DISC DRIVE APPARATUS

A method is described for detecting a mechanical shock in a disc drive apparatus ( 1 ) of a type comprising: scanning means ( 30 ) for scanning record tracks of a disc ( 2 ) and for generating a read signal (SR); actuator means ( 50 ) for controlling the positioning of at least one read/write element ( 34 ) of said scanning means; a control circuit ( 90 ) for receiving said read signal (SR), deriving at least one error signal (RE) from said read signal, and generating at least one actuator control signal (SCR) on the basis of said error signal. The method comprises the steps of: -determining a shock sensitivity function (SSHOCK) which describes the relationship between shocks (OExT) and said error signal; determining or at least approximating an inverse shock sensitivity function (S-lSHOCK) as the inverse of said shock sensitivity function (SSHOCK);-and applying said inverse shock sensitivity function (Sl-SHOCK)on said error signal.