為滿足無線網絡技術具有低功耗、節點體積小、網絡容量大、網絡傳輸可靠等技術要求，設計了一種以MSP430單片機和CC2420射頻收發器組成的無線傳感節點。通過分析其節點組成，提出了ZigBee技術中的幾種網絡拓撲形式，并研究了ZigBee路由算法。針對不同的傳輸要求形式選用不同的網絡拓撲形式可以盡大可能地減少系統成本。同時針對不同網絡選用正確的ZigBee路由算法有效地減少了網絡能量消耗，提高了系統的可靠性。應用試驗表明，采用ZigBee方式通信可以提高傳輸速率且覆蓋范圍大，與傳統的有線通信方式相比可以節約40%左右的成本。 Abstract: To improve the proposed technical requirements such as low-ower， small nodes， large capacity and reliable network transmission， wireless sensor nodes based on MSP430 MCU and CC2420 RF transceiver were designed. This paper provided network topology of ZigBee technology by analysing the component of the nodes and researched ZigBee routing algorithm. Aiming at different requirements of transmission mode to choose the different network topologies form can most likely reduce the system cost. And aiming at different network to choose the correct ZigBee routing algorithm can effectively reduced the network energy consumption and improved the reliability of the system. Results show that the communication which used ZigBee mode can improve the transmission rate， cover more area and reduce 40% cost compared with traditional wired communications mode.
上傳時間： 2013-10-09
上傳用戶：robter
針對UHF讀寫器設計中，在符合EPC Gen2標準的情況下，對標簽返回的高速數據進行正確解碼以達到正確讀取標簽的要求，提出了一種新的在ARM平臺下采用邊沿捕獲統計定時器數判斷數據的方法，并對FM0編碼進行解碼。與傳統的使用定時器定時采樣高低電平的FM0解碼方法相比，該解碼方法可以減少定時器定時誤差累積的影響；可以將捕獲定時器數中斷與數據判斷解碼相對分隔開，使得中斷對解碼影響很小，實現捕獲與解碼的同步。通過實驗表明，這種方法提高了解碼的效率，在160 Kb/s的接收速度下，讀取一張標簽的時間約為30次/s。 Abstract: Aiming at the requirement of receiving correctly decoded data from the tag under high-speed communication which complied with EPC Gen2 standard in the design of UHF interrogator， the article introduced a new technology for FM0 decoding which counted the timer counter to judge data by using the edge interval of signal capture based on the ARM7 platform. Compared with the traditional FM0 decoding method which used the timer timed to sample the high and low level， the method could reduce the accumulation of timing error and could relatively separate capture timer interrupt and the data judgment for decoding， so that the disruption effect on the decoding was small and realizd synchronization of capture and decoding. Testing result shows that the method improves the efficiency of decoding， at 160 Kb/s receiving speed， the time of the interrogator to read a tag is about 30 times/s.
上傳時間： 2013-11-10
上傳用戶：liufei
通過比較各種隔離數字通信的特點和應用范圍，指出塑料光纖在隔離數字通信中的優勢。使用已經標準化的TOSLINK接口，有利于節省硬件開發成本和簡化設計難度。給出了塑料光纖的硬件驅動電路，說明設計過程中的注意事項，對光收發模塊的電壓特性和頻率特性進行全面試驗，并給出SPI口使用塑料光纖隔離通信的典型應用電路圖。試驗結果表明，該設計可為電力現場、電力電子及儀器儀表的設計提供參考。 Abstract: y comparing characteristics and applications area of various isolated digital communications， this article indicates advantages of plastic optical fiber in isolated digital communications. Using the standardized TOSLINK interface， it helps to control costs and difficulty in hardware development and design. Then it gives the hardware driver circuit of plastic optical fiber module， explains the noticed details in design process， gives results on the basis of the optical transceiver module voltage characteristics and frequency characteristics tests. Finally，it gives typical application circuit of the SPI communication port by using plastic optical fiber isolation .The results show that this design can be referenced for the power field， power electronics and instrumentation design.
上傳時間： 2014-01-10
上傳用戶：gundan
同步技術是跳頻通信系統的關鍵技術之一，尤其是在快速跳頻通信系統中，常規跳頻通信通過同步字頭攜帶相關碼的方法來實現同步，但對于快跳頻來說，由于是一跳或者多跳傳輸一個調制符號，難以攜帶相關碼。對此引入雙跳頻圖案方法，提出了一種適用于快速跳頻通信系統的同步方案。采用短碼攜帶同步信息，克服了快速跳頻難以攜帶相關碼的困難。分析了同步性能，仿真結果表明該方案同步時間短、虛警概率低、捕獲概率高，同步性能可靠。 Abstract: Synchronization is one of the key techniques to frequency-hopping communication system， especially in the fast frequency hopping communication system. In conventional frequency hopping communication systems， synchronization can be achieved by synchronization-head which can be used to carry the synchronization information， but for the fast frequency hopping， Because modulation symbol is transmitted by per hop or multi-hop， it is difficult to carry the correlation code. For the limitation of fast frequency hopping in carrying correlation code， a fast frequency-hopping synchronization scheme with two hopping patterns is proposed. The synchronization information is carried by short code， which overcomes the difficulty of correlation code transmission in fast frequency-hopping. The performance of the scheme is analyzed， and simulation results show that the scheme has the advantages of shorter synchronization time， lower probability of false alarm， higher probability of capture and more reliable of synchronization.
上傳時間： 2013-11-23
上傳用戶：mpquest
Abstract: Most hand-held products lack accurate battery-charge monitors ("fuel gauges") because of the misconception that an accurate fuel gauge is difficult to achieve. This article debunks the myths and discusses how to accurately monitor charge at all temperatures, charge and discharge rates, and aging conditions. 無線通信和數據在新一代手機和PDA中的融合為再一次的生產力飛躍創造了條件。。隨之而來的將是經濟的增長和全新的工作方式，在便攜式計算機領域，PC筆記本曾經扮演了類似的開拓者角角。
上傳時間： 2013-10-17
上傳用戶：erkuizhang
Abstract: Most hand-held products lack accurate battery-charge monitors ("fuel gauges") because of the misconception that an accurate fuel gauge is difficult to achieve. This article debunks the myths and discusses how to accurately monitor charge at all temperatures, charge and discharge rates, and aging conditions.
上傳時間： 2014-03-18
上傳用戶：wenwiang
提出了一種以ARM微處理器為控制核心的遠程無線視頻監控終端的設計方案，其監控終端的硬件設計包括視頻采集處理、中央管理控制、無線傳輸3個模塊。并給出了監控終端的軟件開發平臺和開發模式的系統啟動代碼、嵌入式Linux系統移植以及驅動程序和應用程序。測試結果表明，該監控終端設計方案合理、有效，基本滿足監控需求。 Abstract: A remote wireless video monitoring terminal design， which uses ARM microprocessor as its core control， is proposed in this paper.The hardware design of monitoring terminal system is composed of the video acquisition and processing module， the central management and control module， wireless transmission module.Meanwhile the monitoring terminal-s software development platform and development patterns are designed. Also the design of the system-s start codes， embedded Linux system-s transplantation process， driver and the corresponding applications are given. The results showed that the monitoring terminal design is reasonable， effective， basically meet monitoring requirements.
上傳時間： 2013-11-13
上傳用戶：wanqunsheng
The C++ Programming Language Special 3rd Edition。 經典C++教材
標簽： Programming Language Edition Special
上傳時間： 2013-11-20
上傳用戶：netwolf
Abstract: Using a wafer-level package (WLP) can reduce the overall size and cost of your solution.However when using a WLP IC, the printed circuit board (PCB) layout can become more complex and, ifnot carefully planned, result in an unreliable design. This article presents some PCB designconsiderations and general recommendations for choosing a 0.4mm- or 0.5mm-pitch WLP for yourapplication.
標簽： Considerations Guidelines and Design
上傳時間： 2013-11-09
上傳用戶：ls530720646
Abstract: This application note explains how to layout the MAX20021/MAX20022 automotive quad powermanagementICs (PMICs) to maximize performance and minimize emissions. Example images of a fourlayerlayout are provided.
上傳時間： 2013-10-10
上傳用戶：dljwq
