Some people in the tech field with useful stuff

• Chris Stratford GSM MATLAB simulators
  
• Phil Karn DSP for Ham radio, includes Viterbi decoder
  
• Randy Yates Introduction to fixed point arithmetic
  
• Evert Rozendaal Aliasing, transforms, etc.
  
• Rakesh Dugad Hidden Markov Model tutorial
  
• Vinay Chande Coding theory