Harmonic ProView 7100 - Page 213

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. 213 ProView 7000 v.2.6, Rev. E
port
A port is an input to or an output from a component, an adapter, or a module.
program
In MPEG-2 Systems, a program is a collection of video, audio, and data elementary streams carried in a
TS that share a common clock reference.
PSI
Program Specific Information. A set of MPEG-2 inband control tables. The tables contain tuning
information, information about the relationships between the various elementary streams, and
conditional access information. See also SI.
PSIP
Program and System Information Protocol
PTS
Presentation Time Stamp. An MPEG-2 defined field that can be present in the PES packet header to
indicate the time the access unit is to be presented (displayed) to the viewer.
Q
QAM
Quadrature Amplitude Modulation. Transmits 4 bits (16 QAM) to 8 bits (64 QAM) at the same time by
varying the phase and amplitude of a signal. See also QPSK.
QPSK
Quaternary Phase Shift Keying. QPSK transmits 2 bits at the same time by varying the phase of the
signal. See also QAM.
R
Redundancy
A back-up system of Harmonic components that ensures uninterruptible service in the event of
a component failure.
Reed-Solomon decoder
A device that performs error correction on the incoming data stream.
reference clock
The 27-MHz abstract clock from which various physical clocks are instantiated. The encoder maintains
a 27 MHz encoder clock, and via correct placement of PCR values into the Transport Stream, the
decoder is able to reconstruct the reference clock in the form of a decoder clock.
reference level
Reference level is the nominal level to which all parts of an audio signal chain are aligned. This is
commonly +4 dBu or 0 dBu for analog audio systems. It is measured in an out of service measurement
where a sine-wave tone of the nominal level is introduced at the entrance of the system and then the