基于單DSP的VoIP模擬電話適配器研究與實現(xiàn):提出和實現(xiàn)了一種新穎的基于單個通用數(shù)字信號處理器(DSP)的VoIP模擬電話適配器方案。DSP的I/O和存儲資源非常有限，通常適于運算密集型應(yīng)用，不適宜控制密集型應(yīng)用[5]。該系統(tǒng)高效利用單DSP的I/O和片內(nèi)外存儲器資源，采用μC/OS-II嵌入式實時操作系統(tǒng)，支持SIP和TCP-UDP/IP協(xié)議，通過LAN或者寬帶接入，使普通電話機成為Internet終端，實現(xiàn)IP電話。該系統(tǒng)軟硬件結(jié)構(gòu)緊湊高效，運行穩(wěn)定，成本低，具有廣闊的應(yīng)用前景。關(guān)鍵詞：模擬電話適配器；IP電話；數(shù)字信號處理器；μC/OS-II
【Abstract】This paper presents a VoIP ATA solution based on a single digital signal processor (DSP). DSPs are suitable for arithmetic-intensiveapplication and unsuitable for control-intensive application because of the limitation of I/O and memory resources. This solution is based on a 16-bitfixed-point DSP and μC/OS-II embedded real-time operating system. It makes good use of the limited resources, supports SIP and TCP-UDP/IPprotocol. It can connect the analog telephone to Internet and realize the VoIP application. This system has a great future for its high efficiency andlow cost.【Key words】Analog telephone adapter (ATA); Voice over Internet protocol (VoIP); Digital signal processor (DSP); μC/OS-II
Research and Implementation of VoIPATA Based on Single DSP
基于LabVIEW和單片機的空調(diào)溫度場測量系統(tǒng)的研究:室內(nèi)溫度是空調(diào)系統(tǒng)舒適性的重要指標,對其及時、準確地測量顯得非常重要。介紹單片機AT89C51 和數(shù)字式、單總線型溫度傳感器DS18B20 組成矩形測量網(wǎng)絡(luò)采集空調(diào)室內(nèi)40 點溫度,LabVIEW作為開發(fā)平臺,二者之間通過串口實現(xiàn)數(shù)據(jù)通信,利用LabVIEW強大的數(shù)據(jù)處理和顯示功能對采集的空調(diào)溫度場數(shù)據(jù)進行實時處理、分析和顯示,詳細介紹了系統(tǒng)的硬件結(jié)構(gòu)和軟件模塊的設(shè)計方案。關(guān)鍵詞:單片機;DS18B20 ;LabVIEW;串行通信
Abstract : Temperature is a very important criterion of air condition system′s comfort , so it is very significant to measure it accurately and real timely. This paper int roduces a data acquisition system of measuring 40 point s temperature for air condition room based on single wire digital sensor DS18B20 and microcont roller AT89C51 which are composed of rectangle measuring meshwork. The data communication between LabVIEW and microcont roller is executed via serial port ,and the temperature field data of air condition room are processed analyzed and displayed on LabVIEW. The hardware and software modules are also given in detail.Keywords : single chip ;DS18B20 ;LabVIEW; serial communication
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
Integrated EMI/Thermal Design forSwitching Power SuppliesWei ZhangThesis submitted to the Faculty of theVirginia Polytechnic Institute and State Universityin partial fulfillment of the requirements for the degree of
Integrated EMI/Thermal Design forSwitching Power SuppliesWei Zhang(ABSTRACT)This work presents the modeling and analysis of EMI and thermal performancefor switch power supply by using the CAD tools. The methodology and design guidelinesare developed.By using a boost PFC circuit as an example, an equivalent circuit model is builtfor EMI noise prediction and analysis. The parasitic elements of circuit layout andcomponents are extracted analytically or by using CAD tools. Based on the model, circuitlayout and magnetic component design are modified to minimize circuit EMI. EMI filtercan be designed at an early stage without prototype implementation.In the second part, thermal analyses are conducted for the circuit by using thesoftware Flotherm, which includes the mechanism of conduction, convection andradiation. Thermal models are built for the components. Thermal performance of thecircuit and the temperature profile of components are predicted. Improved thermalmanagement and winding arrangement are investigated to reduce temperature.In the third part, several circuit layouts and inductor design examples are checkedfrom both the EMI and thermal point of view. Insightful information is obtained.
在Multisim 10軟件環(huán)境下，設(shè)計一種由運算放大器構(gòu)成的精確可控矩形波信號發(fā)生器，結(jié)合系統(tǒng)電路原理圖重點闡述了各參數(shù)指標的實現(xiàn)與測試方法。通過改變RC電路的電容充、放電路徑和時間常數(shù)實現(xiàn)了占空比和頻率的調(diào)節(jié)，通過多路開關(guān)投入不同數(shù)值的電容實現(xiàn)了頻段的調(diào)節(jié)，通過電壓取樣和同相放大電路實現(xiàn)了輸出電壓幅值的調(diào)節(jié)并提高了電路的帶負載能力，可作為頻率和幅值可調(diào)的方波信號發(fā)生器。Multisim 10仿真分析及應(yīng)用電路測試結(jié)果表明，電路性能指標達到了設(shè)計要求。
Abstract:
Based on Multisim 10， this paper designed a kind of rectangular-wave signal generator which could be controlled exactly composed of operational amplifier， the key point was how to implement and test the parameter indicators based on the circuit diagram. The duty and the frequency were adjusted by changing the time constant and the way of charging and discharging of the capacitor， the width of frequency was adjusted by using different capacitors provided with multiple switch， the amplitude of output voltage was adjusted by sampling voltage and using in-phase amplifier circuit，the ability of driving loads was raised， the circuit can be used as squarewave signal generator whose frequency and amplitude can be adjusted. The final simulation results of Multisim 10 and the tests of applicable circuit show that the performance indicators of the circuit meets the design requirements.
TheTool is highy customizable map editor(based on QT) which can be extended via LUA scripts. A first implentation is ready and can be published to the public. The editor is the perfect tool who wants to design some 3d games but don t have time to write
This article is based in part on Bob Place s ADO is AOK (a simple ADO tutorial). Wrapper Usage This is consist of 2 classes. CDyndb : This Class manages connections and recordsets. Recordsets are organized as linked list (CList) and you can access them using their ids. CDynRec : This class is the node to populate for each recordsets. ADO封裝器類 這篇文章一部分基于Bob Place的《ADO is AOK》 (簡單的ADO指導(dǎo)) 。 包裹的用法 由2個類組成。 類CDyndb: 這個類別管理連接和記錄集。記錄集是連接起來的記錄的集合，你可以通過他們的ID訪問他們。 類CDynRec: 這個類別存放記錄集的代碼。
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