Installation Guide

Glossary
4035812 Rev B 31
phase and amplitude of carrier waves are altered to represent the binary code. By
manipulating two factors, more discrete digital states are possible and therefore larger binary
schemes can be represented.
QAM256
A QAM technique that produces 256 discrete states, each state representing 8 bits of
information. The most complex of common QAM techniques.
QAM64
A QAM technique that produces 64 discrete states, each state representing 6 bits of
information.
QPSK
quadrature phase-shift keying. A phase modulation technique for representing digital
information. QPSK produces four discrete states, each state representing two bits of
information.
R
RCA
A type of electrical connector commonly used in consumer products to carry audio and video
signals. The name derives from Radio Corporation of America, which originally developed
the connector.
reverse path
Signal flow direction toward the headend.
RF
radio frequency. The frequency in the portion of the electromagnetic spectrum that is above
the audio frequencies and below the infrared frequencies, used in radio transmission systems.
RX
receive or receiver.
S
S/N or SNR
signal-to-noise ratio. The ratio, in decibels, of the maximum peak-to-peak voltage of the video
signal, including synchronizing pulse, to the root-mean-square voltage of the noise. Provides
a measure and indication of signal quality.
SAP
second audio program. In a BTSC-encoded television sound carrier, a separate monaural
audio subcarrier that accompanies the main audio channel. Typically used to transmit audio
in a different language.