A method for providing tracking error signals in an optical digital storage system , the optical digital storage system including a transducer head and a wobble detection system , the method comprising: receiving a wobble signal having a first frequency from the wobble detection system, the wobble detection system including an optical pick up unit that detects positions of the transducer head relative to lands and grooves, the wobble signal for the optical pick up unit centered on a land being 180 degrees out of phase with the wobble signal for the optical pick up unit centered on a groove, the wobble signal being amplitude modulated for positions intermediate between the land and the groove; receiving a primary tracking error signal from the wobble detection system; and characterised by : multiplying the wobble signal with a square wave signal having the first frequency to produce a product signal , the product signal being positive for a first direction of motion and negative for a second direction of motion that is opposite that of the first direction; and integrating the product signal to obtain a quadrature track error signal , the quadrature track error signal being 90 degrees out of phase with the primary track error signal, the quadrature track error signal and the track error signal in combination providing direction information about movement of the transducer head across data tracks. receiving a wobble signal having a first frequency from the wobble detection system, the wobble detection system including an optical pick up unit that detects positions of the transducer head relative to lands and grooves, the wobble signal for the optical pick up unit centered on a land being 180 degrees out of phase with the wobble signal for the optical pick up unit centered on a groove, the wobble signal being amplitude modulated for positions intermediate between the land and the groove; receiving a primary tracking error signal from the wobble detection system; and characterised by : multiplying the wobble signal with a square wave signal having the first frequency to produce a product signal , the product signal being positive for a first direction of motion and negative for a second direction of motion that is opposite that of the first direction; and integrating the product signal to obtain a quadrature track error signal , the quadrature track error signal being 90 degrees out of phase with the primary track error signal, the quadrature track error signal and the track error signal in combination providing direction information about movement of the transducer head across data tracks. multiplying the wobble signal with a square wave signal having the first frequency to produce a product signal , the product signal being positive for a first direction of motion and negative for a second direction of motion that is opposite that of the first direction; and integrating the product signal to obtain a quadrature track error signal , the quadrature track error signal being 90 degrees out of phase with the primary track error signal, the quadrature track error signal and the track error signal in combination providing direction information about movement of the transducer head across data tracks. <EOS>