I applied through college or university. I interviewed at National Instruments (Troy, NY) in Nov 2012
Interview
Interview comprised of behavioral and technical parts. Behavioral parts included questions on leadership and teamwork. The technical questions were:
1. If you have an array of 100 numbers, but one of them is missing, can you write code to determine the missing number?
Ans: Sum the numbers and subtract from the sum of an array without the missing number.
2. Demonstrate the hardware required to take an audio signal an display that signal as a digital output.
Ans: Microphone to filter to analog-digital converter to amplifier to display
I would suggest knowing the answers but not outright saying them. Walk through them slowly. The interviewer may even walk you through it as he did with me.
Interview questions [1]
Question 1
The second technical question threw me off, but I slowly worked through it with the help of the interviewer.