ECE Board
Exam April 2001
An SWR
reading which has a short circuit termination.
Infinity
ECE Board
Exam November 2000
In an open
wire transmission line, what is the normal separation between its two (2)
conductors?
2 to 6 cm
ECE Board
Exam April 2000
Which of the
following term is used to describe the attenuation and phase shift per unit
length of a transmission line?
Propagation constant
ECE Board
Exam November 1999
An
indication in radio communication when the voltage standing wave ratio is equal
to zero.
No input power
ECE Board
Exam April 1999
Refers to a
connector that normally connects RG-213 coaxial. cable to an HF transceiver.
PL-259
ECE Board
Exam November 1998
Width of
frequency band just enough to ensure the transmission of information at a
required rate and quality required, and under a specified condition and class
of emission.
Necessary bandwidth
ECE Board
Exam. April 1998
Best
describe a dip meter.
A variable LC oscillator with metered
feedback current
ECE Board
Exam. April 1997
The standard
test tone.
0 dBm
ECE Board April 1997
If
voltage change is equal to twice its original value,. what is it corresponding
change In dB?
6 dB
ECE Board Exam November 1996
Energy that has neither been-radiated
into space,nor completely transmitted.
Standing waves
ECE Board
Exam April 1997
To a couple
a coaxial line, it is better to use a________
Balun
ECE Board Exam November 2000
What is the main reason,why coaxial cable
is not used in microwe signal transmission?
High attenuation
ECE Board Exam April 1997
What is impedance of a balance 4-wire
with a diameter of 0.25 spaced 2.5 cm apart using an insulator with a
dielectric constant of 2.56?
100 ohms
ECE Board
April 2000
In wire
communications, non-resonat transmission lines are referred to as __________
Flat lines
ECE Board
Exam November 1999
An
electronic equipment used in radio communications to measure standing wave
ratio.
Reflectometer
ECE Board
Exam April 1999
How does a shorted half-wave line act at a
certain operating frequency?
Series resonant circuit
ECE Board
Exam November 1998
Best choice
of transmission line component to couple a coaxial line to a parallel-wire
line.
Balun
ECE Board
Exam April 1998
Referred to
the dielectric constant of a transmission line material.
Velocity factor
ECE Board
Exam April 1997
What is the
characteristic impedance of a single wire with a diameter d=0.25 mm placed at
the center between grounded parallel planes separated by 1 mm apart? The wire
is held by a material with a velocity factor of 0.75?
75 ohms
ECE Board Exam March 1996
The power of standard test tone is
normally ______
1mW
ECE Board Exam November 1996
Which tester is used to measure SWR?
Reflectometer
ECE Board Exam March 1996
The
characteristic impedance of a transmission line does not depend upon its________
Length
ECE Board Exam April 2000
What is the input impedance equivalent of
an open ended transmission line which is longer than a quarter wavelength?
As pure inductor
ECE Board Exam November 1999
In the study of transmission cable, twin
lead. is also referred to as a_________
ribbon cable
ECE Board Exam April 1999
The greater the diameter of a wire, the
_________ is the resistance.
Lesser
ECE Board Exam November 1998
What determines the velocity factor in
transmission line?
Dielectrics in the
line
ECE Board Exam April 1998
Technical study which deals with
production, transport and delivery of a quality signal from source to
destination
Transmission
System Engineering
ECE Board Exam April 1997
If you have available number of power amplifiers
with a gain of 100 each how many such amplifiers do you need to cascade to give
an overall gain of 60 dB?
3
amplifiers
ECE Board Exam March 1996
What :is the reference tone level for
dBm?
-90dBm
ECB Board Exam April 2060
What is the term for the ratio of actual
velocity at which a signal travels through a line to the speed of light in a
vacuum?
Velocity
factor
ECE Board Exam November 1999
Referred to as a cause of crosstalk.
Electrical
coupling between transmission media
ECE Board Exam November 1998
What is the meaning of the term velocity
factor of a transmission line?
The
velocity of the wave on the transmission line divided by the velocity of the
light in a vacuum
ECE Board Exam April 1998
It is used to connect computers in the
same building or in same area.
LAN
ECE Board Exam April 1997
What do you call the energy that was not
radiated into space or completely transmitted?
Standing
waves
ECE Board Exam November 1996
What is the applied power if a thermal RF
wattmeter is connected to a transmitter through
variable attenuator? The wattmeter reads 84 mW when 15 dB of attenuation
is used.
2.656
Watts
ECE Board Eaagl.March 1996
If the terminating impedance is exactly
equal to the characteristic impedance of the transmission line the return loss
is ______
infinite
ECE Board Exam April 1997
A singie.q nductor running from the
transmitter to the antenna.
Single
line wire
ECE Board Exam November 1996
Ina transmission line if the maximum
current to minimum current ratio is 2:1. what is the ratio of the maximum
voltage to minimum voltage?
2.1
ECE Board Exam March 1996
What is the main purpose of a communications
system?
To
provide an acceptable replica of the information at the destination
ECE Board Exam April 1997
__________ sets the limit on the maximum
capacity of a channel with a gin noise level.
Shannon-Hartley
theorem
ECE Board
Exam November 1996
Which stands
for dB relative level?
dBr
ECE Board Exam March 1996
To connect coaxial line to a
parallel-wire, _______ is the best to use
Balun
ECE Board
Exam November 1998
Which of the
following determines the characteristics of a transmission line?
Physical dimensions
ECE Board
Exam.April 1998
Which of the
fotlowing is an impedance matching ratio of coax balun?
4:1
ECE Board
Exam November 1997
An
electronic equipment used to measure standing wave ratio.
Reflectometer
ECE Board Exam
April 1997
What
frequency does oxygen cause excessive attenuation?
60 GHz
ECE Board
Exam November 1996
The standing
wave ratio is equal to _________ if the load is properly matched with the
transmission line.
1
ECE Board
Exam March 1996
Characteristic
impedance of a transmission line is the impedance measured at the ____ when its
length is infinite.
Input
ECE Board
Exam March 1996
What.quarterwave
transformer will match a 100 ohms line to an antenna whose value is 175 ohms?
132.29 ohms
ECE Boardd
Exam March 1996
When a
transmission line uses ground return, it is called a/an __________ line.
Unbalanced
ECE Board Exam November 1996
Transmission lines when connected to
antenna have
resistive
load atthe resonant frequency
ECE Board Exam March 1996
Termination means
load
connected to the output end of a transmission line
ECE Board Exam March 1996
Transmission lines are either balanced or
unbalanced will respect to
ground
ECE Board Exam March 1996
What is the velocity factor for non-foam
dielectric 50 or 75 ohms flexible coaxial cable such as RG 8, 11, 58, and 59?
0.66
Board Exam November 1997
Propagation mode of microwave in a waveguide
is known as _____
TE
Board Exam November 1998
A transmission line consisting of two
conductors that have equal resistance per unit length.
Balanced
line
ECE Board Exam November 1966
What is the equivalent output of a circuit
in dBm, if it has an output of 10 Watts?
40
dBm
ECE Board Exam March 1996
Power is always ___________
a
definite amount of energy
the
rate at which energy is used
expressed
in watts
ECE Board Exam November 1998
Which of the following is not a common
transmission line impedance?
A. 50
ohms
B. 120 ohms
C. 75 ohms
D. 650 ohms
ECE Board Exam November 1997
The Width of the frequency band which is
just sufficient to ensure the transmission of information of information at the
rate and with the quality required under a specified condition and class of
emission.
Necessary
bandwidth
ECE Board Exam November 1996
Transmission line must be matched to the
load to
transfer
maximum power to the load
ECE Board Exam November 1996
When electromagnetic waves are propagated
through a waveguide, they
are
reflected from the walls but do not travel along them
ECE Board Exam November 1997
Coaxial lines are used on those system
operating
Below
2 GHz
ECE Board Exaru.November 1996
You are measuring a voice channel at a -4
dB test point level, the meter reads 73 dBm (pure test tone) convert the reading
into dBrnCO.
21
dBrnCO
ECE Board Exam November 1996
1 micron is equal to ___________ meter(s)
10^-6
ECE Board Exam November 1998
Best reason for pressurizing waveguides
with dry air.
To
reduce the possibility of internal arcing
ECE Board Exam November 1997
The outer conductor of a coaxial transmission
line is always.grounded at the
input
and output
ECE Board Exam November 1996
You are measuring noise in a voice
channel at 7 dB test point level. The meter reads -56 dBm (FIA weighted). What
is the reading in dBrnC?
34
dBrnC
ECE Board Exam November 1998
What do you call the phenomenon in
digital circuits that describe the duration of time digital signal passes a
circuit?
Propagation delay