Abstract: A system for generating respective X and Y beam deflection command signals as respective running binary counts in X and Y deflection counters utilizing digital computations based on the straight line expressions Y=X tan .alpha., where .alpha. is the line slope. Relative clock rates are defined by the tan .alpha. relationship therebetween, and, by defining a line as lying in one of eight 45.degree. octants, and a circle as successive points of tangency of a plurality of lines tangent to the circle comprising circumferential segments in eight contiguous ones of the octants, the system effects generation of respective X and Y counts to trace a line of selected length and slope as well as a circle of selected radius utilizing but a single table of tangents for angles between 0.degree. and 45.degree. as the required data storage.

Abstract: A device for receiving data on a plurality of parallel lines wherein the data on specific ones of said parallel lines occur at different rates. The apparatus utilizes clock information obtained with said data. The apparatus further samples each line at a rate at least as fast as the data on any line can be presented but only places the sampled data in scratch pad memory once for each clock occurrence. Upon completion of assembly of each data word, it is transferred to buffer storage memory. The apparatus as described will eliminate or dump data from prescribed sources by placing all undesired data words in an unaccessed or write only place in buffer storage memory while forwarding the desired data words to their appropriate retrievable places in buffer storage memory.