Abstract: As many as three of the four heads spaced at 90.degree. intervals around the periphery of a head wheel may be in contact with the magnetic tape of a video recorder and reproducer at the same time. Oblique tracks are recorded on the tape record video date in blocks corresponding to sectors, each composed of the same numbers of lines, each track beginning with a video sector and ending with another video sector with small audio blocks inbetween. Four different sector designations succeed each other in turn. The video data of each block is preceded by an identification signal of which the two most significant bits designate the sector. The sector designations are separated from the outputs of each of the magnetic heads and control a PROM, the output of which controls a crosspoint switch to direct data blocks in accordance with the sector identification to four memories and the audio blocks to an audio memory.

Abstract: A filter for use in the filtration of molten metals comprises a ceramic foam having a gasket made from fibrous material surrounding its peripheral surface and a metallic foil, such as aluminum foil, fixed to the gasket, for example by means of an adhesive, around the outer peripheral surface of the gasket.

Abstract: A video conference installation has transmission and reception devices for handling audio and video signals from a plurality of subscriber points via a shared processor which assigns individual subscriber units to the subscriber points. A digital communication system connects subscriber telephone sets (F) to the shared processor via subscriber circuits (AL) having two utility channels and a signalling channel. Audio is pulse code modulated for transmission over one utility channel and compressed video is transmitted over the other. Each subscriber point has a video monitor (B) and video camera (K). Control symbols (SS, SY) are displayed on the subscriber's monitor via an overlay generator (OG). The subscriber can initiate control and switching actions by pointing to displayed symbols on the screen using a cursor, light pen or position sensitive screen input.

Abstract: The head wheel of a video recorder-reproducer is equipped with a set of four advanced read heads, in addition to the usual sets of four read and write heads, so that each advanced read head can read the contents of an oblique track on a magnetic tape on which one of the write heads will be able to record thereafter and which will be read still later by one of the normal read heads. The advanced read heads are so located that while one of them is reading a track, one of the normal read heads is out of contact with the tape. The advanced read heads are used for reading out audio sections of video tape tracks for processing and rerecording in accordance with a previously known processing procedure used in editing newly recorded video tapes for better audio recording. The normal read heads are available for an after-check of the rerecorded audio.

Abstract: Data blocks recorded on oblique tracks on magnetic tape are preceded by synhronizing signals and block identification signals. The serial data identification signals are converted to 8-bit parallel form and then are split between an undelayed channel and a channel delayed by one data block. Under control of a sync detector the parallel data are made to correspond with data words and are then decoded for comparison of the block numbers. Since the block numbering is consecutive, the delayed decoded block number is incremented by one for comparison. When a positive comparison is obtained the block number of the delayed decoded signals is made available to identify the data block. A counter in a so called fly wheel circuit assures provision of a new block start signal if a synchronizing signal is missed and prevents the timing of the circuit from being put off by a false detection of a synchronizing signal. A block identification output appears only if its block number is in sequence.

Abstract: Test node equipment is provided between successive component groups operating in cascade and each test node is connected to a data bus system through which test patterns can be provided by a test pattern generator and from which signals can be evaluated by a test pattern analyzer, the test pattern generator and the test pattern analyzer being under control of a test computer. Each test node has a state in which the output of the preceding component group passes through it to the next component group with only a possibility of monitoring possible deficiencies by the test computer and other states in which the cascade operation of component groups can be interrupted at a test node for inserting a test pattern to a following component group or receiving a processed test pattern from a preceding component group.

Abstract: A system for testing and/or monitoring a digital videotape apparatus makes use of the presence several identically equipped recording and reproducing channels to detect or test for errors by comparing the treatment of the same data in two or more channels. Comparisons are made at test nodes between reference "signatures" and actual "signatures" in normal operation or in test operation. Syndrome units are used to test or monitor circuits for protection against errors and for error correction. The monitoring and testing is done in a system which connects a microcomputer to test nodes of the equipment to be tested or monitored over a test bus.

Abstract: Four picture field memories which contain storage places for luminance data, chrominance data, error flags and write flags are switchable from write in to read out by changeover switches controlled by an access control unit for connection of the address and control inputs of the memories either to a write in control circuit or a read out control circuit. The access control unit can be set for operation at normal speed, which is the recording speed of the tape from which signals are read out, below normal speed or above normal speed. The read-out control circuit is synchronized by a synchronizing signal that contains a vertical scan frequency reference pulse. The several picture field memories are cyclically interchanged, written into and read out from. One of the picture field memories is read out while the others are available for write-in. The incoming error flags are passed on. Use is made of write flags and error flags to improve operation at speeds different from the recording speed.

Abstract: An elongate tubular porous ceramic filter for use in the filtration of fluid media, e.g. the filtration of particulate matter from hot gases, is formed from a plurality of shorter tubular portions (10, 11, 12, 13, 14, 15, 20, 21) adhered together by a high-temperature adhesive at bonding points (30, 31) to provide long filter tubes.

Abstract: For transmission of serial digitally coded signals over a path having a high-pass frequency characteristic synchronizing signals are transmitted in synchronizing word pairs at the beginning of each data block in which the synchronizing words are either identical or else both have the same number of bits of each of the two binary logic levels, for reduction of d.c. and low-frequency components while permitting the choice of a synchronizing signal word which occurs at most rarely in a television video signal, for example.

Abstract: A conventional multiple recognition unit provides a multiple error signal whenever digitally coded television signals supplied in successive data blocks to the error recognition unit finds by reference to check-words that the error correction capabilities of the unit are exceeded in any data block. In order to determine when such multiple errors are related to faulty tracking, the multiple error signals are prolonged in duration, overlaps between the multiple error signal and a preceding prolonged signal are detected, and the latter are then integrated. The level of the integrated signal determines the likelihood or presence of tracking error.