Abstract: Apparatus is disclosed for separating two audio signals on two input channels and combining them to provide three output signals on three output channels in which the separation is based on comparisons of the average absolute values of the highest amplitudes of the signals on the input channels with the average absolute value of the difference between the signals on the input channels.

Abstract: An audio signal amplitude detector for applying stereo audio signals above a predetermined amplitude to at least one pair of speakers. The audio signal for each channel is amplified and compared with two reference voltages. When the amplified audio signal is below a lower one of the reference voltages, the signal is blocked to the connected speaker amplifier. As the amplitude of the audio signal increases between the first and second reference voltages, an increasing portion of the audio signal is applied to the connected speaker amplifier until a maximum signal is applied when the amplitude is above the second reference voltage.

Abstract: An improved film supply and take-up transport for use with a motion picture projector. At least two horizontal film platters are connected through bearing plates to a single vertical drive shaft. A circular film winding core is selectively positioned concentric with the shaft on one platter. The core engages a mechanism for locking the platter through the bearing plate to the drive shaft for operating the platter in a take-up mode. A motor is controlled to rotate the drive shaft for winding the film onto the core at the same rate that the film is advanced through the projector. Film is supplied to the projector from the center of a film coil on another platter which is coupled through its bearing plate to the drive shaft. An auxiliary motor is intermittently operated to initially accelerate the supply platter when the projector is first started and to control the supply platter speed to maintain a desired film supply rate.

Abstract: An improved transport system for a motion picture projector which permits either intermittent or continuous drive of a film advancement sprocket. The transport is capable of use selectively with film having, for example, either two or four perforations per picture frame. During normal operation of the projector, the sprocket is intermittently driven to advance the film through a gate while a shutter interrupts the projection light. For automated film rewind through the projector, the sprocket is driven at a continuous speed which is preferably higher than the average speed in which the film is intermittently advanced through the projector.

Abstract: A motion picture projector having an improved electric transport system for incrementally advancing film through a light gate. A constant, but adjustable, velocity rotating shutter periodically interrupts the projected picture to permit advancing the film through the light gate to the next frame. As the shutter moves to a position blocking the projected picture, a shutter position detector generates a signal for triggering a control circuit which drives an electric servomotor to rotate a film drive sprocket. The servomotor is driven to rotate the sprocket to advance the film one frame and then to hold the sprocket in a fixed position to prevent any motion of the film while the picture is projected. Power is applied from a non-linear control circuit to the servomotor. Error signals applied to the servomotor are of a peak magnitude when the servomotor is stopped with the film framed in the light gate so that small position errors drive the servomotor to the desired position with a maximum torque.

Abstract: An improved film supply and take-up transport for use with a motion picture projector. At least two horizontal film platters are connected through bearing plates to a single vertical drive shaft. A circular film winding core is selectively positioned concentric with the shaft on one platter. The core engages a mechanism for locking the platter through the bearing plate to the drive shaft for operating the platter in a take-up mode. A motor is controlled to rotate the drive shaft for winding the film onto the core at the same rate that the film is advanced through the projector. Film is supplied to the projector from the center of a film coil on another platter which is coupled through its bearing plate to the drive shaft. A brake is intermittently operated to slow the supply platter below the speed of the drive shaft to maintain a desired film supply rate.

Abstract: An improved lamphousing having a magnetically stabilized arc lamp. The arc lamp, such as a high-pressure short-arc xenon lamp, is mounted within the lamphousing such that the arc is positioned at the focal point of a reflector formed from a paramagnetic material. One or more permanent magnets are mounted on the exterior of the reflector to establish a magnetic flux within the reflector which stabilizes the plasma flame sufficiently to permit horizontal operation of the arc lamp at any current levels especially below the rated level for that arc lamp.