针对传统集成电路（ASIC）功能固定、升级困难等缺点，利用FPGA实现了扩频通信芯片STEL-2000A的核心功能。使用ISE提供的DDS IP核实现NCO模块，在下变频模块调用了硬核乘法器并引入CIC滤波器进行低通滤波，给出了DQPSK解调的原理和实现方法，推导出一种简便的引入?仔/4固定相移的实现方法。采用模块化的设计方法使用VHDL语言编写出源程序，在Virtex-II Pro 开发板上成功实现了整个系统。测试结果表明该系统正确实现了STEL-2000A的核心功能。 Abstract: To overcome drawbacks of ASIC such as fixed functionality and upgrade difficulty, FPGA was used to realize the core functions of STEL-2000A. This paper used the DDS IP core provided by ISE to realize the NCO module, called hard core multiplier and implemented CIC filter in the down converter, described the principle and implementation detail of the demodulation of DQPSK, and derived a simple method to introduce a fixed phase shift of ?仔/4. The VHDL source code was designed by modularity method , and the complete system was successfully implemented on Virtex-II Pro development board. Test results indicate that this system successfully realize the core function of the STEL-2000A.
上传时间： 2013-11-19
上传用户：neu_liyan
为了在CDMA系统中更好地应用QDPSK数字调制方式，在分析四相相对移相（QDPSK)信号调制解调原理的基础上，设计了一种QDPSK调制解调电路，它包括串并转换、差分编码、四相载波产生和选相、相干解调、差分译码和并串转换电路。在MAX+PLUSⅡ软件平台上，进行了编译和波形仿真。综合后下载到复杂可编程逻辑器件EPM7128SLC84-15中，测试结果表明，调制电路能正确选相，解调电路输出数据与QDPSK调制输入数据完全一致，达到了预期的设计要求。 Abstract: In order to realize the better application of digital modulation mode QDPSK in the CDMA system， a sort of QDPSK modulation-demodulation circuit was designed based on the analysis of QDPSK signal modulation-demodulation principles. It included serial/parallel conversion circuit, differential encoding circuit, four-phase carrier wave produced and phase chosen circuit, coherent demodulation circuit, difference decoding circuit and parallel/serial conversion circuit. And it was compiled and simulated on the MAX+PLUSⅡ software platform,and downloaded into the CPLD of EPM7128SLC84-15.The test result shows that the modulation circuit can exactly choose the phase，and the output data of the demodulator circuit is the same as the input data of the QDPSK modulate. The circuit achieves the prospective requirement of the design.
上传时间： 2013-10-28
上传用户：jyycc
在Multisim 10软件环境下，设计一种由运算放大器构成的精确可控矩形波信号发生器，结合系统电路原理图重点阐述了各参数指标的实现与测试方法。通过改变RC电路的电容充、放电路径和时间常数实现了占空比和频率的调节，通过多路开关投入不同数值的电容实现了频段的调节，通过电压取样和同相放大电路实现了输出电压幅值的调节并提高了电路的带负载能力，可作为频率和幅值可调的方波信号发生器。Multisim 10仿真分析及应用电路测试结果表明，电路性能指标达到了设计要求。 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.
上传时间： 2014-01-21
上传用户：shen007yue
The Molgedey and Schuster decorrelation algorithm, having square mixing matrix and no noise . Truncation is used for the time shifted matrix, and it is forced to be symmetric . The delay Tau is estimated . The number of independent components are calculated using Bayes Information Criterion (BIC), with PCA for dimension reduction.
标签： decorrelation and algorithm Molgedey
上传时间： 2013-12-13
上传用户：c12228
简单混合衰落信道 This mfile inputs an unmodulated sinewave through a simple Rayleigh two path fading channel and shows the output with phase, gain, and attenuation characteristics via animation.
标签： unmodulated Rayleigh sinewave through
上传时间： 2015-05-17
上传用户：CSUSheep
C++ Demystified: A Self-Teaching Guide by Jeff Kent ISBN:0072253703 McGraw-Hill/Osborne © 2004 This hands-on, step-by-step resource will guide you through each phase of C++ programming, providing you with the foundation to discover how computer programs and programming languages work.
标签： Self-Teaching Demystified McGraw-Hill 0072253703
上传时间： 2013-12-13
上传用户：1427796291
The Hopfield model is a distributed model of an associative memory. Neurons are pixels and can take the values of -1 (off) or +1 (on). The network has stored a certain number of pixel patterns. During a retrieval phase, the network is started with some initial configuration and the network dynamics evolves towards the stored pattern which is closest to the initial configuration.
标签： model distributed associative Hopfield
上传时间： 2015-06-17
上传用户：l254587896
The same two-stage decoder as above. However, when transforming the symbols prior to Viterbi decoding, the amplitude information is ignored and only the phase of the received symbol is employed in the metric computation stage.
标签： transforming two-stage However decoder
上传时间： 2015-07-05
上传用户：sevenbestfei
This mfile illustrates a simple two path Rayleigh multipath fading channel This mfile inputs an unmodulated sinewave through a simple Rayleigh two path fading channel and shows the output with phase, gain, and attenuation characteristics via animation
标签： mfile This illustrates multipath
上传时间： 2014-08-30
上传用户：lindor
Blind Equalizer 的演算法主要是利用CMA及 LMS 的配合，当CMA将EYE打开，使讯号趋近于正确值，就切换到LMS，利用Slicer的输出当作training sequence来调整Equalizer的系数，而Carrier Recovery 的部份，则是将phase error track出来
上传时间： 2013-12-28
上传用户：it男一枚
