Abstract: An analog input signal to a digital oscilloscope is sampled and digitized to form a representative waveform data sequence. A waveform is then displayed on a screen of the oscilloscope to represent the magnitude of the waveform as a function of time as indicated by the waveform data sequence. The waveform is formed by a set of vectors, each vector comprising a straight line between two points on the screen at elevations representing magnitudes of two successive input signal samples, and at horizontal positions representing timing of the two samples. The screen provides a display organized into an array of pixels, each of which may be illuminated with variable intensity, and each vector is represented by illuminating pixels having center points bounding the trajectory of the vector on the screen. The intensity of each such illuminated pixel is modulated in accordance with the distance between the pixel and the vector trajectory.

Abstract: A method is provided for maintaining the viscosity of a consumable water-containing ink supply at a constant value by measuring water vapor content of the vapor in equilibrium with the ink supply and adding a sufficient amount of water to restore the water vapor content to a predetermined value. The method has particular application for controlling the viscosity of ink used in jet ink printers.