
Glossary
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Pilot Channel The Lowest and Highest of the channels (9 max total)
selected as criteria for TILT.
Pilot Level Level in dBmV of Pilot Channel used for TILT.
Pixel A Pixel (Picture Element) is the smallest area of a television picture
capable of being delineated by a signal passing through the system.
PSK Phase-Shift Keying modulation: shifting the carrier frequency plus or
minus 90- degrees in phase to represent “0” and “1”, respectively, for digital
transmissions.
QAM Quadrature Amplitude Modulation (QAM) changes both amplitude and
phase simultaneously from symbol to symbol QAM is a special case of pass
band pulse amplitude modulation (PAM), two carriers on the same
frequency, but 90 degrees out of phase and modulated by the real and
imaginary parts of a complex-valued baseband signal. A polar plot of
amplitude and phase for each discrete modulation level produces a
constellation of points representing the amplitude of the in-phase and
quadrature components of the transmitted Cartesian coordinates.
Reverse Sweeping Sweeping upstream toward the Headend of a CATV
system. Usually limited to within 5-42 or 5-65 MHz. See Sweeping.
Reference Level In Stealth SPECT Mode, the reference level is the top of
the screen/graph. In SWEEP mode the reference level is the middle of the
screen/graph.
Roll Off A gradual or sharp attenuation of gain at either or both ends of a
transmission pass band.
SCAN In the Stealth system, SCAN Mode shows on one display the voltage
levels of all carriers across a given spectrum. Video and Audio carrier levels
are shown, separately, in dBmV.
SECAM The television broadcast standard used in France, the Middle East,
and most of Eastern Europe. SECAM broadcasts an analog signal at 625
lines of resolution, 25 interlaced frames a second, and uses sequential
encoding of primary colors in alternating scan lines.
SLM Signal Level Meter
Slope Difference in gain between the ends of a band of frequencies.
Spectrum Inversion Spectrum Inversion designates whether or not the
signal is inverted.
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