CDC Questions Flashcards
What is an example of analog-to-digital and digital-to-analog techniques?
Pulse code modulation (PCM) and continuously variable slope delta (CVSD) modulation
What converts analog signal information into an analog carrier signal?
Analog modulation
What convers analog signal information into a digital carrier signal?
Digital Modulation
The information-carrying components that occur on either side of a carrier are called…
sidebands
Amplitude modulation (AM) requires a bandwidth that is
twice that of the modulating signal
The upper sideband in a single-sideband suppressed carrier (SSBSC) modulation is eliminated by
filtering.
We can express the 6-to-1 improvement of the single-sideband suppressed carrier (SSBSC) modulation over conventional amplitude modulation (AM) as
8 db of improvement
The only basic waveform in nature is a
pure sine wave
A modulated waveform that contains a carrier plus two sidebands for each modulation frequency is a description of
an amplitude modulation (AM)
If 100% modulation is exceeded and there is distortion in the modulating signal, additional sidebands are generated. We identify these sidebands as what?
splatter
The amount of deviation in a frequency modulation (FM) signal is directly proportional to the modulating signal’s
amplitude
The amount of phase shift in a phase modulation (PM) signal is directly proportional to the
amplitude of the modulating signal
What form of modulation is insensitive to signal variations?
Binary-phase shift keying or bi-phase shift keying (BPSK)
In quadrature-phase shift keying (QPSK) the radio frequency (RF) bandwidth for a quadripphase signal is what of that required by a bi-phase signal, given the same data rate
half
What is the main advantage of differential phase shift keying (DPSK)?
It requires a less complex receiver than basic phase shift keying (PSK) signal
Which of the following is not considered an analog modulation techniques?
pulse-code modulation (PCM)
The form of pulse modulation in which the pulse is varied within a set range of positions is known as
pulse-position modulation (PPM)
Quantized analog modulation is actually
analog-to-digital conversion
How many bits per character of a 16-step pulse-code modulation (PCM) system are used to describe the quantized analog sample?
4
The process of coding pulse code modulation (PCM) quantized pulses to make them a constant duration and amplitude is
encoding
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?
time slot
The two major types of frame structures are
CCITT and low speed
The method of multiplexing the T1 multiplexer uses is
time division
Wave-division multiplexing (WDM) creates the virtual channels for multiplexing them together for transmission by using different
wavelengths or lambdas
The most common wave-division multiplexing (WDM) system uses how many wavelengths?
Two wavelengths
Individual pulses within a digital signal are
bits
What unit is most commonly used in data systems to express signaling speed?
Bits per second
Bit count integrity problems are primarily caused by
system timing faults
Three categories of synchronization used in digital data circuits are
synchronous, asynchronous, and isochronous
Which option is a characteristic of synchronous data operation?
All data bits are the same length in time
A digital signal that contains synchronizing bits within the signal stream describes
Asynchronous operation
In what type of signal is the information contained in the transition, and there is transition from one state to the other only when a mark bit is sent?
Non-return-to-zero mark
In what type of signal does the signal level move to one of the discrete signal levels, but returns to the zero level after predetermined time?
Return-to-zero
Which statement best describes an alternate mark inversion (AMI) signal?
A logic one is transmitted as positive voltage if the previous logic one was negative
Digital coding techniques such as binary with eight-zero substitution (B8ZS) signal?
Bipolar violations are intentionally inserted into a data signal to break up long strings of zeros.
The major difference between conditioned di-phase (CDI) and other schemes is the
use of mid-bit transitions for timing
How many bits are in the D4 framing sequence?
12
How many bits are in the extended super frame format (EDF) framing sequence?
24
What communications control signal uses a two-frequency dialing
Tone dialing
What communications information signal uses a continuous 350- and 440- Hz frequency pair?
Dial tone
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?
Busy signal
What communications supervisory signal uses a continuous application of direct current voltage for signaling?
Loop0start
When is the voltage applied in loop-start signaling?
Off-hook condition
In common associated signaling (CAS), what is the seventh bit in frames 6 and 12 used to convey signaling information known as?
Bit robbing
In what common channel signaling (CCS) mode are the messages relating to signaling between two points conveyed directly interconnecting these signaling points?
Associated mode
What are the two principle weighting characteristics in use with telecommunication circuit noise?
CCITT psophometric and C-message
While timing makes sure the equipment is sending and receiving bits at the same time intervals, synchronization makes sure that the
receive equipment can find its place in the bit stream
What term is associated with the delay or lag introduced in the application of voltage from one section to the next?
Latency
Attenuation distortion is caused by
differing attenuation rates for the various frequency components comprising a voice frequency transmission
Jamming a portion of the frequency spectrum is an example of
electronic attack
The definition of electronic attack can be found in which publication?
Air Force Doctrine Document 2-5.1
Any actions we take to protect our forces, facilities, and equipment for electronic action that can destroy or degrade our capabilities is considered
electronic protection
Varying the pulse repetition frequency on a radar set is an example of
electronic protection
Electronic warfare support includes devices such as
radar warning receivers and intelligence systems
When a multimeter has three input terminal jacks, which jack is always used?
Voltage terminal
When using a multimeter, which mode should be used if the reading is unreadable due to fluctuations?
Display hold
When using a multimteter, which mode should be used if the reading fluctuates and a more accurate reading is desired?
minimum/maximum (min/max)
When using a ohmmeter to take a resistance reading, what preliminary precaution should you take?
Disconnect the power from the circuit being tested
What principle of operation does the time domain reflectometer use to test cables?
Radar
Which push-buttons would you select to get 125-ohm (Ω) impedance on the time domain relectometer?
50Ω and 75Ω
What is the power that is reflected back to an optical source in the time domain reflectometer(TDR)?
Backscatter
What are the two major sections of a bit error rate test (Bert) set?
Transmitter and receiver
Which section of a bit error rate test (BERT) set measures the received test pattern?
Receiver
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?
Extended superframe
When performing a bit error rate test (BERT), what determines the size of a test pattern segment?
The number of bits that can represent the total number of bits in the test pattern
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?
Bipolar violation
On a breakout box, how many RS-232 key interface signals can be monitored and accessed individually?
25
The purpose of the miniature ON/OFF switches on a breakout box is to
allow the interruption of the individual interface conductors
What happens when more bits are added to a digital signal arranged in a sequence understood by the sender and receiver?
A code set is established
How many possible symbols can 4 bits represent?
16
In networking, a byte is identified as a/an
octet
What organization sets important computer networking wiring standards for residential and commercial network cabling?
Electronic Industries Alliance (EIA)
What Electronic Industries Alliance (EIA)/Telecommunications Industry Association (TIA) standard is used for commercially building telecommunications cabling?
568A
Which of the following is an International Telecommunication Union (ITU) standardized format used for digital telecommunications services backbone system?
E-carrier
There is a worldwide nonprofit association of technical professionals that promotes the development of standards called the
Institute of Electrical and Electronics Engineers (IEEE)
A collection of standards for local area network (LAN) architectures, protocols, and technologies called Project 802 were developed by the
Institute of Electrical and Electronics Engineers (IEEE)
The “parent” organization, headquartered in Geneva, Switzerland, for all other telecommunications organizations is the
International Telecommunication Union (ITU)
What organization is responsible for the X-series and V-series standards?
International Telecommunications Standardization Sector (ITU-T)
Which series of standards are recommended for data transmission using the telephone network?
V
The definition of the Open System Interconnect (OSI) reference model was a major contribution to networking made by the
International Organization for Standardization (ISO)
Within how many feet of the data communications equipment (DCE) connection does the Electronics Industries Alliance (EIA) RS-232-C standard prescribes bipolar-voltage serial data transmission?
50
Which Electronics Industries Alliance (EIA) interface standard has the ability to work in either balanced for unbalanced electrical circuits?
RS-530
What transmission rates does Electronic Industries Alliance (EIA) RS-530 accommodate?
20Kbps to 2 megabits per seconds (Mbps)
What two sublayers did the Institute of Electrical and Electronics Engineers (IEEE) divide the Open System Interconnect (OSI) data link layers into?
Logical Link Control (LLC) and Media Access Control (MAC)
At what Open System Interconnect (OSI) layer are common data compression and encryption schemes used?
Presentation
What Open System Interconnect (OSI) layer is closest to the end user?
Application
In the Open System Interconnect (OSI) model, a layer will communicate with three other OSI layers. Which one is not one of those layers?
Lowest layer
Which information unit, whose source and destination are network-layer entities, uses connectionless network service?
Datagram
What data communication protocol is used to govern the flow and format of information between systems?
Character-oriented
In binary-synchronous protocol, what character is used to establish and maintain character synchronization prior to the message block and during transmission?
SYN
What data communication protocol is based on bits and the position of the bits?
Bit-oriented
What data communication protocol ensures that the receiving station can distinguish information from garbage?
High-Level Data Link Control (HDLC)
A group of computers and associated devices that share a common communications line within a small geographic area is a
Local Area Network (LAN)
The interconnection of several networks in a city into a single larger network is a
Metropolitan Area Network (MAN)
What type of network connects networks that are typically separated by geographical distances?
Wide Area Network (WAN)
What type of network enables a group of two or more computer systems to communicate over the public internet?
Virtual Private Network (VPN)
Which type network enables users to share resources, files, and printers in a decentralized way?
Peer-to-peer
What Network layer protocol provides information about how and where data should be delivered, including the data’s source and destination addresses?
Internet Protocol (IP)
Which Network layer protocol matches a known internet protocol (IP) address for destination device to a Media Access Control (MAC) address?
Address Resolution Protocol (ARP)
Which Network Layer protocol provides the internet protocol (IP) address for a device that knows its own Media Access Control (MAC) address?
Reverse Address Resolution Protocol (RARP)
Which Transport layer protocol does not guarantee that packets will be received at all?
User Datagram Protocol (UDP)
Which Application layer protocol is used to send a receive files by way of transmission control protocol/internet protocol (TCP/IP)?
File Transfer Protocol (FTP)
Which protocol is simpler than File Transfer Protocol (FTP) when transferring files between computers?
Trivial File Transfer Protocol (TFTP)
