第一章 逻辑代数及逻辑函数的化简
1.1、用布尔代数的基本公社和规则证明下列等式。
1、AB?BD?AD?DC?AB?D
证:左边=AB?BD?AD?AD?DC?AB?BD?D?DC?AB?D=右边 2、ABD?ABD?ABC?AD?ABC
证:左边=AD(B?B)?ABC?AD?ABC=右边 3、BC?D?D(B?C)(DA?B)?B?D
证:左边=BC?D?(B?C)(DA?B)?BC?D?DAB?DAC?BC?B?D=右边 4、ACD?ACD?AD?BC?BC?B?D 证:左边=AD?AD?B?D?B=右边 5、AB?BC?CA?(A?B)(B?C)(C?A)
证:右边=(AB?AC?B?BC)(C?A)?(AC?B)(C?A)?AC?BC?AB=左边 6、ABC?ABC?AB?BC?CA
证:右边=ABBCCA?(A?B)(B?C)(C?A)?(AB?AC?BC)(C?A)?ABC?ABC 7、AB?BC?CA?AB?BC?CA
证:左边=AB?BC?CA?CA?AB?BC?AB?BC?CA=右边 8、(Y?Z)(W?X)(Y?Z)(Y?Z)?YZ(W?X)
证:左边=(YZ?ZY)(W?X)(Y?Z)?YZ(W?X)=右边 9、(A?B)(A?B)(A?B)(A?B)?0
证:左边=(A?AB?AB)(A?AB?AB)?AA?0=右边 10、(AB?AB)(BC?BC)(CD?CD)?AB?BC?CD?DA 证:左边=(ABC?ABC)(CD?CD)?ABCD?ABCD
右边=ABBCCDDA?(A?B)(B?C)(C?D)(D?A)
=(AB?AC?BC)(CD?AC?AD)?ABCD?ABCD=左边
11、A?B?C?A⊙B⊙C
证:左边=(AB?AB)C?(AB?AB)C?ABC?ABC?ABC?ABC =A(BC?BC)?A(BC?BC)? A⊙B⊙C=右边
12、如果A?B?0,证明AX?BY?AX?BY
证:AX?BY?(A?X)(B?Y)?AB?AY?BX?XY?AB?AB
=AB?AY?BX?XY?AB?BY?AX =AB?AB?BY?AX?BY?AX=右边
1.2、求下列函数的反函数。
1、F?AB?AB 解:F?(A?B)(A?B) F?ABC?ABC?ABC?ABC解:F?(A?B?C)(A?B?C)(A?B?C)(A?B?C) 2、
3、F?AB?BC?C(A?D) 解:F?(A?B)(B?C)(C?AD) 4、F?B(AD?C)(C?D)(A?B) 解:F?B?(A?D)C?CD?AB 5、F?RST?RST?RST 解:F?(R?S?T)(R?S?T)(R?S?T) 1.3、写出下列函数的对偶式。
1、F?(A?B)(A?C)(C?DE)?E 解:F'?[AB?AC?C(D?E)]E 2、F?ABCBDAB 解:F'?A?B?C?B?D?A?B 3、F?A?B?B?C?A?C?B?C 解:F'?ABBCACBC 4、F?XYZ?XYZ 解:F'?X?Y?ZX?Y?Z 1.4、证明函数F为自对偶函数。
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证:F?C(AB?AB)?C(AB?AB)?C(AB?AB)?ABC?ABC =ABC?ABC?ABC?ABC
F'?[C?(A?B)(A?B)][C?(A?B)(A?B)]?C(A?B)(A?B)?CAB?AB ?C(AB?AB)?C(AB?AB)?ABC?ABC?ABC?ABC?F 1.5、用公式将下列函数化简为最简 “与或”式。
1、F?AB?(AB?AB?AB)C?A?B?(A?B)C?A?B?C?AB?C 2、F?(X?Y)Z?XYW?ZW?XYZ?XYW?ZW
=XYZ?XYW?XZ?YZ?XYW 3、F?AB?AC?BC 经检验已是最简 。或F?AB?AC?BC 4、F?AB?ABC?BC?AB?(AB?B)C?AB?AC?BC?AB?AC 5、F?AB?AC?BC?AD?AB?BC?AC?AC?AD ?AB?BC?A?AD?BC?A?D
6、F?AB?ACD?AC?BC?AB?BC?AC?ACD?AC ?AB?BC?AC?AC?AB?BC?AC
或:F?AB?ACD?AC?BC?AB?AC?BC?AB?AC?BC 7、F?AC?AB?BCD?BEC?DEC
?AC?AB?C(BD?EBD)?AC?AB?BC?BCD?EC =AC?AB?BC?BD?EC?AC?AB?BD?EC 8、F?A(B?C)?A(B?C)?BCD?BCD
=AB?AC?AB?AC?BCD?BCD
=AB?AC?AB?AC?AB?AC?AB?AC?BC?AB?AC?BC 或:=AB?AC?AB?AC?BC?AB?AC?BC 9、F?XY?(X?Y)Z=XY?XZ?YZ?YZ?XY?XZ?Z?XY?Z 10、F?(X?Y?Z?W)(V?X)(V?Y?Z?W)
=(XV?X?VY?XY?VZ?XZ?VW?XW)(V?Y?Z?W) =(X?VY?VZ?VW)(V?Y?Z?W)
=XV?XY?XZ?XW?VY?VYZ?VYW?VYZ?VZ?VZW?VYW?VZW?VW =XV?XY?XZ?XW?VY?VZ?VW =XV?VY?VZ?VW
1.6、逻辑函数F?(A?B)(A?B)(A?B)(AD?C)?C?A?B(BCD?CD)。若A、B、C、D、
的输入波形如图所示,画出逻辑函数F的波形。
F?(A?B)(A?B)(A?B)(AD?C)?C?A?B(BCD?CD) A =(A?AB?AB)(AD?AC?ABD?BC)?ABC(BCD?CD) B C =A(AD?AC?ABD?BC)?ABC
D
1.7、逻辑函数F1、F2、F3的逻辑图如图2—35所示,证明F1=F2=F3。 F A A A + B B B C C + F3 C F1 F2 D + + D D F E E “1”
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“1” “0” + 图2—35
解:F1?ABCDE?AB?CD?E
F2?A?B?C?D?E?AB?CD?E F3?AB?CD?E 可证:F1=F2=F3
1.8、给出“与非”门、“或非”门及“异或”门逻辑符号如图2—36(a)所示,若A、B的波形
如图2—36(b),画出F1、F2、F3波形图。
A B A B ⊕ F2
F1
图2—36(a)
A B + F2
A B F1?AB 图2—36(a)
F2?A?B F3?A?B BA DC 00 00 1 01 11 10 1.9、用卡诺图将下列函数化为最简“与或”式。
1、F??m(0,1,2,4,5,7); 解:F?B?AC?AC
2、F??m4(0,1,2,3,4,6,7,8,9,11,15); 解:F?AB?AD?BC
3、F??m(3,4,5,7,9,13,14,15); 解:F?BCD?ABD?ABD?BCD
4、F??m(2,3,6,7,8,10,12,14);
43BA C 00 0 1 1 01 11 10 1 1 1 1 1 题1图 01 11 10 1 01 1 11 1 1 10 01 1 1 1 1 1 1 BA DC 00 00 01 1 11 10 CBA ED 000 4 1 1 1 1 1 1 1 BA DC 00 00 01 11 题2图
11 10 题3图 001 1 1 10 1 1 题4图
1 1 1 1 解:F?BD?AD
5、F??m5(4,6,12,14,20,22,28,30) 解:F?AC
011 010 110 111 101 100 00 01 11 10 题5图
1 1 1 1 1 1 1 1 1.10、将下列具有无关最小项的函数化为最简“与或”式;
BA 1、F??m4(0,2,7,13,15)
无关最小项为?d(1,3,5,6,8,10);
解: F?D?AC
?d(1,3,4,5,6,8,10)?0
2、F??m(0,3,5,6,8,13) 无关最小项为?d(1,4,10);
解:F?ABC?ACD?ACD?ABC ?d(1,4,10)?0
4DC 00 01 11 10 00 1 φ φ 1 φ φ 1 φ 01 1 φ 10
11 1 φ 题1图 BA DC 00 01 11 10 00 1 φ 1 φ 1 1 01
1 1 10 11 φ 题2图
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3、F??m(0,2,3,5,7,8,10,11) 无关最小项为?d(14,15);
解:F?AB?AC?ACD
4、F??m4(2,3,4,5,6,7,11,14) 无关最小项为?d(9,10,13,15);
解:F?B?CD
4BA DC 00 00 1 01 11 01 11 10 ?d(14,15)?0
1 10 1 1 1 φ 1 φ 1 1 题3图
BA DC 00 01 11 10 00 1 1 01 1 11 10 1 1 φ φ 1 φ 1 φ 题4图
1 ?d(9,10,13,15)?0
1.11、用卡诺图将下列函数化为最简“与或”式; BA BA 00 01 11 10 C 00 01 11 10 1、F?ABC?ABC?ABC?ABC?ABC; C 1 0 1 1 0 1 1 1 解:F?BC?AC?AB?ABC 1 1 1 1 1 1 1 题1图 题2图 2、F?AC?ABC?AC?ABC?BC;
解:F?A?BC?BC BA BA
3、F?BD?ABCD?ABC; 解:F?BD?ABCD?ABC
4、F?ABCD?ABC?DC?DCB?ABC; 解:F?DC?BC?BD
5、F?AB?AC?BCD?BCE?BDE; 解:F?AB?AC?CE?BCD
1.12用卡诺图化简下列带有约束条件的逻辑函数 (1)P1 (A,B,C,D)=
CBA ED 000 001 011 010 110 111 101 100 DC 00 00 1 01 1 11 01 1 10 1 1 11 10 DC 00 00 01 11 10 1 01 11 1 10 1 1 1 1 1 1 1 题3图 题4图
00 01 11 10 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 题5图 ?m(3,6,8,9,11,12)?4?d(0,1,2,13,14,15)
C?BD?BCD(或ACD) =A
(2)P2(A,B,C,D)=
?m4(0,2,3,4,5,6,11,12)??(8,9,10,13,14,15)
dC?BCD? =B
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1.13、用最少的“与非”门画出下列多输出逻辑函数的逻辑图。 1、 F?AC?BC?AC G?AB?BC?AB
解: F?AB?AC?AC?ABACAC G?AB?AC?AB?ABACAB 逻辑图:
F??m4(2,3,4,10,11,15) 2、 G??m4(0,2,4,8,10,11,15)
4BA C 00 0 1 1 01 11 10 1 1 F 1 1 A B C F B A C 00 01 11 10 0 1 1 1 1 1 1 G
G
BA DC 00 00 01 1 11 10 01 11 10 H??m(0,2,4,6,10,11,15)
解:
F
1 1 1 1 1 BA DC 00 00 1 01 1 11 01 11 10 1 10 G
1 1 1 1 F?ABCD?ABD?BC?ABCDABDBC G?ABCD?ABD?AC?ABCDABDAC
H?ABCD?ABD?AD?BCD?ABCDABDADBCD
逻辑图:
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B C
G
D F
A BA DC 00 00 1 01 1 11 10 01 11 10 1 1 H
1 1 1