PAM
Pulse Amplitude Modulation produces a
sequence of possibly overlapped pulses with
the amplitude of each modulated by a symbol.
QAM, PSK, BPSK, PRK, QPSK, DPSK, and
AM-PM are all special cases of passband
PAM
Pass band
The range of frequencies accommodated by a
given filter, amplifier, or circuit.
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.