Subject: Re: First moment of a spectrum From: Eric Delory <eric(at)ARL.NUS.EDU.SG> Date: Mon, 12 Jun 2000 15:25:44 +0800Al , This sounds correct to me, so being defined as the abscissa of the mass centre of the drawn surface. To define the location (and spreading -2nd order moment) of a Heisenberg box in a time frequency plane we also use the same integral, one in time, the other in frequency. Here you deal only with frequency and their corresponding amplitudes, your calculation resulting in the frequency "mass" location along the frequency axis. It makes sense to call it the first moment, or just as well, the mean frequency (estimate). Eric. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Eric Delory Acoustic Research Laboratory Dept of Electrical Engineering National University of Singapore Block WS2, Level5, Room 05#30 1, Engineering Drive 3 Singapore 117576 Email: eric(at)arl.nus.edu.sg Tel: 65- 874 8326 Fax: 65- 874 8325