Angular displacement measuring apparatus with strobe means

Apparatus for providing digital bytes or characters of output data comprising:

• a data source including a pair of tracks and a plurality of additional tracks with each of said tracks being composed of a sequence of cells containing indicia representing digital information with the said cells of respective said tracks being laterally aligned by forming multi-bit characters,
• said pair of tracks being arranged so that the indicia contained therein differs for at least a substantial portion around the center of said cells thereof for a given lateral alignment,
• one of the indicia for said pair of tracks for a given lateral alignment being substantially centered in the cell thereof with a width less than the width of the said cell containing said one indicia,
• a plurality of sensors for detecting the indicia from said tracks including first and second sensors for detecting indicia from respective tracks of said pair and for producing first and second output signals corresponding thereto,
• means for producing an enabling signal whenever said first and second output signals differ, and
• gating means responsive to said enabling signal for reading multi-bit characters from at least some of said tracks, whereby relative motion between said sensors and said tracks will not result in character reading ambiguities around the lateral boundaries between said cells.