基于通用集成運算放大器，利用MASON公式設(shè)計了一個多功能二階通用濾波器，能同時或分別實現(xiàn)低通、高通和帶通濾波，也能設(shè)計成一個正交振蕩器。電路的極點頻率和品質(zhì)因數(shù)能夠獨立、精確地調(diào)節(jié)。電路使用4個集成運放、2個電容和11個電阻，所有集成運放的反相端虛地。利用計算機(jī)仿真電路的通用濾波功能、極點頻率和品質(zhì)因數(shù)的獨立控制和正交正弦振蕩，從而證明該濾波器正確有效。
Abstract:
A new multifunctional second-order filter based on OPs was presented by MASON formula. Functions， such as high-pass， band-pass， low-pass filtering， can be realized respectively and simultaneously， and can become a quadrature oscillator by modifying resistance ratio. Its pole angular frequency and quality factor can be tuned accurately and independently. The circuit presented contains four OPs， two capacitors， and eleven resistances， and inverting input of all OPs is virtual ground. Its general filtering， the independent control of pole frequency and quality factor and quadrature sinusoidal oscillation were simulated by computer， and the result shows that the presented circuit is valid and effective.
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(biāo)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(fù)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(biāo)達(dá)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.
Full support for extended regular expressions (those with intersection and complement); Support for some kinds of cycles in grammar; DFA-based operation; Unicode support; C++ only, requires a modern compiler; Lexical analyzers can be configured to get symbols from any input class (built-in support for std::istream, std::wistream and FILE *); Designed to work with Whale, but can work standalone or interface to other parsers.
XMail is an Internet and intranet mail server featuring an SMTP server, POP3 server, finger server, multiple domains, no need for users to have a real system account, SMTP relay checking, RBL/RSS/ORBS/DUL and custom ( IP based and address based ) spam protection, SMTP authentication ( PLAIN LOGIN CRAM-MD5 POP3-before-SMTP and custom ), a POP3 account syncronizer with external POP3 accounts, account aliases, domain aliases, custom mail processing, direct mail files delivery, custom mail filters, mailing lists, remote administration, custom mail exchangers, logging, and multi-platform code. XMail sources compile under GNU/Linux, FreeBSD, OpenBSD, NetBSD, OSX, Solaris and NT/2K/XP.
項目描述: slsnif is a serial port logging utility. It listens to the specified serial port and logs all data going through this port in both directions. Serial line sniffer是一個串行端口記錄工具。它監(jiān)聽指定的串行端口并記錄所有通過這個端口的兩個方向的數(shù)據(jù)。 來源：http://freshmeat.net slsnif是一個串行端口日志工具。它監(jiān)聽特殊的串口，記錄所有通過這具串口的兩個方向的數(shù)據(jù)。 類別: Development Status: 5 - Production/StableEnvironment: Console (Text Based)Intended Audience: DevelopersLicense: GNU General Public License (GPL)Operating System: LinuxProgramming Language: CTopic: Communications, Debuggers
項目描述: slsnif is a serial port logging utility. It listens to the specified serial port and logs all data going through this port in both directions. Serial line sniffer是一個串行端口記錄工具。它監(jiān)聽指定的串行端口并記錄所有通過這個端口的兩個方向的數(shù)據(jù)。 來源：http://freshmeat.net slsnif是一個串行端口日志工具。它監(jiān)聽特殊的串口，記錄所有通過這具串口的兩個方向的數(shù)據(jù)。 類別: Development Status: 5 - Production/StableEnvironment: Console (Text Based)Intended Audience: DevelopersLicense: GNU General Public License (GPL)Operating System: LinuxProgramming Language: CTopic: Communications, Debuggers
This Program uses the 2131 dev board s push buttons and seven-segment LED for limited keyboard functionality and is based on the EZ-USB firmware frameworks.
