期末复习比较器chenyu

1、6.9 Comparators（比较器）6.10 Adders, Subtractors, and ALUs(加减器和算术逻辑单元)6.9 comparator（比较器）(P458)比较2个二进制数值并指示其是否相等的电路等值比较器：检验数值是否相等数值比较器：比较数值的大小（,=,B（A=1, B=0）则 AB=1 可作为输出信号 AB3)LT = EQ GT = ( EQ + GT )或 (A3 = B3) (A2 = B2) (A1B1)或 (A3 = B3)(A2 = B2)(A1 = B1) (A0B0)或 (A3 = B3) (A2B2)A3 B3A2 B2A1 B1A0 B0+输

2、出高有效!74x856.9.4 Standard MSI Comparatorsthe 74x85 4-bit comparator A0A1A2A3ALTBINAEQBINAGTBIN级联输入，用于扩展ALTBOUT = (AB高位A高位=B高位 & A低位B低位ABAEQBOUT = (A=B)AEQBINAGTBOUT = (AB) + (A=B)AGTBIN74X85Serial Expanding Comparators(比较器的串行扩展)XD11:0YD11:03:07:411:8XY+5VABIABOA0A3B0B374x85ABIABOA0A3B0B374x85ABIABOA0

3、A3B0B374x853片74x85构成12位比较器低位高位Digital Logic Design and Application (数字逻辑设计及应用)8-bit comparator 74x682 (P463)P0P1P2P3P4P5P6P78-bit comparator 74x682(P463)问题1：怎样用输出来表示下列条件？ DIFF高电平有效：P DIFF Q EQ高电平有效：P EQ Q GE高电平有效：P GE Q LT高电平有效：P LT Q （P463 Figure 6-80）GELT问题2：能否扩展？注意：没有级联输入端3片74x682构成24位比较器P0P7 P=Q

4、Q0Q7 PQP0P7 P=QQ0Q7 PQP0P7 P=QQ0Q7 PQ7:015:823:16P23:0Q23:0PEQQPGTQParalel Expanding Comparators(比较器的并行扩展)exercise Design a circuit to compare three 4-bit binary numbers A(a3a2a1a0), B(b3b2b1b0), C(c3c2c1c0) with two 4-bit comparators 74X85. You need to give three outputs: Fequal, FAmax, FAmin. Fequal =1 indicates A=B=C; FAmax =1 indicates A is the biggest one among them; FAmin =1 indicates A is the smallest one among them. Show your work. (Y