Modulation. Basic types of modulation.

Modulation is the process of superimposing the information contents of a modulating signal on a carrier signal (which is of high frequency) by varying the characteristics of carrier signal according to the modulating signal.

Modulation is a process in which the base band signal modifies another high-frequency signal called the carrier.

We can modulate the information-bearing signal into two types namely.These

are called Modulation Techniques.

1. Analog Modulation

2. Digital Modulation

Analog modulation is the process of converting an analog input signal into a

signal that is suitable for RF transmission.

Digital modulation is the process of converting a digital bistream into an analog signal suitable for RF transmission.

Television. Principles of image formation.

A television system involves equipment located at the source of production, equipment located in the home of the viewer, and equipment used to convey the television signal from the producer to the viewer. The purpose of all of this equipment is to extend the human senses of vision and hearing beyond their natural limits of physical distance. A television system must be designed, therefore, to embrace the essential capabilities of these senses, particularly the sense of vision. The aspects of vision that must be considered include the ability of the human eye to distinguish the brightness, colors, details, sizes, shapes, and positions of objects in a scene before it. Aspects of hearing include the ability of the ear to distinguish the pitch, loudness, and distribution of sounds. In working to satisfy these capabilities, television systems must strike appropriate compromises between the quality of the desired image and the costs of reproducing it. They must also be designed to override, within reasonable limits, the effects of interference and to minimize visual and audial distortions in the transmission and ... (200 of 21,814 words).

Basic components of data communication.

Communication is the basic process of exchanging information. The basic components of an electronic communication system are:

1) Transmitter.

2) Communication channel.

3) Receiver.

A Transmitter is a collection of electronic circuits designed to convert the information into a signal suitable for transmission over a given communication medium.

A Receiver is a collection of electronic circuits designed to convert the signal back to the original information.

The Communication channel is the medium by which the electronic signal is transmitted from one place to another.

A radio communication system sends signals by radio. Types of radio communication systems deployed depend on technology, standards, regulations, radio spectrum allocation, user requirements, service positioning, etc. The radio equipment involved in communication systems includes a transmitter and a receiver, each having an antenna and appropriate terminal equipment such as a microphone at the transmitter and a loudspeaker at the receiver in the case of a voice-communication system.