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P
LP :
(Physical Layer Pipe) from 1 to 256 channels are available in DVB-T2 to transport inde-
pendent multiplexes.
P
OLARIZATION:
Polarization of a signal from the satellite. It can be either:
linearly polarized, horizontally or vertically:
Circularly polarized to the right or the left
In ground reception, the polarization is generally horizontal (the stalks of antennas are horizon-
tal). Some receptions in band VHF are in vertical polarization (Canal+). In this case, the stalks of
the antenna are vertical.
P
OSITIONER:
A motorized system for the rotation of a satellite dish. Positioners are operated
by DiSEqC commands
Q
AM
:
Quadrature Amplitude Modulation.
This kind of modulation is used for digital transmissions (cable networks and DTT).
Q
PSK:
Quadrature Phase Shift Keying (or 4PSK)
A kind of modulation mostly used for satellites.
8
PSK
:
A type of modulation identical to QPSK, but with an 8-possibility (3-bit) coding. This kind
of modulation enables
higher rates than QPSK and is compatible with DVB-S2.
R
EED-S
OLOMON
:
An algorithm used to correct errors in digital transmissions
S
TANDARD:
Any norm that defines the characteristics of a modulation.
Analogical standards: L, BG, DK, etc.
Digital standards:
QAM for
cable television
QPSK, 8PSK for
satellite television
COFDM for
terrestrial digital television