A BCD-to-seven-segment decoder is a combinational circuit that converts a decimal digit in BCD to an appropriate code for the selection of segments in a display indicator used for displaying the decimal digit in a familiar form. The seven outputs of the decoder (a, b. c. d. e. f. g) select the corresponding segments in the display, as shown in Fig. P4-16(a). The numeric designation chosen to represent the decimal digit is shown in Fig. P4-16(b). Design the BCD-to-seven-segment decoder using a minimum number of NAND gates. The six invalid combinations should result in a blank display.
