ime the books are very loaded on theory and it's hard to connect that to practice and concepts. I don't know of any book that touches on what poles/zeros mean o

ime the books are very loaded on theory and it's hard to connect that to practice and concepts. I don't know of any book that touches on what poles/zeros mean or why they're useful outside what are (seemingly) contrived properties of formulae like stability. It's one of those things that's just useful to go through in a university course, even just auditing it. The practical problems and lectures are extremely useful, particularly due to the overhead of notation (the practice is relatively young and derived from a different tradition of education, and a lot of contemporary notation can seem a little foreign, or is filled with shorthand). Applied Digital Signal Processing by Manolakis & Ingle is the book I always turn to for reference and the code examples don't suck. Oppenheim & Schafer is a classic but frankly only useful as a reference, that tome is a bit dated otherwise. The Scientists and Engineer's guide to DSP is also not bad as a practical text.