Multi-scroll Chaotic Systems And Circuit Implement Based On Current Mode Devices

Chaos circuit is the core part of the whole chaotic communication system,which is used to generate chaotic signals required.Chaos circuit has been a hot research topic of chaotic theory.In particular,generating various complex multi-scroll chaotic attractors by using some simple electronic devices have been developing rapidly in recent years.Many methods of generating multi-scroll attractors have been proposed and validated by experiments,but their functions were mainly built with conventional operational amplifier,can't generate multi scroll chaotic attractors with high frequency.Compared with the operational amplifier,the gain bandwidth product of the current mode device is not a constant,so its working frequency is higher,so the chaotic circuit using current mode device has higher work frequency.In addition,compared with the operational amplifier,the current mode device has a large dynamic range,can produce more scroll chaotic atractors,which can increase the complexity of chaotic dynamics,and increase the security of chaotic encryption algorithm.So the research of multi scroll chaotic system and circuit implement based on the current mode device has important significance in high frequency communication system and chaotic encryption algorithm.Based on the above described,the main thesis research and innovation includes the following two aspects:one is the study of multiscroll chaotic attractor;the other is to explore how to design high-frequency multiscroll chaotic circuit using current mode device and its application in hybrid image encryption.The specific innovative works of this paper are as follows:(1)A grid multiscroll chaotic electronic oscillator based on the current feedback operational amplifier(CFOA)is proposed.The proposed grid multiscroll chaotic circuit only needs two CFOAs as current integrators,passive RC,and nonlinear elements in the form of current stair nonlinear function series realized with CFOAs.Compared with existing grid multiscroll circuits such as Chua's circuit and Jerk circuit,etc.,its component count is reduced.Mathematical models of the proposed generators are derived.Theoretical analysis and numerical simulations of the derived models are included.Moreover,the experimental results are verified that the chaotic electronic oscillator can generate grid multiscroll chaotic attractors with higher frequency.(2)We propose a grid multiscroll chaotic attractors generator based on the second generation current conveyor(CCII),used for hybrid image encryption of physical chaos encryption and advanced encryption standard(AES)encryption algorithm.Because CCII has higher speed and larger dynamic range than operational amplifier,it can generate multiscroll physical chaotic signal with higher frequency and more complex dynamics properties.The hybrid encryption system of multiscroll physical chaos encryption and AES encryption based on CCII,has no assured relationship between plaintext and ciphertext,and the statistical characteristics of ciphertexts in this algorithm should be better than that of any other encryption system.We designed and implemented the chaos circuit based on CCII,simulated the hybrid image encryption system.The simulated results are shown in agreement with the theoretical analyse,and show that the more number of scrolls chaotic system causes the weaker correlation of ciphertexts.(3)The grid multiscroll hyperchaotic attractor generated by positive-type second generation current conveyor(CCII+)is proposed.A fourth-order grid multiscroll hyperchaotic system is presented by introducing two nonlinear functions into hyperchaotic system.Dynamical behaviors of this hyperchaotic system are investigated.Then the system is physically implemented by using CCII+.The experiment results are verified that the oscillator can generate grid multi-scroll hyperchaotic attractors with higher frequency.(4)A grid multiscroll chaotic circuit based on CMOS CCII is proposed.Build CMOS CCII with large dynamic range and high frequency,and then use the CMOS CCII as active modules to achieve multi scroll chaotic circuit easily integrated with high frequency.Multisim circuit simulation shows that the chaotic oscillator can produce higher frequency,low-voltage multi-scroll chaotic attractors.