- •Учреждение образования «высший государственный колледж связи» «чтение и перевод технических текстов по специальности ткс»
- •Часть I
- •Введение
- •Unit 1 (17) Antennas
- •17.1 Types of antennas
- •17.1.1 Antennas used in communications
- •17.2 Basic properties
- •17.3 Generic antenna types
- •17.3.1 Radiation from apertures
- •1 Learn the words & word combinations:
- •2 Read & translate the text (orally) 17.1 – 17.3.2:
- •5 Answer the questions:
- •17.3.2 Radiation from small antennas
- •17.3.3 Radiation from arrays
- •17.4 Specific antenna types
- •17.4.1 Prime focus symmetric reflector antennas
- •17.4.1.1 Parabolic reflectors
- •17.4.1.2 Aperture fields and radiation patterns
- •17.4.1.3 Gain of reflector antennas
- •1Learn the words & word combinations:
- •2 Read & translate the text (orally) 17.3.2 – 17.4.1:
- •5 Answer the questions:
- •17.4.2 Dual symmetric reflector antennas
- •17.4.3 Offset reflectors
- •17.4.4 Horn feeds for reflector antennas
- •17.4.4.1 Rectangular or square horns
- •17.4.4.2 Small conical horns
- •17.4.4.3 Multi-mode conical horns
- •17.4.4.4 Conical corrugated horns
- •17.4.4.5 Array feeds
- •1 Learn the words & word combinations:
- •2 Read & translate the text (orally) 17.4.2 – 17.4.4:
- •5 Answer the questions:
- •17.5 Antennas used in communication systems
- •17.5.1 Microwave line of sight radio
- •17.5.2 Earth station antennas
- •1 Learn the words & word combinations:
- •2 Read & translate the text (orally) 17.5.1 – 17.5.2:
- •5Answer the questions:
- •17.5.3 Satellite antennas
- •17.5.3.1 Telemetry, tracking and command (tt&c)
- •17.5.3.2 Spot beams
- •17.5.3.3 Multiple beams
- •17.5.3.4 Shaped beams
- •17.5.4 Vhf and uhf communications
- •17.5.5 Hf communications
- •1 Write out the words and word combinations which are still unknown to you and learn them. Unit 2 (20) Frequency division multiplexing
- •20.1 Fdm principles
- •20.2 History
- •20.3 Fdm hierarchy
- •20.3.1 General considerations
- •20.3.2 Channel bandwidth
- •20.3.3 Group and supergroup
- •20.3.4 Higher order translation
- •20.3.4.1 15 Supergroup assemblies
- •20.3.4.2 Mastergroup
- •20.3.4.3 Bell system
- •1 Learn the words & word combinations:
- •2 Read & translate the text (orally) 20.1 – 20.3.4:
- •4Find English equivalents:
- •5 Answer the questions:
- •20.4 Frequency translation
- •20.4.1 Ring bridge modulator/demodulator design considerations
- •20.4.1.1 Carrier compression.
- •20.4.1.2 Carrier and signal suppression
- •20.5 Carriers
- •20.5.1 Carrier frequency accuracy
- •20.5.2 Carrier purity
- •20.5.3 Carrier level
- •20.6 Pilots
- •20.6.1 Translation equipment pilots
- •20.6.1.1 Use of reference pilots for automatic gain control
- •20.6.2 Line equipment pilots
- •20.6.2.1 Regulation pilots
- •20.6.2.2 Frequency comparison pilots
- •1 Learn the words & word combinations:
- •2 Read & translate the text (orally) 20.4 – 20.6
- •5. Answer the questions:
- •20.7 Noise contributions
- •20.7.1 Definitions
- •20.7.2 Psophometric weighting
- •20.7.3 Thermal noise
- •20.7.4 Noise due to unlinearity
- •20.7.4.1 Single channel load
- •20.7.4.2 Multichannel load
- •20.7.4.3 Unlinearily characterisation
- •20.7.4.4 Determination ofunlinearity noise from a multichannel load
- •20.7.4.5 Approximate value for the weighted intermodulation noise contribution
- •20.7.4.6 Weighted noise power in pWOp
- •20.7.4.7 Determination of unlinearity noise using spectral densities
- •1 Learn the words & word combinations:
- •2 Read & translation the text (orally) 20.7:
- •5 Answer the questions:
- •20.8 Measurement of noise contributions
- •20.9 Overload
- •20.9.1 Overload measurement.
- •20.9.1.1 Harmonic/intermodulation products
- •20.9.1.2 Gain change
- •20.10 Hypothetical reference system
- •20.10.1 Noise contributions
- •20.10.2 Line sections
- •1 Learn the words & word combinations:
- •2 Read & translate the text (orally) 20.8 -20.10:
- •5 Answer the questions:
- •20.11 Companding
- •20.11.1 Compander characteristics
- •20.11.2 Multichannel load increase
- •20.11.3 Compandor noise advantage
- •20.13 Transmultiplexers
- •20.13.1 Synchronisation
- •20.13.2 Pcm alarms
- •20.14 Repeatered cable line equipment
- •20.14.1 Pre-Emphasis
- •20.14.2 Thermal noise
- •20.14.3 Regulation
- •20.14.3.1 Regulation range
- •20.14.4 Power feeding
- •Translate the text 20.11 – 20.14.4
- •Translate in written form point 20.13 “Transmultiplexers”
- •«Чтение и перевод технических текстов по специальности ткс»
- •Часть I
20.3.4.1 15 Supergroup assemblies
Supergroups 2 to 16 (Figure 20.2) are translated to the band 312 to 4028kHz and form the 15 supergroup assembly or 'hypergroup'. Note that supergroup 2 is not translated and passed forward directly to sit in the higher order spectrum at 312 to 552kHz.
Hypergroups (900 channels) are used as building blocks to assemble large groupings up to 60MHz, the most important is the 12MHz 2700 channel system. The carrier frequency chart up to 12MHz is shown in Figure 20.4.
20.3.4.2 Mastergroup
The mastergroup (Figure 20.5) is a 5 supergroup assembly using supergroups 4 to 8 and spans 812kHz to 2044kHz. This is an alternative scheme for building large systems, which avoids the large 15 supergroup blocks but introduces more stage of translation. Three mastergroups, mastergroup 7, 8 and 9, are translated to a supermastergroup 8516kHz to 12338kHz and supermastergroups are used in further translations stages for 12MHz, 18MHz, and 60MHz systems.
20.3.4.3 Bell system
The Bell system (Figure 20.6) has adopted a different mastergroup arrangement in that 10 supergroups are required to form a mastergroup. The supergroup carrier frequencies vary according to the system usage resulting in different mastergroup frequency allocations. The U600 mastergroup is used as a building block for further translations whereas the L600 mastergroup is used directly for transmission as a 600 channel system. Six mastergroups form a supermastergroup of 3600 channels.
1 Learn the words & word combinations:
Frequency transmission |
Сдвиг, смещение частоты |
To stack |
Укладывать, пакетировать |
Wide band |
Широкая полоса частот |
Carrier frequency |
Частота несущей |
Sideband |
Боковая полоса |
Lower sideband |
Нижняя боковая полоса |
Channel frequency |
Частота канала связи |
Spacing |
Шаг, период, параметр |
Channel spacing |
Разрешение каналов |
Path |
Траектория, путь |
Frequency difference (shift) |
Сдвиг частоты |
Carrier signal |
Сигнал несущей |
Line frequency |
Частота строк |
Line spectrum |
Линейный спектр |
Adjacent channel |
Соединительный канал |
Intermodulation noise |
Интермодуляционный шум |
Audio frequency |
Звуковая частота |
Hierarchy |
Иерархия |
Channel bandwidth |
Ширина полосы пропускания канала |
Voice frequency |
Тональная частота |
Transmission bandwidth |
Ширина полосы пропускания |
Cannel capacity |
Пропускная способность |
Supergroup |
Вторичная группа каналов |
Mastergroup |
Третичная группа каналов |
Bandwidth |
Ширина полосы |
Channel transmission stage |
Каскад канала передачи |
Openwire |
Воздушный провод Беспроводной канал (связи) |
Bias |
Смещение |
Overload |
перегрузка |