Foundations of Signal Processing – Martin Vetterli, Jelena Kovacevic, and Vivek K Goyal
 Download here -> Key focus: Free ebook on Signal processing Read it here: https://www.gaussianwaves.com/gaussianwaves/wp-content/uploads/2017/02/FSP_v1.1_2014.pdf Licensed under Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License