Abstract: When an optical disk recorder having readback circuits is used with pulse width modulated (PWM) signals a phase error of a clocking system with respect to the phase of a data signal is used to generate an amplitude detection threshold offset for serving of the amplitude detection threshold by the phase error signals tending to increase the probability of faithful detection of data carried by the PWM or other signals.

Abstract: In an optical disk player, such as for a magnetooptic player, wherein the data recorded on the optical medium are at recording at such high densities then intersymbol interference causes the peaks of the readback signals to become closer together resulting in phase errors. A transition selecting means is operative to select a transition indicated by the readback signal or a substitute transition indicated by a timed delay means generates a signal based upon the immediately preceding transition received from optical medium. Various embodiments of the invention are illustrated.

Abstract: This disclosure deals with an optical disk recorder/player (drive) of the type that receives a removable disk for signal exchanging operations. Once a disk is inserted into the drive, the rotation of the disk begins a period of accelerating rotational speed called spin up. During spin up, the focus and tracking systems of the drive are calibrated. Once the disks reach a desired operating rotational speed, a menu is provided for determining when to calibrate a laser in the drive for recording operations. Such writing or recording calibration of the laser occurs at different times in accordance with the types of signal processing functions to be performed with respect to the particular disk. Description includes a media library in which a plurality of optical disk drives are controlled in a manner for minimizing access times to any optical disk within the media library.

Abstract: An antisaturation circuit comprising a differential input pair monitors the collector-base voltage of a protected transistor to detect the condition prior to the protected transistor going into saturation mode. To prevent the protected transistor from operating in the saturation mode, the differential input pair sinks a portion of the protected transistor's collector current. This reduction in collector current causes an increase in the collector voltage thus keeping the collector-base junction reverse biased and the protected transistor out of the saturation mode. This antisaturation technique does not steal base current from the protected transistor, hence leaving its input impedance unaffected. This antisaturation technique is thus useful in higher performance non-linear circuits as well as in linear circuits.