In Question 2 in the example exam, we are asked to calculate the delay of RAM.
The answer was big-theta(n). the course book doesn’t include an explanation to the calculation nor it is specified in the exam solution.
Why is the delay big-theta(n) instead of big-theta(log n)?
In a synchronic circuit the delay is the delay of the longest path, while each path does not go through any FF’s. so:
d(RAM(2^n))=max{d(Decoder(n)), d(MUX(2^n:1))}=max{log n, n}=Theta (n)
also even if the path was Decoder(n) and then MUX(2^n:1), the delay would still be Theta(n) because of asymptotics