Title: Recommended Words for Cable Telecommunication Postgraduate Entrance Examination
The Cable Telecommunication Postgraduate Entrance Examination is a highly competitive exam that requires a strong foundation in the field of telecommunications. In order to prepare effectively, it is recommended that students focus on mastering advanced topics such as digital signal processing, network optimization and architecture, and wireless communication systems. Additionally, it is essential to have a solid understanding of mathematical principles such as linear algebra, calculus, and probability theory. Attention should also be given to practical applications of these concepts through hands-on experience and research projects. It is crucial for applicants to exhibit their critical thinking skills and problem-solving abilities during the examination by analyzing complex scenarios and developing innovative solutions. Finally, effective communication skills are essential for success in this field, including the ability to present ideas clearly and concisely in written or oral form. By following these recommendations and dedicating sufficient time and effort to preparation, candidates can increase their chances of excelling in the Cable Telecommunication Postgraduate Entrance Examination.
As the field of cable telecommunication continues to grow and evolve, so does the need for professionals with in-depth knowledge and expertise. One way to gain entry into this competitive industry is by pursuing a postgraduate degree in cable telecommunications. To excel in this field, it is essential to have a strong foundation in the key concepts, technologies, and terminology. This article provides a list of recommended words for the postgraduate entrance examination in cable telecommunications, covering various aspects of the field.
1. Coaxial cable (同轴电缆)
Coaxial cables are one of the most common types of cable used in cable telecommunication systems. They consist of two concentric conductors wrapped around a central wire, separated by a thin layer of insulation. The outer conductor is typically copper and the inner conductor is made of aluminum. Coaxial cables are highly resistant to electromagnetic interference (EMI) and are therefore widely used in applications such as television, radio, and data transmission.
2. Frequency division multiplexing (频分复用)
Frequency division multiplexing (FDM) is a technique used to transmit multiple channels of data over a single frequency band by dividing the frequency spectrum into different time slots. Each channel is transmitted independently, allowing for greater bandwidth utilization and improved signal quality. FDM is commonly used in cable television systems to transmit standard and high-definition video signals, as well as audio channels like music and voice.
3. Time-division multiplexing (时分复用)
Time-division multiplexing (TDM) is another technique used to transmit multiple channels of data over a single frequency band by assigning each channel a specific time slot on the frequency spectrum. TDM is similar to FDM, but instead of dividing the frequency spectrum into time slots, it divides it into symbols or bits. TDM is often used in more advanced cable telecommunication systems, such as fiber-optic networks, to transmit high-speed data traffic like Internet Protocol (IP) packets.
4. Coded symbol period (CST)
Coded symbol period (CST) is a measure of the time required to transmit a single coded symbol using a particular transmission method, such as FDM or TDM. It is typically expressed in milliseconds (ms) or microseconds (μs). The CST determines the maximum data rate that can be achieved with a given transmission system and is an important factor in selecting the appropriate cable type and configuration for a given application.
5. Error vector magnitude (EVM)
Error vector magnitude (EVM) is a measure of the amount of distortion present in a digital signal caused by noise or other errors during transmission. It is calculated by taking the magnitude of the difference between the original signal and its reconstructed version using techniques like inverse error correction (ICE). EVM is an important performance metric for cable telecommunication systems, as it determines the ability of the system to maintain reliable and accurate transmission of data.
6. Optical fiber communication (OPC)
Optical fiber communication (OPC) is a technology based on the use of optical fibers to transmit data between devices. Unlike coaxial cables, which rely on electrical signals, optical fibers utilize light waves to carry information. OPC has several advantages over traditional wired and wireless communication systems, including higher data rates, lower latency, greater bandwidth efficiency, and immunity to electromagnetic interference. OPC is commonly used in applications such as long-distance data transmissions, high-speed networking, and satellite communications.
7. Quadrature amplitude modulation (QAM)
Quadrature amplitude modulation (QAM) is a technique used to encode binary data into multiple levels of amplitude using a set of parallel signals representing different bits. QAM allows for greater data compression than simple binary modulation and is commonly used in cable telecommunication systems to transmit high-definition video and audio content over long distances. QAM schemes with higher order bits provide even greater gains in compression efficiency but also increase the complexity of the encoding and decoding process.
8. Channel coding (CC)
Channel coding (CC) is a method used to add additional layers of information to raw signal data, such as error correction codes or spatial diversity signals, to improve their reliability and robustness in noisy environments. CC is commonly used in cable telecommunication systems to mitigate interference from neighboring channels or equipment failures, and can also be used for adaptive bit allocation and rate adaptation techniques like channel bonding and vectoring.
9. Vectoring (向量化)
Vectoring (或称向量调制、矢量编码)是一种利用多个独立的正交信号来表示原始数据的技术，在有线通信系统中，矢量编码常用于实现多路复用(如FDM和TDM)以及提高抗干扰能力和信道容量，矢量编码的主要优点是它可以在保持数据传输速率的同时减少所需的带宽资源，矢量编码技术包括空时分组码(BPSK)、正交幅度调制(QAM)、多进制相移键控(MPSK)等。
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