AMS 380 UNIT 2 EXAM QUESTIONS
AND ANSWERS ALL CORRECT
What are the principal frequencies that appear at the output of a mixer circuit? A. Two
and four times the original frequency.
B. The sum, difference and square root of the input frequencies.
C. The original frequencies and the sum and difference frequencies.
D. 1.414 and 0.707 times the input frequency. - Answer- C. The original frequencies and
the sum and difference frequencies.
If a receiver mixes a 13.8 MHz VFO with a 14.255 MHz receive signal to produce a 455
kHz intermediate frequency signal, what type of interference will a 13.345 MHz signal
produce in the receiver?
A. Local oscillator interference.
B. An image response.
C. Mixer interference.
D. Intermediate frequency interference. - Answer- B. An image response.
What might occur in a receiver if excessive amounts of signal energy overdrive the
mixer circuit?
A. Automatic limiting occurs.
B. Mixer blanking occurs.
C. Spurious mixer products are generated.
D. The mixer circuit becomes unstable and drifts - Answer- C. Spurious mixer products
are generated.
What degree of selectivity is desirable in the IF circuitry of a wideband FM phone
receiver?
A. 1 kHz.
B. 2.4 kHz.
C. 4.2 kHz.
D. 15 kHz. - Answer- D. 15 kHz.
Which one of these filters can be used in micro-miniature electronic circuits?
A. High power transmitter cavity.
B. Receiver SAW IF filter.
C. Floppy disk controller.
D. Internet DSL to telephone line filter. - Answer- B. Receiver SAW IF filter.
A receiver selectivity of 2.4 kHz in the IF circuitry is optimum for what type of signals?
,A. CW.
B. Double-sideband AM voice.
C. SSB voice.
D. FSK RTTY. - Answer- C. SSB voice.
To couple energy into and out of a waveguide use:
A. Wide copper sheeting.
B. A thin piece of wire as an antenna.
C. An LC circuit.
D. Capacitive coupling. - Answer- D. Capacitive coupling.
The permanent magnetic field that surrounds a traveling-wave tube (TWT) is intended
to:
A. Provide a means of coupling.
B. Prevent the electron beam from spreading.
C. Prevent oscillations.
D. Prevent spurious oscillations. - Answer- B. Prevent the electron beam from
spreading.
Prior to testing any RADAR system, the operator should first:
A. Check the system grounds.
B. Assure the display unit is operating normally.
C. Inform the airport control tower or ship's master.
D. Assure no personnel are in front of the antenna. - Answer- D. Assure no personnel
are in front of the antenna.
In the term "ARPA RADAR," ARPA is the acronym for which of the following?
A. Automatic RADAR Plotting Aid.
B. Automatic RADAR Positioning Angle.
C. American RADAR Programmers Association.
D. Authorized RADAR Programmer and Administrator. - Answer- D. Authorized RADAR
Programmer and Administrator.
Which of the following is NOT a precaution that should be taken to ensure the
magnetron is not weakened:
A. Keep metal tools away from the magnet.
B. Do not subject it to excessive heat.
C. Keep the TR properly tuned.
D. Do not subject it to shocks and blows. - Answer- A. Keep metal tools away from the
magnet.
Exposure to microwave energy from RADAR or other electronics devices is limited by
U.S. Health Department regulations to _______ mW/centimeter.
A. 0.005
B. 5.0
C. 0.05
, D. 0.5 - Answer- B. 5.0
What frequency synthesizer circuit uses a phase comparator, look-up table, digital-to-
analog converter, and a low-pass antialias filter?
A. A direct digital synthesizer.
B. Phase-locked-loop synthesizer.
C. A diode-switching matrix synthesizer.
D. A hybrid synthesizer. - Answer- A direct digital synthesizer.
A circuit that compares the output of a voltage-controlled oscillator (VCO) to a frequency
standard and produces an error voltage that is then used to adjust the capacitance of a
varactor diode used to control frequency in that same VCO is called what?
A. Doubly balanced mixer.
B. Phase-locked loop.
C. Differential voltage amplifier.
D. Variable frequency oscillator. - Answer- Phase-locked loop.
3 RF input to a mixer is 200 MHz and the local oscillator frequency is 150 MHz. What
output would you expect to see at the IF output prior to any filtering?
A. 50, 150, 200 and 350 MHz.
B. 50 MHz.
C. 350 MHz.
D. 50 and 350 MHz - Answer- 50, 150, 200 and 350 MHz.
What happens to the beamwidth of an antenna as the gain is increased? The
beamwidth:
A. Increases geometrically as the gain is increased.
B. Increases arithmetically as the gain is increased.
C. Is essentially unaffected by the gain of the antenna.
D. Decreases as the gain is increased. - Answer- D. Decreases as the gain is
increased.
A common shipboard RADAR antenna is the:
A. Slotted array.
B. Dipole.
C. Stacked Yagi.
D. Vertical Marconi. - Answer- A. Slotted array.
Conductance takes place in a waveguide:
A. By interelectron delay.
B. Through electrostatic field reluctance.
C. In the same manner as a transmission line.
D. Through electromagnetic and electrostatic fields in the walls of the waveguide. -
Answer- D. Through electromagnetic and electrostatic fields in the walls of the
waveguide.
AND ANSWERS ALL CORRECT
What are the principal frequencies that appear at the output of a mixer circuit? A. Two
and four times the original frequency.
B. The sum, difference and square root of the input frequencies.
C. The original frequencies and the sum and difference frequencies.
D. 1.414 and 0.707 times the input frequency. - Answer- C. The original frequencies and
the sum and difference frequencies.
If a receiver mixes a 13.8 MHz VFO with a 14.255 MHz receive signal to produce a 455
kHz intermediate frequency signal, what type of interference will a 13.345 MHz signal
produce in the receiver?
A. Local oscillator interference.
B. An image response.
C. Mixer interference.
D. Intermediate frequency interference. - Answer- B. An image response.
What might occur in a receiver if excessive amounts of signal energy overdrive the
mixer circuit?
A. Automatic limiting occurs.
B. Mixer blanking occurs.
C. Spurious mixer products are generated.
D. The mixer circuit becomes unstable and drifts - Answer- C. Spurious mixer products
are generated.
What degree of selectivity is desirable in the IF circuitry of a wideband FM phone
receiver?
A. 1 kHz.
B. 2.4 kHz.
C. 4.2 kHz.
D. 15 kHz. - Answer- D. 15 kHz.
Which one of these filters can be used in micro-miniature electronic circuits?
A. High power transmitter cavity.
B. Receiver SAW IF filter.
C. Floppy disk controller.
D. Internet DSL to telephone line filter. - Answer- B. Receiver SAW IF filter.
A receiver selectivity of 2.4 kHz in the IF circuitry is optimum for what type of signals?
,A. CW.
B. Double-sideband AM voice.
C. SSB voice.
D. FSK RTTY. - Answer- C. SSB voice.
To couple energy into and out of a waveguide use:
A. Wide copper sheeting.
B. A thin piece of wire as an antenna.
C. An LC circuit.
D. Capacitive coupling. - Answer- D. Capacitive coupling.
The permanent magnetic field that surrounds a traveling-wave tube (TWT) is intended
to:
A. Provide a means of coupling.
B. Prevent the electron beam from spreading.
C. Prevent oscillations.
D. Prevent spurious oscillations. - Answer- B. Prevent the electron beam from
spreading.
Prior to testing any RADAR system, the operator should first:
A. Check the system grounds.
B. Assure the display unit is operating normally.
C. Inform the airport control tower or ship's master.
D. Assure no personnel are in front of the antenna. - Answer- D. Assure no personnel
are in front of the antenna.
In the term "ARPA RADAR," ARPA is the acronym for which of the following?
A. Automatic RADAR Plotting Aid.
B. Automatic RADAR Positioning Angle.
C. American RADAR Programmers Association.
D. Authorized RADAR Programmer and Administrator. - Answer- D. Authorized RADAR
Programmer and Administrator.
Which of the following is NOT a precaution that should be taken to ensure the
magnetron is not weakened:
A. Keep metal tools away from the magnet.
B. Do not subject it to excessive heat.
C. Keep the TR properly tuned.
D. Do not subject it to shocks and blows. - Answer- A. Keep metal tools away from the
magnet.
Exposure to microwave energy from RADAR or other electronics devices is limited by
U.S. Health Department regulations to _______ mW/centimeter.
A. 0.005
B. 5.0
C. 0.05
, D. 0.5 - Answer- B. 5.0
What frequency synthesizer circuit uses a phase comparator, look-up table, digital-to-
analog converter, and a low-pass antialias filter?
A. A direct digital synthesizer.
B. Phase-locked-loop synthesizer.
C. A diode-switching matrix synthesizer.
D. A hybrid synthesizer. - Answer- A direct digital synthesizer.
A circuit that compares the output of a voltage-controlled oscillator (VCO) to a frequency
standard and produces an error voltage that is then used to adjust the capacitance of a
varactor diode used to control frequency in that same VCO is called what?
A. Doubly balanced mixer.
B. Phase-locked loop.
C. Differential voltage amplifier.
D. Variable frequency oscillator. - Answer- Phase-locked loop.
3 RF input to a mixer is 200 MHz and the local oscillator frequency is 150 MHz. What
output would you expect to see at the IF output prior to any filtering?
A. 50, 150, 200 and 350 MHz.
B. 50 MHz.
C. 350 MHz.
D. 50 and 350 MHz - Answer- 50, 150, 200 and 350 MHz.
What happens to the beamwidth of an antenna as the gain is increased? The
beamwidth:
A. Increases geometrically as the gain is increased.
B. Increases arithmetically as the gain is increased.
C. Is essentially unaffected by the gain of the antenna.
D. Decreases as the gain is increased. - Answer- D. Decreases as the gain is
increased.
A common shipboard RADAR antenna is the:
A. Slotted array.
B. Dipole.
C. Stacked Yagi.
D. Vertical Marconi. - Answer- A. Slotted array.
Conductance takes place in a waveguide:
A. By interelectron delay.
B. Through electrostatic field reluctance.
C. In the same manner as a transmission line.
D. Through electromagnetic and electrostatic fields in the walls of the waveguide. -
Answer- D. Through electromagnetic and electrostatic fields in the walls of the
waveguide.
