Glossary
Numerics A B C D E F G H I J L M N O P Q
R S T U V W Y
© 2012 Harmonic Inc. 203 ProView 7000 v.2.6, Rev. E
AFD
Active Format Description. Signaling describes certain spatial characteristics of a high definition or
standard definition video image. AFD and Bar Data are intended to be broadcast with the video signal
that they describe. AFD information is intended to assist DTV displays in optimizing the displayed
images. AFD may also be used by intermediate professional video equipment in conversion of video
images of one aspect ratio into an image of another aspect ratio. Bar Data information is used to signal
the precise unused areas of active video when the active image does not completely fill the picture
area, in particular widescreen cinema material carried letterboxed in a frame with bars top and
bottom. AFD is documented by SMPTE 2016 (multiple part document) and its carriage in compressed
video is documented in DVB/ETSI TS 101 154, ATSC A/53 Part 4, ATSC A/72 Part 1, SCTE 128, and other
standards.
AGC
Automatic Gain Control. Keeps the output signal of a circuit constant while the input signal amplitude
varies.
Alarm Indicator
Displayed in the title bar of each web client page of the device. It appears in red when an alarm is
issued and notifies of a fault and of its nature.
AMOL
Automated Measurement of Lineups
ARP
Address Resolution Protocol. Used for communications between network devices. See BOOTP.
ASI
Asynchronous Serial Interface. A DVB-defined electrical interface for carrying MPEG-2 transport
streams at a defined transmission rate within a 270 Mbps carrier.
ATSC
Advanced Television Systems Committee. Establishes standards for digital terrestrial television system
in the US and other countries.
B
balanced audio
Audio that is transmitted differentially, that is, sending the positive and negative signals of an audio
waveform so that the audio arrives undistorted because noise is cancelled out. See also unbalanced
audio.
bandwidth
The maximum amount of data that a transmission device (cable, fiber-optics link, satellite feed, and so
on) is capable of carrying.
BER
Bit Error Rate. The ratio of bits transmitted in error to the total bits sent. For example, a BER of 10
6
means 1 bit in a million is received in error.
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