“…Overspeed profile and corresponding data availability, the angular velocity of the turntable motor, and the components of Glossary loss in optical energy (absorption coefficient) per unit length within a laser diode or photodiode, in m-I difference between energy levels in a photonic device, in e V number of tracks crossed during a seek action average number of tracks crossed during a seek action distance between the disc center of gravity and the rotation axis, in mm average seek length, in s low-frequency sensitivity of the focus loop low-frequency sensitivity of the radial loop focal depth, in ",m spatial frequency for the MTF, in lines / ",m or ",m-I quantum efficiency of a photonic emitting device recording efficiency external quantum efficiency of a photo detector internal quantum efficiency of a photo detector angle between the direction of the zeroth order and the direction normal to the incidence plane, in rad reflection angle inside the resonator of a laser diode, in rad angle between the direction of the mth order and the direction normal to the incidence plane, in rad wavelength of the laser light, in nm damping ratio of a second-order system time constant, in s electrical time constant, in s lifetime of excess holes in the n-region of a photodiode, in s <Pm r «Pspot 'l/JlO phase margin of a control loop, in rad confinement factor within a semiconductor laser diameter of the laser spot, in /lm xxi phase shift between zeroth and first diffracted orders, in rad angular frequency, in rad/s disc angular frequency, in rad/s Notational conventions (2,10) 3T B(Sx) Cl …”