Hi, just my two cents on sine wave fitting.
A undamped sine wave is the solution of the difference equation sig(n+1)=2*cos(w)*sig(n)-sig(n-1) This is a linear system of equations mapping the sum of the samples n+1 and n-1 to the sample n. The factor 2*cos(w) is the unknown. The least-squares solution of the overdetermined system is pure linear algebra, no nonlinear fitting involved. The trick also works for a damped sine wave. Care must be taken for high 'oversampling' rates, it works best for 4samples/sinewave, ie near Nyquist/2. Cheers Detlef DD4WV _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
