X-Y ALPHANUMERIC CHARACTER GENERATOR FOR OSCILLOSCOPES

A method and apparatus is disclosed by which any general purpose external trigger laboratory oscilloscope can be utilized to display alphanumeric characters. Each character to be displayed is composed of a plurality of segments appearing at various segment positions in various segment rows to define a conventional matrix, various ones of the segments being displayed during each horizontal sweep of the oscilloscope trace. In between character segments to be displayed, or when no display is desired, the trace is effectively blanked by a vertical clamping voltage so as to position the oscilloscope trace in an off-screen position. The "clamping" technique of the invention, i.e., biasing the oscilloscope trace to an off-screen position when no character segment is to be displayed, eliminates the necessity of providing Z-axis modulation to effect blanking.