114 # Takes

Question 1

Frequency of failure and network recovery time after a failure is measures of the ____ of a network.

Answer 1

RELIABILITY

Question 2

Determine the characteristic
impedance for an air-filled concentric
transmission line with D/d ratio of 6.

Answer 2

107.064 ohms

Question 3

Which statement is correct?

Answer 3

Multiplexing uses a single channel to transmit multiple signals.

Question 4

What is the electrical wavelength of a 500 MHz signal?

Answer 4

W= 60cm

Question 5

Determine the input impedance for a transmission line 1.25 λ long with a characteristic impedance of 50 ohms and a load impedance of 30 + j40 ohms?

Answer 5

Zin = 30– j40 Ω

Question 6

Indicate the false statement: If SWR
on a transmission line is infinite, the
line is terminated in

Answer 6

Complex Impedance

Question 7

Areal-valued signal x(n) is called as anti-symmetric if_

Answer 7

x(n)= - x(-n)

Question 8

zero state response is also known as

Answer 8

Forced response

Question 9

All energy signals will have an average power of

Answer 9

Zero

Question 10

A rectangular waveguide is operating in the dominant TE10 mode. The associated flux lines are established

Answer 10

transversely across the narrow dimension of the waveguide

TNW

Question 11

______ cable consists of an inner copper core and a second conducting outer sheath.

Answer 11

Coaxial cable

Question 12

A quarter-wavelength of a line is used as a/an

Answer 12

Impedance Transformer

Question 13

Which agency developed standards for physical connection interfaces and electronic signaling specifications?

Answer 13

The Electronic Industries Alliance (EIA)

Question 14

If the bandwidth efficiency is 6 bits per cycle, and the baud rate is 20k baud, determine the bit rate in kbps. Answer in numeric form. Do not include unit.

Answer 14

Bitrate = 120kbps

Question 15

Consider the analog signal x(t)=5cos400πt. If the signal is sampled at 1000Hz, the discrete time signal obtained will be

Answer 15

x(n) = 5cos(0.4pi*n)

Question 16

When the angle of incidence is _______ the critical angle, the light beam bends along the interface

Answer 16

Equal to

(Corrected)

Question 17

Signals with a frequency above 30 MHz use _____ propagation.

Answer 17

Line of sight (PB)

Note: < 2 MHz Ground

Corrected

Question 18

If the earth station downlink signal received is at fs 54.08 GHz, what local oscillator frequencies Fl0 are needed to achieve IFs of 770 and 140 MHz? 2 decimal places

Answer 18

53.31 GHz and 53.94 GHz, respectively.

Corrected

Question 19

If {x(n)} is the signal to be analyzed, limiting the duration of the sequence to L samples, in the interval 0 ≤ n ≤ L-1, is equivalent to…?

Answer 19

Rectangular Window

Question 20

A rectangular waveguide has a width
of 0.65 in and a height of 0.38 in. What is the cutoff frequency?

Answer 20

9.0769 GHz

or 9.07 GHz (?)

Question 21

A lossless transmission line having a characteristic impedance of 50Ω is terminated by an impedance 40+j30Ω. The VSWR is

Answer 21

2

Solved

Question 22

Sixteen different levels (symbols) are used to encode binary data. The channel bandwidth is 36 MHz. The maximum channel capacity is

Answer 22

288 Mbps

Question 23

Digital multiplexing is based on the principle of _____ from two or more digital signals.

Answer 23

Interleaving

Question 24

Transmission media lie below the _______layer.

Answer 24

Physical Layer

Question 25

What determines the velocity factor in a transmission line

Answer 25

Dielectric materials used in the line

Question 26

Which of the following justifies the linearity property of z-transform? [x(n)↔X(z)]

Answer 26

x(n)+y(n) ↔ X(z)+Y(z)

Question 27

The dominant mode in most rectangular waveguide is

Answer 27

TE 10

Corrected

Question 28

In _____ transmission, the channel capacity is shared by both communicating devices at all times

Answer 28

Full-duplex

Question 29

The difference between phase and
frequency modulation

Answer 29

Lies in the different definitions of the modulation index

(How carrier signal is affected)

Question 30

A parabolic reflector antenna has a diameter of 5 ft. Calculate the lowest possible operating frequency

Answer 30

196.8

Question 31

When the electric field in a waveguide is perpendicular to the
direction of propagation, the mode is said to be?

Answer 31

Transverse electric

Question 32

A set of rules that governs data communication

Answer 32

Protocol

Question 33

A magnetic field is introduced into the waveguide by a

Answer 33

Probe

Question 34

The value of the resistor creating thermal noise is doubled. The noise power generated is therefore.

Answer 34

Unchanged

Question 35

A Fade Margin of 28 dB has a reliability of

Answer 35

99.9% or 0.999

Question 36

Find the velocity (in km/s) of a satellite in a circular orbit 500km above the earth surface. 2 decimal places

Answer 36

V = 7616.28

Question 37

In the Bilinear Transformation mapping, which of the following is correct?

Answer 37

All points in the LHP & RHP of s are mapped inside & outside the unit circle in the z-plane

Question 38

Which is not true about AM?

Answer 38

The carrier frequency changes

Question 39

If the carrier of a 100 percent modulated AM wave is suppressed, the percentage power saving will be

Answer 39

66.67%
Sure