I had a telephone interview with a number of members of the engineering team prior to a face-to-face interview. The face-to-face interview was with several of the individuals that I spoke with during the phone interview as well as additional individuals. All of the people with whom I met were very friendly, and very good conversations were had on both sides. There was a single exception to this --- during the on-site interview I met with one manager who conducted himself in the most arrogant and patronizing manner I have ever experienced in my career of 30 years. During this portion of the interview I was asked a technical question about interfacing a pressure transducer to a microcontroller, and how I would go about it. This type of engineering problem is one that I have executed many times over the course of my career, and in fact, within the past six months I had actually designed a complete product for the aerospace industry that involved that exact interface. As I discussed the problem with this individual, he asked me to describe how I would correct for errors in the overall system. I explained to him that a very common method for removing errors from these types of systems is calibration. Apparently this answer was unacceptable to him, and he asked me to explain how I could remove errors in the system that could not be removed by calibration. I explained that there aren't any errors of which I am aware that could not be removed by calibration -- after all, that is what calibration is meant to accomplish! I explained that calibration is accomplished by injecting a known input signal and examining the system's output signal. Since the system response to a known input signal is known, the difference between the actual system response and the proper system response is the calibration factor. This individual continued to insist that there are errors in a system that cannot be corrected by calibration. In this interest of trying to move the discussion along, I said to him, "Well, I am unaware of any kind of system error that cannot be removed by calibration, but if you are, please tell me what it is, and we can continue our discussion." In a very annoyed tone of voice he replied, "Drift!" I looked at him quizzically and replied, "Drift? Of course drift can be removed by calibration! I've developed numerous systems that are calibrated periodically to remove the effects of drift. That is a standard method for mitigating system errors due to drift --- periodic calibration." Apparently, pointing that fact out to him made him even more annoyed, so he changed the subject. He replied with, "Well, how do you inject that known signal to calibrate the system?" I replied by saying that there were several ways to do it, but the most common methods are to either build self-calibration hardware into the system itself, or bring up calibration equipment and perform the calibration that way. "Well," he said, "Suppose you don't have any external equipment and you can't build in calibration hardware. Then what do you do?" Upon hearing this question, and seeing that this individual, for whatever reason, was hell-bent on tripping me up over some minor point of design, I simply replied with, "I don't know." He proceeded to enlighten me with his superior intellect by saying, "Auto-zero!" Once he said that I understood what he was thinking about, and so I replied with, "Oh, okay, you are referring to shorting the input holding capacitors on the analog-to-digital converter. Well, that is exactly equivalent to injecting a known signal into the system --- in this case, the known signal is 'zero volts', and that is exactly equivalent to what I was describing just a minute ago. In this case, the auto-zero circuitry in the analog-to-digital converter is acting as the self-calibration hardware."
At that point, our time slot was just about over, and so we moved on to other things. I had already concluded at that point, that there is no way I would be getting an offer from this company, but more fundamentally, there is no way I would work for a company that employs a manager who has an attitude problem that severe.