Harmonic ProView 7000 User Manual page 218

Glossary

Numerics A B
 
QPSK
Quaternary Phase Shift Keying. QPSK transmits 2 bits at the same time by varying the phase of
the signal. See also
R
RAID
Redundant Array of Independent Disks
RCA connector
A plug and socket for a two-wire coaxial cable used to connect consumer audio and video
components.
Redundancy
A back-up system of Harmonic components that ensures uninterruptible service in the event of
a
component
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 output of each device in the chain is checked in turn versus the nominal level.
This is an analog concept and measurement. The setting permits the encoder to adjust its gain
structure to ensure that the resulting digital audio level for a sine-wave tone at Reference Level will
be 20 dBFS.
In the digital domain the Facility Reference Level should be equivalent to -20 dBFS (decibels
below Full Scale) per SMPTE RP155.
Reference Service
An input service that its content is streamed via an output service. The output service is
automatically updating according to changes detected in the specific input service.
relay
An electrical switch that allows a lower voltage to control a higher one. A small current energizes
the relay, which closes a switch, allowing a large current to flow through.
© 2011 Harmonic Inc.
C D E F
    
Q R S T
  
.
QAM
failure.
G H I J
   
U V W Y
   
218
L M N O
   

ProView 7000 v.2.4, Rev. A
P
