What is the difference between folding and un-folding techniques? Draw the signal flow graph for z(n)= a.z(n-7) + x(n) and the 2-unfolded version (J=2) of the same. Can the unfolded version be re-folded back to the original graph? What can be the maximum unfolding possible for the given graph? Draw the architecture for circular CORDIC and explain its operation in details. How can the structure be modified to make it suitable for both circular and hyperbolic trigonometric calculations? What is the critical path for such design?