Deutsche Thomson-brandt Gmbh

Engelbert Laufer

Hans-Robert Kuhn

Friedrich Fuldner

Richard Rutschmann

Hirohito Takagi

Arthur Kurz

Dieter Storz

Peter Hoch

Wilfried Rohde

The present invention relates to a device for writing to or reading from optical recording media which have data tracks for recording or reading out information. It has a scanning means for scanning the data tracks, a detection means which emits a signal which is modulated in accordance with the information stored on the optical recording medium and a track detector, which generates a mirror signal by means of a reference value transmitter, which mirror signal indicates whether the scanning means is scanning a data track or the region between two tracks. The device is capable of forming a reliable mirror signal without a high outlay. For this purpose, the reference value transmitter is designed as an adaptive reference value transmitter to which the mirror signal is fed as input variable.

Device for writing to or reading from optical recording media

Resilient scanning head support made of deformable material

A process and an arrangement for identifying the type of defects in optical information from an optical information carrier includes circuitry for detecting the displaying various types of defects which can occur in the information carrier. A processing circuit is linked to a display device to enable the cause of the defect to be displayed. The invention facilitates evaluation of the fidelity of reproduction of optical information carriers,

Signalization of types of defects of an optical information carrier

In a control loop for automatically adjusting variable-gain amplification, a sinusoidal signal with a frequency f.sub.o that is critical for the control loop is superimposed over a positioning parameter W. Two synchronous rectifiers S1 and S2 filter out the oscillation components of a control parameter x and of a control difference x.sub.d that contain frequency f.sub.o, and the components are compared in a comparator VL. A control and regulating circuit C continues to vary the variable-gain amplification at controls RG until the amplitudes of the oscillation components being compared in the comparator are equal. The variable-gain amplification is correct at that point. The variable-gain amplification can even be adjusted in a compact-disk player while the player is in operation.

Method of and circuitry for automatically adjusting the variable-gain

Growing community of inventors

St. Georgen, Germany

Engelbert Laufer