Abstract: A tester for image intensifier tubes used in night vision goggles used by aircraft crew members includes a photosensor, dc. power supply, lamp, optical filter, neutral density optical filters, feedback control, and columnating lens. The intensity of the lamp is controlled with reference to the magnitude of an electrical variable that changes with the intensity of light produced by the lamp. A differential amplifier having a constant current bridge circuit varies base current to cascaded transistor amplifiers in accordance with changes in the electrical variable. The bridge and amplifier stages stabilize the intensity of light produced by the lamp. An array of optic filters of graduated intensity shows the intensity of light in a range of wavelengths near infrared able to pass through an ANVIS filter.

Abstract: A system for rotating images on a raster display device through an angle includes a tilt angle signal, first and second tilt angle sine function modulators and first and second tilt angle cosine function modulators. The horizontal deflection circuit of the display device is driven by a ramp signal which is the sum of the horizontal sweep generator output multiplied by the second cosine function modulator plus the vertical sweep generator output multiplied by the second sine function modulator. Similarly, the vertical deflection circuit of the display unit is driven by a ramp signal which is the sum of the vertical sweep generator output multiplied by the first cosine function modulator plus the horizontal sweep generator output multiplied by the first sine function modulator. Variation of the tilt angle signal varies the sine and cosine functions and produces a corresponding rotation of the display image.