HS code tagging in tariff databases

List of the contents of this article:

• 1,HS code tagging in tariff databasesAsk for answers~Modern Communication System
• 2. Principles of Modern Communication Systems, Ask for Answers
• 3, "The Principles of Digital Communication (Third Edition)" textbook after-class exercises
• 4. () in the mobile communication system belongs to the self-interference system.
• 5, The so-called gate limit effect refers to ___; weighting technology is often used in communication systems, which can improve ___...
• 6, Communication System Principle-Guo Yuchun-4, 5, Chapter 6 Answers to after-class questions

ask for answers~modern communication system

FDMA/TDMA, GMSK ( ) half-dupluplex communication mode, using ___ channels for signal transmission. A. A b. Two c. One or two ( ) source coding and channel coding technologies are adopted in the ___ communication system.

Internet servicesProvider (ISP, Internet Service Provider): ISP is an organization or company that provides Internet access services. They enable individual users and enterprises to connect to the Internet by establishing network infrastructure and providing network access services.

Communication refers to the exchange and transmission of information between people or between people or between people and nature through a certain behavior or medium. Broadly speaking, it refers to the two or more parties that need information use arbitrary methods and arbitrary media to transmit information from one party to another accurately and safely without going against their respective wishes.

There are various modern communication methods. The following are some common communication methods: telephone communication: traditional voice calls, suitable for instant communication and exchange. SMS and MMS: Communicate by sending text messages and pictures and videos through mobile phones.

[Satellite phone] The phone based on the satellite communication system to transmit information is the satellite phone. Satellite telephone is a product of modern mobile communication. Its main function is to fill the areas that cannot be covered by existing communication terminals (wired communication, wireless communication) and provide more sound services for people's work.

Modern communication system principle, seek the answer

The generation matrix of the known (7,4) code is, write down all the allowed code groups, and find the supervision matrix. If the receiving code group is 1101101, calculate the correction. Solution: (1) Find all the allowed code groups: the supervision bit r=3, the information bit k = use the rows of the G matrix to add up all the code groups, as shown in the table on the right.

Communication Principle 2023 Chapter Test Answer_Communication Principle Super Star Elegant Answer Chapter 5 Quiz [Single-choice Question] In the telecommunication system, the transmission of ( ) is realized through ( ).

Probability density function f(x)=8 of Gaussian distribution. The Gaussian process is a Gaussian process after passing through a linear system, and a steady process is a steady process after passing through a linear system. CertainThe expectation of a steady stochastic process is a, and the transmission function of a linear system is H (ω), so the average value of the output stochastic process is aH (ω).

Wednesday, November 2, 2-1 The autocorrelation function of the steady stochastic process is to try to find: the power spectrum density; the average power S and DC power; the variance. 2-2 The bilateral power spectrum density of the known steady Gaussian white noise is. After a linear system with an impact response, the output is, if the known energy is, the power is sought.

Communication principles final exam paper and answers fill-in-the-blank questions (total score 24, a total of 12 questions, 1 point per blank) The effectiveness of the digital communication system is measured by the transmission frequency band utilization rate, and the reliability is measured by the error rate.

According to whether the signal transmitted in the channel has been modulation, the communication system can be divided into baseband transmission system and frequency band (modulation) transmission system.Baseband transmission is the direct transmission of unmoduted signals, such as audio city telephones; frequency band transmission is to modulate the baseband signal and then transmit it to the channel.

"Principles of Digital Communication (Third Edition)" Textbook After-class Exercises and Answers

1, "Principles of Digital Communication" Exercises and Answers Chapter 1 Overview 1-1 The characteristics of analog signals and digital signals respectively What is it? Analog signals are characterized by continuous amplitude; digital signals are characterized by discrete amplitudes.

2. Is it interesting? Like this! You either choose all A or all choose B. If I were you, I wouldn't do it all unless it was an exam.

3. Final exam papers and answers of communication principles fill-in-the-blank questions (total score24, a total of 12 questions, 1 point for each blank) The effectiveness of the digital communication system is measured by the utilization rate of the transmission frequency band, and the reliability is measured by the error rate.

4. Communication Principle 2023 Chapter Test Answer_Communication Principle Super Star Elegant Answer Chapter 5 Quiz [Single-choice Question] In the electronic communication system, the transmission of ( ) is realized through ( ).

5. Textbook Chapter 6 Exercises and Answers to Computer Questions 1. Design a Butterworth low-pass filter, which requires the pass-band cut-off frequency fp=6kHz, the maximum pass-band attenuation ap=3dB, the impedance band cut-off frequency fs=12kHz, and the minimum attenuation of the impedance band as=25dB. Find the filter normalized system function G(p) and the Ha(s) of the actual filter.

() in the mobile communication system belongs to the self-interference system.

1. CDMA system belongs to self-interference system. It belongs to the third generation of mobile communication technology.

2. Number of frequency points: The number of 900 megabytes of frequency points of Unicom is 27, while the number of frequency points of mobile is 94. In the global mobile communication system, this is a self-interference system. The more frequency points, the less interference. Operation time and technical management: Unicom's operation time is relatively short, and the technology and management may not be as sound as Mobile.

3. WCDMA is a way to divide the code into multiple addresses and network at the same frequency. The more users, the denser the base station and the more interference. There will be interference between users. So it's self-interference. It is a kind of 3G. GSM is a frequency division and time division system. In addition, the user will not interfere with the user.

4. There is a problem of "far and near effect" in mobile communication. The so-called far and near effect, if the mobile station sends a signal with the same power, the strength of the mobile station signal away from the base station to the base station is much weaker than that of the mobile station far away from the base station, so it is submerged by the signal.

5. That is to say, the useful signal from the same frequency point is higher than a certain ratio of the interference signal. The capacity of the GSM system cell depends on the load-to-dry ratio and hardware configuration, and the upper and down-line capacity is symmetrical.

6. GSM is mobile, Unicom 2G network format, and telecom networks are CDMA and CDMA2000, which is the guarantee of high-speed Internet access and confidential calls. You can log in to the online business hall of Anhui Telecom to buy mobile phones, apply for gift packages, broadband packages and other services, and enjoy more discounts in the online hall.

The so-called gate limit effect refers to ___; weighting technology is often used in the communication system, which can improve ___...

1. [Answer]: When the input signal-to-noise ratio is reduced to a certain gate limit value, the output signal-to-noise ratio of the system will deteriorate significantly, and the noise will suddenly increase significantly. This phenomenon is called Gate effect $ output signal-to-noise ratio.

2. The so-called gate limit effect is a phenomenon that when the input signal-to-noise ratio of the envelope detector is reduced to a specific value, the output signal-to-noise ratio of the detector deteriorates sharply. The input signal-to-noise ratio of the gate effect is called the gate value. This gate effect is caused by the nonlinear demodulation of the envelope detector.

3. First of all, let me explain that the OSI seven-layer model is a kind of idea, which is the general standard followed by manufacturers when developing software. It interprets the process of data communication. It is an abstract concept. Answer 1: It is neither the TCP/IP protocol of the operating system nor the network device. Because these two only complete a function in the 7th layer.

Communication System Principle-Guo Yuchun - Chapters 4, 5, 6 After-class Questions Answers

-6t0T2T3T4T5T sampling points are each zero point, and there is no inter-code interference communication system original Li Guo Yuchun Zheng Hongyun 15-6 is known to be transmitted binary sequence ak1011010011, and try to draw the corresponding PSK signal waveform for the following situations.