Generate buzzer sound
Based on the spectrum, it looks to me like this was generated by FM synthesis. The mathematics of starting with a sound and working backwards to generate it using FM synthesis can be time consuming. The best reference I know of is Computer Music. I've seen pdf editions of this book online that I thought were legal, but I'm only seeing illegal looking things now, so I'm not linking.

Some simpler approximations that might work, but almost certainly won't sound the same:


white noise with a bandpass filter. (maybe plus a little clipped sine wave)
a clipped sine wave or square wave through a low pass filter. (subtractive synthesis)