It was for about 45-50mins tech phone interview: Math: 1. Singular matrix? 2. Rank of a matrix and what is its importance? 3. Null space? 4. Inverse of a 2x2 square matrix (For given values)? 5. Given two vectors, what is the angle between them? 6. What is Eigen vector? Importance of Eigen values and vectors. 7. Given acceleration of a body. What is the velocity for a give t value. Programming concepts: 1. Local and global scope? 2. Recursive functions? 3. Call by value and call by reference? 4. Multicore processors?? 5. Difference between break and continue? Signal processing: 1. Nyquist sampling theorem? 2. Aliasing? 3. Convolution? 4. Difference between FIR and IIR filters? 5. BIBO? 6. Given y(n) = x(n)+C, comments on its linearity, Time variance and Casuality 7. Stability/instability region in discrete time domain? 8. what is PSD and what is it for white noise? 9. Autocorrelation? Matlab: 1. difference between * and .*? 2. How to plot in Matlab? 3. How to open a file from command window? 4. Differences between script file and function? 5. How to display variable/variables in command window? (whos) 6. How to computer numerical length of an array? (numel) C Programming: 1. what is #include? 2. Differences between and " " and < > in #include? 3. typedef? 4. malloc? 5. null pointer?