Abstract: In a video disk system a mark along a record data track is modulated in length to represent multi-bit binary code blocks of a first length (such as three or fout bits) and the player system associated with the disk operates in multi-bit code blocks that are generally longer (for example eight bits) so that two marks on the disk may represent a single code block in the associated system. The bits of the code block in the associated system are assigned to bit positions of the appropriate number of marks on the disk in a way that minimizes the effect of errors in the operation of initially writing or subsequently reading a mark. The increments of mark length are also made non-linear to further minimize the effect in the associated system of errors in mark length.

Abstract: An apparatus for performing a Hadamard transform on video data for compression of data to be recorded and decompression of data read from a record for display achieves the necessary high rate by means of two or more adders and two subtractors operating in parallel. A store that holds the data during successive passes through an arithmetic unit has accessing circuits and a set of registers and associated gates that fetch and store the data in a repetitive sequence that simplifies storage accessing. Data is processed in units that represent for example eight lines of a television picture and an output buffer is provided for the decompressor of a video disk player that receives data as it is processed and holds previously processed data unit by a storage accessing circuit that minimizes the amount of buffer storage that must be provided in the player.

Abstract: A video recording disk is adapted to be rotated at a uniform angular velocity and to have bit positions of substantially equal length along a track, and the longer outer tracks are given more storage positions than the shorter inner tracks. Variable numbers of frames are located on each track revolution, depending on the data capacity of the track. Frames are divided into data units that correspond to a few horizontal lines, and frames on the same track are interlaced so that the data units of each frame are distributed evenly around the track revolution. The associated record player has simplified data storage requirements, particularly for freeze frame display of the television picture and for playing disks that hold video information in a data compression format.

Abstract: Improved features for a fabrication arrangement that reduces the number of LSI chips required in a bit stream measurement system comprised of a plurality of measurement elements, each element including a large programmable array. The improvements are on the basic fabrication arrangement of patent application Ser. No. 482,824. The improvements relate the chip and measurement element fabrication to the detection significance of parts of the bit stream by substituting delay shift registers for array portions to handle the less significant parts of the bit stream in some measurement elements. The detection operations can then be concentrated on the more significant parts of a bit stream, such as the part representing the top, bottom, left or right portion of an optical character recognition machines bit stream represented character frame. The resulting modifications in chip and element fabrication result in a further reduction in the average number of chips required in the measurement system.