I think the concepts are relatively straightforward; however, in application, they can get very messy and frustrating.
For instance, O/W 4.21 has a number of Fourier transforms we are supposed to compute. The setup is typically straightforward -- put it in an integral (except in a few hard-to-calculate cases) as per the formula, change the sin's and cos's to exponentials, and chug away. However, the beautiful transform equation turns into alphabet soup after all this happens, and it's really hard to keep track of everything.
So, it seems that I'm spending a lot of time practicing nasty questions from calculus instead of learning about signals and systems.
