Signal Transmission Flashcards
uses the available RF bandwidth much more efficiently than analog modulation
Digital modulation
the smallest unit of digital information. can take the value one or zero
bit
a group of bits (usually 8) sometimes referred to as a digital word
byte
4 bits
nibble
8 bits
Octet or Byte
a term related to digital communications speed
Baud
HSD
High Speed Data
bps
bits per second
QPSK
Quadrature Phase Shift Keying
Data is typically divided into chunks known as
blocks, frames, or packets.
QoS
quality of Service
specifies certain minimum performance levels for the customer
Quality of Service or QoS
OSI
Open Systems Interconnection
OSI Layer 1
Physical
OSI Layer 2
Data link
OSI Layer 3
Network
OSI Layer 4
Transport
OSI Layer 5
Session
OSI Layer 6
Presentation
OSI Layer 7
Application
OSI Layer that regenerates the physical signal and contains connectorization or the transport medium
Layer 1 / Physical Layer
OSI Layer responsible for Switches use media access control or hardware addresses, such as Ethernet for routing and filtering. Layer 2 contains two sublayers: MAC and LLC
Layer 2 / Data Link Layer
OSI Layer responsible for routing and path determination, IP, ICMP, OSPF, RIP & BGP
Layer 3 / Network Layer
OSI Layer responsible for the end-to-end flow control using TCP or UDP
Layer 4 / Transport Layer
OSI Layer responsible for the dialog control for setup, maintenance, and termination of the communication circuit
Layer 5 / Session Layer
OSI Layer responsible for the encryption/decryption, compression such as MPEG, MIDI, QuickTime, PICT, TIFF, JPEG, ASCII & EBCDIC
Layer 6 / Presentation Layer
OSI Layer responsible for the file, print, message, application, and database services
Layer 7 / Application Layer
IP
Internet Protocol
a defined set of rules for moving digital data through a network.
Internet protocol or IP
This information at the beginning of a frame in OSI Layer 2 is called
header
This information at the end of a frame in OSI Layer 2 is called
trailer
MPEG
Moving Picture Experts Group
working group that was formed to establish standards for audio and video compression and transmission
Motion Picture Experts Group or MPEG
method of reducing the number of bits required to transmit a given piece of information
compression
HEVC
High-Efficiency Video Codec
SPTS
single program transport stream
ES
elementary streams
PES
Packetized elementary stream
PCR
Program clock reference
PMT
program map table
MPTS
Multi-program transport stream
MTU
Maximum transmission unit
What is the next-generation compression system that allows operators to compress UHD signals to be sent to their customers?
HEVC
Digital data modulated onto a digital carrier is known as
digital modulation
type of modulation typically used for digital data.
QAM
QAM
Quadrature Amplitude Modulation
four steps in converting an analog signal to a digital signal.
Sampling, Quantitizing, Encoding, Decoding
first step in the A/D conversion process; means periodically measuring the amplitude of an analog signal.
Sampling
second step in the A/D conversion process; thought of as “rounding” the sample to the closest discrete digital value.
Quantitizing
Third step in the A/D conversion process; assigns each of the quantizing intervals a binary number.
Encoding
Fourth step in the A/D conversion process; The binary signals that represent each samples are converted back into a sequence of pulses,
Decoding
produced proof that showed that the full information content of any continuous signal can be recovered if the signal is measured and coded at a rate that is twice the frequency of the highest sinusoidal component of that signal.
Harry Nyquist
the inverse of the Nyquist frequency is this
The Sampling interval
The two most common types of multiplexing are
Frequency Division Multiplexing (FDM), Time-Division Multiplexing (TDM)
the multiplexing technique used in the downstream path to deliver video signals, high-speed data, and voice.
Frequency Division Multiplexing (FDM)
number of sources are multiplexed over a communication medium by assigning each a different time slot.
Time-Division Multiplexing (TDM)
WDM
Wavelength Division Multiplexing
TDMA
Time-Division Multiple Access
a form of TDM in which multiple users have access to a single communication medium.
Time-Division Multiple Access (TDMA)
ATDMA
Advanced Time-Division Multiple Access (Advanced TDMA)
includes the use of higher-order modulation to improve throughput and enhanced coding to improve immunity to interference
Advanced Time-Division Multiple Access (Advanced TDMA)
S-CDMA
Synchronous code division multiple access
128 different orthogonal or non-interfering codes are used to encode the data such that up to 128 different data signals to be sent simultaneously.
Synchronous code division multiple access (S-CDMA)
this type of multiplexing allows multiple cable modem to transmit data to the CMTS over a single connection
TDMA
In this, users messages are sent within the same RF channel that the STB is tuned to in order to receive the desired program
In-band signaling
uses a dedicated RF carrier for set-top data and requires a separate tuner to receive messages.
Out-of-band signaling
The process of re-assigning channel numbers to the individual de-multiplexed television signals is known as
channel mapping
When channel mapping data is transmitted to set-top boxes within the same RF channel that the STB is tuned to that is known as what kind of singling
In- Band
