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    What are the main characteristics of the development of the global Internet of Things industry?

    The government attaches great importance to it and strongly supports it. In order to lead the development of the Internet of Things in the future, the European Commission has been committed to encouraging and promoting the development of the Internet of Things industry within the EU in recent years; it has made the development of the Internet of Things an important part of the EU’s digital economy. In Japan, the government has issued an action outline for the CT Hatoyama Plan, a digital Japan innovation project. The combined force of government guidance and demonstration and enterprise R&D promotion has been brought into play, and the application of the Internet of Things has been launched. South Korea’s IT839 strategy takes ubiquitous IoT USN as one of the three major infrastructures.

    What are the main reasons for the non-linearity?

    • The conversion principle of many sensors is nonlinear. For example, in temperature measurement, the relationship between thermal resistance and thermocouple and temperature is nonlinear.
    • The conversion principle of many sensors is nonlinear. For example, in temperature measurement, the relationship between thermal resistance and thermocouple and temperature is nonlinear.

    What factors should be considered in the system design of the car?

    ①Temperature range ~ generally requires -40 ~ 125 ℃.
    ②The influence of oil, water, smoke, dust and chemical corrosive substances that may be encountered.
    ③The influence of mechanical vibration, turbulence and impact.
    ④Electromagnetic compatibility problem: The system must have the ability to withstand external electromagnetic interference and not cause electromagnetic interference to the environment (the electromagnetic field of the home environment is 3 V/m-1, the electromagnetic field of the factory environment is 10 V/m-1, and the electromagnetic field of the automobile environment may be greater than 200V/m-1).
    ⑤ Environmental protection issues. The emissions from work (including sound, light, electromagnetic, oil and gas, etc.) must meet environmental protection requirements, and also consider the disposal of components and vehicles when they are scrapped.
    ⑥ Possible failures and possible misoperations, such as reverse connection of the power supply, wire loss, short circuit/open circuit, friction, etc., should cause as little loss as possible.
    ⑦Protection measures in the event of an accident or the impact on safety should be fully considered.
    ⑧Any component must ensure high reliability, and the probability of failure within the required service cycle should be small enough.
    ⑨ Cost price of mass production.
    The in-vehicle network system should also consider the following factors:
    ①The electrical and mechanical characteristics of the connection joints between nodes and buses, and the number of joints.
    ②Evaluation and performance testing methods of network systems and application systems.
    ③ fault tolerance and fault recovery issues.
    ④ Real-time control of the time characteristics of the network.
    ⑤ Wiring during installation and maintenance.
    ⑥Increase of online nodes and update of software and hardware (expansibility).
    The automotive network system should be reliable, cheap, integrated with the application system, simple in wiring and good in real-time performance. It is characterized by a small range and a small number of nodes, and the transmission speed required by most applications is not high.

    What are the advantages of smart sensors?

    High-precision information collection can be achieved through software technology, and the cost is low. It has certain programming automation ability and diversified functions.

    What are the main components of the walkie-talkie host?

    1. Shell: The professional machine generally adopts the plastic material PC ABS with very good performance, which has good appearance and gloss, not easy to age and wear, and the product is sturdy and durable. Commercial machines often use engineering plastic ABS, which can well meet the requirements in terms of appearance, strength, wear resistance, and aging. The keys are made of silicone, which is wear-resistant, not easy to age, and feels good. The aluminum shell is made of light-weight aluminum alloy ADC12, which is easy to form and follow.
    2. Host: generally includes face shell, PTT button, headphone and power jack plug, PCB assembly, LCD part, volume/switch button, coding knob, indicator light, MIC, etc. The PTT button acts as a transmitter switch, generally on the side. The indicator light indicates the working status, usually at the top. The top of the radio also has a volume/on/off button and an encoder knob (to select a channel). The LCD part visually displays the working status of the walkie-talkie. The PCB component is the core part of the walkie-talkie. The important components are all on the PCB, and non-professionals are not allowed to disassemble. Most walkie-talkies have special shielding covers, aluminum shells (fixed PCB), etc. due to technical performance and anti-drop characteristics. Professional machines also have waterproof requirements, and the structure is more complicated.
    3. Battery: The battery is divided into Ni-Cd, Ni-MH and Li-ion battery, the capacity is 600mAh, 800mAh, 1100mAh, 1500mAh. Lithium batteries are expensive and are still in the development stage. Ni-Cd and Ni-MH batteries are commonly used, and Ni-MH batteries are generally recommended for large-capacity batteries. The battery surface and bottom case are ultrasonically welded, which is firm and reliable.
    4. Belt clip: The function is to fix the walkie-talkie on the belt. For the convenience of customers, the belt clip is removable.
    5. Antenna: It is divided into two parts: the antenna jacket and the antenna core. The antenna jacket is made of high-performance TPU material, which has good bending resistance and aging resistance. The antenna core is generally connected to the host by a threaded structure, which is easy to disassemble.
    6. Cradle Charger: Share with Huo Niu to charge the battery or the whole machine. The structure generally includes a DC socket, charging shrapnel, indicator lights, buttons, etc. The DC socket is connected to the fire cow, the shrapnel is connected to the battery pole piece, the indicator light indicates the charging state, and the button is used to discharge. The cradle charger can generally charge the battery and the whole machine.
    7. In addition, the walkie-talkie has accessories such as leather cases and earphones.

    Which feedback modes does the Cyclone III PLL support?

    Normal feedback mode; 0-delay driver feedback mode; no compensation mode.

    The software design of digital control system generally adopts modular structure design. What are the general basic principles of software functional module segmentation?

    The logical relationship between the modules is clear. The functions of each module are centralized, single, and easy to implement. The functions of each module are relatively independent to avoid coupling.

    How to set the TFDU6300 working mode to SIR (2.4 kbps)?

    • Set the input level of SD pin to high level;
    • Set the input level of TXD pin to low level (ts≥200 ns);
    • Set the level of SD pin to low level;
    • Hold time th ≥200ns.

    What is the role of the gate Resistors of the electron triode?

    1. R1 provides a DC voltage for the gate, and the Gl gate is grounded through Rl. The Gl cathode voltage is greater than 0V, so the grid voltage is negative relative to the cathode, reaching electrons. The gate is a negative voltage requirement when the tube is amplified.
    2. Inside the tube, a small amount of electrons will fall on the grid during the movement of the cathode electrons to the screen. The electrons are negative charges, and the electrons on the grid make the grid voltage negative. If there are too many electrons falling on the gate, the gate voltage is too low, which will affect the normal amplifying work of the triode. After adding Rl, the electrons on the gate flow to the ground through Rl, providing a leakage path for the electrons, so Rl is also called gate-drain resistance.
    3. R1 is also the load resistance of the pre-stage circuit, the signal voltage is added to this load resistance, and the AC signal output by the pre-stage circuit is the input signal of Gl.

    What is the detection method for the sunshine sensor?

    • Remove the sunshine sensor, and use a multimeter to detect both ends of the sensor in the sunshine sensor circuit.
    • Check the resistance of the sunshine sensor in the dark, the resistance value should be infinite, and it should be in a non-conducting state. And illuminate the sensor with the lamp, its resistance value should be 4kQ, in the conduction state.


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