Cisco Model D-PCG1000 PowerKEY CAS Gateway User Guide

Glossary

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PSI

program-specific information. Associated with MPEG-2 digital configuration; system data

comprised of PAT, PMT, CAT, and NIT.

PVR

See DVR.

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).

QPSK modulator/demodulator

The QPSK modulator works with the QPSK demodulator and the DHCT to provide forward

signaling and a reverse communications path for interactive video and data services. The

QPSK modulator and demodulator convert digital bit streams to RF format and RF signals to

digital bits, respectively.

radio frequency. The range of electromagnetic frequencies above the audio range and below

infrared light. Most wireless transmission uses RF, including radio, TV, satellites, portable

phones, cellular phones, and wireless networks.

RMA

Return material authorization.

RPPV

reservation pay-per-view. Requires the subscriber to use the telephone to reserve a PPV event.

SAM

Service Application Manager. Associates a specific service with an application that defines the

medium to be used for that service, such as the World Wide Web. The SAM maintains the

application in a specific directory to be used when needed by the DHCTs.