Functional Block Diagram - Blonder Tongue Laboratories Inc.

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Broadband Specification Guide CATV Terms & Definitions Modulator A device, which produces a TV channel from baseband audio/ video, inputs. Monochromatic Consisting of a single wavelength or color. In practice, radiation is never perfectly monochromatic but, at best, displays a narrow band of wavelengths. Monomode optical waveguide Synonym for single mode optical waveguide. MTS Multiple Television Sound. Referred to as BTSC, system allows TV stereo sound transmission with a second audio program (SAP). Similar to FM stereo, composite baseband audio signal consists of L+R, L-R, and a 15,734 KHZ pilot carrier. Multimode Emission at several frequencies simultaneously, generally closely spaced, each frequency representing a different mode of laser oscillation in the resonant cavity. A term that describes optical waveguide that permits the propagation of more than one mode. Multimode Fiber A fiber that supports propagation of more than one mode of a given wavelength. Multiplexer A device which combines two or more optical signals onto one communications channel. The signals can be of different wavelengths (wavelength -division multiplexing) or can occupy different time slots (time-division multiplexing). Combination of information signals from several channels into one single optical channel for transmission. Noise Figure (NF) A measure of how much noise an active device, such as a TV amplifier, adds to the thermal noise level constant of –59 dbmv Off Channel Processsing Processing a channel on a frequency other than its’ received frequency. Example: Channel 40 UHF processed and distributed as Channel 5; Channel 4 processed and distributed as Channel 10. OMT Orthomode Transducer. A section of waveguide connected to the feed at the focal point of the TVRO antenna that separates horizontal and vertical polarities. An OMT is required for simultaneous reception of even and odd number transponders from a given satellite. On Channel Processing Processing a channel on its received frequency. Example: Channel 2 off air being processed and distributed as Channel 2. Optical Detector A transducer that generates an output electrical signal when irradiated with optical power. Optical Fiber Any filament or fiber, made of dielectric materials, that guides light, whether or not it is used to transmit signals. Optical Link Any optical transmission channel designed to connect two end terminals or to be connected in Series with other channels. Optical Power Colloquial synonym for radiant power. Optical Spectrum Generally, the electromagnetic spectrum within the wavelength region extending from the vacuum ultraviolet at 40 nm to the far infrared at I mm. Optical Time-domain Reflectometer An instrument which locates faults in an optical fiber by sending a short pulse of light through the fiber, then timing the arrival of backscattered signals, which originate at discontinuities in the fiber. Opto-electronic Pertaining to a device that responds to optical power, emits or modifies optical radiation, or utilizes optical radiation for its internal operation. Any device that functions as an electrical-to-optical or optical-to-electrical transducer. Note: Photodiodes, LED's, injection lasers and integrated optical elements are examples of opto-electronic devices commonly used in optical waveguide communications. Oscillator A circuit generating an alternating current wave at some specific frequency. Output Capability Defines the relationship between the intermodulation distortion introduced, and the operating output signal levels of an amplifier, with the traffic loading of the device as a factor. Output Power Radiant power, expressed in Watts. Pad See Attenuator. Paired Cable Cable in which the conductors are combined in pairs, i.e.: two wires which are twisted about each other. Each wire of the pair has its distinctive color of insulation. Parabolic Antenna Consists of a round (parabolic) reflector, which focuses all received RF energy to a single point. Commonly referred to as a “dish.” 90
Broadband Specification Guide CATV Terms & Definitions Passive Describing a device which does not contribute energy to the signal it passes. Phase Lock The control of an oscillator such that its output signal maintains a constant phase angle relative to a second, reference signal. Photodetector Any device which detects light, generally producing an electronic signal with intensity proportional to that of the incident light. Photodiode A diode designed to produce photo-current by absorbing light. Photodiodes are used for the detection of optical power and for the conversion of optical power to electrical power. Photon A quantum of electromagnetic energy. Pico- A prefix denoting one millionth of a millionth; one trillionth (10-11). Pronounced "pie-ko." Pigtail A short length of optical fiber, permanently fixed to a component, used to couple lightwave power between it and the transmission fiber. PIN Photodiode A diode with a large intrinsic region sandwiched between p-doped and n-doped semiconducting regions. Photons absorbed in this region create electron-hole pairs that are then separated by an electric field, thus generating an electric current in a load circuit. Plant A general term applied to any of the physical property of a service company, which contributes to the furnishing of power or communication services. Polarization A waveform characteristic of electromagnetic radiation. Two types of polarizations are used, linear (horizontal and vertical) and circular (right and left hand). Power Energy per unit of time. Pre-Amplifier Low noise amplifier usually mounted in close proximity to a receiving antenna. Used to compensate for down lead losses. Pulse Broadening An increase in pulse duration. Note: Pulse broadening may be specified by the impulse response, the root-mean-square pulse broadening, or the full-duration-half-maximum pulse broadening. Pulse Decay Time The time required for the instantaneous amplitude of an electrical wave to go from 90% to 10% of the peak amplitude. Pulse Length The time duration of the burst of energy emitted by a pulsed laser; also called pulse width. Usually measured at the "half-power" points (0.707 times the full height of a voltage or current pulse). Pulse Rise Time The time required for the instantaneous amplitude of an electrical wave to go from 10% to 90% of the peak amplitude. Quadrature Amplitude Modulation (QAM) QAM is a modulation technique employing both phase and amplitude modulation. It is widely used to transmit digital CATV programs and cable Internet service. There are different QAM levels based upon the number of modulation states used. QAM64 utilizes 6 bits for 64 modulation states, QAM128 uses 7 bits for 128 states, QAM 256 uses 8 bits for 256 states, etc. Quadrature Phase Shift Keying (QPSK) QPSK uses four phase angles to represent each 2 bits input. It is similar to QAM4 without amplitude modulation. QPSK is used in many CATV satellite transmissions. Radiant Energy Energy (joules) which is transferred via electromagnetic waves; there is no associated transfer of matter. Ray A geometric representation of a light path through an optical device: a line normal to the wave front indicating the direction of radiant energy flow. Rayleigh Scattering Scattering of a lightwave propagating in a material medium due to the atomic or molecular structure of the material and variations in the structure as a function of distance. The scattering losses vary as the reciprocal of the fourth power of the wavelength. The distances between scattering centers are small compared to the wavelength. Rayleigh scattering is the fundamental limit of fiber loss in the operating wavelength region (0.8-1.6 um) of optical fiber systems. Ratio The relative size of two quantities indicated by the quotient obtained by dividing one quantity by the other. Receiver A unit including a detector and signal-processing electronics that converts optical input into electronic output; often used in communications. 91
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Functional Block Diagram - Blonder Tongue Laboratories Inc.

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