I've always been told to do my best at things, well I have. I've studied long and hard, I know the material pretty well (my homework, labs, and projects I've gotten A averages) but I always seem to mess up on exams in my digital design class. Sometimes I space out and can't think, or it takes me time to understand the problem and even sometimes (like what happened on one of the problems on my finals) I can misinterpret the problem and what is asked and usually their is some good reasoning for my interpretation. The price is expensive for thinking different from others especially when you thought the path you took to solve a problem was the right one with the right specifications when in reallity the professor was asking for something similar but not quite what you thought was asked and thus a totally different path in solving the problem than you had originally planned. In the real world, your conceptional design of specifified company problems and product needs have a deadline, but they are not exams and thus you have time to think clearly about the specification and talk to your bosses in detail about the specifications of the design problem. On exams you don't have much time to think about the conceptial design and it takes even more time away if you walk down a floor to the professor's office to ask for clarification when they probably wouldn't give you much clarification on the problem since it is and exam problem and not a design project. Paradox....

Here is a list of percentages in the class that I have gotten so far:

Digital Logic Design Class Grades
-----------------------------------------------------------
Homework 93.48%
Design Project 95.83%
Exams (2) 62%
Laboratory 97.57%
Final Exam 63.5%
*Overall 77.71% *

I had 2 exams in the exam category of which I had gotten a "41" and an "80". The final exam was worth 25% of our grade. Wonderful emphasis on test scores =) , I'm being sarcastic !

My overall percentage is a 77.7%. I had done a small amount of extra credit in the class and I am really hoping that the professor will decide to grade on a curve and I can possibly get a B- or a B for my final grade.The worst case scenerio would probably be a C+ or a C for the class. I guess I'm not all too upset about my final grade because I know that it could have been worst, with missing a 50 point problem and not being able to fully finish other problems (see below for a description of my final exam). I was expecting to get like a 50 on my final exam, but I am satisfifed that my final percentage for the class is close to a B average.

Let me explain why I did so badly on the final exam. I even went to the teacher and talked to him about one of the problems. I was so so nervous when I talked to him about the exam but I knew that I needed to talk about one of the problems or else I might not get partial credit for the conceptial part of the exam.

Firstly, I would like to say that I did study on for the final. I know the material, I have done well on the homework and design projects in the class. However, the exams are usually designed to take too long. The final exam had a total of 5 problems with about 9 sheets, one problem being multiple choice with about 15 separate problems on the sheet. The first problem took me about a half hour and I would have liked to spend about 45 minutes on it. I had to triple check part a of the problem because if you mess up on that part --you're really screwed on the rest of the problem! The reason that I wish that I had more time for the problem was to minimize the logic and diagram with the problem. I mean it's not that hard to work the problem but the real challenge is in minimizing everything (specifically the k-maps, multiplexor implentations, and the number of gates used to implement the logic). I ended up not being able to minimize stuff too much during the exam due to time constraints, afterall there is another 4 long problems left to do in 1 1/2 hours. The next problem I can't remember!

The problem after that was another easy but time consuming problem. We were giving an input sequence and an output sequence for a finite state machine with a Moore Representation. These problems are not difficult, but what is time consuming is a.) coming up with a state diagram for the machine and b. ) MINIMIZING that!!!! If you have no idea what I am talking about, don't worry. Basically the problem is to decode a bunch of 1's and 0's and look for patterns and express a 1 or a 0 output if the pattern or sequence is recognized. If I remeber correctly, we had to make a minimized state diagram to recognize the sequences 101 and 010. The number of inputs in 1 and the number of outputs are 1. So here is an example of a possible sequence. Oh, by the way to make this problem harder, this is NON-RESETTING which means you can recognize the sequence 1010 and out put a 1 because there is a 010 embedded in the input.

Example of a Sequence
-------------------------------------
Input 00011010001110001110101010100110001110010101
Output 00000001000000000000111111110000000000001111

Hopefully I was able to write this example correctly. If you know digital logic design and see any mistakes in this example sequence, let me know!

This example can be expressed in a state diagram and then minimized or if you're really good you can minimize this while making the state diagram (which I can't quite doo well yet).

Then I had another part of the problem with a NEW sequence that would recognize odd parity three bits which would be the bits:
001
011
101
111

We had to use a mealy machine for this

This is even more complicated because the state diagram must take in account for 4 sequences and not 2! I had about 11 states before minimizing the sequence down to 8 I think.

That was it fo problem #3, sadly enough I had skipped part of the odd parity question and came back to it about 20 minutes before the end of the exam and was able to come up with a state diagram but didn't have time to finish my minimized one. I would have liked to spend 30-45 minutes on this problem.

No after skipping the second part of problem 3 I was now on to problem #4, the by far hardest portion of the exam. This problem was worth 50 points!

We had to design a mealy system for the movement of a robot that has a sensor. The problem said that the robot had two control lines TR and TL from a remote controller (which was the machine that we were designing). The robot also had a sensor on it and if an obstacle was detected, the robot would turn right until not obstacle was detected and continue going straight. This is how I interpreted the problem: Three inputs : obstacle, turn right, button, turn left button). After all we were designing a remote controller, I thought the controller had buttons to input to the robot to turn left and to turn right. That made the most sense for me. The outputs that I thought should go were turn left, turn right, and go straight.

to be continued....