Abstract: Gray scale modulation of a field emission display is provided by sampling the video data portion of an NTSC signal to obtain a plurality of samples corresponding in time to the position of the emitters in each row of the display. The samples are used to generate respective pulses having a width corresponding to the magnitudes of the samples. The pulses drive the respective emitters low during the horizontal retrace portion of the NTSC signal. The extraction grids in a selected row are driven high during the horizontal retrace portion to cause the emitter in the selected row and column to emit electrons. The extraction grids in the selected row are then driven low at the end of the horizontal retrace period to terminate the emission of electrons.