An audio visual system comprising a reproduction system for reproducing audio sound information and picture data information recorded on a recording medium, a speaker system for audio sound output purposes, and a color TV screen for providing a visual display in accordance with the picture data information. The picture data information comprises a pattern data and instruction commands for selecting a desired display section on the color TV screen and a desired operation mode to be conducted by the audio visual system. The operation mode can be selected from the entire screen unicolor selection mode, background color change mode, pattern color change mode, display shift mode, small letter display mode, and capital letter display mode.

An address generator for synchronizing access to a rotating memory store is disclosed. Digital counting circuits are used for accumulating current segment addresses therein obviating the need for address tracks on the memory store. The pulses of a read/write clock signal are counted in a bit counter. The bit counter produces an output pulse each time the count reaches the modulo of the counter. This modulo is selected to equal the number of bits storable in a segment. The bit counter output is accumulated in a segment counter. Variable modulo bit counters are used to adapt the address generator for use with different input/output controllers and data processors characterized either by operation with different fixed sizes of addressable units of information or by a capability for dynamically varying the size of such addressable units of information. This adaptation is accomplished by having either a static or dynamically varied segment length selecting signal supplied to the address generator. In multi-zone systems, a plurality of read/write clock signals are generated to control data transfer at the several predetermined frequencies associated with the several zones. The read/write clock signals are derived from a single source of timing data associated with the memory store. Circuits for frequency multiplication and division are coupled to provide read/write clock signals at each of the frequencies associated with the several zones. In some embodiments, bit and segment counters are provided for each of the read/write clock signals. In other embodiments, the appropriate read/write clock signal for the selected zone is generated and counted.

An instrument for providing accurately timed recording signals for the sector and address tracks in the rotating drum or disc-type magnetic memories of digital computers, data processors, and the like; and for performing a wide variety of counting and other functions which are essential in the development, manufacture and maintenance of such computers and data processing. The instrument of the invention has the capability of counting timing bits, or revolutions of the rotating memory of the computer or data processing equipment; and it also has the capability of writing origin pulses, multiple index markers, and sector markers on the drum or disc of such equipment; as well as of copying from one track to another of the memory of such equipment with a variable phase delay, of adjusting bit symmetry in the timing track of the memory in the equipment; and of many other functions. In addition, special plug-in pattern logic boards may be provided for the instrument to enable it to write particular address or sector tracks on the rotating memory of a computer or data processor in accordance with the user's individual specifications.