

The basic units of a communication system are:

• Transmitter
• Transmission Channel

### Forms of the Communication System

The information usually is in the form of a continuous waveform. There are two forms of a communication system;

• Analog
• Digital

### The Bandwidth of a System

Every message signals constitute various ranges of frequencies, which are very vital for the necessary and optimal transmission of information in the signal. Any practical communication supports a few ranges of frequencies.

### What Is Modulation?

Frequencies which are low cannot travel long distances, and for that, they are being superimposed with a high-frequency carrier signal in order to flow smoothly. They are various types of modulation:

• Pulse Position Modulation (PPM)
• Pulse Width Modulation (PWM)
• Pulse Duration Modulation (PDM)
• Pulse Amplitude Modulation (PAM)

### Important Questions

1. The maximum amplitude and minimum amplitude for an amplitude-modulated wave are found to be 20V and 2V, respectively. Determine the modulation index, µ and find out the value of µ if the minimum amplitude is zero volts.
2. In order to have a modulation index of 85%, what should be the peak voltage of the modulating signal if the carrier wave has a peak voltage of 15V and is used to transmit a message signal?

Related Topics:

CBSE Notes for Physics Class 12

NCERT Solutions for Class 12 Physics Chapter 15

NCERT Exemplar for Class 12 Physics Chapter 15

## Frequently Asked Questions on CBSE Class 12 Physics Notes Chapter 15 Communication Systems

Q1

### What is electronic communication?

Electronic communication is any form of communication that’s broadcast, transmitted, stored or viewed using electronic media, such as computers, phones, email and video.

Q2

### What is a transmission channel?

A path between two nodes in a network. It may refer to the physical cable, the signal transmitted within the cable or a subchannel within a carrier frequency.

Q3

### What is an analog signal?

An analog signal is a continuous signal in which one time-varying quantity represents another time-based variable.