Abstract: Apparatus for synchronising a plurality of independent video signal generators comprises a first input (12) for receiving field or frame synchronising signals from a first video signal generator, a second input (14) for receiving field or frame synchronising signals from a second video signal generator, a comparator (13) for comparing the phase of the first and second synchronisation signals, a master clock generator (1), a slave clock generator (4), the slave clock generator (4) having a frequency different from that of the master clock generator (1), means for applying the master clock signal to a first output (7) for application to the first video signal generator, means for applying the slave clock signal to a second output (9) for application to the second video signal generator, and means (5) for means for applying the master clock signal to the second output (9) in place of the slave clock signal when the synchronising signals from the first and second synchronising signals are in phase.

Abstract: An apparatus for processing image data of a computerized tomography system having image data acquisition and main storage devices is provided. The image processing apparatus includes an image processor memory for storing image data and a plurality of operation means having processing apparatus for sequentially performing processing operations on the image data. The apparatus further includes a process controller for providing the image processor memory and the operation means with control data specifying the processing operations to be sequentially performed by the plurality of operation means and for generating sequence selection data. The apparatus also includes a sequencer means for selecting the sequence in which the processing operations are to be performed in accordance with the sequence selection data.

Abstract: A system for sequentially providing external circuit data for an external circuit comprising: a memory having a plurality of memory locations identified by addresses, each memory location containing an instruction comprising external circuit data and memory location data, the memory further comprising an address input terminal for currently accessing one of the memory locations in response to receipt of the address for that memory location at the address input terminal; a sequencer, coupled to the memory to receive memory location data from the currently addressed one of the memory locations, for selecting the address of another of the memory locations in response to the next memory location data; a first register, coupled between the sequencer and the address input terminal of the memory to receive the address of the other of the memory locations from the sequencer for storing the address selected by the sequencer to make the address available at the address input terminal of the memory to access the other o

Abstract: A data disc system for a computed tomography X-ray scanner employing a plurality of disc drives for writing data into and reading data from corresponding discs. The disc drives are asynchronously operated in conjunction with a processor which writes data in parallel into the same cylinder of different ones to the discs and subsequently reads data in parallel from different cylinders of different ones of the discs to convert data from source fan format into detector fan format. In the alternative, the processor writes data in parallel to different cylinders of different ones of the discs and reads data in parallel from the same cylinder of different ones of the discs to convert data from source fan format into detector fan format.