3abc and 8 please. The subject is computer engineering.

want to build a circuit to compute the two's complement of We -bit number. We will do this with n modules, each of which complements that bit and th bit. Thus, the first three bits of a block diagram of the circuit will look like en adds the carry from the next lower a1 b2 b1 by Show a block diagram for each of the boxes using NAND gates. (Design the first-on the right-box specially.) a. b. Compute the delay for n bits. mprove the speed by designing 2 bits at a time. Show a gate circuit and compute the total delay 8. We wish to design a decoder, with three inputs, x, y, z, and eioht active high outputs, labeled 0, 1,2, 3, 4, 5,6,7. There is no enahl. input required. (For example, if xyz = 011 , then output 3 wouldbe I and all other outputs would be 0.) The only building block is a two-input, four-output decoder (with an active high enable), the truth table for which is shown below EN A BO12 3 EN Draw a block diagram of the system using as many o building blocks as are needed