MODES OF COMMUNICATION

                    MODES OF COMMUNICATION

MODES OF COMMUNICATION

1. POINT-TO-POINT COMMUNICATION

    [LINE COMMUNICATION GUIDED]

2. BROADCAST

   [E.M. WAVES COMMUNICATION]

         # POINT-TO-POINT COMMUNICATION

                                [LINE COMMUNICATION GUIDED]

1. TWISTED PAIR DEVICE SMALLER THAN 50mHz

2. COAXIAL CABLE 50-750mHz

3. OPTICAL FIBER 750-1000mHz

                            # BROADCAST

                        [E.M. WAVES COMMUNICATION]

1. GROUND LESS THAN 40mHz

2. SKY 40-100mHz

OPTICAL FIBER COMMUNICATION IS BEST FOR THE COMMUNICATION TILL NOW.

# POINT-TO-COMMUNICATION [LINE COMMUNICATION] CONSISTS OF 3 TYPES:-

1. TWISTED PAIR WIRE

IN THIS TWISTED-PAIR WIRE, WHEN 2 COPPER WIRES ARE TWISTED OVER EACH OTHER AND HAVING LESS INSULATION.

PROPERTIES:-

1.1 LESS INSULATION AND LARGE HEAT FORMATION.

1.2 LESS BANDWIDTH

1.3 LARGE ATTENUATION [LOSS OF ENERGY]

2. COAXIAL CABLE WIRE

IT CONTAINS 2 COAXIAL COPPER AND SILVER WIRE HAVING TWICE INSULATION ATTENUATION IS VERY LESS AND COMPARED TO TWISTED CABLE. THIS WIRE IS USED IN TELEVISION SIGNALS.

3. OPTICAL FIBER

THESE ARE THE VERY THIN FIBER MADE UP OF THE CENTRAL CORE AND COATING WITH CLADDING MATERIAL. An optical fiber is a flexible, transparent fiber made by drawing glass or plastic to a diameter slightly thicker than that of a human hair.

BROADCAST [EM WAVE COMMUNICATION]

1. GROUND WAVE

THESE ARE THE LOW-FREQUENCY WAVES UPTO3MHZ. THESE WAVES ARE USED IN LOCAL TRANSMISSION. THEY GLIDE OVER THE SURFACE OF THE EARTH AND ATTENUATION IN THEM IS VERY LARGE DUE TO ACCELERATION DUE TO GRAVITY OR DUE TO AIR FRICTION.

2. SKY WAVE

THESE ARE WAVES HAVING THE BANDWIDTH OF 3MHZ TO 40MHZ [VERY HIGH FREQUENCY]. THESE WAVES ARE TRANSMITTED TOWARDS THE SKY FROM THEIR AND THEY REFLECT BY IONOSPHERE [FROM A PARTICULAR LAYER WHERE THE ION DENSITY IS MAXIMUM KNOWN AS KEENLY HEAVY SIDE LAYER] THAN THE PARTICULAR FREQUENCY BY WHICH THE WAVE ARE INCIDENT TOWARDS THE IONOSPHERE IS KNOWN AS CRITICAL FREQUENCY.