Bode Plot
  • testing a gopro gimbal

    At low frequency (0.6Hz to 20Hz), why is the phase between -30 to -180 degrees in the Bode Plot? I know the gimbal responds almost perfectly at those Hz rates. I'd expect the response to be maybe -5 to -20 degrees at low Hz.
  • In the instruction of reading a bode plot (http://support.motioneng.com/utilities/bode/bode_16.html), it shows a nice example of starting off a 0 amplitude error and 0 phase shift and moving to a frequency where the system stops working (-10 to -45 dB at a phase error of -90 degrees). Makes sense.

    But in the example shown on the Simple BGC 32-bit Manual (Section 14, System Analysis Tool), the lines start out at 0 dB -180 degrees. Why?