Estimation Analysis
The Basic Idea
We are big on what we call Estimation Analysis. It is a fancy word for something many people do more or less everyday. When you are in the check out line of a store you often try to estimate how much groceries you actually are buying so you can see if the charge is reasonable! This way of thinking can be taken much further. Often in engineering and physics it is referred to as hand calculations or back-of-the-envelope calculations. We feel these casual expressions do not quite convey the usefulness of the calculations, instead they confer somewhat of a sloppy picture which is far from the truth. So we call it Estimation Analysis! We have defined it as a four step process:
- Simplify - In this step we try get to the core behavior of the system/circuit in question by creating a simple mathematical model describing the behavior. It involves removing the 'fat', the unimportant distractions.
- Solve - For a simple enough model this should be easy to do.
- Verify - This is often neglected in practice and it is perhaps the most important step. There are various ways to do this; look at extreme cases, compare to other calculations, or spot check with simulations. If the model in 1. is not correct, we need to go back to step 1) and try again.
- Evaluate - What does the solution/model mean? Does it suggest a way to counteract the problem if there is such?
The experienced engineer recognizes of course these steps and one of the key benefits is step 1. where we keep track of the simplifications and make sure we understand the problem properly. Our book 'Fast Techniques for Integrated Circuit Design' describes this flow in much greater detail.
