Bode/Nyquist plot.....

[StephenG1CMZ]

(05-16-2015 10:53 AM)alexzkter Wrote:  Hi again, I didn't know f1 and f2 was the frequency range (rad/s). You typing [-1,1] and [-2,2] on some examples confused me since negative frequencies don't exist.

I've been trying to plot this:


and I got this:


But, I don't understand why the 'x' takes negative values, since that's the frequency axis. How am I supposed to read the frequency values, mate? Thanks in advance

I haven't studied the graph, but some physicists argue that negative frequencies exist, much like negative distances or displacements. Consider for example a clock, with a second hand rotating clockwise. Apply a negative rotational force - the frequency that the second hands sweeps clockwise will reduce and eventually reach 0. continue to apply the force. The second hand will begin to sweep anti-clockwise at a positive frequency - or clockwise at a negative frequency, if you like. Just like walking -5m North really. Though perhaps it could be called something else, like we distinguish 5m distant (positive) from 5m North (signed).