Abstract: High storage density information carriers, particularly optically readable video discs and digital records, can only be read error-free by a playback device when the high requirements made of freedom from warping also remain guaranteed over long storage times. A cassette is provided to support and fix an information carrier only within its central portion which is free of information tracks and, by a sufficient spacing of the information carrier in the support-free area between a bottom portion and a cover portion contact with the information carrier in this area is avoided, even given consideration of maximally-admissible warping tolerances of the storage cassette and of the information carrier.

Abstract: It is necessary in the manufacture of high packing density, optically-readable, disc-shaped information carriers to undertake a continuous fabrication inspection of the disc with respect to manufacturing errors. Upon consideration of the fact that the information to be stored on the information carrier occurs in the form of an error-correcting code which is interpreted by an error correction system in the playback device during playback, it is proposed to base such an error detection device on commercially-available playback devices whose error correction systems, with respect to its error identification or error signal output, is connected via an interface to an error interpretation unit which, in turn, is sub-divided into error channels pertaining to different errors, and that, preferably, a plurality of such playback devices connected to error interpretation units via interfaces cooperate via an interrogation device with an error registration device shared in common by all error interpretation units.

Abstract: An optically readable, high storage density information carrier usually in the form of a disk, for example, a digitally recorded audio disk (CD) or a video disk (VLP) including a base, and a microstructure on the base which contains the recorded information, and consists of spiral or annular tracks or channels on one or both sides thereof. A reflective layer of a suitable metal or alloy is applied to the side of the information disk carrying the microstructure in at least that portion in which the microstructure exists. The present invention provides an improved reflective layer which, in turn, is covered by a protective layer. The improved reflective layer is a metal alloy selected from one of the following groups of alloys: (1) a Cu-Cr alloy containing from 0.3 to 1.5% chromium, (2) an Al-Mg-Si alloy containing 0.5 to 1.5% each of magnesium and silicon, and (3) an Mg-Mn-Si alloy containing 1.2 to 2% manganese and 0.05 to 0.1% silicon.

Abstract: High storage density, optically-readable information carriers not only require a read-out side free of contaminants or dust for a faultless reading, but must also be protected against unintentional scratching when being handled on this side. For protection against scratches that usually occur due to dislocation of a disc deposited on its support, concentric elevations are provided that are structured under given conditions by clearances on the read-out side in the edge region and in the central region of the disc outside of the information structure which fills a concentric annular surface. The disc is able to slide on the elevations when deposited on the support without the annular surface, provided with the microstructure, coming into contact with the support.

Abstract: Strict care must be taken in the mass production of high packing density, disc-shaped information carriers such as represented, for example, by the manufacture of compact discs, that no mix-ups occur of workpieces having different informational content during the production sequence. Proceeding on the basis that disc magazines are employed for conveying the disc-shaped workpieces from work station to the next, it is proposed that the disc magazines have a processing sequence for the workpiece stack they contain which is rigidly defined for all work stations by means of fitting parts. Also, each workpiece stack and thus each disc magazine accepting a workpiece stack therein is accompanied by an identifier disc whose shape corresponds to the shape of a workpiece. The identifier disc thus assumes the initial position in the rigidly defined hierarchy of a workpiece stack within a disc magazine.

Abstract: A storage cassette suitable for the simultaneous storage of two and more tracked disks is provided with a box-shaped center part having an intermediate bottom part which is respectively terminated at its upper side and under side with a cover in the form of a box-shaped floor part, whereby each floor part is hingeable mounted in a hinge at one side at the center part. The cassette construction enables a disk to be supported and held in the cassette adjacent each floor part and on either side of the intermediate bottom part by virtue of a raised seat and peg arrangement centrally disposed on those parts.

Abstract: A method is proposed for eliminating or suppressing unwanted acoustic signals in audio programs to be edited for reproduction in studios, in which the perceived disrupted segments in the signal are determined with respect to their time positions, and the signal ends having signal flow/polarity changes adjacent to the disrupted signal location are bridged by a transfer function, preferably in the shape of a semi-sine. The semi-sine is stored in the form of sampling values in an addressable read-only memory and can be read therefrom.

Abstract: A method for encoding analog signals for storage or transmission includes the steps of sampling momentary values of the analog signals and converting the sampled values into PCM code words and forming PCM differential code words from two successive PCM words, each of the differential PCM words being of a prescribed length. The length of the generated differential PCM words are continuously compared to a reference code word and upon the length of a differential code word exceeding a specified length the word is either abbreviated by a companded differential PCM word by eliminating some of the least significant code elements, or by division of the excess-length word into two successive code words respectively comprising the least significant and most significant bits of the excess-length word, the differential PCM words additionally being replaced by PCM words when the associated signal content does not exceed the length prescribed by the reference code word.

Abstract: A method is disclosed for the joining or mixing-in or fading of two program segments which appear in the form of digital pulse sequences, free of interfering signals, particularly audio signals digitally stored on magnetic tape, whereby code word sequences which are present in both signal segments in the region of an editing location or fading location are scanned, together with their associated time codes, and are fed to respective intermediate memories. Then, by an acoustically-monitored cyclical circulation of the contents of the intermediate memories, controlled in frequency and direction, an editing location of comparable information for each program segment is determined which is free of interfering signals. A transition, controlled by the time codes is then occasioned from the first signal segment to the second signal segment or a fading of the second signal segment is occasioned relative to the first signal segment.

Abstract: A method for encoding analog signals for storage or transmission purposes, particularly for the digital recording of audio signals in studio devices, samples periodic values of the analog signals and converts the sampled values into pulse-code modulation code words. Successive pulse-code modulation code words are transformed by means of subtraction into pulse-code modulation difference code words and, together with additional auxiliary code elements, form a reference code word having a selected constant length. A reduction of the digital signal flow is achieved as a result of the reference code word, including the auxiliary code elements, being selected shorter than the maximum possible length of a pulse-code modulation difference code word.

Abstract: A method for manufacturing high information density storage disks, suitable for optical reading, out of transparent synthetics having a high glass temperature and high dimensional stability. The present injection molding method avoids potential double diffraction disruptive effects created by frictional or shearing forces. The synthetic material which is to be pressed is injected into one of the mold halves at a temperature that significantly exceeds the pressing temperature of the compression form and is injected so as to form a lump of the material. The pressing step wherein the compression form is closed down to a squeezing gap width is initiated prior to the termination of the injection operation. Likewise the cooling operation is initiated prior to the termination of the pressing step and both the cooling and pressing operations chronologically proceed at approximately an exponential rate.

Abstract: A centering device for the manufacture of a center hole in disks, particularly metallized video disks with spiral information tracks and an information-free center, employs a measuring head for the emission of a light beam onto the disk surface. The light beam is precisely situated at a boundary between the information portion and the information-free portion of the disk during a full disk revolution (a transition criterion) and that said criterion is evaluated for the identification of the center. An electronic control circuit is provided for the control of the displacements required for the measuring head and of the disk centered in planes which are parallel relative to one another.

Abstract: A synchronizing system for the control of the transmission of digital information which is composed of blocks separated by gaps and for which synchronization requires the production of a reference pulse. Each field of information includes a series of spaced coded synchronizing control words each of which is a coded representation of the separation between the word and the position required for the synchronizing signal. The synchronizer (FIG. 3) includes a decoder composed of read-only memories (IC2, IC3) which can set a counter (IC4, IC5 and IC6) in accordance with the separation. The decoded synchronizing control signal is compared by comparator IC8 and a read-only memory IC7 with the instantaneous contents of the counter and the counter is adjusted only if parity is not detected. If parity is detected and continues to be detected for each synchronizing control word, the counter counts towards a datum whereupon the synchronizing signal is produced.

Abstract: An anode case is immersed within a deposition cell of a galvanic bath and is supported on an electrically conducting guide or support bar arrangement via a perforated contact plate which extends over the entire length of the anode case and is welded on in the vicinity of the feed opening of the anode case. The anode case is also covered by an anode enclosure which is not permeable to an anode slurry. The enclosure is slid into position in the vicinity of the contact plate in the slot between the contact plate and the anode case.

Abstract: A device for measuring acoustic reverberation time incorporates a transmission unit and a reception unit combined together into one assembly. Both units share a single series of filters, one of which filters is inserted into a signal path for the transmission unit and for the reception unit. The device serves to measure accurately the acoustic reverberation time of acoustic spaces such as recording rooms, sound studios and the like.

Abstract: A disc-shaped information carrier for high-density storage, in particular for video signals, has the information provided on both sides of the carrier and stored in the form of a beam-relfecting surface structure which is covered by a layer of translucent material. A disc-shaped base element is formed by injection molding, pressing, stamping or the like to exhibit a surface structure corresponding to the information to be stored on both sides thereof. Each side has a thin metallic coating applied thereto which maintains the same surface profile and the information structure is protected on each side with a layer of transparent material.

Abstract: A disc-shaped information carrier for high-density storage, in particular for video signals, has the information provided on both sides of the carrier and stored in the form of a beam-reflecting surface structure which is covered by a layer of translucent material. A disc-shaped base element is formed by injection molding, pressing, stamping or the like to exhibit a surface structure corresponding to the information to be stored on both sides thereof. Each side has a thin metallic coating applied thereto which maintains the same surface profile and the information structure is protected on each side with a layer of transparent material.