Cisco Cisco Explorer Set-top Software Version 2.1 Guia Do Utilizador
Glossary
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time on television sets or other devices. With PIP feature of TV, one program will be
displayed on the entire TV screen, and another program or programs will be displayed in
individual smaller squares on the screen.
POST
Power on self test. Set of hardware diagnostics that runs on a hardware device when that
device is powered up.
PPV
pay-per-view. Service for which subscribers are charged a user fee for individual program
events. See also IPPV.
PTS
Presentation time stamp.
PVR
See DVR.
Q
QAM
quadrature amplitude modulation. A frequency modulation technique primarily used for
program audio and video. QAM supports data rates from 27 Mbps to 36 Mbps.
QAM modulator
A device that uses QAM techniques to modulate a digital signal onto an HFC network to
deliver voice, video, and data to a DHCT.
QPSK
Quadrature Phase-Shift Keying. Digital modulation scheme that send data by modulating the
phase of a reference signal (the carrier wave).
R
Radio Frequency
Logical grouping of information that includes a header containing control information and
(usually) user data.
RAM
Random access memory. Volatile memory that can be read and written by a microprocessor.
RDC
Reverse data channel.