Thursday, 26 November 2015

HOW TO DESIGN A BASIC GATES IN QCA TECHNOLOGY?

BASIC GATES OF QCA TECHNOLOGY:



MAJORITY GATE:
 
QCA Majority Gate Perhaps the most important logic gate in QCA is the majority gate. Figure 5 shows a majority gate with three inputs and one output. In this structure, the electrical field effect of each input on the output is identical and additive, with the result that whichever input state ("binary 0" or "binary 1") is in the majority becomes the state of the output cell — hence the gate's name. For example, if inputs A and B exist in a “binary 0” state and input C exists in a “binary 1” state, the output will exist in a “binary 0” state since the combined electrical field effect of inputs A and B together is greater than that of input C alone.


 OTHER GATES:
 
Other types of gates, AND gate namely  and OR gate, can be constructed using a majority gate with fixed polarization on one of its inputs. A NOT gate, on the other hand, is fundamentally different from the majority gate, as shown in Figure 6. The key to this design is that the input is split and both resulting inputs impinge obliquely on the output. In contrast with an orthogonal placement, the electric field effect of this input structure forces a reversal of polarization in the output.




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