Triple-Play Service Deployment

Glossary
Attenuation The decrease in power of a signal. In optical fibers, loss of average optical power
due to absorption, scattering and other radiation losses. It is generally expressed in
dB without a negative sign.
Attenuation Coefficient The rate of optical power loss with respect to distance along the fiber, usually
measured in decibels per kilometer (dB/km) at a specific wavelength.The lower the
number, the better the fiber’s attenuation. Attenuation is specified at 850 and
1300nm for multimode fiber and 1310 and 1550nm for single mode fiber, over a
temperature range of -60°C to +85°C.
Attenuation Dead Zone For a reflective or attenuating event, the region after the event where the displayed
trace deviates from the undisturbed backscatter trace by more than a given vertical
value _F (usually 0.5 dB or 0.1 dB).Telcordia specifies a reflectance of - 30 dB, a loss
of 0.1 dB and gives different locations. In general, the higher the reflected power
sent back to the OTDR, the longer the dead zone. The attenuation dead zone
depends on the pulse width, the reflectance, the loss, the displayed power level and
the location. It usually indicates the minimum distance after an event where the
backscatter trace can be measured.
ATU-C ADSL Transceiver Unit–Central Office
ATU-R ADSL Transceiver Unit–Remote
ATV Advanced Television. North American standard for digital broadcasting
Auto-Negotiation Procedure for adjusting line speeds and other communication parameters
automatically between two devices during data transfer
Backscattering Portion of scattered light which returns in a direction generally reverse to the
direction of propagation
Bandwidth In digital communications, this is the measure of the data rate, in bits per second, of
a data flow in a given content such as a channel, or physical interface. In relation to
a physical transmission medium, the difference, expressed in Hertz (Hz), between
the highest and the lowest frequencies passing through the fiber or the frequency
spectrum used to carry data overt a copper medium.
Note:This term is often used to specify the bandwidth (MHz x km) of a multimode
fiber.
Bend Radius (minimum) The amount a fiber can bend as measured by the radius of the bend, before
increased loss or mechanical damage occurs.
BER Bit Error Ratio
B-frame A bidirectionally predicted picture, or a picture created by reference to preceding
and subsequent pictures used in MPEG compression technologies.
Bitrate The rate at which a bit stream arrives at a given point typically measured in bits per
second.
Bits per Tone Used in the context of DSL technologies, it is the number of data bits assigned to a
given discrete multi-tone (DMT). Measurement and display allows analysis of the
bits assigned per DMT; significant dips can reveal the presence of AC interference.
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