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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 

QPSK

Quaternary Phase Shift Keying. QPSK transmits 2 bits at the same time by varying the phase of

the signal. See also

QAM .

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

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 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.

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