> I am not disagreeing with you but I still do not see why. In a series > resonant circuit, the the capacitance dominates the imedance below > resonance and the inductor dominates above resonance. In a parallel > resonant circuit the opposite is true so one might expect the shape of > the resonant curve to be different for these two cases. But they can't > be otherwise the geometric mean would not be able to describe the > centre frequency in both cases. But that's the point, it's *geometric* relationship, not a linear one. The response of a resonant circuit is symmetric between 1/2 and 2x the center frequency, 1/3 and 3x, 1/10 and 10x, etc. The response will therefore look symmetric on a logarithmic plot of frequency but not a linear one. This is also why the geometric mean works, but a regular average (think of a linear mean) doesn't. ***************************************************************** Embed Inc, embedded system specialists in Littleton Massachusetts (978) 742-9014, http://www.embedinc.com -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email listserv@mitvma.mit.edu with SET PICList DIGEST in the body