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    What software is used in the hardware part of the coordinator?

    ZigBee wireless module and expansion backplane; Body condition monitor consists of wireless module and self-designed functional backplane.

    Which applications are considered for ZigBee technology?

    The equipment distance is small;
    The equipment cost is very low, and the amount of data transmitted is very small;
    The size of the device is small, and it is not allowed to place large rechargeable batteries or power modules;
    Only one-time batteries can be used, and there is no sufficient power support;
    It is impossible to replace the battery frequently or charge it repeatedly;
    A larger area needs to be covered.

    How is the embedded system composed?What are the characteristics?

    The embedded system is composed of embedded microprocessor, peripheral hardware equipment, embedded system and user application software.

    Model name of capacitor and method of marking capacitor

    Model name of the capacitor:
    1) The model naming of capacitors in various countries is very inconsistent. The naming of domestic capacitors consists of four parts:
    The first part: the name is represented by letters, and the capacitor is C.
    Part II: Materials are represented by letters.
    Part 3: Classification by numbers.
    Part 4: Use numbers to represent the serial number.
    2) The marking method of the capacitor:

    1. Direct marking method: use letters and numbers to directly mark the model and specification on the shell.
    2. Text notation method: Use a regular combination of numbers and text symbols to represent capacity. The text symbol indicates the unit of its capacitance: P, N, u, m, F, etc. It’s the same way to express resistance. The nominal allowable deviation is also expressed in the same way as the resistance. For capacitors less than 10pF, the allowable deviation is replaced by letters: B——±0.1pF, C——±0.2pF, D——±0.5pF, F——±1pF.
    3. Color scale method: It is the same as the expression method of resistance, and the unit is generally pF. The withstand voltage of small electrolytic capacitors is also color-coded, and the position is close to the root of the positive lead wire.
    4. Marking method of imported capacitors: Imported capacitors generally consist of 6 items.
      Item 1: Use letters to indicate categories.
      The second item: Use two digits to indicate its shape, structure, packaging method, lead start and relationship with the shaft.
      The third item: the temperature characteristics of temperature compensation capacitors, there are letters and colors. Its meaning is shown in the following table: serial number letter color temperature coefficient allowable deviation serial number letter color temperature coefficient allowable deviation 1A gold 10012R yellow-2202B gray 3013S green-3303C black 014T blue-4704G±3015U purple-7505H brown-30±6016V-10006J± 12017W-15007K±25018X-22008L Red-80±50019Y-33009M±100020Z-470010N±250021SL 350~-100011P Orange-15022YN-800~-5800. Remarks: The unit of temperature coefficient is 10e-6/℃; the allowable deviation is %.
      The fourth item: Use numbers and letters to represent the withstand voltage, the letters represent the effective value, and the numbers represent the power of 10 of the multiplicand.
      Item 5: Nominal capacity, represented by three digits, the first two are valid values, and the third is a power of 10. When there is a decimal, use R or P to represent it. The unit of ordinary capacitor is pF, and the unit of electrolytic capacitor is uF.
      The sixth item: allowable deviation. It is represented by a letter, and the meaning is the same as that of domestic capacitors. There is also a color-coded method, and the meaning is the same as the marking method of domestic capacitors.

    What are the most famous logic synthesis tools in FPGA/CPLD design?

    There are three most famous logic synthesis tools in FPGA/CPLD design:
    FPGA Express, FPGA Compiler and FPGA Compiler II from Synopsys;
    Synplify and Synplify Pro from Synplicity;
    Leonardo Spectrum from Mentor Graphics.

    What are the currently widely used stochastic mobile models based on independent and identical distribution?

    Random way point model (random way point, RWP), random walk model (random walk, RW) and random direction model (random direction, RD) and so on.

    What are the applications of automotive sensors?

    Air flow meter, pressure sensor, position sensor, speed sensor, temperature sensor, gas concentration sensor, etc.

    Which instructions are included in the transfer class instruction?

    1. Accumulator A Compare Equal Transfer Instruction
    2. Subtract l is not 0 branch instruction
    3. CCR transfer instruction
    4. Bit test branch instruction
    5. Unconditional branch instruction

    What is the application of ZigBee technology?

    ZigBee technology fills the gap in the low-cost, low-power and low-speed wireless communication market. The key to its success is rich and convenient applications, not the technology itself.
    With the announcement of the official version of the agreement, more attention and research and development will be transferred to the design and implementation of applications, interconnection testing and market promotion.
    It is reasonable to believe that in the near future, more and more devices with built-in ZigBee function will enter life, which will greatly improve people’s life style and experience.

    Several failure modes related to supercapacitors

    1. The well-known bathtub curve reflects early failure and wear failure. The failure rate drops rapidly at the beginning of the device’s use. Initial failures are masked out by routine testing at manufacturers and customers because design flaws are not detected during failure mode and cause analysis during development. It is more likely to be a change in the manufacturing process or a change in the quality of the material. Variations in the production process can be caused by tool wear, changes in operation, and shape defects. Therefore, Weibull model theory does not account for these early failure modes.
    2. The internal pressure of the unit is too large, causing the cavity to crack and lead. Voltage and temperature create air pressure inside the unit, increasing operating time. When the voltage reaches a limit, a mechanical fuse, usually a groove in the vessel wall or a pressure valve, will slowly open to prevent an explosion. But the electrical function of the supercapacitor still works. The rate of capacity loss increases slowly. Some salts in small amounts of electrolyte are found in these cavities. The solvent evaporates from the device. Therefore, modules requiring supercapacitors must be ventilated. If open, the device must be replaced.
    3. In terms of leakage “old”, similar to the previous case, the results are almost the same. The reasons for the failure may be excessive internal pressure, poor sealing, weak welding, and broken holes in the wall during electrode contact etc. Sometimes it is difficult to detect this kind of leakage. It is also possible that during the production process, the residual electrolyte is adsorbed in some hard-to-reach places and becomes very obvious during use.
    4. When the capacity of the capacitor is lower than the standard When 80% of the capacity is weighed, the effective carbon surface and the number of effective ions decrease during the cycle.
    5. When the series resistance is twice the normal series resistance, the adhesion of the electrode to the aluminum foil increases with time and temperature weakened. The available effective ions will also decrease.


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