| S |
| SAW (Surface Acoustic Wave) Filter |
| A solid state filter that yields a sharp transition between regions of transmitted and attenuated frequencies. |
| Satellite Receiver |
| The indoors electronic component of an earth station which downconverts, processes and prepares satellite signals for viewing or listening. |
| Scanning |
| The organized process of moving the electron beam in a television picture tube so an entire scene is drawn as a sequential series of horizontal lines connected by horizontal and vertical retraces. |
| Scrambling |
| A method of altering the identity of a video or audio signal so it cannot be received intelligibly in order to prevent its reception by persons not having authorized decoders. |
| Screening |
| A metal, concrete or natural material that screens out unwanted TI from entering a dish or a metal shield that prevents the ingress of unwanted RF signals in an electronic circuit. |
| Section |
| A portion of a table that conforms to the MPEG defined syntex |
| Serialized Products |
| Any product or device made available by the SMS- Operator for release into the marketplace, that could be uniquely identified by a serial number, for example. decoders or smartcards |
| Serrated Vertical Pulse |
| The television vertical sync pulse which is subdivided into six serrations. These sub-pulses occur at twice the horizontal scanning frequency. |
| Service |
| Also called a channel such as M-Net or FilmNet Plus, to which a TV or decoder is tuned. A Service Provider offers one or more services and negotiates with the SMS Operator to market his services as one or more products |
| Service Provider |
| The company or institution that provides one or more services. For example, the Service Provider in SA is M-NET and in Europe is FilmNet. Service Providers may operate studios or provide a service via a backhaul link |
| SI |
| Service Identification |
| Servo Hunting |
| An oscillatory searching of the feedhorn probe when use of inadequate gauge control cables results in insufficient voltage at the feedhorn. |
| Side Lobe |
| A parameter used to describe the ability of a dish to detect off-axis signals. The larger the side lobes, the more noise and interference a dish can detect. |
| Single Channel Per Carrier (SCPC) |
| A satellite transmission system that employs a separate carrier for each channel, as opposed to frequency division multiplexing that combines many channels on a single carrier. |
| Signal Dropout |
| The loss of signal that occurs when the signal becomes too weak to be usable |
| Signal-to-Noise Ratio |
| S/N - The ratio of signal power to noise power in a specified bandwidth, usually expressed in decibels |
| Skew |
| A term used to describe the adjustment necessary to fine tune the feed polarity detector when scanning between satellites. |
| Slant Range |
| The distance that a signal travels from a satellite to a TVRO. |
| SMS-Operator/Provider |
| The SMS Operator manages customers who subscribe to one or more services. The Service Provider requests that the SMS Operator manages and gather subscription fees from his subscribers and also perform othe |
| Snow |
| Video noise or sparklies caused by an insufficient signal- to-noise input ratio to a television set or monitor. r subscriber-related tasks |
| Solar Outage |
| The loss of reception that occurs when the sun is positioned directly behind a target satellite. When this occurs, solar noise drowns out the satellite signal and reception is lost. |
| Sparklies |
| Small black and/or white dashes in a television picture indicating an insufficient signal-to-noise ratio. Also known as snow. |
| Spherical Dish |
| A dish system using a section of a spherical reflector to focus one or more satellite signals to one or a series of focal areas. |
| Splitter |
| A device that takes a signal and splits it into two or more identical but lower power signals. |
| Subcarrier |
| A signal that is transmitted within the bandwidth of a stronger signal. In satellite transmissions a 6.8 MHz audio subcarrier is often used to modulate the C-band carrier. |
| Subscriber Management System - SMS |
| A sub-system on the BS that manages all subscriber related information such as number, names, addresses, telephone numbers, etc... |
| Subscription Products |
| Any piece of programming supplied by a program- provider and made available by the SMS-Operator for broadcasting thus enabling a customer to subscribe. This includes PPV and IPPV products. |
| Surface Acoustic Wave |
| A sound or acoustic wave traveling on the surface of the optically polished surface of a piezoelectric material. This wave travels at the speed of sound but can pass frequencies as high as several gigahertz. |
| Synchronizing Pulses |
| Pulses imposed on the composite baseband video signal used to keep the television picture scanning in perfect step with the scanning at the television camera. See SAW Filter. |
|
| T |
| TCP/IP |
| Transfer Control Protocol/Information Protocol |
| TVRO |
| A television receive-only earth station designed only to receive but not to transmit satellite communications. |
| Table |
| An MPEG structure that can be updated in sections and which can contain any of a variety of data |
| Tap |
| A device that channels a specific amount of energy out of the main distribution system to a secondary outlet. |
| Television Receive-Only (TVRO) |
| A satellite system that can only receive but not transmit signals. |
| Terrestrial Interference (TI) |
| Interference of earth-based microwave communications with reception of satellite broadcasts. |
| Tilt |
| The uneven attenuation of a broadband signal as it travels through a coaxial cable. In general, attenuation increases as signal frequency increases. |
| Thermal Noise |
| Random, undesired electrical signals caused by molecular motion, known more familiarly as noise. |
| Time-Shifted Event |
| The same program broadcast on two or more channels, each broadcast starting a fixed period of time after the previous one. This is mainly intended for PPV. For example, the same movie can be started on nine different channels, each delay 10 minutes from the previous one. A subscriber then has to wait a maximum of 10 minutes for the start of this movie. The fact that the same movie is transmitted more tha |
| Trace |
| The movement of the electron beam from left to right on a television screen. n once is usually transparent to the subscriber. |
| Threshold |
| A minimal signal to noise input required to allow a satellite receiver to deliver an acceptable picture. |
| Transponder |
| One circuit on a satellite that receives, modulates, amplifiers and re-transmits an uplinked signal |
| Transport Stream |
| An MPEG-2 multiplex with short, fixed-length packets carrying many programs intended for general broadcast over potentially error-prone media, such as a satellite broadcast. |
| Trap |
| An electronic device that attenuates a selected band of frequencies in a signal. Also known as a notch filter. |
| U |
| UHF |
| Ultrahigh frequencies ranging from 300 to 3,000 MHz. North American TV channels 14 through 83. African and European TV channels 21 to 69. |
| Upconverter |
| A device that increases the frequency of a transmitted signal. |
| Uplink |
| The earth station electronics and antenna which transmit information to a communication satellite. |
|
| V |
| VCR |
| An abbreviation for video cassette player. |
| VSWR |
(Voltage Standing Wave Ratio)
The ratio between the minimum and maximum voltage on a transmission line. An ideal VSWR is 1.0. Ghosting can result as the VSWR increases. It is also a measure of the percentage of reflected power to the total power impinging upon a device. |
| Vertical Blanking Pulse |
| A pulse used during the vertical retrace period at the end of each scanning field to extinguish illumination from the electron beam. |
| Vertical Sync Pulse |
| A series of pulses which occur during the vertical blanking interval to synchronize the scanning process at the television with that created at the studio. See also Serrated Vertical Pulse |
| VHF |
| Very high frequencies. The lower frequency range for terrestrial television broadcasts. |
| Video Signal |
| That portion of the transmitted television signal containing the picture information. |
| Voltage Tuned Oscillator (VTO) |
| An electronic circuit whose output oscillator frequency is adjusted by voltage. Used in downconverters and satellite receivers to select from among transponders. |
| Video Monitor |
| A television that accepts unmodulated baseband signals to reproduce a broadcast. |
|
| W |
| Wave Length |
| The length in one complete vibration of an electromagnetic signal. Wavelength decreases as signal frequency increases |
| Wind Loading |
| The force exerted by the wind on the surface of a dish which can cause misalignment or, in the worst case, damage to the system. |
