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See also
Satellite systems
Tail links, 308–10
Index
445
Telecommunications network
Time slot reassignment (TSR), 74
Tracking, telemetry, and command
maintenance, 385–86
Telemetry and command (T&C) links,
(TT&C), 280–86
antenna systems, 280–81
197
Telemetry downlink, 197
ground segment, 368
network, 284
Teleport Earth stations, 411–12
Telesat, 53
omnidirectional antenna, 285–86
satellite tracking and ranging, 281–82
Terrestrial microwave links, 309
Terrestrial networks, paralleling, 421–22
spacecraft command system, 284–85
spacecraft telemetry system, 282–84
Thermal control, 286–88
active, 287
See also
Spacecraft bus subsystems
Tracking, telemetry, and command
passive, 287
Three-axis configuration, 196, 260–61
(TT&C) stations, 16, 280,
314–19
flat panel, 268
general arrangement, 261
capability, 314
communication monitoring, 318
stability, 261
structural arrangement, 289
communications equipment, 17
economics, 400, 404–5
See also
Spacecraft
Thrusters
general arrangement, 315–17
link interconnection/switching, 317
axial, 276
bipropellant, 277
location cost, 405
operations, 16–17, 281
comparison, 276
electrically heated (EHT), 277–78
personnel and equipment, 405
photograph, 316
Hall, 278
ion, 278
satellite control center, 317–19
Tracking and data relay satellite (TDRS),
monopropellant, 277
performance parameters, 275
64
Traffic
pulsed plasma (PPT), 278
radial, 276
flow, 413–14
flow conversion, 414–15
Time division multiple access (TDMA),
48, 105, 136, 175–77, 330
requirements determination, 412–15
Training and development, 386–87
carrier hopping, 326
data rate, 211
Transmission Control Protocol/Internet
Protocol (TCP/IP), 12, 74, 77–78,
defined, 175
Earth station, 324–26
87
Transmit EIRP, 294–95
frame assignment, 175
frequency hopping, 177
Transmitting stations, 133–39
block diagram, 135
input/output spectra, 188
modems, 325
encoding and modulation, 135–36
frequency conversion and RF
narrowband, 176
RF equipment for, 324–25
amplification, 136–37
high-power amplification, 137–39
terminals, 325–26
timeframe example, 176
Transponders, 140–42
arrangement, 141
transponder resource sharing, 182
See also
Multiple access
assignment, 142
defined, 3, 140–42
Time division multiplexing (TDM),
72–73, 154, 204, 283
FDMA for, 173
446
Index
Transponders (continued)
U
frequency plan, 142
UHF band, 26–27
gain control, 234–36
Ultrasmall aperture terminal (USAT), 209
intermodulation impairment, 185–89
Uninterruptible power system (UPS), 293
Ka-band, 235
Unshielded twisted pair (UTP), 311
linearization, 234–36
Unsymmetrical dimethyl hydrazine
resource sharing, 182
(UDMH), 350
standard GEO services, 376–79
Upconverters, 304
Traveling wave tube amplifiers (TWTAs),
Uplink C/I, 191
56, 138–39, 228–32
Uplink power control (UPC), 305
defined, 138, 228
User network monitor and control,
379–81
high-power, 216
nonlinear characteristics, 184
V
nonlinear property, 235
Van Allen Belt, 342
power levels, 200
V-band, 35–36
power outputs, 138
Very small aperture terminals (VSATs),
Traveling wave tube (TWT), 228, 229
18, 19, 295
amplification, 230
automatic UPC, 305
collector, 230
defined, 105
as heat producing component, 287,
effectiveness, 106
288
low-power, 234
high-power, 231
multicast feature, 71
schematic diagram, 230
networks, 105–6
three-stage collector, 231
return links, 105
Troposphere, 129
video teleconferencing services, 330
TV broadcasting, 89–93
See also
VSAT star networks
backhaul of event coverage, 92–93
VHF band, 26–27
ground antenna utilization, 93
Video distribution, 89–96
networks, affiliates, independent
cable television, 93–96
stations, 90–91
TV broadcasting, 89–93
program acquisition and playback,
See also
Point-to-multipoint networks
322
Video-on-demand (VOD), 94
satellite content distribution, 91–92
Video teleconferencing services, 330
TV receive-only (TVRO) Earth station,
Virtual circuits, 75
330–34
Voice over IP (VoIP), 75
antenna diameter, 331
Voice quality, 83–85
antenna sizing, 331
VSAT star networks, 326–30
cable head end configuration, 332–33
architecture, 327
direct-to-home, 333–34
hub and network control station,
receiving encrypted programming, 334
327–28
See also
Earth stations
proprietary protocol, 330
TV uplinks/broadcast centers, 319–22
RF terminal, 329
routing and switching, 321–22
terminal configuration, 328–30
video distribution, 321–22
terminals, 326–30
video equipment chain, 320–21
See also
Very small aperture terminals
(VSATs)
See also
Earth stations
Index
447
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