Design Of Three-variable Threshold Circuit And Realization Of Functions Based On RTD

Nano-electronic device and technology is one of the ways to solve the bottleneck of traditional semiconductor process technology.The resonant tunneling diode(RTD)is widely used in the field of high-speed and low-power digital circuit as a mature nano-electronic device.The monostable bistable transition logic element(MOBILE)composed of RTDs is an important logic unit based on RTD circuits,which can give full play to the characteristics of the RTD,such as high frequency,high speed,low power consumption and negative resistance.And the threshold circuit can be easily designed by MOBILE.The content of this thesis includes two aspects: design of RTD-based three-variable threshold circuit and realization of RTD-based three-variable and n-variable functions.The designed three-variable threshold circuit consists of three-variable XOR gate,full adder,three-variable characteristic threshold logic gate and three-variable universal threshold logic gate,which can be designed by MOBILE and its input branch.Since the three-variable XOR function itself is not a threshold function,it needs to be transformed into a more simple generalized threshold logic function.By this method,the three-variable XOR gate is designed in this thesis.And the full adder can be composed of the designed three-variable XOR gate and the carry output circuit that can also be designed by MOBILE.Through the HSPICE simulation and performance comparison,the designed full adder and three-variable XOR gate can not only reduce the number of devices,but also reduce the circuit power consumption and delay-time.The three-variable characteristic threshold logic gate and three-variable universal threshold logic gate are the three-variable universal logic gate that can be used to realize arbitrary three-variable threshold functions.The two logic gates are designed by using the spectral technique to analyze three-variable threshold functions.Through the HSPICE simulation and performance comparison,the designed circuit can not only reduce the area of the circuit,but also reduce the power consumption of the circuit.The realization of non-threshold functions is important in the realization of three-variable functions.Three-variable non-threshold functions can be divided into four categories by spectral coefficients.According to the properties of the spectral technique,the four types of non-threshold functions can be transformed into threshold functions with one XOR conversion.And the corresponding realization method of three-variable functions is proposed in this thesis.The circuit obtained by this method can be designed by using the RTD-based three-variable universal logic gate and XOR gate.And the circuit has the advantages of simple circuit structure,lessnumber of devices,low power consumption and so on.N-variable functions can be realized by the function decomposition method and the three-layer network structure method.In this thesis,the corresponding algorithms are proposed:function decomposition algorithm and three-layer network structure algorithm.The function decomposition algorithm is realized by using the theory of simple non-intersecting decomposition and the proposed K matrix.The algorithm can effectively reduce the number of three-variable functions after the decomposition.And three-variable functions can be realized by the method of three-variable function realization proposed in this thesis.The three-layer network structure algorithm is realized by using the three-layer network structure that is in the binary neuron network model,and the related theorem.The algorithm can not only improve the accuracy and efficiency of the algorithm,but also make the owned circuit more simple.