The flashcards below were created by user
on FreezingBlue Flashcards.
Power ratio is a term used to express
what property of an antenna?
A standing-wave ratio (swr) describes
which of the following quantities?
- The amount of mismatch between a
- transmission line and its load
Directivity refers to which of the
following properties of a radiated beam?
Narrowness of the beam
Surface angular measurements for
antenna directivity in radar and
communications systems are made in
relationship to which of the following
Horizontal plane only
Radar range is determined as a function
of which of the following measures?
Pulse travel time
The parabolic reflector is often used
because it produces a radiation pattern
with which of the following antenna
In a lens antenna, what is the purpose of
the collimating lens?
- It forces radial segments of the
- wavefront into parallel paths
A lens antenna which accelerates some
portion of the wavefronts so that all
wavefronts exit the lens at the same timeis referred to as the
In a delay-type lens, the amount of delay
in the phase of the wave passing through
the lens is determined by which of the
The dielectric constant of the lens
What is/are the basic type(s) of antenna
array(s) in common use?
Parasitic and driven
In a frequency-sensitive antenna, the
physical length of the serpentine section
and its relationship to the wavelength of
the applied energy determines which of
the following characteristics?
Direction of the beam
In a horizontal-slot antenna, the
polarization of the energy is radiated in
Modern number systems are built around
which of the following components?
Unit, number, and radix
What term describes a single object in a
modern number system?
What is a number?
A symbol representing a unit or a quantity.
What term describes the number of
symbols used in a number system?
What is the base of a number system
using all the letters of the
alphabet A=0, B=1, C=2, and so forth?
A number system uses the symbols 0
through 4. What is its base?
Using positional notation, what two
factors determine the value of a number?
Symbol and position
The power of a number is indicated by the
What is the value of 5 times 100?
What term describes the symbol that
separates the whole and fractional
numbers in any number system?
What term is defined as a number to be
added to a preceding number?
In subtraction, the (a) is subtracted from
(a) Subtrahend (b) minuend
The result of subtraction is known as the
Which of the following terms accurately describes a synchro?
What are the two general classifications
of synchro systems?
Torque and control
What is the difference in application
between the two classifications of
Light versus heavy load
Which of the following types of synchro
devices provides a mechanical output?
A torque receiver
A 115-volt, 400-Hz torque transmitter
with a diameter of 2.36 inches will have
what military standard designation code?
A 3.5-inch diameter differential receiver
will have what Navy prestandard
What does the arrow on a synchro schematic symbol indicate?
The angular position of the rotor
What are the two major components of a
The rotor and the stator
What type of rotor can be composed of a
single winding or three Y-connected windings?
Drum or wound
How does the stator of a TX receive
By a magnetic coupling with the rotor
What part of a synchro provides a point
for external connections?
The terminal board
Which of the following terms is defined
as the amount of load a machine can
Which of the following units should be
used in measuring the amount of turning
force of a synchro?
An overloaded synchro will probably
exhibit which of the following conditions?
A synchro receiver has which of the following characteristics that is NOT found in an ordinary transformer?
A primary that can rotate in relation to the secondary
Damping is necessary for which of the
following synchro devices?
The primary purpose of damping is to reduce which of the following conditions in a synchro device?
In a simple synchro system, what leads are connected to the source voltage?
S1 and S2
When a synchro transmitter, and receiver are in correspondence, what is the relative value of the (a) current through the stators and (b) receiver torque?
(a) Minimum (b) minimum
What term applies to the angle through which a synchro transmitter rotor is rotated mechanically?
If a synchro receiver is required to rotate in a direction opposite to the rotation of the transmitter rotor, what leads should be reversed?
S1 and S3
If a synchro receiver and transmitter are always 180 degrees out of phase with each other, what leads are reversed?
R1 and R2
What type of synchro can accept two signals simultaneously and add or subtract?
What are the two types of synchro devices that will accept two inputs?
TDR and TDX
What types of synchro devices have (a) one electrical and one mechanical input and an electrical output; and (b) two electrical inputs and a mechanicaloutputs?
(a) TDX (b) TDR
What determines whether a differential synchro device adds or subtracts its inputs?
The way it is connected in the system
In a TDX system, for the TR rotor to follow the TX rotor exactly, in what position must the TDX rotor be kept?
240 degree position
For a TDX system to add its inputs rather than subtract them, what leads must be reversed between (a) the TX and TDX, and (b) the TR and TDX?
(a) S1 and S3 (b) R1 and R3
For a TDR system to add its inputs rather than subtract them, what leads must be reversed at the TDR?
R1 and R3
If a TDR system is connected for addition and the TX rotor connected to the TDR rotor turns counterclockwise, in what direction will the TDR rotor field rotate?
Which of the following types of synchros is used in a system requiring large amounts of power and high accuracy?
What are the three types of control synchros?
CX, CT, CDX
The CX and CDX differ from the TX and TDX because the CX and CDX have which of the following characteristics?
Higher impedance windings
What is NOT a characteristic of the rotor of a control transformer (CT) rotor?
It is connected to an ac source
When a control transformer is at electrical zero, the rotor is perpendicular to what winding?
Which of the following terms applies to the output of a control transformer?
If the output of a control transformer is zero, what is the relationship of the rotors of the control transformer and the control transmitters?
Out of correspondence
Synchro capacitors are used to provide which of the following characteristics in a synchro system?
What synchro devices uses a synchro capacitor?
What type of current is eliminated by synchro capacitors?
To maintain system accuracy, where are synchro capacitors physically placed in a synchro circuit?
Midway between the TX and CT
Synchro systems that transmit data at two
different speeds are referred to by which of the following terms?
Multispeed synchro systems have which
of the following advantages over singlespeed
What does the gear ratio between the two transmitters in a dual-speed synchro system determine?
The speeds of transmission
Which of the following synchro systems, if any, should be used to transmit very large quantities?
Which of the following is a disadvantage of a double receiver as compared to two single receivers?
The entire unit must be replaced if one portion fails
The voltage used to prevent false synchronizations is known by what term?
What is the reference point for the alignment of all synchro units?
What is the most accurate method of aligning a synchro?
The ac voltmeter method
During synchro alignment, what is the purpose of the coarse setting?
To ensure a setting of zero degrees rather than 180 degrees
If a synchro receiver is properly zeroed, when do the stator windings have electrical zero voltages?
When the rotor is at its reference position
When a 115-volt synchro transmitter is
set on its coarse-zero position, approximately what voltage should be read on a voltmeter?
When a 115-volt source is used during the alignment of a differential synchro, what is the maximum time the circuit can be energized without causing damage to the synchro?
After a control transformer has been zeroed and clamped down, what is the final step in the zeroing procedure?
Recheck the zero voltage reading
The output voltage of a control transformer on electrical zero is which of the following relative values?
When a tri-speed synchro system is being zeroed, which synchro should be zeroed first?
What method of zeroing a synchro is the fastest but NOT the most accurate?
The electrical-lock method
The electrical-lock method of zeroing a synchro requires accessible leads and which of the following conditions?
A supply voltage to the stators
A synchro is zeroed by the use of a synchro tester. After it is zeroed, the S1 and S3 leads are shorted together, and the synchro tester dial moves. What does this indicate?
The synchro is not zeroed correctly
If you find that a synchro has bad bearings, which of the following actions should you take?
Replace the synchro
Which of the following troubles is common in newly installed synchro systems?
What type of indicating device is usually installed in the stator circuit of a torque synchro system?
A voltmeter indicator
A synchro system with four receivers is malfunctioning. All of the receivers have incorrect readings. Which of the following is/are the most likely cause(s) of the trouble?
An ac voltmeter is connected between windings S1 and S3 of a synchro transmitter. Which of the following rotor positions should give a zero voltage reading?
When a synchro tester is used in place of a synchro transmitter, which of the following precautions will help to keep the tester from being overloaded?
Use only one syncho receiver