Abstract: Disclosed is a moving map display having a mass memory storing a complete map of the terrain to be traversed by a vehicle, a scan memory storing a portion of the complete map corresponding to the area immediately surrounding the vehicle, a computer for controlling the updating of the portion of map stored in the scan memory and for controlling the refreshing of the map data displayed on a cathode ray tube display, a scan memory address generator receiving parameters computed by the computer for generating addresses sequential outputting the digital map data stored in the scan memory in a predetermined sequence, a video display generator for converting the map data output from the scan memory for utilization by the cathode ray tube display, and a timing generator for synchronizing the generation of the addresses by the scan memory address generator with the scan field of the cathode ray tube display.

Abstract: An address generator responsible to input parameters for generating addresses to read out the content of a memory along parallel lines disposed at an angle to the orthogonal rows and columns of storage elements. The address generator has a first pair of registers coupled by an adder to generate line corrected X addresses, a second pair of registers coupled by an adder for generating first address corrections, an adder summing said line corrected X addresses with said first address corrections to generate X addresses, a third pair of registers coupled by an adder to generate line corrected Y addresses, a fourth pair of registers coupled by an adder to generate second address corrections, and an adder summing said line corrected Y addresses with said second address corrections to generate Y addresses.

Abstract: A spirometer includes an expansible chamber of the piston type fitted with an indicia strip. The indicia comprise two columns of alternating light and dark bars. The columns are offset from one another by one-half the thickness of a bar and are respectively viewed by two photodetectors which generate signals which are shifted 90.degree. from one another as the columns pass through their respective fields of view. The signals are continuously sampled as digital words and consecutive words are compared to determine whether a counter should be incremented or decremented by one or two counts.