Functional Block Diagram - Blonder Tongue Laboratories Inc.

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Broadband Specification Guide CATV Terms & Definitions Reflection 1. Reflected energy which substantially covers the spectrum occupied by the originating signal. 2. The abrupt change in direction of a light beam at an interface between two dissimilar media so that the light beam returns into the medium from which it originated. Refraction The bending of a beam of light at an interface between two dissimilar media or in a medium whose refractive index is a continuous function of position (graded-index medium). Refractive Index The ratio of the velocity of light in a vacuum to the velocity of light in the specified medium. Remote Local Origination Closed-circuit program generated some place other than the headend. Example: Sub-channel origination. Repeater A signal amplification device, often used along cables to extend transmission distances. Response The fidelity with which the output of a system, device, or network corresponds to its input. Responsivity The ratio of an optical detector's electrical output to its optical input, the precise definition depending on the detector type; generally expressed in Amperes per Watt or Volts per Watt of incident radiant power. Return Loss A ratio expressed in dB between the reflected signal and the total signal applied to a device. In 75 ohm systems, the closer the device’s impedance is to 75 ohms, the higher the return loss. Return Loss, Structural The return loss of coaxial cable as established by discrete discontinuities introduced during the manufacturing process. RF Radio Frequency (10 KHz-100GHz). RFI Radio Frequency Interference. Undesired RF signals. Ribbon Cable A cable whose conductors lie side by side in a single plane. Usually has a molded polyethylene insulation. Rise Time For an emitter, the time it takes for light intensity to rise from 10% to 90% of peak output. Detector rise time, also called response time, is the time in which the detector output goes from 10% to 90% of peak. Riser Term generally used to describe a simplified single line distribution drawing. In buildings, a riser refers to a location where cable routing can pass from floor to floor. Second-order Distortion Spurious signals generated when two or more carriers are passed through a nonlinear circuit. The spurious signals are sum and difference products of any two carriers. Sometimes referred to as second-order "beats." Second order distortion is calculated as a power addition. Second Window Characteristic of an optical fiber having a region of relatively high transmittance surrounded by regions of low transmittance in the wavelength range of 1200 to 1350 nanometers. Semiconductor A material whose resistivity is between that of conductors and insulators, and whose resistivity can sometimes be changed by light, an electric field, or a magnetic field. Current flow is sometimes by movement of negative electrons, and sometimes by transfer of positive holes. Used in transistors, diodes, photodiodes, photocells, and thermistors. Some examples are: silicon, germanium, selenium, and lead sulfide. Semiconductor, n-type A semiconductor material, such as germanium or silicon, which has a small amount of impurity, such as antimony, arsenic, or phosphorous added to increase the supply of free electrons. Such a material conducts electricity through movement of electrons. Semiconductor, p-type A semiconductor material which has been doped so that it has a net deficiency of free electrons. It therefore conducts electricity through movement of "holes," which see. Sensitivity Imprecise synonym for responsivity. In optical system receivers, the minimum power required to achieve a specified quality of performance in terms of output signal-to-noise ratio or other measure. Scattering The change in direction of light rays or photons after striking a small particle or particles. It may also be regarded as the diffusion of a light beam caused by the inhomogeneity of the transmitting medium. Signal Level Meter (SLM) A tuned radio frequency voltmeter, usually calibrated in decibels per millivolt (dBmV) as well as voltage. Signal-to-noise Ratio (S/N ratio) The difference in amplitude of a signal (before modulation or after detection of a modulated carrier), and the noise present in the spectrum occupied by the signal, when both are measured at the same point in the system. 92
Broadband Specification Guide CATV Terms & Definitions Single-cable Design A technique for designing CATV systems that utilizes a single type of amplifier with identical transmission levels throughout the system. It may, or may not, actually require some placement of paralleling cables in portions of the system. Single-mode Fiber An optical waveguide through which only one mode will propagate. Single-mode waveguide is produced by reducing the diameter of the core of the waveguide to 2 to 10 microns. The diameter of the core is dependent on the difference in the refractive index of the core and cladding. As the difference in the refractive index of the core and cladding decreases, the diameter of the core increases. Theoretically, the core could be infinitely large as the difference in index become infinitely small. Single-mode operation is desirable because all modes except the lowest and simplest mode are excluded. This reduces time distortion of signals propagating in unwanted modes, retains phase relationships, and reduces dispersion to the lowest possible value. Slope Difference in attenuation between specified low and high frequencies. SLM Signal Level Meter. Test equipment used to measure RF signal strengths in CATV/MATV systems. Also referred to as FSM. SNR Acronym for signal-to-noise ratio. Source A device that, when properly driven (with electrical energy), will produce information-carrying optical signals. Sparklies Black or white dots or streaks that may appear in a satellite program’s picture. This condition is caused by an insufficient carrier-to-noise ratio. Spectrum A range of frequencies within which waves have common characteristics. For example, audio spectrum, radio spectrum, etc. Radio spectrum is generally accepted to include the range between 8 KHz and 300 GHz. Splice A permanent connection of two optical fibers. Splitter A network or device that divides its input energy equally between two outputs. It is possible to cascade (serially connect) splitters to provide more than two outputs, but usually the input energy is not then equally divided across those outputs if the outputs are not multiples of two. Star Coupler A passive device in which power from one or several input waveguides is distributed amongst a larger number of output optical waveguides. Step-index Fiber A type of fiber which has an abrupt change in index of refraction at the core/cladding interface. Generally such fibers have larger cores, higher losses, and lower bandwidths than graded-index types. Step-index Profile A refractive index profile characterized by a uniform refractive index within the core and a sharp decrease in refractive index at the corecladding interface. Strip Amplifier Slang expression for a channelized high-output AGC’d amplifier used in processing VHF or UHF channels in a headend. Sub-Band The radio spectrum between 5 and 40 MHz. Sub-Split Two-way cable communication frequency plan. Consists of an incoming frequency range of 5-40 MHz and an out-going of 50-450 MHz. Subscriber Converter See Converter, subscriber. Subscriber’s Loop Circuit between a local office and a subscriber's telephone set. Super-Band The radio spectrum between 216 and approximately 400 MHz. Super-Trunk A sub-system cable transmission link for transporting television signals between two discrete locations. Sync Pulse Information included in a composite video signal to synchronize the television receiver's picture tube electron beam with the electron beam in the television camera which originated the video signal, or with any other source of a video signal. Tap, Subscriber A device that diverts a predetermined amount of its input energy to one or more tap outputs for the purpose of feeding energy into subscriber service drop cables. The remaining balance of the input energy is presented to a tap output port for propagation farther out into the system. Tap, Optical A device for extracting a portion of the optical signal from a fiber. Tapoff Device to provide a small amount of signal from a distribution line to feed a TV set. Provides an asymmetrical signal split. TASO Television Allocation Study Organization, Industry group that advised the Federal Communications Commission on TV matters. 93
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Functional Block Diagram - Blonder Tongue Laboratories Inc.

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