Functional requirements

Electronic product R & D process listening to voice
When designing a hardware system, several points should be clear:
1. Functional requirements:
1.1 power supply mode and protection
There are two ways: the built-in power supply board is directly supplied from the mains power supply or the external DC regulated power supply), the built-in power supply board is adopted, and the switching power supply board generally needs to be designed separately. According to the different design specifications of switching power supply in different industries, it needs to be designed according to different industry standards. The external DC regulated power supply can simplify the power supply part of the hardware system, But you need an external power supply.
Industrial control equipment or medical equipment need to be powered by POE (power over Ethernet). POE: existing cat Ethernet 5 technology that can provide DC power supply for some IP based terminals (IP phone, WLAN access point AP, network camera, etc.) while transmitting signals without any change to the infrastructure. IEEE 802.3af (output voltage 44-57v and output power 15.7w) is the first standard and the mainstream implementation standard. IEEE 802.3at (output voltage 50-57v and output power 25.5w) is generated by high-power terminal.
1.2 input and output signals;
1.3 wireless communication function
Gprs-23bps can be used as a serial port in the developed GPRS module, and one can be used in the developed gprs-23bps communication module, WiFi (ieee802.11x) is the main technical standard of WLAN at present. The portability of WLAN solves the communication needs of users in the last 100m. WiFi formulates the physical layer (PHY) and media access control layer (MAC) of the protocol, and takes TCP / IP as the network layer.
1.4bluetooth (full duplex transmission) is a radio technology that supports equipment short-range communication (< 10m);
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1.5 IrDA (short for infrared data organization, IrDA1.0 standard formulates a serial and half duplex synchronization system. Its data protocol consists of three basic protocols: physical layer, link access layer and link management layer. IrDA codec IC and transceiver suppliers mainly include Ti, ATMEL, NXP, Vishay, sharp microelectronics, Everlight electronics, Taiwan HL, Holtek semiconductor);
1,6 NFC (short-range wireless communication technology), non-contact identification and interconnection technology, combined with inductive card reader, inductive card and point-to-point function on a single chip, can identify and exchange data with compatible devices in a short distance. The distance of NFC is about 10cm,
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1.7 UWB wireless carrier communication technology
1.8 linear frequency modulation spread spectrum technology
1.9 RFID radio frequency identification technology, also known as wireless identification technology, is divided into active (short-range identification, second-generation ID card, bus card, meal card and bank card), passive (intelligent transportation, intelligent parking lot) and semi-active products (combining the advantages of active and passive, low-frequency trigger for accurate positioning, long-distance identification and data upload)
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2. Overall performance requirements
The overall performance requirements include: the processing capacity of input data, the requirements of system operation on temperature and humidity environment, the requirements of fault-free and stable working time of the system, the energy efficiency grade of the system and the self-protection requirements of the system
2.1 the performance requirements for data include the maximum bandwidth that can process data, the real-time performance of processing data and the accuracy of collecting data,
2.2 for the adaptability of the system to the environment, the temperature and environmental grade of the product shall be determined in the demand stage. The temperature and environmental grade of the product are 0-70 鈩�, industrial grade – 40-85 鈩� and military grade – 55-150 鈩�,