3D153 V1
Cdc 3D153 volume 1 ure
- 1.
What reason for modulation involves modulating low frequency signals for transmission over long distances?
- A.
Spectrum conservation
- B.
Channel allocation
- C.
Ease of radiation
- D.
Companding
Correct Answer
C. Ease of radiation -
- 2.
What are the three general catergories used to produce modulation in radio frequency (RF) transmission today?
- A.
Binary amplitude shift keying, frequency shift keying, and phase shift keying
- B.
Pulse amplitude, pulse width, and pulse postion
- C.
Amplitude, frequency, phase
- D.
Analog, digital, and shift keying
Correct Answer
C. Amplitude, frequency, phase -
- 3.
When the modulating signal and carrier signal are combined within a modulator, the ouput signal contains a/an
- A.
Modulating signal, upper sideband, lower sideband
- B.
Carrier, upper sideband, lower sideband
- C.
Upper sideband and modulating signal
- D.
Carrier and modulating signal
Correct Answer
B. Carrier, upper sideband, lower sideband -
- 4.
If a carrier frequency of 1 MHz and a modulating tone of 10 KHz goes to the modulator, the output signal include
- A.
1.01 MHz, 1MHz, 0.99 MHz
- B.
1.1 MHz, 1 MHz, 0.9 MHz
- C.
1.11 MHz, 1 MHz, 0.99 MHz
- D.
1.111 MHz, 1 MHz, 0.999 MHz
Correct Answer
A. 1.01 MHz, 1MHz, 0.99 MHz -
- 5.
If the modulating audio signal is 10 KHz wide, what is the bandwidth of the transmitted ampiltude modulated signal?
- A.
5 KHz
- B.
10 KHz
- C.
15 KHz
- D.
20 KHz
Correct Answer
D. 20 KHz -
- 6.
The bandwith of an amplitude modulated signal is
- A.
Two times the modulated signal
- B.
The same as the modulated signal
- C.
Determined by the the modulating index
- D.
Defined in terms of maximum amount of modulation
Correct Answer
A. Two times the modulated signal -
- 7.
The amount of effect or change that the intelligence has on the carrier in an amplitude modulated signal is expressed as the
- A.
Percent of modulation
- B.
Modulation index
- C.
Bandwidth
- D.
Deviation
Correct Answer
A. Percent of modulation -
- 8.
Which statement concerning bandwith is true?
- A.
Overmodulating increases bandwith due to the production of harmonics
- B.
Undermodulating increases bandwith due to the production of harmonics
- C.
Overmodulating increases bandwith due to the output's increased amplitude
- D.
Undermodulating increases bandwith due to the output's decreased amplitude
Correct Answer
A. Overmodulating increases bandwith due to the production of harmonics -
- 9.
Reducing modulation to less than 100 percent gives
- A.
More total power
- B.
A reduction in carrier power
- C.
No reduction in carrier power
- D.
A reduction in carrier and sideband power
Correct Answer
C. No reduction in carrier power -
- 10.
In frequency modulation (FM), the amount of oscillator frequency change is
- A.
Inversely proportional to the amplitude of the modulating signal
- B.
Directly proportional to the amplitude of the modulating signal
- C.
Inversely proportional to the phase of the modulating signal
- D.
Directly proportional to the phase of the modulating signal
Correct Answer
B. Directly proportional to the amplitude of the modulating signal -
- 11.
In frequency modulation (FM), what is considered a significant sideband?
- A.
Sidebands containing at least 1 percent of the total transmitted power
- B.
Sidebands containing at least 3 percent of the total transmitted power
- C.
Sidebands containing at least 10 percent of the total transmitted power
- D.
Sidebands containing at least 0.1 percent of the total transmitted power
Correct Answer
A. Sidebands containing at least 1 percent of the total transmitted power -
- 12.
What is the formula to find the modulating index?
- A.
Deviation divided by frequency of modulation
- B.
Deviation times frequency of modulation
- C.
Sideband divide by carrier frequency
- D.
Sideband times carrier frequency
Correct Answer
A. Deviation divided by frequency of modulation -
- 13.
In phase modulation (PM), the carrier's
- A.
Phase is shifted at the rate of the modulating signal
- B.
Phase is shifted with the phase of the modulating signal
- C.
Amplitude is shifted at the rate of the modulating signal
- D.
Amplitude is shifted with the phase of the modulating signal
Correct Answer
A. Phase is shifted at the rate of the modulating signal -
- 14.
What is the advantage of adding more phase shifts?
- A.
Easier detection
- B.
Smaller bit error rate
- C.
Better signal-to-noise ratio
- D.
Higher data rates within a given bandwith
Correct Answer
D. Higher data rates within a given bandwith -
- 15.
What is the first step in pulse code modulation (PCM) process?
- A.
Discrete amplitudes are assigned to the sampling pulses
- B.
A binary code number is assigned to the sample
- C.
The quantizer limits the amplitude of the pulses
- D.
The analog signal is band-limited
Correct Answer
D. The analog signal is band-limited -
- 16.
What part of the pulse code modulation (PCM) process converts a continuous time signal into a discrete time signal?
- A.
Sampling
- B.
Rectifying
- C.
Oscillating
- D.
Band limiting
Correct Answer
A. Sampling -
- 17.
A type of pulse modulation (PM) that changes the amplitude of the pulse train to vary according to the amplitude of the input signal is called
- A.
Pulse width modulation (PWM)
- B.
Pulse postion modulation
- C.
Pulse duration modulaton
- D.
Pulse amplitude modulation
Correct Answer
D. Pulse amplitude modulation -
- 18.
If an error should occur, what data transmission is lost in a synchronous transmission?
- A.
One character
- B.
Block of data
- C.
A parity bit
- D.
Sychronization (SYNC) bit
Correct Answer
B. Block of data -
- 19.
When using vertical redundancy check (VRC), what significance does the amount of ones have in a data bit pattern?
- A.
Determines parity
- B.
Determines transmission rate
- C.
Determines whether transmission is in American Stadard code for Information Interchange (ASCII) format
- D.
Determines whether transmission is sychronous or asynchronous
Correct Answer
A. Determines parity -
- 20.
What two error dectection methods, when used together, are 98 percent effective in detecting errors?
- A.
Checksum and cyclic redundancy check
- B.
Longitundinal redundancy check and checksum
- C.
Cyclic redundancy chack and vertical redundancy check
- D.
Vertical redundancy check and longitundinal redundancy check
Correct Answer
D. Vertical redundancy check and longitundinal redundancy check -
- 21.
What error detection method adds stacked characters, divides it by 255, and disregards the answer except for the remainder?
- A.
Checksum
- B.
Block check character
- C.
Cyclic redundancy check
- D.
Vertical redundancy check
Correct Answer
A. Checksum -
- 22.
What error-correction technique send a retransmittal request by the reciever to the sender if it finds an error in a recieved frame?
- A.
Error-correcting code
- B.
Forward error control
- C.
Redundant data transfer
- D.
Automatic retransmit on request
Correct Answer
D. Automatic retransmit on request -
- 23.
When using forward error control as a method of error correction, where does error correction take place?
- A.
Recieving end
- B.
In the oscillator
- C.
Transmitting end
- D.
In the primary buffers
Correct Answer
A. Recieving end -
- 24.
What does an optical source do?
- A.
Terminates fiber optics cable
- B.
Converts electrical energy into optical energy
- C.
Extends the distance and to preserve signal integrity
- D.
Accepts optical signals and converts them into electrical signals
Correct Answer
B. Converts electrical energy into optical energy -
- 25.
Light sources that are applicable to fiber optic waveguide are light-emitting diodes (LED) and
- A.
Photo transistors
- B.
Hybrid photodiodes
- C.
Semiconductor laser diodes
- D.
Integrated photodiode preamplifiers
Correct Answer
C. Semiconductor laser diodes -
- 26.
What type of light is emitted form a laser?
- A.
Incoherent
- B.
Coherent
- C.
Ordinary
- D.
Invisible
Correct Answer
B. Coherent -
- 27.
Laser diode power coupling is measured in which range
- A.
Megawatt
- B.
Microwatt
- C.
Milliwatt
- D.
Kilowatt
Correct Answer
C. Milliwatt -
- 28.
A device that accepts optical signals from an optical fiber and converts them into electical signals is called an optical
- A.
Regenerator
- B.
Transmitter
- C.
Amplifier
- D.
Receiver
Correct Answer
D. Receiver -
- 29.
Small current that flows from a photdiode even with no light is called
- A.
Dark current
- B.
Dispersion
- C.
Distortion
- D.
Ionization
Correct Answer
A. Dark current -
- 30.
The responsivityof a photo dector is dependent on the
- A.
Emitter rise time
- B.
Wavelength of light
- C.
Signal-to-noise ratio (SNR)
- D.
Emitter modulation speed
Correct Answer
B. Wavelength of light -
- 31.
What are two main types of photodectors?
- A.
Positive intrinsic negative and avalanche photodiode
- B.
Light-emitting diode (LED) and avalanche photodiode
- C.
LED and semiconductor diodes
- D.
Tunnel and zener diodes
Correct Answer
A. Positive intrinsic negative and avalanche photodiode -
- 32.
What photo detector converts one photon to one electron?
- A.
Light emitting diode (LED)
- B.
Avalanche photodiode
- C.
Positive intrinsic negative (PIN) diode
- D.
Intergrated photodiode/preamplifier (IDP)
Correct Answer
C. Positive intrinsic negative (PIN) diode -
- 33.
What is used to extend the distance of a fiber optic communication systems link?
- A.
Receiver
- B.
Transmitter
- C.
Repeater
- D.
Patch cords
Correct Answer
C. Repeater -
- 34.
Which repeater amplifies optical signals without converting to and from the electrical domain?
- A.
Repeaters
- B.
Regenerators
- C.
Optical amplifiers
- D.
Receiver
Correct Answer
C. Optical amplifiers -
- 35.
Short sections of a single fiber cables that has a connector at each end is called a
- A.
Pigtail
- B.
Patch cord
- C.
Jumper
- D.
Breakout cables
Correct Answer
B. Patch cord -
- 36.
Which fiber-optic connector uses a quick-release, keyed bayonet couplings that are preferred in situations where severe vibrations are not expected?
- A.
Biconic
- B.
Field connector (FC)
- C.
Straight tip (ST)
- D.
Sub-miniature, type A (SMA)
Correct Answer
C. Straight tip (ST) -
- 37.
Which fiber optic connector uses a push-pull engagement for mating?
- A.
Biconic
- B.
Field (FC)
- C.
Subscriber (SC)
- D.
Sub-miniature, type A (SMA)
Correct Answer
C. Subscriber (SC) -
- 38.
What initial nuclear radiation elements generate electromagnetic pulses?
- A.
Gamma rays and neutrons
- B.
Thermally generated x-rays
- C.
Transient radiation effects on elctronics
- D.
Neutrons and thermally generated x-rays
Correct Answer
A. Gamma rays and neutrons -
- 39.
High-altitude electromagnetic pulse is what type of frequency phenomenon, and involves which frequency range?
- A.
Secondary; 1 hertz to 1 gigahertz
- B.
Wideband; 1 hertz to 1 gigahertz
- C.
Secondary; 10 hertz to 10 gigahertz
- D.
Wideband; 10 hertz to 10 gigahertz
Correct Answer
B. Wideband; 1 hertz to 1 gigahertz -
- 40.
A system-generated pulse is a problem for satellites and reentry vehicles that are
- A.
Susceptible to the wideband frequency phenomenon
- B.
Directly exposed to nuclear radiations from a high-altitude burst
- C.
Affected by the azimuthal magnetic fields and time-varying air conductivity
- D.
Influenced by the signal fading or waveform distortion caused by the structured plasma field
Correct Answer
B. Directly exposed to nuclear radiations from a high-altitude burst -
- 41.
Which distinct region of the source region electromagnetic pulse is produced by the interactions between the weaon products and the earth's atmosphere?
- A.
Secondary
- B.
Radiated
- C.
Plasma
- D.
Source
Correct Answer
D. Source -
- 42.
what electromagnetic pulse region is the principal threat to electronics systems by cable?
- A.
Local
- B.
Source
- C.
Radiated
- D.
Long-line
Correct Answer
C. Radiated -
- 43.
How does scintillation effect communications?
- A.
Large attenuation of the transmitted signal causing the recieved signal-to-noise ratio (SNR) to fall below unity
- B.
Transmitted signal fading caused by multiple path propagation throught the structured plasma field
- C.
Layers of charged electrons are trapped and prevent tranmissions throught the layer
- D.
Absorption of the transmitted signal through the contaminated area
Correct Answer
B. Transmitted signal fading caused by multiple path propagation throught the structured plasma field -
- 44.
Atmospheric disturbances from initial nuclear radiation on higher frequencies affect communications by which types of effects?
- A.
Blackout
- B.
Absorption
- C.
Scintillation
- D.
Attenuation
Correct Answer
C. Scintillation -
- 45.
Which one of the following statements are true concerning shielding?
- A.
Cables should be of unshielded construction
- B.
Only ventilation ports are shielded along the walls
- C.
Sensitive equipment will be located within the shielded barrier
- D.
All power lines supplying the shielded areas does not require filters
Correct Answer
C. Sensitive equipment will be located within the shielded barrier -
- 46.
What is the purpose of bonding?
- A.
To isolate facility from any external electrical electromagnetic propagation
- B.
To reduce interference coupling around circuits and around interconnecting lines
- C.
To ensure a mechanically strong, low impedance interconnection between metal objects
- D.
To eliminate harmful differences of potential between the various telephone cables entering facility
Correct Answer
C. To ensure a mechanically strong, low impedance interconnection between metal objects -
- 47.
What types of filters are always used in combination with surge arresters?
- A.
Linear
- B.
Alternating current (AC) line
- C.
Direct current (DC) line
- D.
Power line
Correct Answer
A. Linear -
- 48.
If the interference can be eliminated by disconnecting the recieving antenna, the source of the disturbance is most likely
- A.
Line noise
- B.
Internal to the raadio
- C.
External to the radio
- D.
Radio reciever trouble
Correct Answer
C. External to the radio -
- 49.
What is an example of intentionally induced electromagnetic interference (EMI)?
- A.
Jamming
- B.
Spurious responses
- C.
Intermodulation
- D.
Power line noise
Correct Answer
A. Jamming -
- 50.
What type of electromagnetic interference (EMI) occurs when a reciever responds to off-frequency signals?
- A.
Rusty bolt
- B.
Co-channel
- C.
Brute force
- D.
Spurious rsponses
Correct Answer
D. Spurious rsponses -
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Current Version
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Jan 29, 2013Quiz Edited by
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Aug 18, 2011Quiz Created by
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