The first round was an HR behavioral interview. They asked me questions like:

• How do you resolve a conflict in your team?
• Have you ever been a team leader?

And similar kinds of questions.

The second round was technical, and I had chosen Digital Signal Processing.

Math Questions:

• What is a singular matrix?
• What is cross-correlation?
• What is a random process?
• What is the eigenvalue of this matrix?
• What is the eigenvector of this matrix?
• What is the inverse of a 2x2 matrix?
• What is a symmetric matrix?
• What is dy/dx?
• What is partial differentiation?
• What is the difference between a differential equation and a partial differential equation?
• Given acceleration, find velocity.
• What is auto-correlation?
• What is a null matrix?
• How do you find the rank of a matrix?
• What is integration?
• What is differentiation?
• What is a derivative?
• What is the relation between differentiation and integration?
• They gave me sums on partial differential equations.

Java:

• What is the difference between JRE and JDK?
• What is the use of String and StringBuffer?
• int vs. Integer?
• Java application vs. Java applet?
• Break and continue.
• Pointers?
• Why is Java machine-independent?
• Call by value and call by reference?
• What does Java use: call by value or reference?
• What are wrapper classes?
• What is an abstract class?
• What does the final keyword do?

Signal Processing:

• Aliasing?
• Z-transform?
• Fourier transform?
• Convolution?
• Difference between convolution and correlation?
• What are anti-aliasing filters?
• Impulse response?
• What are IIR and FIR filters?
• Is this IIR or FIR? (They gave me four sums on the same)
• What are causal systems?
• What is a BIBO (bounded input, bounded output) system?
• They gave me a question and asked whether it was stable/unstable, and why.
• In a graph, where does a stable system lie and where does an unstable system lie?

Matlab:

• What is a.b vs. ab?
• Script vs. function.
• Workspace of a script vs. workspace of a function?
• plot(x,y,'o'); what does that mean?
• How to suppress comments?
• How to plot position vs. time and position vs. distance on the same graph?
• How do you concatenate strings?
• How do you find the inverse of a matrix?
• They gave a problem and asked if I could put two x-axes or something similar on the graph (the question wasn't entirely clear).
• How to find the number of elements in MATLAB? (using the 'numel' function)

The interview went for 55 minutes. I am sure about the rest of the questions. The total number of questions was between 80-100.

A partial differential equation was given. Given y(0), solve for x and y.