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Definition
| The topology where signals originate in the headend and are transmitted long distances via trunk cables, Which have branches for directing the signal to customers. |
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Definition
| A network architecture that typically uses fiber optic cables to bring signals to selected areas of the system called nodes, which are usually based on number of subscribers to be served. An advantage of fiber is that it has bandwidth many times greater than coaxial cable and can travel great distances without amplification. From the node, conventional coaxial cable, and amplifiers where required, deliver the signals to the feeder cables. |
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| FCC Proof-of-Performance: |
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Definition
| Bi-annual tests, performed in the headend and at a number of end-of-line locations, to determine if the network meets minimum specifications set by the FCC. |
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| The cumulative effect of return path distortions they are added to the signal at various locations in the coaxial portion of the network. |
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National Television Standards Committee
Specifications standards approved by the FCC in 1953 for commercial analog color TV broadcasting. |
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| That portion of the electromagnetic spectrum used to send and receive telecommunications signals over the air. |
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| Signals that flow downstream, from the headend to the network. |
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Definition
| Signals that flow in the upstream direction, from the customer to headend. |
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Definition
| Device that separates or combines based on frequency. |
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Definition
| The lowest possible power level determined by the thermal noise generated within the electrical components being tested. |
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Definition
| The highest power level (Amplitude) reached by a carrier. |
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Definition
Composite Second Order:
A clustering of beats 1.25MHz above the visual carriers in a CATV network. |
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Definition
Composite Triple Beat:
A form of interference or noise resulting from the mixing of all of the various carriers in a CATV network. |
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| Benefits of an (HFC) network: |
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Definition
*Enhanced picture quality
*Increased Reliability
*Decreased cost of system maintenance
*Cost effective system bandwidth upgrades
*Small segmented areas allow greater return path functionality |
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Definition
| Having or relating to a frequency below the audibility range of the human ear |
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Definition
| A stream of atomic nuclei that enter the earth's atmosphere from outer space at speeds approaching that of light. |
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Definition
| Light is measured in micrometers, or more typically nanometers. The most common wavelengths used by CATV industry are 1310nm && 1550nm and are both in the "near-infared" spectrum |
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Definition
| An electronic process that combines several individual signals into a single medium |
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Definition
Wave Division Multiplexing:
Combines multiple optical signals in order to amplify them as a group and transported over a single fiber. |
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Definition
Dense Wave Division Multiplexing:
Allows multiple wavelengths above and below a center wavelength to be carried on a single optical fiber. |
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Term
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Definition
*Core 8-10 µm
*Cladding 125 µm
*Coating 250 µm |
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Definition
*Fiber Optic Cable
*Transmitter (Laser)
*Receiver (NODE) |
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Term
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Definition
| Made of a silica glass that has been heated to a high temperature and then drawn into a thin fiber rought the size of a human hear. Individual fibers are bundled into groups that are then put into buffer(small plastic) tubes to reduce damage. Each fiber and individual buffer tubes is color coded for identification. |
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Term
| Types of Lasers (Transmitter) |
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Definition
*Fabry-Perot (F-P)
*Distributed Feedback (DFB)
*Yttrium-Aluminum-Garnet (YAG) |
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Term
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Definition
| A dark fiber is a spare fiber installed during the construction of the network that was reserved for future use. |
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Passive Optical Netork:
A fiber-based network which uses passive splitters to deliver signals to multiple locations. |
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Definition
| A high-speed line or series of connections that forms a major pathway within a network. The term is relative as a backbone in a small network will likely be much smaller than many non-backbone lines in a large network. |
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Definition
| This means that the network is operational 99.99% of the time, which translates into less than 50 minutes of downtime per year. |
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Term
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Definition
| This means that the network is operational 99.999% of the time, which translates into less than 5 minutes of downtime per year. |
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Definition
| A network architecture where nodes, hubs, or headends may be connected with fiber optic cables to provide redundancy or increase services. |
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Definition
| A facility between the headend and the customer that performs many of the functions of a headend. Also called a hub. |
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Definition
Optical Transition Node:
Similar in function to a hubsite, but serving fewer customers. |
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Term
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Definition
| Usually a passive device such as a splitter or directional coupler used to combine radio frequency signals from one source with those from another. |
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Term
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Definition
| Usually a passive device that divides a signal into two equal paths. It may be found on a trunk, feeder, or drop cable. |
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Term
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Definition
| Device used to combine the channels for entry onto the cable or fiber optic transmitter. |
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Term
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Definition
| The difference, in dB, of a signal level, injected into one output port, and the measured level of that same signal on another output port, with the input port properly terminated. |
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Term
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Definition
| Obtained by measuring the attenuation between the two output ports (A & B) when the common port (input port) is terminated in the correct value of impedance. An RF generator signal is applied to port A and an RF voltmeter reading is taken at Port B. |
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Term
| Optical splitters / combiners: |
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Definition
| An optical splitter performs the same splitting or combing function as an RF splitter but they do it at the light wave level. They are available 5% increments such as, 50/50 95/5 1/99 |
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Term
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Definition
| A discontinuous signal whose various states are discrete intervals apart. |
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Term
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Definition
| Device used to convert an analog signal to a digital signal. |
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Term
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Definition
Binary Digit:
The smallest unit of computerized data. Bits are defined as single characters of 0 or 1. Bandwidth is usually measured in bits-per-second (bps) or (kbps) |
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Term
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Definition
| A set of bits that usually represent a single character. Usually there are 8 bits in a byte. |
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Term
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Definition
| Four bits make up a nibble. |
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Term
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Definition
| The number of changed states that can occur per second. |
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Term
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Definition
| A continuously varying signal with an unlimited number of possible values of amplitude and frequency. |
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Term
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Definition
| Analog to Digital Conversion |
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Term
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Definition
| Digital to Analog Conversion |
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Term
| 3 Components of Digital Conversion: |
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Definition
*Sampling
*Quantization
*Encoding |
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Term
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Definition
| Is the "measuring" of the analog signal at specific intervals. The more samples taken, the more accurate the process |
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Term
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Definition
| Is the assigning of a specific value to each of the samples. |
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Term
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Definition
| Is the process by which the specific values are converted into a data or bit stream. |
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Term
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Definition
| Signals must be sampled at twice the highest frequency for proper recreation. |
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Term
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Definition
| The process of varying the amplitude, frequency, or phase of a carrier to be in step with the instantaneous value of the modulating wave form. |
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Term
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Definition
Amplitude Shift Keying:
Data transmission scheme wherein the carrier is shifted in amplitude. |
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Term
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Definition
Frequency Shift Keying:
Digital modulation scheme wherein the frequency of the carrier is shifted |
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Term
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Definition
Phase Shift Keying:
Data modulation where the phase of the carrier is shifted. |
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Term
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Definition
Quadrature Phase Shift Keying:
*Digital modulation scheme wherein the carrier is shifted in 90 degree steps. There are four possible phase states and the magnitude is constant.
*Four phase changes
*Two Carriers ("I" && "Q")
*Two Bits per symbol |
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Term
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Definition
| A Graphic depiction of the four phase states of a Quadrature Phase Shift Key Signal. |
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Term
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Definition
Time Division Multiple Access:
Is a digital transmission technology that splits the frequency band into a number of channels. The channels are each assigned a specific time slot, so that several transmissions can share a single channel without interfering with one another. |
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Term
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Definition
Pre and Post FEC & BER
Constellation Display
Diagnosis MER
Digital Channel Average Power |
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Term
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Definition
Modulation Error Rate
The digital equivilent of Singal-to-Noise, which is the baseband measurement equivalent to Carrier-to-Noise. MER measures the ratio of Error power to average power in an ideal QAM signal. |
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Term
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Definition
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Term
| Digital Channel Average Power: |
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Definition
| The strength of a digital signal is measured differently that than of an analog channel, its measured by its average power. |
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Term
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Definition
(LAN) Local Area Network
(MAN) Metropolitan Area Network
(WAN) Wide Area Network |
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Term
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Definition
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Term
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Definition
| Allows characters to be sent at irregular intervals by preceding each character with a 0 and by ending each character with a 1. |
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Term
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Definition
| An extra bit added to help check if the data that is being transferred is correct. |
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Term
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Definition
| The condition that occurs when two events happen in a specific time relationship with each other and both are under control of a master clock. In synchronous characters are spaced by time not by start and stop bits. |
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Term
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Definition
| Synchronizing bits used in synchronous transmission to maintain synchronization between transmitter and receiver. |
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Term
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Definition
Header - 5 bytes --\
Payload - 93 bytes -- > Overhead
Trailer - 2 bytes --/ |
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Definition
Simple Network Management Protocol
A method of managing devices, or network elements (NE) in a data network. Mainly used to remotely monitor and configure network elements |
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Definition
| A network built on twisted pair, with speeds of up to 10 Mbps Resides in the lowest levels of the OSI model: the physical and datalink protocols. |
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Definition
Network Operations Center {BSAC}
The monitoring center for high-speed Internet and telephony. Technical customer service calls are escalated to the NOC for investigation and network troubleshooting. |
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Term
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Definition
Data Over Cable Service Interface Specification:
The leading standard for cable modems, currently version 3.0 |
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Term
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Definition
Cable Modem Termination System:
A unit consisting of various hardware and software entities that acts as the hand-off point between RF based networks and other networks such as the internet and the PSTN |
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Term
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Definition
| Public Switch Telephony Network |
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Term
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Definition
Dynamic Host Configuration Protocol
This server sets up the MAC and IP addresses for the cable modem. |
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Term
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Definition
Time of Day Server:
This server sets up a common clock between the CM and the CMTS |
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Term
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Definition
Trivial File Transfer Protocol Server:
This server allows non-protected file transfers, such as a configuration file for a modem |
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Term
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Definition
Network Access Point:
The point of access into the internet |
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Term
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Definition
Point of Presence:
A switch or collection of switches connecting multiple Networks |
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Definition
| In addition to letting everything above 50 MHz to pass allows a small spectrum below 50MHz to pass. |
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Term
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Definition
| Allows only signals above 50MHz to pass through |
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