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1、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 年月日一二三四五六七八九十总分评卷教师I. To fill the answers in the “ ( )”( 2 X 15 = 30 ) 1. Given ABCF)5,4 , 1(, then ABCF( 0,2,3,6,7), F=ABC( 1)+ABC( 0,1). 2. ( 1001 0011 )8421BCD=( 1111 0011)2421BCD. 3. ( 0101 1101 )2=( 0111 0011)Gray. 4. Open-drain output
2、has two states, Low and ( Hi-Z/open ). 5. A twos-complement =0110 1010, C ones-complement =1111 1011, A-Ctwos-complement=( 0110 1110). Is it overflow for A-Ctwos-complement? (Yes or No) No 6. XOR gate in positive logic level is equivalent to ( XNOR) gate in negative logic level. 7. Five variables ca
3、n make ( 32) minterms. The sum of all the minterms must be ( 1). 8. If the function ABCF)6 ,3 ,2, 1 (, then ABCF( 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
4、 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 ) 名师资料总结 - - -精品资料欢迎下载 - - - - - - - - - - - - - - - - - - 名师精心整理 - - - - - - - 第 1 页，共 6 页 - - - - - - - - - 1. Which of the following codes has the self-complem
5、ent 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? (
6、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?ZC. F=W?Y+W ?Z +X ?Y ?Z+Y ?ZD. F=W ?Y+W ?Z +X ?Y ?Z+W ?X?Y6. Which of the following statements is correct? ( D) A. The duality of the minimal sum expression is its minimal product. B. Th
7、e 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 111
8、1 . 0100)2, its equivalent values for A10 and A16 are ( B) A. (96.58)10, (60.94)16B. (63.25)10, (3F.4)16 C. (96.58)10, (60.49)16 D. (63.25)10, (3F.94)16名师资料总结 - - -精品资料欢迎下载 - - - - - - - - - - - - - - - - - - 名师精心整理 - - - - - - - 第 2 页，共 6 页 - - - - - - - - - 9. Given the timing diagram as shown in
9、Figure 2, the output function is ( A). A. xyzf)7 ,6 ,5 ,3(B. xyzf)4,2, 1 ,0(C. xyzf)6,2, 1 ,0(D. xyzf)7 ,2, 1 ,0(10. A self-dual logic function is a function such that F=FD. Which of the following functions is self-dual? ( C) A. xyzF)7 ,5 ,2, 1 (B. F=X ?Y?Z +X?Y ?Z +X ?ZC. F=X ?Y+X ?Z+Y ?Z D. )4, 3,
10、0(xyzFIII. Combinational Circuit Analysis And Design: 40 1.Given F(A,B,C,D)= BC (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
11、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；名师资料总结 - - -精品资料欢迎下载 - - - - - - - - - - - - - - - - - - 名师精心整理 - - - - - - - 第 3 页，共 6 页 - - - - - - - - - Fminimal-sum (A,B,C,D)=B/C/+B/D+C/D3.“与非 -与非“表达式正确1 分FNAND-NAND (A,B,C,D)= (B/C/)/(B/D)/(C/D)/2. A combinational circuit is shown as
12、below. (8 ) (1) Write out the sum-of-product expression of output F(W,X,Y,Z) for the circuit. (2) Analysis all conditions that the static hazard may exit for the circuit, and indicate types of static hazard. (3)Write out the minimal sum of output F(W,X,Y,Z) for the hazard-free. 参考评分标准：1. 原始的积之和表达式正确
13、3 分 ,只要是积之和形式就算对，不管是否为原始积之和，错一个（多一个或少一个）乘积项扣一分，扣完为止；F(W,X,Y,Z)=WX/Y/+XY/Z+XY2.指出所有静态冒险存在的条件2 分，指出静态冒险类型1 分。当 W=Z=1 ， Y=0，X 变化时（ 1 分） ，存在静态1 冒险（ 0.5 分）当 X=Z=1 ， Y 变化时（ 1 分） ，存在静态1 冒险（ 0.5 分）只要描述清楚就得分。3.无冒险的最小和表达式正确2 分。F hazard-free (W,X,Y,Z)=WX/Y/+WY/Z+XY+XZ名师资料总结 - - -精品资料欢迎下载 - - - - - - - - - - -
14、- - - - - - - 名师精心整理 - - - - - - - 第 4 页，共 6 页 - - - - - - - - - 3.Implement F(U,V,W,X,Y ,Z)=U,V,W,X,Y,Z (3,5,7,19,23) using only a 74x138 and a NAND gate. (6 ) (1)Write out the canonical sum expression of F(U,V ,W,X,Y,Z). (2) Draw the logic diagram. 参考评分标准：1. F 的标准和表达式正确2 分F(U,V,W,X,Y,Z)= 5 个标准积之和的
15、形式，错一项扣0.5，扣完为止。2.电路图输入正确占2 分，输出正确占2 分，错一处扣0.5 分，扣完为止。4.A combinational circuit is shown as below, which contains two 74x148 priority encoder and some gates. Input X9_L has the highest priority, and X0_L has the lowest priority.(8 ) (1) List out the truth table for the circuit. (2) Indicate the logi
16、c function of the circuit. 名师资料总结 - - -精品资料欢迎下载 - - - - - - - - - - - - - - - - - - 名师精心整理 - - - - - - - 第 5 页，共 6 页 - - - - - - - - - 参考评分标准：1. 真值表正确6 分，错一行扣1 分，扣完为止。2.电路功能描述正确2 分： 8421BCD 优先编码器，写出正确的输出逻辑表达式也算正确。5. Design a converter circuit of Binary code (B3 B2 B1 B0) to Gray code (G3 G2 G1 G0) u
17、sing only one 74x157 and some gates. Please select B2 as the selection input of 74x157. Please (1)Write out the four logic expressions of output G3, G2, G1, G0. (2) Draw the logic diagram. (10 )1、 四个表达式6 分（真值表正确给2 分，没有真值表不扣分），每错一个表达式扣1.5 分，扣完为止；2、逻辑框图总分4 分，根据实际解题思路酌情给分。不用B2 作为选择端扣4 分；名师资料总结 - - -精品资料欢迎下载 - - - - - - - - - - - - - - - - - - 名师精心整理 - - - - - - - 第 6 页，共 6 页 - - - - - - - - -