Functional Block Diagram - Blonder Tongue Laboratories Inc.

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Broadband Specification Guide CATV Terms & Definitions Filter Device used to reject or pass a specified frequency or range of frequencies. Some examples are band-pass filters, notch filters, channel elimination filter, low & high pass filters. FM Frequency Modulation. Usually means stations in the 88-108 MHz band. Footprint The anticipated EIRP levels of a given satellite displayed upon a map. Used to determine required antenna gain at a particular TVRO site. Forbidden Conversion Term used when referring to a particular UHF to VHF or VHF to VHF channel conversion that cannot be performed due to interferences that occur internal to the unit. Frequency Coordination A computerized service using a database to resolve existing or potential conflicts between users of microwave frequencies. Frequency Reuse A technique in which independent information is transmitted on horizontal and vertical polarization’s to reuse a given band of frequencies. FSM Field Strength Meter. A test instrument for measuring RF signals. Fusion Splicer An instrument which permanently joins two optical fibers by welding their cores together with a brief electric arc. Gain An increase in power produced by an amplifier and expressed in decibels. See Amplifier. Gain Control A device on amplifiers to adjust the gain. Gain Module A mechanical sub-assembly within an amplifier housing which produces gain. Gain, Usable The gain presented for use between the input and output connections of an amplifier housing. Since several accessory items may be included inside the housing, but external to the gain module, such as pads, equalizers, two-way filters, etc., the gain provided by the gain module itself will generally be somewhat higher than the usable gain actually available between the housing cable connections. Gallium Aluminum Arsenide (GaAlAs) The compound used to make most semiconductor lasers that operate at 800 to 900 nanometers in wavelength. Giga A prefix used to represent one billion or 101 or 1,000,000,000; abbreviated as G as in GHz, one billion cycles (Hertz) per second. Gigacycle (Gc) See Gigahertz. Gigahertz (GHz) One billion hertz. One billion cycles per second. See Hertz and Cycle. Graded Index Fiber An optical fiber which has a refractive index that gets progressively lower away from the center. This characteristic causes the light rays to be continually refocused by refraction in the core. A fiber type wherein the core refractive index decreases almost parabolically radially outward toward the cladding. This type of fiber combines high-bandwidth capacity with moderately high coupling efficiency. G/T Figure of merit of a TVRO system relating to gain divided by noise temperature expressed in dB/K. Ghost Single or multiple images on a TV screen. Causes can be multi-path reflections in the receiving path of an antenna, Direct Pick-Up interference (DPI, or impedance mismatches. Guard Band A portion of spectrum left vacant and not utilized between two carriers or bands of carriers, to provide a margin of safety against mutual interference. Guided Wave A wave which is concentrated between materials having different properties, and is propagated within those boundaries. Hard Line Cable Semi-rigid coaxial cable consisting of a solid tubular aluminum outer shield used in CATV trunk and feeder applications. Typical sizes range from .412” OD to 1.0” OD. Headend (HE) The equipment where all signals are received, processed and combined prior to distribution. Hertz (Hz) Frequency of periodic oscillations, expressed in cycles per second. 86
Broadband Specification Guide CATV Terms & Definitions Heterodyne The process of mixing (beating) two frequencies together to generate frequencies of their sum and difference. This process is used for channel conversion. 1. Combining two carriers to generate a new carrier which may be either the sum or difference addition of the original frequencies. 2. To shift a carrier frequency to a new frequency by combining it with another carrier which is locally generated. Heterodyne Signal Processor A unit employed in CATV systems to convert a carrier frequency to an intermediate frequency (IF). The intermediate frequency carrier may then be filtered, regulated, or otherwise conditioned, and then heterodyned back to either the original carrier frequency, or to a completely new carrier frequency. Highband The radio spectrum between 174 and 216 megahertz (MHz). Standard television channels 7 through 13 fall within this spectrum. High-Split Two-way cable communication frequency plan, where the diplex filter’s cross-over frequency is in the high-band. Consists of an incoming frequency range of 7-186 MHz and an out-going of 222-450 MHz. Home Run Cabling Wiring method where each subscriber is fed via a dedicated drop cable. Horsepower A unit of mechanical power equivalent to 550 foot-pounds per second, or to 745.7 Watts. HRC Harmonically Related Carriers. Frequencies plan used by some CATV companies which provides for lower perceived distortion levels in cascaded amplifiers. HRC channels assignments with the exception of channels 5 and 6 (.75 MHz higher than standard). Hum Modulation Undesired low frequency modulation of a carrier at the frequency of the source of the interference, or a harmonic of that frequency, usually 60 Hz or 120 Hz, for example. Hybrid System In Cable Television systems, this refers to a system that incorporates lightwave transmission on optical fibers for a part of the system, and extends the plant on RF broadband coaxial cables for distribution and connection to subscribers. Hydroxylion Absorption Absorption of optical power in optical fiber due to hydroxyl (OH) ions. This absorption has to be minimized for low fiber loss. Hyperband CATV channels AA thru YY (numeric equivalents -37 thru 61) falling in the frequency range of 300 to 450 MHz. IDF Short for intermediate distribution frame, a cable rack that interconnects and manages the telecommunications wiring between an MDF and workstation devices. Cables entering a building run through a centralized MDF, then each individual IDF and then on to specific workstations. For example, an enterprise that encompasses a building with several floors may have one MDF on the first floor and one IDF on each of the floors that is connected to the MDF. Index Matching Material A material, often a liquid or cement, whose refractive index is nearly equal to an optical element index. Material with an index nearly equal to that of an optical fiber's core is used in splicing and coupling to reduce reflections from the fiber end face. Index Profile A characteristic of an optical fiber which describes the way its index of refraction changes with its radius. Impedance Circuit characteristic) voltage divided by current). TV distribution has standardized on 75 ohm and 300 ohm. Insertion Loss The loss introduced into a cable or system by the Insertion of a device or network expressed in decibels. See Loss. Instructional Television Fixed Service (ITFS) ITFS is a microwave transmission in the frequency range of 2500- 2686 MHz used by educational entities for distributing programming employing analog TV transmissions. This band was also referred to as MMDS and was used by wireless cable operators. The FCC has since re-designated this band as BRS (Broadband Radio Service) and EBS (Educational Broadband Service) and has established provisions for digital transmissions. Interference Noise or other disturbances such as spurious signals that, when introduced to a desired signal, reduce the intelligibility of the information carried on that signal. Intermodulation Distortion The distortion introduced when several or many carriers are passed through a nonlinear circuit. This includes the spurious signals (beats) produced as sum and difference additions of the carriers present, and the transfer or superimposition of modulating information from one carrier to another. 87
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Functional Block Diagram - Blonder Tongue Laboratories Inc.

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