pendent communications, 31 amplifiers, 157 Point-to-Point Protocol (PPP), Precipitation effects, 275 PDH. See Plesiochronous Digital absorption, 270 Hierarchy Point-to-point transmissions, 30 attenuation, 245 PDL. See Polarization-Dependent Pointers in SDH, 317-318, depolarization, 246-247 326-327 Prefixes in frame Peak clipping, 16 Polarization synchronization, 49 Peak cross-polarization, 297 antennas, 279-280 Primary Rate Interface, 373-374 Pencil beam antennas, 277-278 coupling loss, 249 Prime-focus symmetric reflector Pencil beam radiation, 281 electromagnetic waves, antennas, 292-294, 299 Per-Hop Behavior (PHB), 233-235 Principal State of Polarization 392-393 SBS, 138 (PSP), 194 Per-Site Forwarding Tables Polarization-Dependent Private/Public Network- (PSFTs), 398 Chromatic Dispersion Network Interface (PNNIs), Performance (PCD), 194 block-coding, 89 Polarization-Dependent Gain Probability density functions, 171 convolutional-coding, 100 (PDG), 155, 189 Profile dispersion, 178 transmission. See Transmission Polarization-Dependent Loss Propagation performance (PDL), 189 electromagnetism, 225-226 Permanent Virtual Circuits Polarization Mode Dispersion free-space, 259-260 (PVCs), 367 (PMD), 189 ground waves, 263-265 Permeability in Maxwell's compensation, 195-196 media, 261-263 equations, 220-221 first-order and higher-order, monochromatic light, 118 Permittivity in Maxwell's multimode fibers, 120 equations, 220-221 nonideal optical fibers, over-the-horizon, 273-274 Peterson's method, 96 189-191 satellite communications, 275 PFI. See Payload FC Indicator bit from optical compensation, sky waves, 265-269 Phase difference in arrays, 285 terrestrial line-of-sight, 269-273 Phase error efficiency, 294 short and long birefringent Propagation delays, 19, 76 Phase in oversampling effect, fibers, 191-192 Propagation time, 46 12-13 single-mode fibers, 127, Protection mechanisms for Phase-insensitive optical 129-130 Ethernet, 415-419 amplifiers, 161 spun fibers for, 194 Provider Backbone Bridges Phase Lock Loop (PLL) circ