Waves of high frequency are called carrier waves. If an audio signal (low frequency) is transmitted as such, it does out after traversing some distance. To reach up larger distance, it is superimposed an high frequency waves called carrier wave

The undesired electrical signals are termed as noise. When a signal is transmitted, the undesired signals get mixed with it, leading to distortion of the signal.

Frequency modulation. (FM) Because it is quite immune to noise as compared to AM.

\(d=\sqrt{2hR}\)
In case, height of tower (h) is increased, the distance (d) upto which TV coverage can be done will also increases.

A transducer is a device that converts information such as pressurc, temperature, sound, picture etc. into an equivalent electrical signal or vice versa.

(i) Satellite vessel monitoring system helps to identify fishing zones.
(ii) Use of barcodes helps to identify time and date of catch, species name, quality of fish.

Mobile communication is used to communicate with others in different locations without the use of any physical connection like wires or cables.

The shortest distance between the transmitter and the point of reception of the sky wave along the surface is called as the skip distance.

The frequency range over which the baseband signals or the information signals such as voice, music, picture, etc. is transmitted is known as Bandwidth.

(i) FM signal produced from PM signal is very stable.
(ii) The centre frequency called resting equency is extremely stable

RADAR stands for RAdio Detection And Ranging.

When the frequency of the baseband signal is zero (no input signal), there is no change in the frequency of the carrier wave. It is at its normal frequency. This is called centre frequency or resting frequency.

i) Noise : Interference of undesirable electrical signal with the transmitted signal.
ii) Attenuation: Loss of strength of a signal.
iii) Medium : It makes some distortion tothe signal.

i) Internet is a fast-growing technology in the field of a communication system with multifaceted tools.
ii) It provides new ways and means to interact and connect with people.
iii) Internet is the largest computer network recognized globally that connects millions of people through computers.
iv) It finds extensive applications in all walks of life.

It is the maximum distance between the source and the destination up to which the signal is received with sufficient strength.