
4 сем / 4 сем дз задания / Task 60
.docxTask 60: Find the English versions of the following sentences in the text.
"These electro-mechanical devices are, of course, limited to low frequencies and useful only in the most simplistic applications."
"But soon, high frequency modulators were developed, using both direct and indirect modulation methods."
"Optical fibers have a certain amount of dispersion, which introduces uncertainty at the detector, related mainly to transmission distance."
"The current swing is reduced, which improves reliability, and the bandwidth is greatly increased because the diode’s drift and transient responses are reduced."
"These devices can rapidly switch the light beam between a direct signal path, or split the beam into two paths with 180-degree phase shift, which cancel when recombined."
Task 61: Translate the following sentences from English into Russian.
Ключевание включения-выключения и амплитудная модуляция (AM) выполняются таким же образом, как радиопередатчик, используя последовательно проходящий транзистор в цепи постоянного тока передающего устройства.
Типичный источник света для оптических коммуникаций - лазерный диод, который легко модулируется путем управления его током.
Эта неопределенность ухудшается при высоких скоростях передачи данных - интеграция может помочь устранить неопределенность, и время интеграции уменьшается с короткими высокоскоростными импульсами.
Это также устраняет проблемы соотношения сигнал/шум при применении модулированного субносителя.
Как и при прямой модуляции, управляющие схемы используют микроволновое проектирование и компоновку для соединения высокоскоростных потоков данных с модулирующими устройствами.
Task 62: Agree or disagree with the following statements.
It is not easy to apply the modulation for either voice transmission or low rate digital information via control of the current to a laser diode or LED.
Disagree. The text states: "It is easy to apply the modulation for either via control of the current to a laser diode or LED."
Microwave design and layout techniques have been used to assure performance of driving circuitry well into the GHz range, removing this as a major limitation.
Agree. The text states: "Microwave design and layout techniques have been used to assure performance of driving circuitry well into the GHz range, removing this as a major limitation."
Ultimately indirect modulation is not limited by the characteristics of the diode itself.
Agree. The text implies that indirect modulation techniques are used to overcome limitations related to the diode: "Modulation of a continuous light beam removes the laser diode-related problems at the cost of greater complexity."
Established methods include delivering the data to electrically modulated crystalline materials such as lithium niobate.
Agree. The text states: "Established methods include delivering the data to electrically modulated crystalline materials such as lithium niobate."
The latest developments in solid state optical switching are slower than EA, so switched optical paths are used, integrated onto the same substrate.
Disagree. The text states: "The latest developments in solid state optical switching are faster than EA, so switched optical paths are used, integrated onto the same substrate."
Summary of the Text
Bibliography: The author is not mentioned, A Tutorial Introduction to Optical Modulation Techniques
Title of the Article: A Tutorial Introduction to Optical Modulation Techniques
Aim of the Article: The aim of the article is to show the reader the different techniques of optical modulation, including their applications, benefits, and limitations.
Research Method: The research method used in the article is description and comparison of various optical modulation techniques.
Brief Content Summary: The article discusses simple modulation schemes, such as on-off keying and amplitude modulation (AM), which are easy to implement with laser diodes or LEDs. It then explains direct modulation, where digital signals modulate the current of a laser diode, highlighting limitations such as time constants and dispersion in optical fibers. The text also covers indirect modulation, using external modulators like lithium niobate or electro-absorption modulators to achieve higher performance at the cost of increased complexity.
Period Described: The article describes the development and evolution of optical modulation techniques without specifying a particular period.
Conclusion: The authors' conclusion is that while direct modulation is simpler, it is limited by the diode's characteristics and transmission medium. Indirect modulation offers higher performance but requires more complex systems. Further study is encouraged for a deeper understanding of optical modulation.
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