basic maths: - cross product of vectors: a= i, b = j+k, what is a*b? - a = i+3j-4k, b = 1-2j +3k, the mapping of b on a? - integral of x*cos(x) over x? linear algebra: - what is symmetric/identity/singular matrix? - how to calculate the singular matrix of a given 2*2 matrix [ 3 2;2 1]? - given [3 -1;1 5], what is its eigenvalue and eigenvector? programming: - what is #define? difference between <> and "" - typedef -null pointers - typecasting. how to cast a double data into integer? C++: -difference between structure and class? - Given a class named Foo, difference between Foo a; and Foo a(); - virtual constructor and virtual destructors. Why virtual constructor is wrong and virtual destructor is necessary? - operator overloading. what kind operator could not be overloaded? - the exception mechanism. signal processing: - Nyquist theorem. given a cos(50HZ)+ sin(250Hz), what should the sample rate be? - what is Anti-aliasing filter? - what is convolution? - what is LTI system? given several systems, determine if they are LTI. - Stability and causality of a system. - h[n] = [1 2 3 0 1]; what is its Z transform? is the system stable/causal? - what is Power Spectral Density? - what is Random process?

Asked me to write a prototype for a simple algorithm in any programming language