An inherent property of all optical media caused by the difference in the propagation velocities of light in the orthogonal principal polarization states of the transmission medium. The net effect is that if an optical pulse contains both polarization components, then the different polarization components will travel at different speeds and arrive at different times, smearing the received optical signal. [Fib111]
Pulse Broadening PMD Diagram courtesy of Fiber Optics Info, http://www.fiber-optics.info/fiber_optic_glossary/p
A device that can be manually or automatically adjusted to select one of two orthogonal polarizations. [Sat07]
Passive Optical Network; a broadband fiber optic access network that uses a means of sharing fiber to the home without running individual fiber optic lines from an exchange point, telco central office (CO), or a CATV headend (HE) and the subscriber’s home. [Fib111]
Post Office Protocol 3
Antenna mechanism permitting steering in both elevation and azimuth through rotation about a single axis. While an astronomer's polar mount has its axis parallel to that of the earth, satellite earth stations utilize a modified polar mount geometry that incorporates a declination offset. [Sat07]
An orbit with its plane aligned in parallel with the polar axis of the earth. [Sat07]
When cable television systems use existing pole lines maintained by utilities, an attachment contract must be negotiated between the parties of interest.
The physical connector on a device enabling the connection to be made. An interface on a computer configured as data terminal equipment and capable of having a modem attached for communication with a remote data terminal. [Arr11]
Post Office Protocol 3 (POP3)
The current version of the most common protocol for receiving e-mail on a TCP/IP network.
Plain Old Telephone Service
Energy per unit of time.
An amplifier that delivers a certain amount of alternating-current power to a load. Used in audio frequency and radio frequency applications.
A means of removing the AC system powering voltage from cable segments or components where the power supply voltage is not desired or required. [Arr11]
Refers to cable modem data service down and upload speeds. Comcast's "PowerBoost" delivers bursts for all but their highest-end and lowest-end tiers, allowing subscribers to use all excess cable node capacity to speed up the first few seconds of downloads. In PowerBoost the connected subscriber’s cable modem is “uncapped” for the initial ten to fifteen seconds of a data/Internet Service Provider (ISP) download from the cable operator headend (HE)/hub to the subscriber. After the PowerBoost period the CM is throttled back to the pre-set account settings established for the subscriber.
The act of turning the electrical power to a device off and then back on, often used to reset the device.
A device used to split the 3.7 to 4.2 GHz satellite signal to feed multiple satellite receivers. [Arr11]
Power doublers achieve improved RF output power and multi-carrier distortion over standard “push-pull” (PP) hybrid amplifiers by operating two (2) cascade PP circuits in parallel and by combining their outputs. To coherently combine the outputs, the phase paths through each half must be equal in length. This is accomplished by carefully designing an input signal splitter that drives each hybrid amplifier half with identical signals. The outputs are then recombined in a similar signal combiner. The overall gain is the sum of each individual hybrid amplifier’s gain minus the small loss in the two signal splitters. The RF output power is 3dB greater than each individual hybrid amplifier minus the loss in the output signal combiner. Power dissipation and thermal demands are increased versus standard PP hybrid amplifiers, but each optical node or line amplifier output stage employing a power doubler has at least 3dB additional RF power output capability at reduced multi-carrier distortion levels.
Two-stage Power Doubler Schematic. Courtesy of RFMD.
Three-stage Power Doubler Schematic. Courtesy of RFMD.
An amplification technique where two amplifying devices are operating in parallel to gain an increase in output capability. [Arr11]
An increase in signal power between one point and another. Used as a specification for power amplifiers.
An electronic device that allows voltage to be put on a coaxial cable line so as to provide power to various amplifiers and electronic devices. [Arr11]
An electronic device in an amplifier housing which converts low voltage AC to regulated DC voltages suitable for operating other modules in the housing. See also power supply. [Arr11]
A device used to split downconverter satellite signals in the 900 to 1500 MHz range to feed multiple satellite receivers. [Arr11]
In cable TV, a step down AC transformer which sup-plies low voltage AC (usually 60 volts) to operate amplifiers in the sys-tem. See also power pack. [Arr11]
A semiconductor transistor designed for power-amplifier applications at audio and radio frequencies.
Peak-to-Peak; the algebraic difference between extreme values of a varying quantity. [Fib111]
Pulse-Position Modulation; a method of encoding data. [Fib111]
A signal amplifier located in the immediate vicinity of an off-air antenna, used to amplify extremely weak television broad-cast signals. [Arr11]
Predicted Grade A Contour
The line representing the service area in which a good picture is computed to be available 90 percent of the time at 70 percent of the receiver locations. Signal contours determine what educational channels are carried on a cable system and, in similar markets, what stations must be carried from other small markets.
Predicted Grade B Contour
The concentric area marking a television station's service area in which a good analog picture is computed to be available 90 percent of the time at 50 percent of the receiver locations.
Increases in the higher frequency components of an FM signal before transmission. Used in conjunction with the proper amount of de-emphasis at the receiver, it results in combating the higher noise detected in FM transmissions. [Arr11]
The glass rod from which optical fiber is drawn. [Fib111]
Preform Diagram courtesy of Fiber Optics Info, http://www.fiber-optics.info/fiber_optic_glossary/p
Cable programming services for which subscribers pay an additional fee above the basic cable service charge. Also called Pay Cable.
Presentation Engine (PE)
In OCAP, the presentation engine is responsible for the appearance of information on the user interface (the display), and enables content to be displayed on a variety of devices. The PE incorporates native code that decodes text (HTML, ECMAScript) into meaningful operations, and utilizes Web-based software from the computer world, the Web browser. However, the PE has only limited ability to perform complex logic and arithmetic operations and lacks the security of the Execution Engine, which is why the EE is also required by OCAP.
A shared secret key passed to both parties in a communication flow, using an unspecified manual or out-of-band mechanism.
Primary Rate Interface (PRI)
An ISDN PRI is an industrial-strength ISDN telephone connection commonly used to service multiple dial-up data connections, large central switchboard “PBX” systems, and other highly-specialized needs. Each ISDN PRI has twenty-three 56 or 64Kbps B Channels and one 64Kbps D Channel.
Primary Service Flow
All CMs have a Primary Upstream Service Flow and a Primary Downstream Service Flow. They ensure that the CM is always manageable and they provide a default path for forwarded packets that are not classified to any other Service Flow.
Prime Focus Feed
A type of satellite antenna receive feed that sits at the focal point of the antenna and directs the satellite signal into a low noise amplifier (LNA) or low noise block converter (LNB). [Arr11]
A way to ensure that information is not disclosed to anyone other than the intended parties. Information is usually encrypted to provide confidentiality. Also known as confidentiality.
Private Branch Exchange (PBX)
A private switching system, either manual or dial, usually serving an organization such as a business company or a government agency and usually located on the customer's premises.
The key used in public key cryptography that belongs to an individual entity and must be kept secret.
A function of spread spectrum CDMA technology used in digital cellular; a measure of the robustness of the system; recovers the processed low power signal used to eliminate noise.
An active device that takes an RF input, amplifies and filters the signal and converts the signal to any cable output channel. [Arr11]
A record stored on a computer containing the settings and preferences for each of the users sharing that computer. Profiles can be set up in Windows, as well as Netscape and other shared Internet applications, and are also used to enable security features in a program (e.g., separate e-mail profiles). Or a profile is a description of a series of minimum configurations, defined as part of the specification, providing different capabilities of the OpenCable system. A profile maps a set of functions which characterize the scope of service options. The number of profiles is small. The mapping of functions into resources and subsequently into hardware entities is out of the scope of the specification and is left to manufacturers.
Dispersion attributed to the variation of refractive index contrast with wavelength. [Fib111]
Program and System Information Protocol (PSIP)
A transport and data format specification formulated by the Society of Cable and Telecommunications Engineers (SCTE) to deliver Service Information to the receiver. See also Service Information.
Program Map Table (PMT)
This is an MPEG-2 entity that contains all of the PIDs that make up a program.
Under FCC rules, a cable system must black-out the programming of a distant television station it carries when the system would duplicate a local station's programming, on the request of the local station.
In MPEG-2, a multiplex of variable-length digital video and audio packets from one or more program sources having a common time-base.
Program-Specific Information (PSI)
In MPEG-2, normative data necessary for the demultiplexing of Transport Streams and the successful regeneration of programs.
A Progressive Scan is an improved scanning format for television systems. Where a standard television uses an interlacing format (alternating lines 60 times a second, creating a full image 30 times a second) higher market televisions and digital television systems use progressive scanning in which the television scans all the lines on the television in succession, and does a full screen 60 times a second. The result is a doubling of the frame rate and drastically improved picture quality. [Glo07]
A satellite transponder provided by the common carrier to a programmer with a built-in insurance policy If the protected-use transponder fails, the common carrier guarantees the programmer that it will switch over to another transponder, sometimes pre-empting some other non-protected programmer from the other transponder. [Sat07]
The set of rules or standards which enables communication between computers on a network. In its simplest form, a protocol is the language used by two computers to transfer information. Or a set of rules and formats that determines the communication behavior of layer entities in the performance of the layer functions.
Protocol Data Unit (PDU)
A packet of data passed across an IP network.
Provisioned Service Flow
A Service Flow that has been provisioned as part of the Registration process, but has not yet been activated or admitted. It may still require an authorization exchange with a policy module or external policy server prior to admission.
A telephone company term meaning to configure. Before an ISDN line can be used, it has to be correctly provisioned to work with the ISDN equipment the customer is installing and enabled for the various options the customer has requested.
A facility that indirectly provides some service or acts as a representative in delivering information, thereby eliminating the need for a host to support the service.
A network component between a LAN and the Internet providing security, administrative control and data caching. It is also a firewall that protects the network from intrusion.
Picosecond; one trillionth of a second or 10-12 seconds. [Fib111]
Payload Service Class Table
Program and System Information Protocol
Public Switched Telephone Network; a domestic telecommunications network usually accessed by telephones, key telephone systems, private branch exchange trunks, and data arrangements. [Fib111]
Positive Temperature Coefficient; current limiting device installed in Arris RMTII and Arris PowerTap to limit current flow down the drop (coax or twisted pair). This protects the subscriber and the electronic system components. [Arr11]
Post Telephone and Telegraph Administration; Refers to operating agencies directly or indirectly controlled by governments in charge of telecommunications services in most countries of the world. [Sat07]
A non-commercial channel set aside by a cable system for use by the public, on a first come first serve, non-discriminatory basis.
The key used in public key cryptography that belongs to an individual entity and is distributed publicly. Other entities use this key to encrypt data to be sent to the owner of the key.
Public Key Certificate
A binding between an entity's public key and one or more attributes relating to its identity, also known as a digital certificate.
Public Key Cryptography
A procedure that uses a pair of keys, a public key and a private key, for encryption and decryption, also known as an asymmetric algorithm. A user's public key is publicly available for others to use to send a message to the owner of the key. A user's private key is kept secret and is the only key that can decrypt messages sent encrypted by the user's public key.
Public Key Cryptography for Cross-Ream Authentication (PKCROSS)
Utilized PKINIT for establishing the inter-realm keys and associated inter-realm policies to be applied in issuing cross-realm service tickets between realms and domains in support of Intradomain and Interdomain CMS-to-CMS signaling (CMSS).
Public Key Cryptography for Initial Authentication (PKINIT)
The extension to the Kerberos protocol that provides a method for using public key cryptography during initial authentication.
Public Key Cryptography Standards (PKCS)
Published by RSA Data Security Inc., these standards describe how to use public key cryptography in a reliable, secure and interoperable way.
Public Key Infrastructure (PKI)
The architecture, organization, techniques, practices, and procedures that collectively support the implementation and operation of a Certificate-based public key cryptographic system. Also a process for issuing public key certificates, which includes standards, Certification Authorities, communication between authorities and protocols for managing certification processes.
Public Switched Networks (PSN)
1. Any common carrier network that provides circuit switching among public users. 2. A switched network accessible to the public for originating and terminating telecommunications messages. 3. Any common carrier switched network, whether by wire or radio, including local exchange carriers, interexchange carriers, and mobile service providers that use the North American Numbering Plan in common with provision of switched services. [Fib111]
Public Switched Telephone Network (PSTN)
The PSTN is the worldwide circuit-switched telephone network. Once only an analog system, telephone networks today increasingly are digital, even though most subscribers are connected via analog circuits. Or the international telephone system based on copper wires carrying analog voice data.
Public Switched Telephone Network Media Gateway (PMG)
A media gateway located within the backbone of the PacketCable™ network which “bridges” calls between the Internet Protocol (IP)-network and the PSTN-network. The PSTN media gateway is responsible for supporting all management interfaces to the PSTN and also supports switching system number 7 (SS7) signaling and various time-domain interface options (e.g., channelized T-1 trunks).
Noncommercial television broadcasting.
The delivery method in which a subscriber demands and receives data from the provider.
A measure of how much force is required to pull a connector off of a cable once it is installed. [Arr11]
A current or voltage which changes abruptly from one value to another and back to the original value in a finite length of time; a short burst of light launched into a fiber. [Arr11]
Pulse Waveform courtesy of Fiber Optics Info, http://www.fiber-optics.info/fiber_optic_glossary/p
Pulse Code Modulation (PCM)
The internationally accepted Codex used by telephone companies to translate between the 56 and 64Kbps digital signaling technologies and the analog signals sent across POTS telephone lines. PCM codes are seven or eight bits in size, meaning each code byte has 128 or 256 possible values. (North American POTS connections generally only use 7 bit codes.) Or a commonly employed algorithm to digitize an analog signal (such as a human voice) into a digital bit stream using simple analog to digital conversion techniques.
The dispersion of an optical signal as it propagates through an optical fiber. Also called pulse spreading. [Fib111]
The light burst that is reflected back to the OTDR’s detector from a reflective splice, the end of the fiber segment, or any change in refractive index. [Arr11]
A power source for signal amplification, typically a 980 nm or 1480 nm laser, used in EDFA applications. [Fib111]
1) In electronic marketing, to send data to another computer without a direct request from that computer. 2) In networking, to send data from a server to a client in compliance with a previous request from the client, as soon as the data becomes available. [Fib111]
A delivery method where the service provider transmits on a fixed, predictable schedule, or in response to an event such as the updating of data in the subscriber's database.
The push-pull circuit topology of CATV hybrid amplifiers provides up to a 6-dB reduction in second order distortion products when properly designed. Push-pull amplifiers can achieve very high gain across a wide frequency range with excellent distortion characteristics (in particular, composite second order (CSO)) at high RF output levels. High quality push-pull amplifiers are ideal for use as input stage and pre-amplifiers within state-of-the-art optical nodes and CATV plant line drivers. The best available push-pull amplifiers achieve industry-leading performance through meticulous design of hybrid splitter, inverter, amplifier, and hybrid combiner stages. High performance push-pull hybrid amplifiers may also possess die with carefully matched gain and second-order distortion characteristics.
Courtesy of “Second-Order Distortion in CATV Push-Pull Amplifiers”, Proceedings of the IEEE, July 1970, William H. Lambert, Jerrold Electronics Corporation
Payload Unit Start Indicator
Permanent Virtual Circuit
Personal Video Recorder
Picowatt; one trillionth of a Watt or 10-12 Watts. [Fib111]
A device which can be quickly switched between states where it causes very low or rather high losses, respectively, for a laser beam sent through it. Such devices are typically used within a laser resonator with the purpose of active Q switching the laser; this is a technique for generating short intense pulses, where the pulse duration is typically in the nanosecond range. Q switches can also be used for pulse generation with cavity dumping, but the detailed requirements on the optical switch are actually somewhat different in that case.