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(ELEC151)[200X](s)midterm~1806^_10281.pdf
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Ouestion 1:
(a). Convert the unsigned binary number 1110102 to

(i) decimal number, (ii)BCD code and (iii)hexadecimal number.
(b). Given a 8-bit word N, N=1110 0101, find the decimal value of N represented if it is
(i)
an unsigned binary number

(ii)
a number in two's complement code


(iii) a number in sign-and-magnitude code
(c) Suppose a memory with a 8-bit word is used to store the unsigned binary integer and another 4-bit word for the binary fraction. What will be on the memory if the number in decimal equals to 3.66?
, ..L .J .,
(0..)\ \ 10 10
"'2 , ()
3 oJ-pQ. -+0V2
J 0>'2-
~ 1) lOS .+ IX.2 Lt -+ Ix. 2
::-:s L +-lG+8-t"2 =-S-2

(il') (S2) =-(0 ~ 0\ tOOO)BG-O If
. /10
Cf(l) l b I :8
\.---_._-~
3 .lO
r'-8\ _
l~ .J Iv (3,A) It.. 1/
. :, '. ( >),' v '\ 7 ~ l l-0
L -1-2 +2---t")., -+-2
Ch) (I) (II [() 0' 0 [;/2 -/2 2t bct -t-?,L -I-4--+' =-2 2 9/(
'-( I \"
(i i) (, (I 0oI 0 I _-:-~ -/() 0 0 II D\ 0 -t )
) ~( / '.
'L 5" ,0
-~) _.-( ova I \0 l \)
( 20-~ 23 + 2'-+ I)
(\C+g +2~()
L 7II
r/'(1) I riD 0 I0 f :j) -~-( 0 1'7 0 r3 /0,)
-------_._--_...._------------
(2 b.J L ~ ) 1.').-l-I) --( /,It+"3,2+(j--+I
7>
I0 II!
(c) {6To /~ I0. / [O(O/l( (J {ilo/~ZQ}
~ :-() I ~ b =
Ouestion4:
A combinational circuit is specified by the following two Boolean functions:
F1(A,B,C)=Im(0,2,3,6)
F2(A,B,C)=(A+B)'+ABC'

(a). Implement the circuit using AND and/or OR and/or NOT gates and draw the circuit schematic.
(b). Implement the circuit with one decoder and NAND gates and draw the circuit schematic.

",f\B . l\B
C \.00 01I' 10 0f I{ , 0
2' ()0 _ D~\J" t '0
F oEEF8iJ 0 -l
t-l ,-> ) J ..L .
1521 00 I I I
O~D]
F( AC -t Be + A F2 = II+B. 4-Ate-
CK)
(b ) ---_..
A ~ e<l -~

F\
c-.. .-.J!)-I
A ~~~;~
15... L.-..-\"
C:_;,l3) _~-~I
1S dJ. lC. &-c.~
t
A -_~-~1)._ ..rC .'
g.
/I-~~'"FL.-
~.. ~---' -
e,-& .
--End of the Paper--
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00 / I 0\ I a, clot.
" ".,.1 f ~lIr p'A r4--. 1"'~l'.J' ('" .
/

Question 2:
(a). Use DeMorgan's theorem to convert F = Ao(B'+C) o(A+D') to NORNOR form.
(b). A circuit is given below,

~'
;-:-~:o
(i). Write the Boolean functions at outputs X and Y. Simplify the two functions.
(ii). Fill in the K-maps of outputs X and Y below.
Output X
""'-AB

CD~
00
\\
\0
I.rI !II,
(iii). Implement the simplified Boolean function of X by 2-input NAND gates only and draw the circuit schematic. -
(a) f A. (B-rc). (A-J-15)
A. t g-f C) .( A-ris )
/) ~ (g~G) ~ (A;:f;)/(

( f> -t BL)l A+D)
1~
(b)ll) X (DfBL)-D"!l+b
(,1-+ Be)l AC)
!b+Bc)'" (D +A+D)
ADD + ABc-I)
Cbf 6 L)
ABc-I>
(\11)
D ~D~A_X
P-y.,
B. B ~)o--V
C ~c --LJ
-3-
Question 3:
Design a combination logic circuit with 4 inputs (A,B,C,D) and one output F, where F=l when an even
number of inputs = I and when A=B=C=D=O.

(a). Fill in truth table provided below.
(b). Express F in sum of minterms representation.
(c). Express F in