2020年国家开放大学《数字电子电路》教学辅导文稿3

经典word整理文档，仅参考，双击此处可删除页眉页脚。本资料属于网络整理，如有侵权，请联系删除，谢谢！2020年国家开放大学《数字电子电路》辅导文稿3第3章组合逻辑电路2已知逻辑表达式化简真值表说明功能逻辑电路图图3-2组合电路一般分析步骤例FFC1①F=②③表3-1（a）例3-1图（a）真值表ABC000001010011F0001ABC100101110111F0111④1图3-3例3-1电路①FFF12②F=A1FAB2③表3-1（b）例3-1图（b）真值表ABC000001010011ABC1001011101110010011110④）看出，图F是C1F2201给定逻辑问题真值表逻辑表达式选器件选器件画逻辑图图组合电路的一般设计步骤n2NnNnn2nn2nn2nn34图3-7二进制编码器框图9。3图3-1074LS148电路及外部引线排列表3-574LS148优先编码器真值表61000000000××××××××111111111011111111110000000011000001011010111110101010111111110YY20YYSYIIIIS67S01YIIIIS为1S为0S01674YSYSSYYSIIIISS(IIII)SEXS01670167YI、I、I、IS=00167YY例AAAA00:用器1AA2A~A870ZZ30AAAA870Y1SSY2S1YY88YYY210图3-11例3-3逻辑图5n2nnN2n。当n2n34图3-14二进制译码器框图33AA802YY807图3-153位二进制译码器逻辑图3Y8S、S和S。123S=123式。6）表3-874LS138真值表123100123456700000101001110010111011111111111111111111111111101111111101111111101111111101111111101111111101111111101111111101100100100100100100100100图是图3-1674LS138外部引线排列例5843938344AFFDCBA为0DCBA为D和7图3-19例3-5逻辑图例444444AFF实0现11变DDCBA为YY的27图3-20例3-6逻辑图8图ag图3-21七段字符显示器RR图3-22二极管驱动电路表3-10七段字形显示译码器真值表输入AAAA字形十进制数YYYYYYYd3210abcefg0123456789000000010010001101000101011001111000100111111100110000110110111110010110011101101100111111110000111111111100119101112131415101010111100110111101111000110100110010100011100101100011110000000暗g）表3-1174LS249真值表II/YYYYYYYYd3210Babcefg111111111111111111000000000100100011010001010110011110001001101010111100110111101111000011111111111111110011111110011000011011011111001011001110110111011111111000011111111111011000110100110010100011100101100011110000000000000000000001111111IBILT10图3-2374LS249外部引线排列IIIYY，BBBag。当YYagIIAAAABRBR3210入0I0。BRYI。BRB）AAAAIY3210BRBR例4和II90是411图3-24例3-7逻辑图2nn图3-25数据选择器框图4选14选1DD03AAYS1012图3-264选1数据选择器4选1AADAAD+AAD+AAD•S100101102103表3-104选1数据选择器真值表10000000110110123D3图4选14选1图3-2774LS153的外部引线排列1A和BC，iii-1Sc1。ii表3-131位加法器真值表ABCscABCSCiiiiiiii1300000101001101100001100101110111100101110SC。ii图3-30卡诺图化简S=ABC+ABC+ABC+ABCiiii-1iii-1iii-1iii-1C=AC+AB+BC