State Diagram of Sequence Detector and Arithmetic Function (DLD)

Thread Starter


Joined Apr 2, 2019
So I have finals on Monday, and I found some past paper questions that are troubling me. They're three questions that I need help with, 3rd one is a bit more comprehensive and requires other things so I'll post it separately.


I do know how state detectors go in general for x bit number, like to detect sequences of 0111, 010, etc (overlap or without overlapping), but I haven't learned how to detect odd/even number of 1s or 0s.

I have tried Youtubing but no help.

Firstly, I'm not sure how to make it for arbitrary bits. (Like max is 8, and there can be any from 1 to 8)
Secondly, I have no idea how the working goes for it too.

Here is my attempt for 3-bit version of the question, I think I got everything wrong.
upload_2019-5-18_18-17-35.png (Apologies for my camera) (G and F go back to A)


Here is my attempt: (can't get image tags to work)
Is this alright?


Joined Mar 31, 2012
It's best to put each problem in it's own thread. Otherwise you are going to end up with a mixed mish mash of answers to each and people responding to an answer to one thinking it was an answer to the other -- chaos will soon reign.

For the first one, think about what information you need to know about the entire history of the string of bits received in order to be able to make a decision, both now and in the future, about whether or not to assert the Y output.