2014数字逻辑期中试题电子科技大学

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；