Communication Flashcards
Define wavelength
the distance between two equivalent points in a wave, measured in meters
Define frequency
the number of cycles of an EM wave propagating past a given point each second, measured in Hz
What is the relationship of freq to wavelength
As frequency increases, wavelength decreases and vise versa
What is amplitude
measure of intensity carried by a EM wave….the height
What is Phase
Section of a complete wave cycle corresponding to an angular offset from a specified reference at a given time
What is EM propagation
What happens as a wave travels through a medium/ encounters matter….often results in signal attenuation/distortion.
Types: Absorption, Reflection, Scattering, Refraction, Diffraction
Define modulation
process of adding information to a carrier wave
define demodulation
process of removing information from a carrier wave
Define Amplitiude modulation
carrier signal’s amplitude varies with the changing amplitudes of the modulating signal…example is HAVEQUICK
Define Frequency modulation
Modulating signal causes the carrier frequency to vary…example is SINCGARS
Define Phase Modulation
Information is conveyed by varying the phase of carrier wave…used to allow higher data rates
Describe the concept of Link Budgeting
To close the link, total gains must overcome total losses so that the Signal Noise Ratio at the receiver is sufficient
Define Gains
Signal strength increased
Define Losses
Signal strength reduced
What are the two main types of antennas
Isotropic = omnidirectional with less focus Directional = aimed with focused power
Define Multiplexing
Many signals COMBINED on one channel
Define Multiple access
usage of a common comm resource by different users
Whats the difference between Frequency-Division Multiple Access, Time-Division Multiple Access, Code-Division Multiple Access, and Demand Assigned Multiple Access
FDMA = Users assigned different freqs TDMA = Users are assigned different time slots on shared channel CDMA = Common freq and time allocation, but users have PRN codes assigned DAMA = channel assigned based on immediate traffic demands
What is the differences between EM noise, EM interference and jamming
Noise is ambient, noncoherent
Interference is specific, coherent signal that negatively impacts
Jamming is intentional interference , but needs power, Frequency, and Access to the receiver to work
What are the 3 requirements to jam comms
power, frequency, and access to the reciver
What are jamming countermeasures for CDO
Passive (preeemptive) - in place before an attack
Active (reactive) - implemented during or after an attack
Describe uplink and downlink SATCOM jamming
Downlink: at the terrestrial receiver, affects local area only (LOS)
Uplink: at the satellite, affects Large-area effect (BLOS)
Illustrate the NIPRNet architecture
Public Internet –> DoD Gateway –> AF Gateway –> AF Base Boundary –> NIPRNet Host level
Illustrate the SIPRNet architecture
DoD SIPRNet –> AF Gateway –> AF Base Boundry –> SIPRNet host level
Define Air Gap
Cyberspace security measure of ensuring a secure computer/network to physically isolate from less secure or unsecure networks…PHSICIALLY ISOLATES
What are consideration of Air Gap
1 Improper move of data across, and air gap creates a ‘virtual cable’
2 Air gapped networks/computers are not visible to enterprise cyberspace defenders
3 Must use secure websites to retrieve planning data
4 ID ‘msn only’ NIPRNet computers and restrict use to msn related work only
Describe IBS report update requirements.
Geo-location, reporting timeline, and filtering…
Time delay between 2 to 30 minutes.
Very loose guidance
Describe the type of IBS links.
IBS-S (simplex): UHF SATCOM, continuous, tailored broadcast
CIB: UHF SATCOM duplex, near real-time, allows modification of tracks, can be SECRET
IBS-LOS: UHF based, anti jam, theater level
IBS-N (network): networked data, can be SECRET//REL and TS//SCI
List similarities and differences between tactical data links and IBS.
Similar: info transfer, common message format, various protocols
Different: configurable, producer certification, man-in-loop (highlighted in class, theater vs worldwide
List three parameters req’d to enter an established Link 16.
Initial data load (IDL), crypto, time sync
State the advantages of TDL
- Rapid dissemination of tactical info
- Shared SA creates synergy
Describe the 6 characteristics of TDLs
- Message Standard - Language with standard message formats and rules
- Media - means of connectivity
- Protocols - rules governing TX & RX of information
- Security - encryption
- Electronic Protection - signal and data countermeasures (e.g. Multiple data paths, freq hopping, msg redundancy, error detect and correct)
- Functionality - how data is organized
List common adversary cyber threat activites
scanning & reconnaissance spear phishing web redirects & malicious web pages automated ops Interactive ops hardware & firmware implants Insiders
List the 4 actions in cyberspace
Cyberspace ISR (gather intel) Cyberspace operational preparation of the environment (non intelligence enabling activities) Cyberspace attack (deny, manipulate) Cyberspace defense (securing)
Match the cyber weapon sys to it’s msn area:
Cyberspace security CONTROL system
msn area: DODIN ops
Match the cyber weapon sys to it’s msn area:
AF Cyberspace DEFENSE
msn area: DCO
Match the cyber weapon sys to it’s msn area:
AF Intranet CONTROL
msn area: DODIN ops
Match the cyber weapon sys to it’s msn area:
Cyber vulnerability assessment/HUNTER
msn area: DCO
Match the cyber weapon sys to it’s msn area:
Cyber DEFENSE analysis
msn arean:DCO
Match the cyber weapon sys to it’s msn area:
Network ATTACK system
msn area: OCO
Match the cyber weapon sys to it’s msn area:
BONUS, cyber C2 msn sys
msn area: C2 for DODIN ops, DCO, OCO
ID the hardware components/terminals and platforms of TDLs
Tactical Data System; JTIDS/MIDS terminal; Encryption; Antenna
Describe TDL interoperability and architecture considerations
Gateway - provides direct connectivity between SADL and LINK 16.
ID who is in charge of data link ops and how guidance is published
Joint Interface Control Officer (JICO); Operational Tasking of Data Links (OPTASKLINK)
Define free space path loss
Loss in energy density as EM waves spread/travel, often one of the largest factors in RF comm link.
