Hint use morgans laws repeat parts through for the function
276  C H A P T E R 

t h e  d i g i t a l 



B  C  F(A, B, C)  
0  0  1 



0  1  0  
1  0  0  

1  1  0 


0  0  1  
0  1  1  

1  0  0 


1  1  1 
e x e r c i s e 5.7 Consider the following four logic expressions:
(A + B)(A · B + C) + C · D
(A · C + B · D)(D + B + A
A + B · D + A · C · D
((A + C) + B + D) + A · C · D
a) Give an implementation using gates for each of the four logic expressions.
e x e r c i s e 5.9  5.7 Summary 

277  

Consider a family of logic gates that operates under the static 
discipline with the following voltage thresholds: VIL = 1.5 V, VOL = 0.5 V, VIH = 3.5 V, and VOH = 4.4 V.
e) What is the highest voltage that must be interpreted by a receiver as a logical 0?
f) What is the lowest voltage that must be interpreted by a receiver as a logical 1? g) Does this choice of voltage thresholds offer any immunity to noise? If so, determine the noise margins.
d) What is the lowest voltage that can be output by an inverter for a logical 1 output?
e) What is the highest voltage that must be interpreted by a receiver as a logical 0?