EC1391 Telecommunication Systems B.E Question Bank : niceindia.com
Name of the College : Noorul Islam College of Engineering
University : Anna University
Degree : B.E
Department : Information Technology
Subject Code/Name : EC 1391 – Telecommunication Systems
Document Type : Question Bank
Website : niceindia.com
Download Model/Sample Question Paper :https://www.pdfquestion.in/uploads/niceindia.com/3039-EC1391_TELACOMMUNICATION_SYSTEMS.pdf
NICE Telecommunication Systems Question Paper
Unit – I Methods Of Communication :
Part – A :
1. Define transmission line :
A transmission line is a two-wire cable that connects the transmitter to the antenna or the antenna to the receiver. The purpose of the transmission line is to carry the RF energy for the desired distance.
Related : Noorul Islam College of Engineering IT1404 Mobile Computing B.E Question Bank : www.pdfquestion.in/3043.html
2.State the classification of transmission line :
** Balanced line
** Unbalanced line
3.Define unbalanced line with an example :
In an unbalanced line, there are two conductors of which one is connected to the ground.
Eg. Co-axial cable
Coax is an unbalanced line since the current in the center conductor is referenced to the braid, which is connected to ground.
4.Define balanced line with an example :
A Balanced line is made up of two parallel conductors spaced from one another by a distance of ½ inch up to several inches.
Eg. a two-wire balanced line
5.State the relation between wavelength and frequency :
Wavelength is the length or distance of one cycle of an ac wave. It is also the distance that an ac wave travels in the time required for one cycle of that signal.
Wavelength is expressed as the ratio of the speed of light to the frequency of the signal
6.Define velocity factor :
Velocity factor F, is the ratio of the transmission speed in the transmission line VL and transmission speed in free space Vs.
7.Define characteristic impedance :
An RF generator connected to the transmission lines sees an impedance that is a function of the inductance and capacitance in the circuit. This impedance is known as the characteristic impedance Zo. It is also referred to as the surge impedance.
8.Define standing waves :
The forward and reflected signals on an incorrectly terminated transmission line produce a wave known as a standing wave. A standing wave is the unique distribution of voltage and current along a transmission line that is not terminated in its characteristic impedance.
9.Define standing wave ratio :
The magnitude of the standing waves on a transmission line is determinedby the ratio of the maximum current to the minimum current along the line, or the ratio of the maximum voltage to the minimum voltage. These ratios are referred to as the standing wave ratio. [SWR]
10. Define polarization :
The direction of the electric field specifies the polarization of the antenna. If the electric field is parallel to the earth, the electromagnetic wave is said to be horizontally polarized. If the electric field is vertical to the earth , the wave is said to be vertically polarized.
11. Define antenna :
An antenna, or aerial is one or more electrical conductors of a specific length that radiate radio waves generated by a transmitter or that collect radio waves at the receiver.
12. What are the modes of radio wave propagation? :
** Ground waves
** Sky waves
** Space waves
13. Define ground waves and what is the frequency range of ground waves? :
The ground or surface wave leaves the antenna and remains close to the earth. The ground wave will actually follow the curvature of the earth and can, therefore, travel at distances beyond the horizon. The ground waves are the main signal path for radio signals in the 30Khz to 3 MHz range.
14. What is sky wave? :
A sky-wave signal is one that is radiated by the antenna into the upper atmosphere where it is bent or reflected back to earth.
15. What is ionosphere? :
The upper atmosphere is ionized by the ultraviolet rays.This ionized region is called as the ionosphere.
16.What are the layers in ionosphere? :
There are four layers in ionosphere. They are D,E,F1 and F2.
17.Define space waves :
A method of radio signal propagation is by direct or space waves. A direct wave travels in a straight line directly from the transmitting antenna to the receiving antenna. It is also referred to as line-of-sight communication.
18.State the function of repeater? :
A repeater is a combination of a receiver and a transmitter. The function of the repeater is to pick up the signal from a transmitter, amplify it, and retransmit it on another frequency to the receiver.
19.State the frequency range of microwaves :
Microwaves are signals with a frequency greater than 1 GHz. The microwave region is generally considered to extend to 30 GHz, although some definitions include frequencies up to 300 GHz.
20.State the challenges of microwaves :
** Measurements
** Components
** Transit time
** Interelectrode capacitance
** Interlead inductance
The analysis of electronic circuits at lower frequencies is based upon current-voltage relationships. The analysis of circuits at higher frequencies is based upon electric field and magnetic field. Power measurements are also common in microwave frequency.