114 # Takes Flashcards
Frequency of failure and network recovery time after a failure is measures of the ____ of a network.
RELIABILITY
Determine the characteristic
impedance for an air-filled concentric
transmission line with D/d ratio of 6.
107.064 ohms
Which statement is correct?
Multiplexing uses a single channel to transmit multiple signals.
What is the electrical wavelength of a 500 MHz signal?
W= 60cm
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?
Zin = 30– j40 Ω
Indicate the false statement: If SWR
on a transmission line is infinite, the
line is terminated in
Complex Impedance
Areal-valued signal x(n) is called as anti-symmetric if_
x(n)= - x(-n)
zero state response is also known as
Forced response
All energy signals will have an average power of
Zero
A rectangular waveguide is operating in the dominant TE10 mode. The associated flux lines are established
transversely across the narrow dimension of the waveguide
TNW
______ cable consists of an inner copper core and a second conducting outer sheath.
Coaxial cable
A quarter-wavelength of a line is used as a/an
Impedance Transformer
Which agency developed standards for physical connection interfaces and electronic signaling specifications?
The Electronic Industries Alliance (EIA)
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.
Bitrate = 120kbps
Consider the analog signal x(t)=5cos400πt. If the signal is sampled at 1000Hz, the discrete time signal obtained will be
x(n) = 5cos(0.4pi*n)
When the angle of incidence is _______ the critical angle, the light beam bends along the interface
Equal to
(Corrected)
Signals with a frequency above 30 MHz use _____ propagation.
Line of sight (PB)
Note: < 2 MHz Ground
Corrected
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
53.31 GHz and 53.94 GHz, respectively.
Corrected
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…?
Rectangular Window
A rectangular waveguide has a width
of 0.65 in and a height of 0.38 in. What is the cutoff frequency?
9.0769 GHz
or 9.07 GHz (?)
A lossless transmission line having a characteristic impedance of 50Ω is terminated by an impedance 40+j30Ω. The VSWR is
2
Solved
Sixteen different levels (symbols) are used to encode binary data. The channel bandwidth is 36 MHz. The maximum channel capacity is
288 Mbps
Digital multiplexing is based on the principle of _____ from two or more digital signals.
Interleaving
Transmission media lie below the _______layer.
Physical Layer
What determines the velocity factor in a transmission line
Dielectric materials used in the line
Which of the following justifies the linearity property of z-transform? [x(n)↔X(z)]
x(n)+y(n) ↔ X(z)+Y(z)
The dominant mode in most rectangular waveguide is
TE 10
Corrected
In _____ transmission, the channel capacity is shared by both communicating devices at all times
Full-duplex
The difference between phase and
frequency modulation
Lies in the different definitions of the modulation index
(How carrier signal is affected)
A parabolic reflector antenna has a diameter of 5 ft. Calculate the lowest possible operating frequency
196.8
When the electric field in a waveguide is perpendicular to the
direction of propagation, the mode is said to be?
Transverse electric
A set of rules that governs data communication
Protocol
A magnetic field is introduced into the waveguide by a
Probe
The value of the resistor creating thermal noise is doubled. The noise power generated is therefore.
Unchanged
A Fade Margin of 28 dB has a reliability of
99.9% or 0.999
Find the velocity (in km/s) of a satellite in a circular orbit 500km above the earth surface. 2 decimal places
V = 7616.28
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
Which is not true about AM?
The carrier frequency changes
If the carrier of a 100 percent modulated AM wave is suppressed, the percentage power saving will be
66.67%
Sure
