Saturday, September 19, 2009 3:59 PM,

A student writes:



	Dr. Patt,
	
	I thought a mux required a not gate on the selector variable? 
	Is this true? (This is a question aimed at 6b.
	Thanks,
	<<name withheld to protect the student who is looking INSIDE the mux>>



Yes, a mux requires an inverter INTERNAL to the mux.  The question said to use 
muxes, but you were not allowed to use inverters.

Analogy: It would be like telling a track coach to build a relay team, but he 
could only use human athletes, and he was not allowed to use legs.

You would answer: No problem.  "I will use just four runners."  Someone then 
says, "Wait a minute, each runner has legs."  Yes, but they are part of the 
runners.  The coach is not allowed (by the statement of the problem) to remove 
a leg from a fifth runner and somehow use it to design a better relay team, 
perhaps by given one of the other four runners three legs.  

Got it?

Yale Patt