HE4000 Encoding System
Glossary
Pixel
Picture Element.
1.
The smallest unit of area of a video screen image that can be turned on
or off, or varied in intensity.
2.
The smallest division that makes up the raster scan line for a video
display.
PLCP
Physical Layer Convergence Protocol. In DS3 transmission, the part of the
physical layer that adapts the transmission facility to perform the distributed
queue dual bus (DQDB) access as defined in IEEE 802.6-1990.
PLL
Phase Locked Loop
ppb
Parts per Billion
ppm
Parts per Million
PSI
Program Specific Information.
PVC
Permanent Virtual Circuit. A logical dedicated circuit between two user ports in
a point-to-point configuration.
P/N
Part Number
Q
QAM
Quadrature Amplitude Modulation
QPSK
Quadrature Phase Shift Keying. The transmission of 2 bits per symbol, with
each symbol being a phase range of the sine wave. In this fashion, a 2:1
compression ratio is achieved, resulting in a doubling of the efficiency with
which a circuit is employed.
R
RAM
Random Access Memory
RCD
Remote Control Device. A computer terminal used to configure and monitor an
encoder or an IRD without using the unit’s control front panel.
RF
Radio Frequency
RF Input
The L-Band, C-Band, or Ku-Band input to an IRD.
ROM
Read Only Memory
rms
Root Mean Square
RU
Rack Unit. 1 RU = 1.75”/4.45 cm
Rx
Receive (Receiver)
RxD
Receive Data
R-S
Reed-Solomon Coding. Reed-Solomon codes are block-based error correcting
codes with a wide range of applications in digital communications and storage.
01-0951-404 Rev B
GL-9