一種無線數(shù)據(jù)采集和傳輸系統(tǒng)的設(shè)計-外文翻譯-其他專業(yè)(文件)
【正文】 electric voltage transfer from 8V to 24V, then, the made it from 5V to . Furthermore,suitable filter capacitance and inductance was introduced to make power’s ripple characteristic perfect as possible. D. Universal Serial Interface Module The main function of Universal Serial interface module is connecting universal terminal equipment, such as signal output equipment or analog collection equipment with AD transfer. At the same time, it provides entrance to the puter terminal data exchange through universal RS232 serial interface. E. Data Buffer and Storage Module It has two kinds of function, one is data buffer, the other is data storage, respectively 8 performed by 32KByte RAM and 16KByte EEPROM. Data buffer district supervise buffering some temporary data, such as transmit data, waiting data. Data storage district supervise some fixed data memory, such as router data, local host, local address and some renewed data for poweroff protective. F. High Frequency Shielding Protecting Moudule In order to prevent electromagic interference from environment, circuit in our designing system is protected with metal enclosure. At the same time, preventing the digital circuit interfere from the radio frequency circuit in the system, we placed the two circuits in different isolated bin, such as figure 3. There is a small hole with diameter less than 1/4 wavelength in the metal box side, which is either easy to pass the line or prevent the electromagic wave from getting in it. Ⅳ .SYSTEM SOFTWARE DESIGN The realization of system performance depends on its effective and reasonable software control. The design of this software is on the basis of the hardware environment to development a wireless work protocol that have functions as data transmission, avoiding conflict, the retransmission when error occurs, and overtime retry, in order to achieve the design goal. The entire work is posed of a host and many scattered terminals, each terminal must have a wireless transceiver node (this system adopts nRF905 singlechip RF transceiver), any nodes of the entire wireless work has a unique identified address which is posed of an unique identified terminal. For convenience’s sake, each terminal wireless transceiver node addresses of the actual system is set by ourselves (4 bytes). In order to improve the reliability of the system, the protocol is designed as stopwait mode. In data link layer, the send process is roughly as follow. Firstly, the data sources send a connection request to the data targets, and it will transfer data after the data sources respond. Then wait for response from data target after each transmission. If the response is correct, another transmission will start. After all the data transmission is done, the data source will send a request to release channel resources, the transmission is finished when the response from the target is received. The receive process is as follow: the data target will receive data after give a response to the source, and will give a effective or uneffective response, until receive a demolition request. Then, save the data and send a response to end the entire process. data values are serially transferred, pumped into a shift register and are then internally available for parallel processing. Here we already see an important point, that must be considered in the philosophy of SPI bus systems: The length of the shift registers is not fixed, but can differ from device to device. Normally the shift registers are 8Bit or integra
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鄂ICP備17016276號-1