Glossary of Cable Engineering Terms
Glossary of Cable Engineering Terms |
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This page provides definitions for some commonly used cable engineering terms.
Please feel free to make copies of this page so long as you maintain the references to Ganymede Test & Measurement.
| Term | Definition |
|---|---|
| Attenuation | The reduction in amplitude of an electrical signal due to a transmission line or other network. |
| Attenuation coefficient | The factor relating transmission line attenuation to unit distance. |
| Attenuation Unbalance | A measure of the inequality of attenuation between two pairs in a multi-pair cable. |
| Balance about earth | See Common Mode Conversion Ratio. |
| Balanced pair | A transmission line in which the two conductors are electrically identical and symmetrical with respect to a common reference point, usually earth. |
| Balun | A transformer device used for matching balanced and unbalanced circuit elements. |
| Capacitance | A measure of the ability of two conductors to store electric charge. |
| Capacitance unbalance | A measure of the inequality of capacitance between the conductors of two adjacent pairs in a multi-pair cable. |
| Characteristic impedance | The terminal impedance that a transmission line tends towards as its length tends to infinity. |
| Coaxial line | A transmission line in which one conductor is located at the centre of a metal tube which acts as the second conductor. |
| Common mode conversion ratio | A measure of the balance of the two conductors of a pair with respect to earth. |
| Conductance | The real (non-reactive) part of the admittance of a circuit, where admittance is the reciprocal of impedance. |
| Conducted interference | Interference that occurs because of inductive or capacitive coupling. |
| Conductor losses | Power losses due to the resistance of conductors. |
| Copper losses | Power losses due to the resistance of copper conductors. |
| Crosstalk | The unwanted coupling of signals between different pairs in a cable. |
| Crosstalk attenuation | See Crosstalk Ratio. |
| Crosstalk distance | The decibel difference between the level of a wanted signal on a transmission line and an unwanted signal caused by crosstalk. |
| Crosstalk ratio | The ratio of crosstalk signal level to the level of the originating source of the crosstalk. |
| Decibel | A logarithmic unit used for expressing the ratio of two powers. |
| Dielectric | A material which acts as an electrical insulator. |
| Dielectric losses | Power losses due to the conductance of dielectric materials. |
| Eddy currents | Currents induced by unwanted inductive coupling between adjacent conductors. |
| Electrical screen | A metal shield which isolates a device from external fields. |
| Electromagnetic compatibility | The capability of different electrical systems to coexist in the electromagnetic environment without causing or being subjected to interference. |
| Far end crosstalk ratio | Crosstalk measured at the far end of a transmission line. |
| Far field | The electromagnetic field which exists at a distance of several wavelengths from the source of radiation. |
| Impedance | The complex ratio of voltage to current. |
| Inductance | The property of a conductor whereby a voltage is induced into it as a result of a changing current. |
| Insertion loss | The loss in power caused by the insertion of a network between a source and a load. |
| Longitudinal mode | A propagation mode in which the two conductor of a pair act as a single conductor. |
| Mayer method | A method of evaluating the propagation delay of a transmission line. |
| Mismatch loss | The loss of power delivered into a load as a result of the interconnection of devices having unequal impedances |
| Near end crosstalk ratio | Crosstalk measured at the transmit end of a transmission line. |
| Near field | The electromagnetic field that exists within one wavelength of a source of radiation. |
| Neper | A logarithmic unit used for expressing the ratio of two voltages. |
| Network analyser | A measuring instrument for evaluating the complex characteristics of linear electrical circuits. |
| Phase coefficient | The factor relating phase to distance. |
| Primary coefficients | The factors relating distance to the basic electrical properties of transmission lines. |
| Propagation coefficient | The complex factor which resolves into the attenuation and phase coefficients of a transmission line. |
| Propagation delay | The time required for a signal to pass along a transmission line |
| Propagation velocity | The velocity of wave propagation along a transmission line. |
| Proximity effect | The redistribution of current in a conductor brought about by the proximity of another conductor. |
| Quad | A series of four separately insulated conductors, generally twisted together. |
| Regularity return loss | See Structural Return Loss. |
| Resistance | The real (non-reactive) part of the impedance of a circuit. |
| Resistance unbalance | A measure of the inequality of the resistance of the two conductors of a transmission line. |
| Return loss | The difference between the power incident upon a discontinuity in a transmission system and the power reflected from the discontinuity. |
| Screening | See Electrical Screen. |
| Screening attenuation | The decibel difference between the signal level present at the input of a device, and the radiated power originating from the device. |
| Secondary coefficients | Attenuation and phase coefficients and characteristic impedance of a transmission line. |
| Skew | A measure of the inequality of propagation delay between two pairs in a multi-pair cable. |
| Skin effect | The tendency of alternating currents to increasingly flow nearer the surface of a conductor as frequency increases. |
| Structural return loss | A measure of the uniformity of a transmission line's impedance. |
| Surface transfer impedance | The ratio of the voltage developed across a transmission line to the current flowing on the outer surface of the screen. |
| Transmission line | A pair of conductors separated by a dielectric. |
| Transverse Mode | A propagation mode in which the two conductor of a pair carry equal and opposite currents. |
| Twisted pair | A transmission line in which two insulated conductors are twisted together. |
| Velocity ratio | The ratio of propagation velocity to the speed of light. |
| Unbalanced pair | A transmission line in which the voltages on the two conductors are unequal with respect to earth. |
Ganymede Test & Measurement
8 Hillman Close
Uxbridge
UB8 1QA
Tel/Fax =+44 (0)1895 251897
August 1996
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