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Tangential tracking During production of the master disc, the cutter is actively led on a straight line across the disc. Therefore it always stands in tangential i.e. rectangular position to the respective radius of the record. During the playback of the record the pick-up should align to the tangent or as close as possible to it.As with a conventional pivoted tonearm the tracking takes place on a circular route, there results a constantly changing deviation of the angle to the tangent, which is called tracking error. The maximum tracking error depends on the length of the tonearm, and the position of its pivot point in reference to the record centre. It is obvious to construct linear tonearms which move the pick-up actively or passively in tangential position to the groove of the record. The disadvantages of these solutions lie in the technical effort required to control the precise movement of the pick-up or the sophisticated linear bearings. Moreover – in consequence of the linear principle – it is hard to achieve a symmetric mass inertia on the pick-up. |