Linear Technology offers some of the highest performance RF and signal chain solutions for wireless and cellularinfrastructure. These products support worldwide standards including, LTE, WiMAX, GSM,W-CDMA, TD-SCDMA,CDMA, and CDMA2000. Other wireless systems include broadband microwave data links, secure communications,satellite receivers, broadband wireless access, wireless broadcast systems, RFID readers and cable infrastructure
提出了一種基于PIC16F877A微控制器和CC2500射頻收發(fā)器芯片的低功耗、低成本RFID(Radio Frequency Identification, 無(wú)線射頻識(shí)別)局域定位系統(tǒng)設(shè)計(jì)方法,介紹了系統(tǒng)的定位工作原理、主要硬件電路模塊及定位算法的設(shè)計(jì)和實(shí)現(xiàn)。采用基于序列號(hào)對(duì)時(shí)隙數(shù)運(yùn)算的排序算法有效解決了多標(biāo)簽識(shí)別碰撞的問(wèn)題,基于射頻輻射強(qiáng)度(Received Signal Strength Indication, RSSI)和圓周定位算法實(shí)現(xiàn)了基于RFID多標(biāo)簽系統(tǒng)的平面定位。實(shí)驗(yàn)測(cè)試表明,這種射頻定位方法能夠?qū)崿F(xiàn)一定精度下的無(wú)線局域定位的功能。
針對(duì)UHF讀寫器設(shè)計(jì)中,在符合EPC Gen2標(biāo)準(zhǔn)的情況下,對(duì)標(biāo)簽返回的高速數(shù)據(jù)進(jìn)行正確解碼以達(dá)到正確讀取標(biāo)簽的要求,提出了一種新的在ARM平臺(tái)下采用邊沿捕獲統(tǒng)計(jì)定時(shí)器數(shù)判斷數(shù)據(jù)的方法,并對(duì)FM0編碼進(jìn)行解碼。與傳統(tǒng)的使用定時(shí)器定時(shí)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(shí)器定時(shí)誤差累積的影響;可以將捕獲定時(shí)器數(shù)中斷與數(shù)據(jù)判斷解碼相對(duì)分隔開(kāi),使得中斷對(duì)解碼影響很小,實(shí)現(xiàn)捕獲與解碼的同步。通過(guò)實(shí)驗(yàn)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(biāo)簽的時(shí)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.
Single-Ended and Differential S-Parameters
Differential circuits have been important incommunication systems for many years. In the past,differential communication circuits operated at lowfrequencies, where they could be designed andanalyzed using lumped-element models andtechniques. With the frequency of operationincreasing beyond 1GHz, and above 1Gbps fordigital communications, this lumped-elementapproach is no longer valid, because the physicalsize of the circuit approaches the size of awavelength.Distributed models and analysis techniques are nowused instead of lumped-element techniques.Scattering parameters, or S-parameters, have beendeveloped for this purpose [1]. These S-parametersare defined for single-ended networks. S-parameterscan be used to describe differential networks, but astrict definition was not developed until Bockelmanand others addressed this issue [2]. Bockelman’swork also included a study on how to adapt single-ended S-parameters for use with differential circuits[2]. This adaptation, called “mixed-mode S-parameters,” addresses differential and common-mode operation, as well as the conversion betweenthe two modes of operation.This application note will explain the use of single-ended and mixed-mode S-parameters, and the basicconcepts of microwave measurement calibration.
The LPC4350/30/20/10 are ARM Cortex-M4 based microcontrollers for embeddedapplications. The ARM Cortex-M4 is a next generation core that offers systemenhancements such as low power consumption, enhanced debug features, and a highlevel of support block integration.The LPC4350/30/20/10 operate at CPU frequencies of up to 150 MHz. The ARMCortex-M4 CPU incorporates a 3-stage pipeline, uses a Harvard architecture withseparate local instruction and data buses as well as a third bus for peripherals, andincludes an internal prefetch unit that supports speculative branching. The ARMCortex-M4 supports single-cycle digital signal processing and SIMD instructions. Ahardware floating-point processor is integrated in the core.The LPC4350/30/20/10 include an ARM Cortex-M0 coprocessor, up to 264 kB of datamemory, advanced configurable peripherals such as the State Configurable Timer (SCT)and the Serial General Purpose I/O (SGPIO) interface, two High-speed USB controllers,Ethernet, LCD, an external memory controller, and multiple digital and analog peripherals
摘要:介紹了基于數(shù)字信號(hào)處理(Digital Signal Processor,DSP)的運(yùn)動(dòng)控制器GT-800在貼片機(jī)控制系統(tǒng)中的應(yīng)用。該系統(tǒng)采用以PC機(jī)為上位機(jī)、GT-800運(yùn)動(dòng)控制器為下位機(jī)的硬件結(jié)構(gòu),上下位機(jī)之間的通訊采用基于ISA總線的雙端口RAM的模式,系統(tǒng)的軟件設(shè)計(jì)采用基于VisualC++6.0的軟件設(shè)計(jì)模式。關(guān)鍵詞:GT-800運(yùn)動(dòng)控制器;貼片機(jī);運(yùn)動(dòng)控制;機(jī)器視覺(jué)
Nios II定制指令用戶指南:With the Altera Nios II embedded processor, you as the system designer can accelerate time-critical software algorithms by adding custom instructions to the Nios II processor instruction set. Using custom
instructions, you can reduce a complex sequence of standard instructions to a single instruction implemented in hardware. You can use this feature for a variety of applications, for example, to optimize software inner
loops for digital signal processing (DSP), packet header processing, and computation-intensive applications. The Nios II configuration wizard,part of the Quartus® II software’s SOPC Builder, provides a graphical user interface (GUI) used to add up to 256 custom instructions to the Nios II processor.
The custom instruction logic connects directly to the Nios II arithmetic logic unit (ALU) as shown in Figure 1–1.