I'm tasked to analyze the power usage of a CMOS circuit, but I cannot figure out the output switching frequency.
Every 10ns, the circuit is stimulated with input vectors
1110, 1111, 1101, 1111, 1100, Repeat
and the output of the circuit is driven by the expression ABCD.
Since CMOS circuits only draw significant power when switching, I need to find the output frequency, but I'm confused on how to do this.
The output of the circuit is
0, 1, 0, 1, 0, 0, 1, 0, 1, 0, 0, 1, 0, 1, 0, 0 ...
It switches for the first 4 inputs but on the fifth, going back to the first one, it doesn't switch.
So every 50ns, it switches every 10ns for the first 40ns and then doesn't switch for the last.
I don't think I can just say the period is 10ns since it doesn't switch on the last input, so how can I find the frequency?