First phone interview : Discuss about job role and Resume based questions and some key questions.
Second Phone Interview : Pure technical interview consisting of DSP , Machine learning based questions, some resume based questions. This is followed by programming test.
Final on site interview : Round 1 : Technical interview : DSP and Machine Learning questions.
Round 2 : Programming Questions mainly in Python , Linux
Round 3 : Interview with senior Authority person mainly technical and other job related questions.
Round 4 : HR interview
All of above usually takes 10-15 business days.