B is a block diagram illustrating a filter tree corresponding to the mapping of FIG. 11A in accordance with an embodiment of the invention. [0030]FIG. 12A is a block diagram illustrating the mapping of FIG. 11A after reverse tuning in accordance with an embodiment of the invention. [0031]FIG. 12B is a block diagram illustrating a filter tree corresponding to the mapping of FIG. 12A in accordance w