2014数字逻辑期中试题电子科技大学
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电子科技大学2013-2014学年第二学期
“数字逻辑设计及应用”课程考试题（半期）（120分钟）考试日期 2014年 月 日
I. To fill the answers in the “( )” ( 2’ X 15 = 30 )
1. Given ∑
=
ABC
F )5,4,1(, then ABC F ∏=( 0,2,3,6,7 ),
F =A ’
∑
BC
( 1 )+A
∑
BC
( 0,1 ).
2. ( 1001 0011 )8421BCD =( 1111 0011 )2421BCD .
3. ( 0101 1101 )2=( 0111 0011 )Gray .
4. Open-drain output has two states, Low and ( Hi-Z/open ).
5. A two’s -complement =0110 1010, C one ’s -complement =1111 1011, [A-C]two’s -complement =( 0110 1110 ). Is it overflow for [A-C]two’s -complement ? (Yes or No) [ No ]
6. XOR gate in positive logic level is equivalent to ( XNOR ) gate in negative logic level.
7. Five variables can make ( 32 ) minterms. The sum of all the minterms must be ( 1 ).
8. If the function ∑
=
ABC
F )6,3,2,1(, then ∑=ABC F '( 0, 4, 5, 7 ).
9. If the information bits are 1001 0010, the check bit is ( 0 ) for odd-parity. 10. To make 2014 code-words, ( 11 ) bits should be used at least.
11. Given the circuit shown in Figure 1, its output expression F=( (b(a+c)+ac)’ ).
Figure 1
II. There is only one correct answer in the following questions.( 3’ X 10=30 )
1. Which of the following codes has the self-complement property? ( D)
A. Gray
B. Biquinary
C. 8421BCD
D. Excess-3
2. Which of the following 2-input gates can form a complete set of logic gates? ( B )
A. OR
B. NOR
C. XOR
D. XNOR
3. Which of the following gates is equivalent to XNOR? ( A)
A. B. C. D.
4. Which of the following connection is correct? ( C)
A. B. C. D.
5. Which of the following expressions has no hazard? ( B)
A. F=W•Y+W’•Z’+X•Y’•Z
B. F=W•Y+W’•Z’+Y•Z’
C. F=W•Y+W’•Z’+X•Y’•Z+Y•Z’
D. F=W•Y+W’•Z’+X•Y’•Z+W’•X•Y’
6. Which of the following statements is correct? ( D)
A. The duality of the minimal sum expression is its minimal product.
B. The minimum sum-of-product expression has no static-1 hazard.
C. The canonical sum must have hazard.
D. The minimum sum-of-product expression has no static-0 hazard.
7. The minimum sum of product for AB+A’C+BCDEFGH is ( A).
A. A•B+A’•C
B. A’•B+A•C
C. A•B+A’•C+B•C
D. A•B+A’•C+B•C
8. Given A=(0011 1111 . 0100)2, its equivalent values for A10 and A16 are ( B)
A. (96.58)10, (60.94)16
B. (63.25)10, (3F.4)16
C. (96.58)10, (60.49)16
D. (63.25)10, (3F.94)16
9. Given the timing diagram as shown in Figure 2, the output function is ( A ). A. ∑
=xyz
f )7,6,5,3( B. ∑=xyz f )4,2,1,0( C. ∑=xyz f )6,2,1,0( D. ∑=xyz f )7,2,1,0(
Figure 2
10. A self-dual logic function is a function such that F=F D . Which of the following functions is self-dual? ( C )
A. ∑
=
xyz
F )7,5,2,1( B. F=X ’•Y •Z ’+X •Y ’•Z ’+X ’•Z
C. F=X •Y+X •Z+Y •Z
D. )4,3,0(xyz F ∏=
III. Combinational Circuit Analysis And Design: [40’]
1.Given F(A,B,C,D)= B ⊕C ⊙(B •C)+A ’•D •(B •C)’, the constraint condition is A •(B+C)=0. Simplify the logic function F(A,B,C,D) into the minimal sum using Karnaugh map, and write out NAND-NAND logic expression of the minimal sum. (8’)
参考评分标准：
1.填写F 的卡诺图正确4分 ，d 占1分，错一格扣0.5分，扣完为止；
2.化简的表达式正确3分，错一个乘积项扣1分；