I wonder , Why when we study communications systems , we just study the theoretical part(Math) , and we never touch the electrical circuits that used to implements this systems , I have asked my DR. that teaching me a communication course , and he told me "know theory , then you simply know the electronic circuits" , then i asked another DR. that given me another course and he told me that is a advanced topics , So Im confused about this , could any one give me a clear answer ?
closed as primarily opinion-based by Joe Hass, Daniel Grillo, Chetan Bhargava, Keelan, Matt Young Apr 10 '14 at 13:26
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I questioned the same thing in school. I think it's because many electrical engineers never have a job that uses this info at all. If you do go into it, then there's a lot of information to understand how each component works. Once you understand how all of the theoretical blocks work, you can view a circuit and "see" that a part of it is just a theoretical building block. If you were to view an entire circuit without understanding the theory, you'd get so confused that you'd just drown in info overload.
Once you understand the theory, you can look into how each block is made. For example, this is what a non-op amp analog multiplier looks like: http://www.freepatentsonline.com/7061300.html
If this was part of a full circuit, you wouldn't have a clue where to start.
Another thing to note is that there's multiple ways to realize each of these theoretical elements. Engineering is all about choice.
Note: I was going to put this as a comment, but it got too big.
A cut-down answer but I feel a reasonable one:
You can be good at something knowing only theory or having only practical experience, but to be really great you need both.
If you only have one, you WILL make a lot of mistakes / waste a lot of time learning the other by trial-and-error.
To do basic design , you need to know either real examples or theory, but to explore new designs, a great designer needs to learn both. With the theory, it is easier to understand why and how any method works.
Real world design requires a lot of experience not readily available to Professors, so the theory is presented and with that you can explore examples. I find the education in Asia uses more modern examples with theory to make the learning experience more relevant.
But communication theory covers a vast number of concepts that are crucial to design evolution, such as work done by Nyquist, Hartley,Turing, Shannon, Werner, Chandler etc. that all assist in error-free efficient coding. These must be understood to appreciate all the tradeoffs in realization, which are more interesting, I think.