114 # Takes Flashcards

1
Q

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

A

RELIABILITY

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2
Q

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

A

107.064 ohms

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3
Q

Which statement is correct?

A

Multiplexing uses a single channel to transmit multiple signals.

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4
Q

What is the electrical wavelength of a 500 MHz signal?

A

W= 60cm

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5
Q

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?

A

Zin = 30– j40 Ω

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6
Q

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

A

Complex Impedance

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7
Q

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

A

x(n)= - x(-n)

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8
Q

zero state response is also known as

A

Forced response

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9
Q

All energy signals will have an average power of

A

Zero

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10
Q

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

A

transversely across the narrow dimension of the waveguide

TNW

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11
Q

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

A

Coaxial cable

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12
Q

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

A

Impedance Transformer

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13
Q

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

A

The Electronic Industries Alliance (EIA)

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14
Q

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.

A

Bitrate = 120kbps

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15
Q

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

A

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

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16
Q

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

A

Equal to

(Corrected)

17
Q

Signals with a frequency above 30 MHz use _____ propagation.

A

Line of sight (PB)

Note: < 2 MHz Ground

Corrected

18
Q

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

A

53.31 GHz and 53.94 GHz, respectively.

Corrected

19
Q

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…?

A

Rectangular Window

20
Q

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

A

9.0769 GHz

or 9.07 GHz (?)

21
Q

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

22
Q

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

23
Q

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

A

Interleaving

24
Q

Transmission media lie below the _______layer.

A

Physical Layer

25
What determines the velocity factor in a transmission line
Dielectric materials used in the line
26
Which of the following justifies the linearity property of z-transform? [x(n)↔X(z)]
x(n)+y(n) ↔ X(z)+Y(z)
27
The dominant mode in most rectangular waveguide is
TE 10 Corrected
28
In _____ transmission, the channel capacity is shared by both communicating devices at all times
Full-duplex
29
The difference between phase and frequency modulation
Lies in the different definitions of the modulation index (How carrier signal is affected)
30
A parabolic reflector antenna has a diameter of 5 ft. Calculate the lowest possible operating frequency
196.8
31
When the electric field in a waveguide is perpendicular to the direction of propagation, the mode is said to be?
Transverse electric
32
A set of rules that governs data communication
Protocol
33
A magnetic field is introduced into the waveguide by a
Probe
34
The value of the resistor creating thermal noise is doubled. The noise power generated is therefore.
Unchanged
35
A Fade Margin of 28 dB has a reliability of
99.9% or 0.999
36
Find the velocity (in km/s) of a satellite in a circular orbit 500km above the earth surface. 2 decimal places
V = 7616.28
37
In the Bilinear Transformation mapping, which of the following is correct?
All points in the LHP & RHP of s are mapped inside & outside the unit circle in the z-plane
38
Which is not true about AM?
The carrier frequency changes
39
If the carrier of a 100 percent modulated AM wave is suppressed, the percentage power saving will be
66.67% Sure