Let's have a servo block to detect the position and feedback that before Fv/m with a constant "Alpha". You can change the value of elements by double-clicking. If this applet looks something weird, please reload it. "Alpha" to feedback the position is "1.0". By the way, look at the block diagram carefully. "AlphaFv/m" is located just parallel for "K/m"!! i.e. (K+AlphaFv)/m has become much larger than K/m. The feedback made the spring "very stiff". The displacement has become as small as 1um as the frequency response says. However, still "Q" is high and it's unstable... Quiz 2 How does the pickup follow the displacement as time goes on?? Hint: You can choose "Step-Res" for the list box on the applet. Here is the answer. See how to decrease the resonance This class is produced by DIGITALFILTER.COM and Ueno Design Factory