Abstract: A color video projector of the type employing red, green and blue cathode ray tubes, dichroic mirrors and a final single lens through which the red, green and blue light from the CRTs is projected on a screen exhibits non-uniform color temperature across the width of the screen. Compensating waveforms for the red, green and blue video signals are generated and multiplied with the respective red, green and blue contrast signals, the products then being multiplied with the red, green and blue video signals respectively and applied to the cathodes (or grids) of the red, green and blue CRTs respectively to provide a more uniform color temperature across the width of the screen.

Abstract: A vector generator includes a linear charge pump in the form of a DAC with a constant but variable current output that can charge a capacitor connected between the output and one of the input terminals of an operational amplifier. A second constant current generator having an output current one-half that of the maximum output current of the DAC and of opposite polarity also is provided for charging the capacitor, the constant current generators being so connected to the capacitor that it can be charged either positively or negatively. A switching network controls whether the capacitor is charging or not depending on the state of the switching network. A second DAC with a constant but variable output voltage is provided and produces an output indicative of the coordinate of the vector to be drawn. The voltage on the capacitor is compared to the output voltage of the second DAC, and, when they are equal, a control signal is produced that changes the state of the switch to terminate charging of the capacitor.