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318 Chapter 17. Advanced communication Systems

f1 f2

Transmitter Repeater Receiver
Baseband Baseband
signal signal

Figure 17.1: Basic block diagram for microwave communication sys-
tem

GHz. Microwave communication system is line of sight (LOS) in na-
ture limited by horizon due to earth’s curvature.
Microwave communication system is classified into two broad cat-
egories namely analog and digital. Analog microwave communication
systems are widely used. The analog system employs analog trans-
mission techniques such as FM modulation and analog multiplexing
technique.

17.2.1 Microwave frequency bands

Designation Frequency range
UHF 300 MHz - 1 GHz
L Band 1-2 GHz
S Band 2-4 GHz
C Band 4-8 GHz
X Band 8-12 GHz
Ku Band 12-18 GHz
K Band 18-27 GHz
Ka Band 27-40 GHz

Table 17.1: Microwave frequency bands

17.2.2 Microwave communication system

A microwave system consists of a terminal transmitter, a number of
repeater stations and a terminal receiver station (see Figure 17.1). The
functions of each blocks are explained below.

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