| Memristor is the fourth basic circuit element in circuit theory besides the other three basicelements, namely, resistor, capacitor, and inductor. The concept of memristor was firstly proposedby Professor Leon O. Chua in1971, until2008HP Labs found that TiO2has the characteristics ofthe memristor at the nanometer scale. Memristor is a passive nonlinear circuit element, theresistance of memristor varies with the current that flow through itself, and once the current is cutoff, the resistance will maintain the state when power is off. That is to say, memristor possesses thecharacteristics of memorability. In a non-volatile memory, artificial neural network and nonlinearcircuit, memristor has wide potential application prospect, however, it hasn’t been accessible to usin market. This paper studies the hardware memristor circuit model, in order to replace actualmemristor for experiment and application circuit, explore new chaotic circuit with memristor, andtry to apply it in the Android platform for mobile phone files btween secrecy transmission. Thispaper mainly follows by several parts:(1) Study the theory of memristor, and design a port-equivalent charge-controlled memristorcircuit model and magnetic-controlled memristor circuit model based on theoretical TiO2memristormodel proposed by HP Labs. The volt-ampere characteristics of circuit model under sine excitationare analyzed theoretically, including multisim simulation and actual circuit experiment. Theoreticalanalysis and experimental results show that volt-ampere characteristic of equivalent circuit modelsis consistent with HP TiO2. For the sake of simulating memorability of actual memristor, a discretecharge-controlled memristor model was constructed based on MCU and digital potentiometer in thispaper, besides the volt-ampere characteristics, it is important to have actual memory characteristic.In the sine wave, triangle wave, square wave and sawtooth wave excitation, the volt-amperecharacteristics of circuit experiment verification is done and get the desired results.(2) Introduce principal theory of chaos, and construct a four-dimensional memristor-basedchaotic system by replacing the Chua’s diode in Chua’s circuit with a magnetic-controlledmemristor model. Using matlab software, the fundamental theoretical analysis and dynamiccharacteristics were conducted, including equilibrium point and stability of the system. Then verifythe chaotic system by using the DSP experimental platform. Finally the pseudorandom sequencewas generated from the system and NIST test was done.(3) Based on the similarities between cryptography and chaos, this paper proposed a scheme toachieve secure data sharing between two Android devices using WiFi-Direct technology, and the secret key used is a series of random sequence extracted from the memristor-based chaotic system.The software has two kinds of working mode, namely, Wi-Fi mode and Wi-Fi Direct mode. InWi-Fi mode, two Android devices communicate with each other via Wi-Fi hotspots while in Wi-FiDirect mode via point-to-point direct connection. Write the software in Eclipse developmentenvironment using Java language, and carry out the actual test between Tiny6410experimentalplatform andAndroid Phone. |
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