一种超混沌PN序列的设计与实现

为了产生性能良好的伪噪声（PN）序列,基于一个新的超混沌系统,文中提出了一种超混沌PN序列的设计与实现方法,在对连续超混沌系统离散、量化的基础上,利用FPGA芯片实现了这种超混沌PN序列。通过一个串口通信模块电路采集了输出序列的全部样本并进行了序列性能分析,分析表明这种超混沌PN序列具有优良的随机特性和自相关特性,可用于扩频通信和信息加密之中。     

基于四维混沌系统的OFDM同步算法

针对传统同步算法计算复杂度高,符号同步和载波同步精度低,保密性差等缺点,提出一种基于四维混沌系统的OFDM同步算法.首先通过分析该四维系统的动力学特性、对初始值的敏感性和计算Lyapunov指数等方式,证明该系统是一个新混沌系统,并分析生成的混沌序列相关性质.然后将混沌序列用于构造一个L等分的同步训练序列,基于该同步训练序列提出一种新的OFDM系统符号同步和载波同步方法.理论分析和仿真结果表明新算法计算复杂度低,符号同步和载波同步精度高,增强了系统保密性.     

一种基于蔡氏电路的混沌扩频序列

本文从混沌序列具有的伪随机特性入手,利用蔡氏电路建立了一个混沌序列发生器,实验统计分析证明可以利用蔡氏电路产生一种较理想的混沌伪随机序列;通过对以混沌伪随机序列为基础得到的混沌扩频序列的特性分析,表明基于蔡氏电路的混沌扩频序列适合于扩频通信中的应用。     

一种伪噪声比特序列发生器的设计与实现

为了产生性能良好的伪噪声(PN)序列,提出了一种超混沌伪噪声比特序列发生器的设计与实现方法.设计中利用一个新的连续超混沌系统作为PN序列的随机信号源,建立了连续系统的离散和量化数学模型,在Simulink平台上借助于DSP Builder里的模块构建了该离散化模型的电路模型,利用 FPGA芯片在实验中获得了数字混沌PN序列.同时对产生的PN序列进行了性能评估,其结果通过了5个基本测试标准.该技术可应用于混沌通信、信息加密等领域.     

一种圆映射电路及其符号动力学研究

设计了一种基于累积-释放模型的圆映射电路,从理论上对该电路的圆映射迭代关系和符号动力学特性进行了分析.通过调整电路和阈值信号参数,能使其工作状态发生变化,可处于各种周期态、混沌态等.研究了利用简单的逻辑判断直接获取符号序列的方法,并用微处理器和简单的逻辑电路构建了符号序列采集系统.从获得符号序列可以比较方便地计算周期、转数等,区别是周期、准周期还是混沌运动,为进一步的研究和应用提供一种有效途径.     

基于MutiSIM的蔡氏混沌序列仿真研究

混沌序列是非线性方程描述的确定系统所产生的介于周期振荡与噪声之间的一种复杂振荡序列.蔡氏电路是一个经典,且简单的三阶自治系统,能够产生丰富的混沌现象。在对蔡氏电路进行数学建模的基础上,采用MultiSIM仿真软件对其进行仿真,并分析其产生的混沌信号的功率谱,从而找出一个最佳的电路参数,得到一个最好的,可用的混沌序列。     

基于混沌和计算全息的光学加密技术

提出一种基于混沌和计算全息的光学加密技术。利用确定性非线性系统的混沌序列构成随机相位列阵,对物光波进行调制编码,并采用修正离轴参考光的博奇编码法,制作计算全息图,作为加密图像。解密时,只要获得正确的混沌序列初始值,就可以得到随机相位列阵,结合正确的系统结构参数,就可以重建清晰的原始图像。与传统的随机相位加密相比,混沌序列初始值作为密钥,减少了密钥的数据量;数字化的加密图有利于信息的保存和传输。模拟实验验证了它的可行性和有效性,并分析了抗裁剪和噪声的鲁棒性。     

分数阶混沌系统的DSP Builder设计方法

为了克服模拟电路分数阶混沌系统设计易受外界条件影响,提出了一种基于DSP Builder设计分数阶混沌系统的方法.以分数阶Jerk系统为例,采用一种数字差分算法设计混沌系统,分析了分数阶混沌系统的动力学特性.仿真结果表明,分数阶混沌系统的DSP Builder设计方法是一种有效的分析方法,这为分数阶混沌系统的数字设计提供了新的思路.     

混沌符号动力学运算电路模型研究

结合混沌符号动力学原理及1-D分段线性映射混沌系统,本文经过理论论证并提出了一种能够实现混沌符号序列运算的运算电路模型.并结合单驱动式恒流源混沌电路和FPGA芯片,对该运算模型进行了实验验证.实验结果表明,在精度允许范围内,两串混沌符号序列经运算得到的结果与真实测量结果之间可进行等效.该模型可应用于数字图像加密处理等混沌信号处理系统中.     

超宽带通信中的伪混沌脉冲位置调制

提出了一种新的适于超宽带脉冲通信的伪混沌脉冲位置调制方式(PCPPM),该方式采用符号动力学对混沌脉冲位置调制方式(CPPM)进行了改进,作为载波的脉冲串的相邻脉冲之间的间隔由混沌映射的符号动力学特性确定,采用脉冲位置调制方式对二进制符号进行调制.系统可以在无辅助握手的情况下获得同步.与CPPM相比,其降低了对脉冲间距的测量精度要求,适合数字方式实现.由丁系统输出的脉冲间隔是随机分布的,具有近似噪声的频谱特性,最后对系统的性能进行了分析和仿真.     

一种基于混沌的随机数发生器设计及其IC实现

在密码学、仿真学以及集成电路测试等许多领域 ,随机数起着重要的作用。在密码学中 ,通常要求所使用的随机数具有不可预测性。基于混沌现象 ,使用开关电容技术 ,用集成电路实现了一种硬件随机数发生器。测试结果表明 ,其产生的序列具有不可预测性 ,可以满足密码学的应用要求。     

Switched-current 3-bit CMOS 4.0-MHz wideband random signal generator

The paper presents a switched-current circuit implementation of a chaotic algorithm to generate a white noise. A 3-bit digital normalizer is utilized to adjust the coefficients in the piecewise-linear transfer function such that the probability of the generated numbers will be very close to a uniform distribution. A 1.0-GHz linear track-and-hold circuit is applied in the random number generator (RNG) to achieve a wide output bandwidth. TSMC 0.25-/spl mu/m one-poly five-metal CMOS process is adopted to carry out the proposed design to verify the wideband performance. When the operating clock is 10.0 MHz, the measured bandwidth of the generated noise is 4.0 MHz.     

一种基于单电子隧穿结和MOS晶体管的混合随机数发生器

提出了一种新颖的单电子随机数发生器(RNG).该随机数发生器由多个单电子隧穿结(MTJ)以及单电子晶体管(SET)/MOS管混合输出电路组成.MTJ被用于实现一个高频率的振荡器.它利用了电子隧穿的物理随机性得到了很大的振荡频率漂移.SET/MOS管输出电路放大并输出MTJ振荡器的输出信号.该信号经过一个低频信号采样后,产生随机数序列.所提出的随机数发生器使用简单的电路结构产生了高质量的随机数序列.它具有简单的结构,输出随机数的速度可以高达1GHz.同时,该电路还具有带负载能力以及很低的功耗.这种新颖的随机数发生器对未来的密码和通讯系统具有一定的应用前景.     

一种基于单电子隧穿结和MOS晶体管的混合随机数发生器

提出了一种新颖的单电子随机数发生器(RNG).该随机数发生器由多个单电子隧穿结(MTJ)以及单电子晶体管(SET)/MOS管混合输出电路组成.MTJ被用于实现一个高频率的振荡器.它利用了电子隧穿的物理随机性得到了很大的振荡频率漂移.SET/MOS管输出电路放大并输出MTJ振荡器的输出信号.该信号经过一个低频信号采样后,产生随机数序列.所提出的随机数发生器使用简单的电路结构产生了高质量的随机数序列.它具有简单的结构,输出随机数的速度可以高达1GHz.同时,该电路还具有带负载能力以及很低的功耗.这种新颖的随机数发生器对未来的密码和通讯系统具有一定的应用前景.     

Physical random number generator based on MOS structure after soft breakdown

We present a novel physical random number generator (RNG) that uses a metal-oxide semiconductor (MOS) capacitor after soft breakdown (SBD) as a random source. It is known that the electrical properties of MOS capacitors after SBD show large fluctuation. When the resistor in an astable multivibrator is replaced with an MOS capacitor after SBD, the multivibrator converts the noise signal into a rectangular wave whose period fluctuates randomly. A 1-bit counter and a flip-flop are used to generate random numbers from the fluctuating rectangular wave. Some high-level tests indicate that the generated random numbers have excellent quality for cryptographic applications. Even though our circuit is small and can be constructed using about 20 complementary-MOS logic gates and several passive devices, high-quality random numbers such as those generated by large physical RNGs can be obtained.     

Thermal noise in a finite bandwidth

In a practical circuit, the output noise due to the thermal noise of a resistor will depend on the actual transfer function of the noise source. The bandwidth will never be infinite because the transfer function of either the noise source or the device measuring the output noise will cause limitations. Consequently, the thermal noise voltage of a resistor in a finite bandwidth is maximum for a given resistor value. That maximum thermal noise voltage depends on the stop frequencies and decreases for both smaller and larger resistor values     

True Random Number Generator With a Metastability-Based Quality Control

We present a metastability-based true random number generator that achieves high entropy and passes NIST randomness tests. The generator grades the probability of randomness regardless of the output bit value by measuring the metastable resolution time. The system determines the original random noise level at the time of metastability and tunes itself to achieve a high probability of randomness. Dynamic control enables the system to respond to deterministic noise and a qualifier module grades the individual metastable events to produce a high-entropy random bit-stream. The grading module allows the user to trade off output bit-rate with the quality of the bit-stream. A fully integrated true random number generator was fabricated in a 0.13 mum bulk CMOS technology with an area of 0.145 mm².     

基于伪随机信号的模拟电路软故障定位方法

针对模拟电路软故障的测试难题,提出了定位模拟电路软故障的伪随机激励测试法.伪随机激励信号是一种包含多个频率成分的连续周期信号,由m序列生成.利用该信号激励模拟电路.通过计算输出响应序列的功率谱密度,不仅可以实现模拟电路软故障的数字化特征提取.而且还可以完成对模拟电路软故障的定位.以状态变量滤波器电路为例,分别利用交流激励信号和伪随机信号进行诊断,通过对比实验,验证了伪随机信号对定位模拟电路软故障的有效性,为实现模拟电路故障诊断的高覆盖率和诊断自动化提供了一种新途径.     

Event-driven Simulation and modeling of phase noise of an RF oscillator

A novel simulation technique that uses an event-driven VHDL simulator to model phase noise behavior of an RF oscillator for wireless applications is proposed and demonstrated. The technique is well suited to investigate complex interactions in large system-on-chip systems, where traditional RF and analog simulation tools do not work effectively. The oscillator phase noise characteristic comprising of flat electronic noise, as well as, upconverted thermal and 1/f noise regions are described using time-domain equations and simulated as either accumulative or nonaccumulative random perturbations of the fundamental oscillator period. The VHDL simulation environment was selected for its high simulation speed, the direct correlation between the simulated and built circuits and its ability to model mixed-signal systems of high complexity. The presented simulation technique has been successfully applied and validated in a Bluetooth transceiver integrated circuit fabricated in a digital 130-nm process.     

Universal Delay-Limited Simulation

Universal, delay-limited simulation of an unknown information source of a certain parametric family (e.g., the family of memoryless sources or Markov sources of a given order), given a training sequence from that source and a stream of independent and uniformly distributed bits, is considered. The goal of universal simulation is that the probability law of the generated sequence be identical to that of the training sequence, with minimum mutual information between the random processes generating both sequences. In the delay-limited setting, the simulation algorithm generates a random sequence sequentially, by delivering one symbol for each training symbol that is made available after a given initial delay, whereas the random bits are assumed to be available on demand. In this paper, the optimal universal delay-limited simulation scheme is characterized for broad parametric families, and the mutual information achieved by the proposed scheme is analyzed. The results are extended to a setting of variable delay.