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课后习题答案_第2章_逻辑代数及其化简

第2章逻辑代数及其化简2-1 分别将十进制数,和转换成二进制数。

解答:10=(1,2…)210=(111,,1100,,1100,…)210=(1,0111,2-2 分别将二进制数101101.和转换成十进制数。

解答:(101101.)2=(45.)102=102-3 分别将二进制数和转换成十六进制数。

解答:=(26.9C)162=(0010,,1100)2=162=(1,0101,,1110)22-4 分别将十六进制数和6C2B.4A7H转换成二进制数。

解答:16=(11,1010,,1110,1011)2(6C2B.4A7)16=(110,1100,0010,,1010,0111)2 2-5 试用真值表法证明下列逻辑等式:(1) AB A C BC AB C(2) AB AB BC AB AB AC(3) AB BC C A AB BC CA(4) AB AB BC AC A BC(5) AB BC CD D A ABCD ABCD(6) AB AB ABC A B证明:(1) AB A C BC AB C++=+真值表如下所示:由真值表可知,逻辑等式成立。

(2) AB AB BC AB AB AC++=++真值表如下所示:由真值表可知,逻辑等式成立。

(3) AB BC C A AB BC CA++=++真值表如下所示:由真值表可知,逻辑等式成立。

(4) AB AB BC AC A BC+++=+真值表如下所示:由真值表可知,逻辑等式成立。

(5) AB BC CD D A ABCD ABCD+++=+真值表如下所示:由真值表可知,逻辑等式成立。

(6) AB AB ABC A B++=+真值表如下所示:由真值表可知,逻辑等式成立。

2-6 求下列各逻辑函数F 的反函数F 和对偶式F :(1) 1F A ABC A C (2) 2()()()F A B A AB C A B C AB ABC (3) 3F A B CD ADB (4) 4F AB BD C AB B D (5) 5F AB AB BC BC (6) 6F CD CD A C DB解答:(1) 1F A ABC A C =++1()()F A A B C A C =+++1'()()F A A B C A C =+++ (2) 2()()()F A B A AB C A B C AB ABC2()()()F AB AA B C A BC A B A B C =+++++++2'()()()F AB AA B C A BC A B A B C =+++++++ (3) 3F A B CD ADB3F ABC DA D B =+++3'F ABC DA D B =+++ (4) 4F AB BD C AB B D4()()()F A B B D C A B BD =+++4'()()()F A B B D C A B BD =+++ (5) 5F AB AB BC BC5()()()()F A B A B B C B C =+++++5'()()()()F A B A B B C B C =+++++ (6) 6F CD CD A C DB6()()()()F C D C D A C D B =++++6'()()()()F C D C D A C D B =++++2-7 某逻辑电路有A 、B 、C 共3个输入端,一个输出端F ,当输入信号中有奇数个1时,输出F 为1,否则输出为0,试列出此逻辑函数的真值表,写出其逻辑函数表达式,并画出逻辑电路图。

解答:由题意可列出真值表如下:由真值表可以得到函数表达式为:F ABC ABC ABC ABC=+++逻辑电路如图T2-7所示:ABCABCFABCABC图T2-72-8 设计一个3人表决电路,要求:当输入A、B、C中有半数以上人同意时,决议才能通过,但A有否决权,如A不同意,即使B、C都同意,决议也不能通过。

解答:定义变量A、B、C,1代表同意,0代表不同意;F为结果,1代表通过,0代表不能通过。

由题意可列出真值表如下:由真值表可以得到函数表达式为F ABC ABC ABC =++,化简可以得到F AC AB =+。

2-9 试用代数公式法证明题2-5中的各等式。

(1)AB A C BC AB C ++=+证明:()AB AC BC AB A B CAB ABC AB C++=++=+=+(2)AB AB BC AB AB AC ++=++证明:()AB AB BC AB BC ABAB BC AC AB AB AB AC ++=++=+++=++(3)AB BC C A AB BC CA ++=++证明:()()()()()()AB BC C A AB BC BC C A AB C A AB BC C A CA AB BCAB CA BC AB BC C A CA BC AB AB BC CA ++=+++++=+++++=++++++++=++(4)AB AB BC AC A BC +++=+证明:(1)AB AB BC AC A BC ACA C BC A BC+++=++=++=+(5)AB BC CD D A ABCD ABCD +++=+证明:()()()()()()AB BC CD DA A B B C C D D A AB A C BC CD CA DA ABCD ABCD+++=++++=++++=+(6)AB AB ABC A B ++=+证明:()()AB AB ABC AB A B ABCA ABC AB B A B++=+++=+++=+2-10 证明下列异或运算公式:(1) 0A A(2) 1A A(3) 0A A(4) 1A A(5) AB AB A(6) A B A B解答:(1)0A A⊕=证明:⊕=+=+=000A A AA AA(2)1⊕=A A证明:A A A A A⊕=+=+=+=11101011(3)0⊕=A A证明:⊕=+=+=00010A A A A A A(4)1A A ⊕=证明:1A A AA AA AA AA A A ⊕=+=+=+=(5)AB AB A ⊕=证明: ()()AB AB AB AB AB AB AB A B A B AB AB AB A ⊕=+=+++=+= (6)A B A B ⊕=⊕证明:()()A B AB AB AB AB AB AB ABAB A B A B AB AB A B ⊕=+=+=+==++=+=⊕2-11 用公式法化简下列逻辑函数为最简与或式: (1) 1()F AB AB AB AB CD (2) 2F ABC AC ABC AC (3) 3()()F AB AB A B AB (4) 4()()F A AB A BC C (5) 5()F AB A CD B C D (6) 6()()()F A B A AB C A B C AB ABC解答:(1) 1()F AB AB AB AB CD =+++化简:1()()()()F AB AB AB AB CD A AB AB CD A B AB CD AB AB CD AB =+++=++=++=+=(2) 2F ABC AC ABC AC =+++ 化简: 2()()()()F ABC AC ABC AC A BC C ABC AC A B C ABC AC ABC ABC ACA BC AC ABC AC ABC A B C AC ABC AB AC AC ABC AB A ABC A A BC =+++=+++=+++=++=⊕+=+=+++=+++=++=+=+(3) 3()()F AB AB A B AB =++ 化简:3()()()000F AB AB A B AB AB AB AB ABAB ABAB =++=+=+=+=(4) 4()()F A AB A BC C =+++ 化简:4()()()()()0F A AB A BC C A B A B C A B ABC =+++=+++=+=(5) 5()F AB A CD B C D =+++化简: 5()()()()()()()()()()()()F AB ACD B C D A B A C D B C D AA AC AD AB BC BD B C D AC AB BC AD BD B C D AC AB AD BD B C D AC AB AD B C D ABC AC ACD AB ABC ABD ABD ACD AD AC AB AD =+++=+++++=+++++++=++++++=+++++=++++=++++++++=++(6) 6()()()F A B A AB C A B C AB ABC =++++++ 化简: 6()()()()F A B A AB C A B C AB ABCA ABC A BC AB ABCAC A BC AB ABCA BC AB A B BCA B C =++++++=+++++=++++=++=++=++2-12 用卡诺图化简下列逻辑函数为最简与或式:(1) 1(3,5,6,7)F m (2) 2(4,5,6,7,8,9,10,11,12,13)F m (3) 3(2,3,6,7,10,11,12,15)F m (4) 4(1,3,4,5,8,9,13,15)F m (5) 5(1,3,4,6,7,9,11,12,14,15)F m (6) 6(0,2,4,7,8,9,12,13,14,15)F m解答:(1)13,5,6,7F m=∑()卡诺图:由卡诺图可知:13,5,6,7F m AC AB BC ==++∑()(2)24,5,6,7,8,9,10,11,12,13F m=∑()卡诺图:10由卡诺图可知:24,5,6,7,8,9,10,11,12,13F m AB AB AC==++∑()(3)32,3,6,7,10,11,12,15F m=∑()卡诺图:由卡诺图可知:32,3,6,7,10,11,12,15F m ABCD A C BC CD==+++∑()(4)4134,5,8,9,13,15F m=∑(,,)卡诺图:由卡诺图可知:4134,5,8,9,13,15F m ABD ABC ABD ABC==+++∑(,,)(5)5134,6,7,9,11,12,1415F m=∑(,,,)卡诺图:由卡诺图可知:5134,6,7,9,11,12,1415F m BD BD CD==++∑(,,,)(6)6024,7,8,9,12,13,14,15F m=∑(,,)卡诺图:由卡诺图可知:6024,7,8,9,12,13,14,15F m AB AC CD ABC BCD==++++∑(,,)2-13 对具有无关项0AB AC的下列逻辑函数进行化简:(1)1F AC AB(2)2F A C AB(3)3F ABC ABD ABD ABCD(4) 4F BCD ABCD ABC ABD (5)5F ACD ABCD ABD ABCD (6) 6F BCD ABCD ABCD解答: (1) 1F AC AB =+1F AC AB AC AB AB AC AC B AC =+=+++=++ (2) 2F A C AB =+ 解:2F A C AB A C AB AB AC B C =+=+++=+ (3) 3F ABC ABD ABD ABCD =+++ 3F ABC ABD ABD ABCD AB ACABC AB ABCD AB ACABC B ABCD ACAC B ACD ACB C ACDB C AD =+++++=++++=+++=+++=++=++(4) 4F BCD ABCD ABC ABD =+++ 4F BCD ABCD ABC ABDBCD ABCD ABC ABD AB ACBCD ACD ABC ABD AB ACABCD ACBD ABC AB ACAB CD AC BD ABCCD BD ABC =+++=+++++=+++++=++++=++++=++ (5) 5F ACD ABCD ABD ABCD =+++5F ACD ABCD ABD ABCDACD ABCD ABD ABCD AB ACACD ABD ABD ABCD AB ACACD AD ABCD AB ACAD ABCD AB ACAD BCD AB ACAD BCD =+++=+++++=+++++=++++=+++=+++=+(6) 6F BCD ABCD ABCD =++ 6F BCD ABCD ABCDBCD ABCD ABCD AB ACBCD AB BCD AC ABDBCD AB AD BCD ACBCD BCD AD =++=++++=++++=++++=++2-14 化简下列具有无关项的逻辑函数:(1) 1(0,1,3,5,8)(10,11,12,13,14,15)F m (2) 2(0,1,2,3,4,7,8,9)(10,11,12,13,14,15)F m (3) 3(2,3,4,7,12,13,14)(5,6,8,9,10,11)F m (4) 4(0,2,7,8,13,15)(1,5,6,9,10,11,12)F m (5) 5(0,4,6,8,13)(1,2,3,9,10,11)F m (6) 6(0,2,6,8,10,14)(5,7,13,15)F m解答:(1)1(0,1,3,5,8)(10,11,12,13,14,15)F m φ=+∑∑卡诺图如图所示:由卡诺图可知:1F ABD BCD BCD =++(2)2(0,1,2,3,4,7,8,9)(10,11,12,13,14,15)F m φ=+∑∑卡诺图如图所示:10 由卡诺图可知:2F B CD CD =++(3)3(2,3,4,7,12,13,14)(5,6,8,9,10,11)F m φ=+∑∑卡诺图如图所示:由卡诺图可知:3F AC A C BD =++(4)4(0,2,7,8,13,15)(1,5,6,9,10,11,12)F m φ=+∑∑卡诺图如图所示:00 01 11 10由卡诺图可知:4F BD BD =+(5)5(0,4,6,8,13)(1,2,3,9,10,11)F m φ=+∑∑卡诺图如图所示:由卡诺图可知:5F B AD ACD =++(6)6(0,2,6,8,10,14)(5,7,13,15)F m φ=+∑∑卡诺图如图所示:由卡诺图可知:6F BD CD =+2-15 用Multism2001将下列逻辑函数式化简为与或形式。

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