CMN-91
Appendix C
Installation and Operation Manual
Glossary
© 2016 Imagine Communications Corp. Proprietary and Confidential.
Revision D | Page 184
Headend In a cable TV system, the facilities where program sources (satellite, terrestrial, VTR, local) are
received and remodulated for distribution through a cable plant.
Headless Operation A unit does not require local keyboard, monitor, and mouse to operate. All
operation can be managed from remote locations.
High Definition Television (HDTV) High definition television has a resolution of approximately twice that
of conventional television in both the horizontal (H) and vertical (V) dimensions and a picture aspect
ratio (H to V) of 16:9.
High Level A range of allowed picture parameters defined by the MPEG-2 video coding specification
which corresponds to high definition television.
HLS HTTP Live Stream. A standard proposed by Apple for Internet streaming to iPhone, iPad, and similar
devices.
HRC Harmonically-Related Carrier
Hue Color tint
ICPM Incidental Carrier Phase Modulation. A measurement of picture carrier phase distortion (affected
by the video signal level) that occurs in the transmitter.
Installation Categories Categories of measurements that occur on circuits attached or not attached to a
live electrical supply outlet. Installation Categories are as follows:
Category I is for measurements that occur on circuits not attached to a live electrical supply outlet
(115/230 VAC). The voltages come from secondary power sources. The secondary power source
includes circuits energized by low-voltage sources and electronics such as batteries.
Category II is for measurements that occur on circuits attached to a live electrical supply outlet
(115/230 VAC).
Category III is for measurements that occur on equipment permanently connected to the building.
The distribution level equipment are usually fixed installations and circuit breakers.
Category IV is for measurements that occur at the main electrical power supply.
IP Internet Protocol
IRC Incrementally-Related Carrier
I.R.E. Refers to the Institute of Radio Engineers, and is used as a unit of measurement. In NTSC
television, 1 volt of signal equals 140 IRE units.
ISP Internet Service Provider
Jitter A deformation of a signal affected by poor synchronization.
Key An effect in television where a selected portion of background video is removed and replaced with
another video.
Key Cut In a key effect, this is the video which designates the portion of background video which is
removed.