1. A method for split processing input data having first and second half data into first and second split transformed data, a whole transform defining first and second radix-2 transforms, the whole transform defining first and second radix-2 transforms, the whole transform and the first and second radix-2 transforms are fast Hartley transforms, the method comprising the steps of, whole transforming the input data into merged transformed data, the merged transformed data equaling the whole transform of the input data, and split combinational processing the merged transformed data into first and second split transformed data, the first and second split transformed data respectively equaling the first and second radix-2 transforms of the first and second half data.