dex multimode fibers, Footprints Frequency Shift Keying (FSK), 39 124-126 satellite communications, 275 Frequency spectrum, 258 Grating lobes, 287, 290-291 spot beam antennas, 302 Fresnel diffraction, 223-225 Gray code, 19 Forced switch commands, 418 Fresnel zone, 272 Gregorian reflector antennas, Forward Error Correction (FEC), Fricatives in speech, 3-4 294-295 79, 81-82 Friis cascade formula, 162-164 Ground conductivity, 255-256 Index Ground reflections of space Horizontally polarized ground Interference waves, 243 wave transmissions, 263 data transmission, 41-43 Ground waves Horn feeds, 296-298 ISI, 36, 179 characteristics, 251-256 H-plane cuts, 279 terrestrial line-of-sight radio wave propagation, HSSG. See High Speed Study propagation, 272 263-265 Group Interior Gateway Protocols Group delay in optical fibers, 119 Huffman coding, 69 (IGPs), 399-400 Group Identification (GID) bit, Human auditory perception, 8-9 Interleaved codes, 92 Human eye, contrast sensitivity, Intermediate saturation, 159-160 Group index for glass, 119 Intermodal dispersion Group Velocity Dispersion Huygen's principle, 223-225 multimode fibers, 122 (GVD), 178 Hybrid codecs, 70 single-mode fibers, 127 Group velocity of optical fibers, Hydrometeors, 245-247 Intermodulation noise, 42 Hydroxyl group (OH), 117 Internal BGP (IBGP) interface, Grouped framing strategy, 21 Hypothetical isotropic antennas, 399-400 Groups of wavelengths in Internet Control Message chromatic dispersion, 177 Protocol (ICMP) packets, G/T. See Gain-to-Noise Temperature ratio IBGP. See Internal BGP interface Internet, video transport over. Gyrofrequency, 248 Ice crystals, 247 See Video transport over ICMP. See Internet Control Internet Message Protocol packets Intersymbol Interference (ISI), 36, H26x compression standard, IDF. See Inverse Dispersion Fiber 60-61 IGPs. See Interior Gateway Intrachannel FWM, 200 Hadamard codes, 91 Protocols Intrachannel XPM, 200 Half-duplex transmissions, 30 Illumination efficiency, 294 Intracoded pictures, 72 Half wave dipoles, 284 ILMs. 