Terminology
A glossary of commonly-used technical terms relevant to Winchester Interconnect products.
AMPLIFIER
A device used to increase the operating level of an input signal. Used in a cable system’s distribution plant to compensate for the effects of attenuation caused by coaxial cable and passive device losses.
ANSI
American National Standards Institute
ATTENUATION
The difference between transmitted and received power due to loss from lines, electronic components, or other transmission devices; usually expressed in decibels (dB).
BACKSCATTER
Any type of electromagnetic Radiation that travels in the opposite direction upon a collision.
BALUN
A Term meaning BAL-anced and UN-balanced, this is a device that is used to bring Electromagnetic radiation into or out of balance.
BANDWIDTH
The width of frequencies encompassing the difference between two defined points.
BODY
Main or largest portion of a connector to which other components are attached.
BRAID
Weave of metal fibers used as a shield covering for an insulated conductor or a group of insulated conductors.
BULKHEAD
Term used to define a mounting style of connectors. Bulkhead connectors are designed to be inserted into a panel cutout from the front or the rear of the panel, and typically secured with a jam nut.
COAXIAL CABLE
Cable composed of an insulated central conducting wire, wrapped in another cylindrical conducting wire or braid. Coax cable has great capacity to carry high speed data typically used in Cable TV, connecting computers and central office switching.
CONTACT
Electrically conductive component designed for use in a multi-circuit connector.
CONTACT ENGAGING AND SEPARATING FORCE
Force required to either engage or separate contacts.
CONTACT RESISTANCE
Measurement of electrical resistance of mated contacts when assembled in a connector under typical service use.
CROSSTALK
Any type of electromagnetic coupling by two adjacent devices that causes mutual interference.
CUTOFF FREQUENCY
The highest frequency that allows usable amounts electromagnetic radiation to pass through a selected geometry.
DECIBEL (dB)
A unit of measurement which expresses the ratio of two power levels on a logarithmic scale. It is used in cable systems to specify losses, k gains, and other ratios of power. The decibel is one-tenth of a Bel.
dBC
Used in describing power ratio of signal carriers, mainly used as a unit of measurement for any type of intermodulation
dBW
Unit of measurement for power levels that are relative to a 1mW reference level.
DIELECTRIC
An insulator that can be polarized under the application of an electric field
DIELECTRIC CONSTANT
The ratio of a given material electric field permittivity to that of free space
DIELECTRIC WITHSTANDING VOLTAGE (DWV)
Otherwise known as Breakdown Voltage. This is the point at which the electric field strength will travel through a given material
FCC
Federal Communications Commission
HEAD END POWER (HEP)
A system by which 480 VAC 3-phase electrical power, to operate auxiliaries, is provided to railroad vehicles from a central source via a trainline system. The power source can be locomotive, power car, or a wayside source
HERMETIC SEAL
A seal that prevents the ingress of gas, liquid, foreign matter.
IMPEDANCE
Resistance to the flow of AC current. In telecommunications and broadcast systems, the characteristic impedance is 75 ohms. If all cable and devices are equal to the characteristic impedance, maximum signal will be transferred with little or no reflection
IMPEDANCE MISMATCH
A situation that results when two components are connected, each having a different characteristic impedance. This generally results in adverse attenuation and return loss.
INSERTION LOSS
That property between the input and output of a device causing a predictable signal loss.
INTERMODULATION
Beats and harmonics creating interference due to the mixing of more than one carrier in an amplifying device. Usually non-linear.
ISO
International Standards Organization
MATCHED IMPEDANCE
Coupling of two components or systems in such a way that the impedance of one system equals the impedance of the other system.
NEBS
National Equipment Building Systems
OHM’s LAW
The relationship between voltage, current, and resistance in an electronic circuit. The third quantity can be found if two are known.
PASSIVE DEVICE
A device used in a cable system not requiring electrical power to operate. It normally represents loss to signals passing through it. Examples of passive devices are splitters, directional couplers, pads, and equalizers.
PHASE
A position of a measurable point on a single wave at given point in time.
RETURN LOSS
The value (in decibels) of the ratio of the power or voltage loss between the forward (transmitted) wave and the reflected wave, as a result of impedance mismatch.
RETURN PATH
The band of frequencies used to return signals to the cable head-end either as control data or for redistribution on the forward path.
RF
Abbreviation for “radio frequency”.
RG/U
(R–radio frequency, G–government approval number, U–universal specification). Symbol for Government specified coaxial cable.
STANDING WAVE
The resultant of one or more electromagnetic waves traveling along a transmission path in opposite directions.
TRAINLINE
An electrical cable system that allows electrical signals to be sent over the entire length of the train. Electrical cable types include power, control, communication and data, often with more than one function contained within the same cable. The trainline may connect to equipment in each vehicle, or may simply pass through, providing a signal path between vehicles on opposite ends of that vehicle.
VSWR
Abbreviation for Voltage Standing Wave Ratio, a measure of return loss of a transmission circuit.