B s = f p − f s f s MathType@MTEF@5@5@+=feaagCart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLnhiov2DGi1BTfMBaeXatLxBI9gBaerbbjxAHXgarqqtubsr4rNCHbGeaGqipG0dh9qqWrVepG0dbbL8F4rqqrVepeea0xe9LqFf0xc9q8qqaqFn0lXdHiVcFbIOFHK8Feea0dXdar=Jb9hs0dXdHuk9fr=xfr=xfrpeWZqaaeqabiGaciGacaqadmaadaqaaqaaaOqaaiaadkeadaWgaaWcbaGaae4CaaqabaGccaaMi8UaaGjcVlaayIW7cqGH9aqpcaaMi8UaaGjcVlaayIW7caaMi8UaaGjcVpaalaaabaGaamOzamaaBaaaleaacaqGWbaabeaakiaayIW7caaMi8UaaGjcVlaayIW7cqGHsislcaaMi8UaaGjcVlaayIW7caaMi8UaamOzamaaBaaaleaacaqGZbaabeaaaOqaaiaadAgadaWgaaWcbaGaae4Caaqabaaaaaaa@588A@
where fp is the parallel resonance frequency and fs is the series resonance frequency in a given mode of vibration
Note 1 to entry: This entry was numbered 561-02-20 in IEC 60050-561:1991.