There was a phone interview with a couple questions on signal processing, physics, and software. These questions weren't that difficult, but they each had one right answer and were designed to test my hard-skills. After that, there were some more conceptual questions about general problem solving approaches. These were more open-ended and designed to test my ability to understand a problem and propose a solution. The phone call was ~30-45 min. After that, I was invited for an on-sight interview. This consisted of a meet & greet, a tour of the workplace, a networking event, and a sit-down 45 minute interview. The interview consisted of 4 parts: First, they told me about what my work would be like; Second, they asked me questions about my hard-skills, i.e. math and software; Third, they asked me about my good and bad experiences with team projects; Fourth, I asked them questions.