Abstract: A video converter operating in real time that responds to frames of N lines of video data in a non-interlaced format to form two fields of interlaced data without loss of any information. The converter operates with a minimum of two lines of memory storage capacity and a minimum of timing structure. The concept in accordance with the invention allows data of substantially any non-interlaced format to be converted for display on an interlaced display unit such as a standard TV system.

Abstract: The nonlinearity between the gate voltage of a first field effect transistor and its source-to-drain impedance is compensated for by a feedback differential amplifier circuit using a reference field effect transistor identical to the first field effect transistor. Linear control is exercised through a potentiometer controlling the voltage on the first of two inputs to the differential amplifier. The other input of the differential amplifier senses the voltage drop across the source and drain of the reference transistor. The output of the differential amplifier is applied to the first transistor gate and as feedback to the reference transistor gate.

Abstract: An improved optical block for use in a high brightness, full color image projection system of the type wherein high intensity (acrhomatic) projection light is modulated by a full color image composed of a plurality of monochromatic images applied to a plurality of polarization modulating light valves. A polarizer accepts the achromatic, unpolarized output of a high intensity source. Light of a preferred polarization orientation emergent therefrom is directed by the polarizer to a two level array of polarization-sensitive dichroic filters and wavelength-tuned biprisms. Input level dichroic filters separate the incoming unmodulated light into a plurality of component wavelength bands and direct each to a wavelength-tuned biprism. Each biprism directs the selected bandwidth of polarized light to the reflective surface of a light valve.