3d152v1

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3d152v1

Volume 1 UREs - Randomized Questions & Answers


Questions and Answers
  • 1. 
    What is an example of analog-to-digital and didgital-to-analog techniques?
    • A. 

      Amplitude modulation (AM) and frequency modulation (FM)

    • B. 

      Pulse code modulation (PCM) and frequency shift keying (FSK)

    • C. 

      Phase modulation (PM) and quadrature phase shift keying (QPSK)

    • D. 

      Pulse code modulation (PCM) and continuously variable slope delta (CVSD) modulation

  • 2. 
    What converts analog signal information into an analog carrier signal?
    • A. 

      Delta modulation (DM)

    • B. 

      Digital modulation

    • C. 

      Analog modulation

    • D. 

      Adaptive modulation

  • 3. 
    What converts analog signal information into a digital carrier signal?
    • A. 

      Delta modulation (DM)

    • B. 

      Analog modulation

    • C. 

      Digital modulation

    • D. 

      Adaptive modulation

  • 4. 
    The information-carrying components that occur on either side of a carrier are called
    • A. 

      Sidebands

    • B. 

      Sine waves

    • C. 

      Frequency translators

    • D. 

      Modulating frequencies

  • 5. 
    Amplitude modulation (AM) requires a bandwidth that is
    • A. 

      Twice that of the modulating signal

    • B. 

      Half that of the modulating signal

    • C. 

      Twice that of the carrier signal

    • D. 

      Half that of the carrier signal

  • 6. 
    The upper sideband in a signal-sideband supppressed carrier (SSBSC) modulating is eliminated by
    • A. 

      Filtering

    • B. 

      Detection

    • C. 

      Compression

    • D. 

      Companding

  • 7. 
    We can express the 6-to-1 improvement of the single-sideband suppressed carrier (SSBSC) modulation over conventional amplitude modulation (AM) as
    • A. 

      2 decibels (dB) of improvement

    • B. 

      4 dB of improvement

    • C. 

      6 dB of improvement

    • D. 

      8 dB of improvement

  • 8. 
    The only basic waveform in nature is a
    • A. 

      Carrier wave

    • B. 

      Pure sine wave

    • C. 

      Resultant wave

    • D. 

      Composite wave

  • 9. 
    A modulated waveform that contains a carrier plus two sidebands for each modulation frequency is a description of
    • A. 

      A phase modulation (PM)

    • B. 

      A pulse modulation

    • C. 

      A frequency modulation (FM)

    • D. 

      An amplitude modulation (AM)

  • 10. 
    If 100 percent modulation is exceeded and there is distortion in the modulating signal, additional sidebands are generated. We identify these sidebands as what?
    • A. 

      Transmitted intelelligence

    • B. 

      Intensity of speech

    • C. 

      Composite waves

    • D. 

      Splatter

  • 11. 
    The amount of deviation in a frequency modulation (FM) signal is directly proportional to the modulating signal's
    • A. 

      Phase

    • B. 

      Amplitude

    • C. 

      Frequency

    • D. 

      Amplitude and frequency

  • 12. 
    The amount of phase shift in a phase modulation (PM) signal is directly proportional to the
    • A. 

      Modulation index

    • B. 

      Rate of phase shift

    • C. 

      Frequency of the modulating signal

    • D. 

      Amplitude of the modulating signal

  • 13. 
    What form of modulation is insensitive to signal variations?
    • A. 

      Delta

    • B. 

      Frequency shift keying (FSK)

    • C. 

      Pulse-amplitude modulation (PAM)

    • D. 

      Binary-phase shift keying or bi-phase shift keying (BPSK)

  • 14. 
    In quadrature-phase shift keying (QPSK) the radio frequency (RF) bandwidth for a quadriphase signal is what of that required by a bi-phase signal, given the same data rate.
    • A. 

      Four times

    • B. 

      Double

    • C. 

      Half

    • D. 

      The same

  • 15. 
    What is the main advantage of differential phase shift keying (DPSK)?
    • A. 

      Carrier presence is required to detect changes

    • B. 

      It requires a less complex receiver than a basic phase shift keying(PSK) signal

    • C. 

      It requires a more complex receiver than a basic PSK signal

    • D. 

      The demodulator needs to detect changes in absolute phase values

  • 16. 
    Which of the following is not considered an analog modulation tehniques?
    • A. 

      Pulse-amplitude modulation (PAM)

    • B. 

      Pulse-duration modulation (PDM)

    • C. 

      Pulse-position modulation (PPM)

    • D. 

      Pulse-code modulation (PCM)

  • 17. 
    The form of pulse modulation in which the pulse is varied within a set range of positions is known as
    • A. 

      Pulse-amplitude modulation (PAM)

    • B. 

      Pulse-duration modulation (PDM)

    • C. 

      Pulse-position modulation (PPM)

    • D. 

      Pulse-code modulation (PCM)

  • 18. 
    Quantized analog modulation is actually
    • A. 

      Pulse-amplitude modulation (PAM)

    • B. 

      Pulse-duration modulation (PDM)

    • C. 

      Less tolerant of noise than frequency modulation (FM)

    • D. 

      Analog-to-digital conversion

  • 19. 
    How many bits per character of a 16-step pulse-code modulation (PCM) system are used to describe the quantized analog sample?
    • A. 

      3

    • B. 

      4

    • C. 

      5

    • D. 

      8

  • 20. 
    The process of coding pulse code modulation (PCM) quantized pulses to make them a constant duration and amplitude is
    • A. 

      Encoding

    • B. 

      Companding

    • C. 

      Uniform quantizing

    • D. 

      Nonuniform quantizing

  • 21. 
    In Time Division Multiplexing (TDM), the transmitting multiplexer will put a bit or a byte from each of the incoming lines into a specifically allocated what?
    • A. 

      Channel

    • B. 

      Trunk

    • C. 

      Time slot

    • D. 

      Port

  • 22. 
    The two major types of frame structures are
    • A. 

      Low speed and high speed

    • B. 

      High speed and EBCDIC

    • C. 

      CCITT and low speed

    • D. 

      EBCDIC and CCITT

  • 23. 
    The method of multiplexing the T1 multiplexer uses is
    • A. 

      Frequency division

    • B. 

      Binary division

    • C. 

      Pulse division

    • D. 

      Time division

  • 24. 
    Wave-division multiplexing (WDM) creates the virutal channels for multiplexing them together for transmission by using different
    • A. 

      Wavelengths or lambdas

    • B. 

      Wavelengths or gammas

    • C. 

      Frequencies or lambdas

    • D. 

      Frequencies or gammas

  • 25. 
    The most common wave-division multiplexing (WDM) system uses how many wavelengths?
    • A. 

      One wavelength

    • B. 

      Two wavelengths

    • C. 

      Three wavelengths

    • D. 

      Four wavelengths

  • 26. 
    Individual pulses within a digital signal are
    • A. 

      Bits

    • B. 

      Bytes

    • C. 

      Codes

    • D. 

      Blocks

  • 27. 
    What unit is most commonly used in data systems to express signaling speed?
    • A. 

      Baud

    • B. 

      Baudot

    • C. 

      Sense interface

    • D. 

      Bits per second

  • 28. 
    Bit count integrity problems are primarily caused by
    • A. 

      Impedance mismatch

    • B. 

      System timing faults

    • C. 

      Improper equipment settings

    • D. 

      Changes in atmospheric conditions

  • 29. 
    Three catagories of synchronization used in digital data circuits are
    • A. 

      Synchronous, asynchronous, and isochronous

    • B. 

      Isochronous, asynchronous, and bisynchronous

    • C. 

      Nonsynchronous, bisynchronous, and synchronous

    • D. 

      Asynchronous, bisynchronous, and nonsynchronous

  • 30. 
    Which option is a characteristic of synchronous data operation?
    • A. 

      Timing pulses are transmitted within the signal stream

    • B. 

      Start and stop pulses control data transmission

    • C. 

      System timing is not of critical importance

    • D. 

      All data bits are the same length in time

  • 31. 
    A digital signal that contains sychronizing bits within the signal stream describes
    • A. 

      Synchronous operation

    • B. 

      Asynchronous operation

    • C. 

      Synchronous and/or isochronous operation

    • D. 

      Asynchronous and/or synchronous operation

  • 32. 
    In what type of signal is the information contained in the transition, and there is a transition from one state to the other only when a mark bit is sent?
    • A. 

      Non-return-to-zero (NRZ) level

    • B. 

      Non-return-to-zero mark

    • C. 

      Non-return-to-zero space

    • D. 

      Return-to-zero level

  • 33. 
    In what type of signal does the signal level move to one of the discrete signal levels, but returns to the zero level after a predetermined time?
    • A. 

      Non-return-to-zero (NRZ) level

    • B. 

      Non-return-to-zero mark

    • C. 

      Non-return-to-zero space

    • D. 

      Return-to-zero

  • 34. 
    Which statement best describes an alternate mark inversion (AMI) signal?
    • A. 

      The information is transmitted in three different voltage levels

    • B. 

      A logic one is transmitted as positive voltage if the previous logic one was negative

    • C. 

      The level always returns to zero for 50 percent of the bit cycle after every transition

    • D. 

      Bipolar violations are intentionally inserted into a data signal to break up long strings of zeros

  • 35. 
    Digital coding techniques such as binary with eight-zero substitution (B8ZS) are becoming more popular because they are designed to
    • A. 

      Provide error-free signaling

    • B. 

      Operate at higher data rates

    • C. 

      Eliminate bipolar violations

    • D. 

      Maintain ones density standards

  • 36. 
    Which statement best describes a binary with eight-zero substitution (B8ZS) signal?
    • A. 

      The information is transmitted in three different voltage levels

    • B. 

      A logic one is transmitted as positive voltage if the previous logic one was negative

    • C. 

      The level always returns to zero for 50 percent of the bit cycle after every transition

    • D. 

      Bipolar violations are intentionally inserted into a data signal to break up long strings of zeros

  • 37. 
    The major difference between conditioned di-phase (CDI) and other schemes is the
    • A. 

      Lack of mid-bit transitions

    • B. 

      Use of mid-bit transitions for timing

    • C. 

      Data being encoded in the mid-bit transitions

    • D. 

      Voltage levels used for signaling the mid-bid transitions

  • 38. 
    How many bits are in the D4 framing sequence?
    • A. 

      8

    • B. 

      12

    • C. 

      24

    • D. 

      48

  • 39. 
    How many bits are in the extended superframe format (ESF) framing sequence?
    • A. 

      8

    • B. 

      12

    • C. 

      24

    • D. 

      48

  • 40. 
    What communications control signal uses a two-frequency dialing combination?
    • A. 

      Pulse dialing

    • B. 

      Tone dialing

    • C. 

      Digit dialing

    • D. 

      Address dialing

  • 41. 
    What communications information signal uses a continuous 350- and 440-Hz frequency pair?
    • A. 

      Dial tone

    • B. 

      Ringback signal

    • C. 

      Off-hook alert

    • D. 

      Call waiting

  • 42. 
    What communications information signal uses a signal cycled on and off for 0.5 second and contains the generation of a 480- and 620-Hz frequency pair?
    • A. 

      Dial tone

    • B. 

      Busy signal

    • C. 

      Off-hook alert

    • D. 

      Call waiting

  • 43. 
    What communications supervisory signal uses a continuous application of direct current voltage for signaling?
    • A. 

      Record warning

    • B. 

      Fast busy signal

    • C. 

      Loop-start

    • D. 

      E and M

  • 44. 
    When is the voltage applied in loop-start signaling?
    • A. 

      When dial tone is present

    • B. 

      On-hook condition

    • C. 

      Off-hook condition

    • D. 

      During the ringback signal

  • 45. 
    In common associated signaling (CAS), what is the seventh bit in frames 6 and 12 used to convey signaling information known as?
    • A. 

      Bit robbing

    • B. 

      Bit stuffing

    • C. 

      Frame correction

    • D. 

      Frame enhancement

  • 46. 
    In what common channel signaling (CCS) mode are the messages relating to signaling between two points conveyed directly interconnecting these signaling points?
    • A. 

      Associated mode

    • B. 

      Nonassociated mode

    • C. 

      Quasi-associated mode

    • D. 

      Multi-associated mode

  • 47. 
    What are the two principle weighting characteristics in use with telecommunication circuit noise?
    • A. 

      Institute of Electronic and Electrical Engineers and CCITT psophometric

    • B. 

      Noise analysis and CCITT psophometric

    • C. 

      CCITT psophometric and C-message

    • D. 

      C-message and noise analysis

  • 48. 
    While timing makes sure the equipment is sending and receiving bits at the same time intervals, synchronization makes sure that the
    • A. 

      Receive equipment timing is set properly

    • B. 

      Transmit equipment timing is set properly

    • C. 

      Receive equipment can find its own place in the bit stream

    • D. 

      Transmit equipment can find its place in the bit stream

  • 49. 
    What term is associated with the delay or lag introduced in the application of voltage from one section to the next?
    • A. 

      Latency

    • B. 

      Phase delay

    • C. 

      Propagation constant

    • D. 

      Phase delay distortion

  • 50. 
    Attenuation distortion is caused by
    • A. 

      A line loss for various frequency components comprising a voice transmission

    • B. 

      The line loss, the distance of transmission lines, and faults in the transmission cables

    • C. 

      Faults in the transmission cables and the number of splices in the line varying with the frequency

    • D. 

      Differing attenuation rates for the various frequency components comprising a voice frequency transmission

  • 51. 
    Jamming a portion of the frequency spectrum is an example of
    • A. 

      Electronic combat

    • B. 

      Electronic protection

    • C. 

      Electronic attack

    • D. 

      Electronic warfare support

  • 52. 
    The definition of electronic attack can be found in which publication?
    • A. 

      Air Force Doctrine Document 2-5.1

    • B. 

      Air Force Instruction 10-101

    • C. 

      Air Force Policy Memorandum 2-1

    • D. 

      Air Force Manual 2-5.1

  • 53. 
    Any actions we take to protect our forces, facilities, and equipment for electronic action that can destroy or degrade our capabilities is considered
    • A. 

      Electronic combat

    • B. 

      Electronic protection

    • C. 

      Electronic attack

    • D. 

      Electronic warfare support

  • 54. 
    Varying the pulse repetition frequency on a radar set is an example of
    • A. 

      Electronic combat

    • B. 

      Electronic attack

    • C. 

      Electronic protection

    • D. 

      Electronic warfare support

  • 55. 
    Electronic warfare support includes devices such as
    • A. 

      Anti-radiation missles and directed energy weapons

    • B. 

      Intelligence platforms and noise jamming systems

    • C. 

      Radar warning receivers and intelligence systems

    • D. 

      Directed energy weapons and radar warning receivers

  • 56. 
    When a multimeter has three input terminal jacks, which jack is always used?
    • A. 

      Voltage terminal

    • B. 

      Common terminal

    • C. 

      Voltage and current terminal

    • D. 

      Common and current terminal

  • 57. 
    When using a multimeter, which mode should be used if the reading is unreadable due to fluctuations?
    • A. 

      Range

    • B. 

      Frequency

    • C. 

      Display hold

    • D. 

      Minimum/maximum (MIN/MAX)

  • 58. 
    When using a multimeter, which mode should be used if the reading fluctuates and a more accurate reading is desired?
    • A. 

      Minimum/maximum (MIN/MAX)

    • B. 

      Display hold

    • C. 

      Frequency

    • D. 

      Range

  • 59. 
    When using an ohmmeter to take a resistance reading, what preliminary precaution should you take?
    • A. 

      Properly seat the test lead into the current input terminal jack

    • B. 

      Disconnect the power from the circuit being tested

    • C. 

      Place the meter in the frequency mode

    • D. 

      Set the range for maximum reading

  • 60. 
    What principle of operation does the time domain reflectometer use to test cables?
    • A. 

      Amplitude

    • B. 

      Frequency

    • C. 

      Audio

    • D. 

      Radar

  • 61. 
    Which push-buttons would you select to get 125-ohm (Ω) impedance on the time domain refelctometer?
    • A. 

      50Ω, 75Ω, and 125Ω

    • B. 

      75Ω and 125Ω

    • C. 

      50Ω and 125Ω

    • D. 

      50Ω and 75Ω

  • 62. 
    What is the power that is reflected back to an optical source in the time domain refelctometer (TDR)?
    • A. 

      Reflection

    • B. 

      Backscatter

    • C. 

      Scatter coefficient

    • D. 

      Refelction coefficient

  • 63. 
    What are the two major sections of a bit error rate test (BERT) set?
    • A. 

      Emitter and detector

    • B. 

      Emitter and receiver

    • C. 

      Transmitter and detector generator

    • D. 

      Transmitter and receiver

  • 64. 
    Which section of a bit error rate test (BERT) set measueres the received test pattern?
    • A. 

      Transmitter

    • B. 

      Emitter

    • C. 

      Detector

    • D. 

      Receiver

  • 65. 
    What type of framing format should you use to conduct a bit error rate test (BERT) on a T1 circuit configured for binary with eight-zero substitution (B8ZS) coding?
    • A. 

      Extended superframe

    • B. 

      Alternate mark inversion

    • C. 

      Return-to-zero

    • D. 

      Superframe

  • 66. 
    When performing a bit error rate test (BERT), what dertermines the size of a test pattern segment?
    • A. 

      The total number of bits in the test pattern

    • B. 

      The total number of bytes that represent the bit test pattern

    • C. 

      The number of bits that can represent the total number of bits in the test pattern

    • D. 

      The number of bits in the number of bytes that are equally divided into the test pattern

  • 67. 
    What type of error is the result of two successive logic one pulses of the same polarity in violation of alternate mark inversion coding rules?
    • A. 

      Cyclic redundancy check

    • B. 

      Bipolar violation

    • C. 

      Bit slip

    • D. 

      Frame

  • 68. 
    On a breakout box, how many RS-232 key interface signals can be monitored and accessed individually?
    • A. 

      12

    • B. 

      20

    • C. 

      24

    • D. 

      25

  • 69. 
    The purpose of the miniature ON/OFF switches on a breakout box is to
    • A. 

      Measure the individual interface signals

    • B. 

      Change the voltage of individual interface signals

    • C. 

      Allow the interruption of the individual interface condcutors

    • D. 

      Allow the cross-patching of the individual interface conductors