卡诺图在数字电路分析和设计中的应用

卡诺图是数字电路中非常重要的分析和设计工具。通过若干实例,揭示了卡诺图的直观性和实用性,系统全面地掌握卡诺图的各种应用,可以大大简化数字电路分析和设计的过程,起到事半功倍的效果。     

A simple hyperchaos generator based on impulsive switching

This paper studies a simple hyperchaos generator. The circuit consists of three capacitors, three voltage-controlled current sources, and one state-dependent impulsive switch. The circuit dynamics are described by a normal form equation and a two-dimensional noninvertible return map is derived. The return map is calculated precisely using the exact piecewise solution and hyperchaos generation is guaranteed by two positive Lyapunov exponents of the return map. Using a simple test circuit, a typical hyperchaotic attractor can be verified in the laboratory.     

A novel design method for discrete time chaos based true random number generators

Discrete time chaos based true random number generators are lightweight cryptographic primitives that offer scalable performance for the emerging low power mobile applications. In this work, a novel design method for discrete time chaos based true random number generators is developed using skew tent map as a case study. Optimum parameter values yielding maximum randomness are calculated using a mathematical model of true random number generator. A practical information measure is used to determine the maximum allowable parameter variation limits. Appropriate mapping between dynamic system and circuit parameters is established and a current mode skew tent map circuit is designed to validate proposed method.     

A comparison of five methods for studying a hyperchaotic circuit

A hyperchaotic oscillator based on an LC oscillator and the Deliyannis single amplifier biquad (SAB), coupled by means of a diode, is studied. The inductor of the resonant circuit is realized in practice by using a generalized impedance converter (GIC). Various methods for detecting chaos, such as the Lyapunov exponents, the Lyapunov dimension, the Poincaré map, the spectrum and the phase portraits, are used, in order to confirm the chaotic behaviour of the chaotic circuit. Experimental results fully coincide with theoretical and simulation results. The paper also attempts to answer the question ‘which of the above methods is the most preferable, and why?'. It is concluded that the Lyapunov exponents, Lyapunov dimension and Poincaré map constitute the more reliable methods of confirming chaos.     

一种基于混沌的鲁棒低功耗真随机数发生器

提出了一种低功耗真随机数发生器,它基于简单的伯努利移位混沌映射,并通过对映射进行特殊扩展来保证在实际实现中保持鲁棒性.映射由开关电流技术实现,从而使其可以完全嵌入到片上密码系统中.采用流水线结构并用简单的异或电路来提高信息熵.该随机数发生器采用HJTC的0.18μm CMOS mixed signal工艺进行流片,并通过测试对其统计特性进行了分析.芯片功耗仅为1.42mW,输出比特率为10Mbit/s.     

Emitter-coupled pair chaotic generator circuit

An emitter-coupled pair chaotic generator is proposed with a control parameter that can be tuned for distinct chaotic behaviors. The proposed circuit is a compact, high-speed implementation of the chaotic map based on the hyperbolic tangent function. It is demonstrated that the circuit and map parameters are analytically related. As an application, we design a random number generator that passes all NIST statistical tests by applying a post-processing to the balanced bit sequence generated by a quantization of the circuit output.     

一种应用于润版液的低成本pH监控仪的研究

为了控制印刷润版液的酸碱度,提高印刷品的质量,设计了一种检测印刷润版液pH值的低成本的监控仪。详细介绍了整个系统的结构示意图、信号处理部分的硬件电路以及系统的校准过程。信号处理电路实现了对高阻抗的pH计的信号采集和处理;控制电路采用内部集成A/D的ATMega8单片机和数字式温度传感器DS18B20,满足了低成本的设计要求。     

CNN cell for computing disparity map

The real-time estimation of the distance of objects from an observer is a critical issue in several application fields. A new cellular neural network circuit that uses a stereo vision algorithm to compute the disparity map is presented     

卡诺图排列方法及在组合逻辑电路竞争冒险中的应用

卡诺图是组合逻辑电路设计和分析常用和有效的数学工具,既可以化简逻辑函数,也可以分析组合逻辑电路的竞争冒险。对于多输入变量的逻辑函数,要排列其卡诺图则不是易事。格雷码的相邻码之间只有1位不同,这与卡诺图的循环邻接有相同之处,因而可以利用格雷码快速排列多变量卡诺图。首先介绍二进制码转化为格雷码的方法并用C语言编程实现其码制转换,接着叙述用格雷码规律快速排列多变量卡诺图的方法,最后举例说明卡诺图在组合逻辑电路竞争冒险中的应用。     

一种基于核最大间距准则的硬件木马检测新方法

在功耗旁路信号统计模型的基础上,提出了一种基于核最大间距准则的硬件木马检测方法及改进的检测方法.将原始功耗旁路信号映射到高维空间,使其具有更高的可分性,然后再投影到低维子空间,从而发现原始数据中的非线性差异特征,实现功耗旁路信号的非线性特征提取与识别.针对AES加密电路中木马电路的检测实验表明,该方法测得超出检测边界的样本数(792)多于Karhunen-Loève变换(400),取得更好的检测效果.     

Effect of Time Lag in Response to Switching Signal in Interrupted Electric Circuit

In this study, we analyze the characteristics of an interrupted electric circuit. In particular, we focus on a special situation where the switching action of the circuit is delayed because of a time lag in the response to the switching signal. This situation is observed in switching circuits driven by a high-frequency switching signal. However, the fundamental characteristics of this type of circuit have not yet been clarified. To address this shortfall, we assume that a time lag of the response to the switching signal occurs in simple interrupted electric circuits, and investigate how this time lag affects circuit characteristics. First, we show the model of a circuit whose switching action is the same as that of a current-mode-controlled dc/dc converter. Here by using logic circuits, we impose an artificial time lag on the response to the switching signal. Next, we define a sampled data model (i.e., a return map) that we analyze in detail. Based on the return map, we derive one- and two-parameter bifurcation diagrams. Finally, we compare the bifurcation diagrams constructed with time lag to those constructed without time lag. The results clearly show that time lag is responsible for a new structure in the return map that does not occur in circuits with ideal switching. This new return map structure is a key to understanding the essential characteristics of circuits with time lag. Furthermore, the mathematical results are verified experimentally.     

超混沌保密通信系统的线性反馈设计方法

本文就超昆沌通信问题，提出了一种超混沌保密通信系统的线性反馈设计方法，并阐明它是一种ＡＰＤ（ａｃｔｉｖｅ－ｐａｓ－ｓｉｖｅ ｄｅｃｏｍｐｏｓｉｔｉｏｎ）同步系统的构造方法。这种设计方法的优点在于采用了固定的线性反馈结构，而与原始系统的形式无关。我们分别给出了两个例子，一个是基于４维流形分段线性超混沌电路的连续系统，一个是基于耦合映象格子的离散系统。解析分析和模拟结果都证明了这种方法的有效性。     

一种基于映射结构的新颖A/D转换器的研究和仿真

本文研究了一种新型的混沌A/D转换器,这是一种基于非线性映射结构的非流水式ADC,并提出基于开关电容的ADC电路设计.理论分析和实验仿真表明本文所提出的A/D转换器克服了流水结构A/D变换器多级之间的增益匹配和每级中A/D和D/A变换之间的匹配等主要影响精度的设计问题,具有对噪声干扰不敏感等特性,降低了对部分元器件的精度等要求,可能为高速高精度A/D转换器的设计提供一种新的途经.     

PWM型开关电容DC-DC变换器的 非线性动力学行为研究

建立了PWM型二阶开关电容DC-DC变换器的二维离散映射模型,用非线性动力学理论分析了映射模型定点的稳定情况.以电压反馈系数为参数,通过数值计算描绘了系统动态演化的分岔图和最大Lyapunov指数变化曲线.以二阶串并电容组合开关电容DC-DC变换器为例,用PSPICE软件对其进行模拟仿真,得到了变换器的混沌吸引子.理论分析、数值计算和模拟仿真保持了一致.     

Truly random number generators based on a non-autonomous chaotic oscillator

A non-autonomous chaotic circuit which is suitable for high-frequency integrated circuit (IC) realization is presented. Simulation and experimental results verifying the feasibility of the circuit are given. We have numerically verified that the bit streams obtained from the stroboscopic Poincaré map of the system passed the four basic tests of FIPS-140-2 test suite. We also have verified that the binary data obtained from the hardware realization of this continuous-time chaotic oscillator in the same way pass the full NIST random number test suite. Then, in order to increase the output throughput and the statistical quality of the generated bit sequences, we propose a TRNG design which uses a dual oscillator architecture with the proposed continuous-time chaotic oscillator. Finally, we have experimentally verified that the binary data obtained by this oscillator sampling technique pass the tests of full NIST random number test suite without Von Neumann processing for a higher throughput speed while compared with the previous one where the proposed continuous-time chaotic oscillator is used alone.     

Floating-Gate Circuits for Adaptation of Saccadic Eye Movement Accuracy

In this paper we describe an analog VLSI circuit, fabricatedusing a standard 2 µm, n-well, BiCMOS process,which utilizes floating-gate structures for non-volatile, on-chip,analog parameter storage. This circuit is designed to operatein the context of a hardware model of the primate oculomotorsystem and performs visually-guided, saccadic adaptation. Thechip contains a one-dimensional array of photoreceptors and floating-gatecircuits which are used to map retinal positions to motor outputcommands. The system's functionality is demonstrated by trainingthe chip with several different mapping functions using a supervised-learningtechnique.     

基于思维导图的高效电路教学法的研究

本文将思维导图这一全新的思维工具应用于电路课程教学中,推出了一种基于思维导图的电路高效教学与学习法,并将其融入到现代化多媒体教学中去。实践表明,教师用此方法会使备课轻松,讲授思路清晰,能让学生快速地学会并且记住要点,从而大幅度提高了教学效率和效果,达到了让学生易学、想学和会学的有效教学目的。     

Chaotic noise MOS generator based on logistic map

The Birkhoff's ergodic theorem (BET), bifurcation diagram (BD) and Lyapunov's exponent (LE) are used in order to design a chaotic noise generator that is governed by the logistic map (LM). For this, a MOS analog circuit that operates in the current-mode, which is based on translinear principle (TLP), is used. To iterate the transference function of this circuit and also to maintain the parameter control of the LM, a current amplifier has been used. The specifications of the design are obtained from the analysis of the model. The results demonstrate the correct operation of the circuit, even when a mismatching of 2% is considered between the devices that control the operation region. The statistical distribution of the output signal on the circuit is similar to uniform distribution and it is related with the parameter value that rules the transfer function of the circuit.     

一种改进的混沌扩频序列研究

通过对混沌映射的研究,针对单一映射产生的扩频序列其系统复杂度低,容易通过反向逆推估计出系统初值的缺点,以Logistic映射为基础,构造出一种新的映射。该映射容易被数字电路实现,且具有较高的系统复杂度。该序列由两个不同初始值的两个Logistic映射复合而成,具有较高的安全性。在此,对复合混沌序列初值敏感性、平衡性、自相关性、功率谱密度进行了分析。研究结果表明,这种新型的序列具有较高的初值敏感性、优良的平衡性、自相关性和伪随机性,是一种有效和可靠的扩频序列。     

一种分段线性映射的混沌随机数发生器特性研究

该文通过对确定性混沌演化本质的分析和对其系统状态空间的划分,使它转变为一个各态历经的信息源以用于设计随机数发生器。然后又分析了一种混沌的分段线性映射的特性,如:混沌吸引子与点吸引子,信源熵与冗余度以及混沌映射产生的序列的分布特性。此外,利用开关电容电路技术用TSMC 0.25m CMOS数模混合工艺实现了此分段线性映射。测试结果表现出非常好的抗干扰性能。