PAL Programmable Array Logic
PAM Pulse Amplitude Modulation
PAR Precision Approach Radar. An X-band radar which
scans a limited area and is part of the ground-con-
trolled approach system.
PATA Polish Air Traffic Agency
PAU Passenger Address Unit
PAX Passenger
PBID Post Burn-In Data
PBX Private Branch Exchange
PC (1) Personal Computer
(2) Printed Circuit
P-Code The GPS precision code
PCB Printed Circuit Board
PCC Pilot Controller Communication
PCI Protocol Control Information. The N-PCI is
exchanged between peer network members (OSI
Model) to coordinate joint information.
PCIP Precipitation
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PCM Pulse Code Modulation
PCU (1) Passenger Control Unit (2) Power Control Unit
PDC Pre-Departure Clearance
PDCU Panel Data Concentrator Unit
PDDI Product Definition Data Interface. Standardizes digital descriptions of part configurations and properties needed for manufacturing.
PDF Primary Display Function
P-DME Precision Distance Measuring Equipment
PDN Public Data Network
PDOP Position Dilution Of Precision. A GPS term for error introduced into the GPS calculations.
PDOS Powered Door Opening System
PDR Preliminary Design Review
PDS Primary Display System
PDU (1) Protocol Data Unit. The N-PDU is a combination of the N-PCI and the N-UD or N-SDU. The N-PDU is the total information that is transferred between peer network members (OSI Model) as a unit. (2) Power Drive Unit
Performance Index A relative number used to compare the performance of different radar systems. It is calculated from trans mitter peak power, antenna gain,pulse width,prf, antenna beam width and the receiver noise figure.
PED Portable Electronic Devices
PET Pacific Engineering Trials
PF Power Factor
PFC Primary Flight Computer
PFCS Primary Flight Control System
PFD (1) Primary Flight Display. An EFIS presentation sub-stituting for the ADI. (2) Primary Flight Director.
PFE Path Following Error
PFR Pulse Repetition Frequency. The rate at which pulses are transmitted.
PGA Pin Grid Array
PHY Physical Interface Device
Phase A signal in which the phase varies (with respect to
Modulation the original signal) with the amplitude of the modula tory signal,while the amplitude of the carrier wave remains constant. Similar to a modified frequency modulated signal.
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