Abstract: A position measuring instrument of the type having a scale and a scanning unit is provided with a plurality of reference marks on the scale. An identification mark is associated with each reference mark, and each identification mark is uniquely coded. The scanning unit operates to read the identification marks and to generate identification signals which are applied to a comparator or to a computer. The comparator or computer compares the identification signal corresponding to each reference mark with a set of designation signals. Only if a correspondence is found between the identification signal and one of the designation signals is the reference mark allowed to go into operation. Thus, by merely changing the designation signals electronically, any desired subset of a total number of reference marks can be enabled. The selected reference marks can readily be changed electronically without physical manipulation of the measuring instrument.

Abstract: A spatial filter system for filtering a matrix of data values by an m.times.n matrix, where the m.times.n matrix is the product of a 1.times.n matrix and a m.times.a matrix. The system includes a first spatial filter adapated to filter each row of the data matrix with the 1.times.m matrix to provide a first filtered value matrix. The system also includes a second spatial filter adapted to filter each column of the first filtered value matrix with the m.times.1 matrix to provide a second filtered value matrix.

Abstract: Apparatus for and method of providing a variable speed cycle time for synchronous machines. The synchronous machine performs a number of functions, wherein the execution time for a given function is dependent upon the input quantities. Timing for the input dependent function is divided into fixed and variable sequences. A synchronous counter is loaded with a quantity representative of the input quantities. The synchronous counter then controls the duration of the variable sequences based upon the representative quantity. Since it is clocked by the system clock, the synchronous counter controls the variable sequences synchronously with the controlling of the fixed sequences.