Tektronix, Inc.

Judd L Sirotiak

Jerrold J Rogers

A compensation circuit is described for use in a line scan type recording apparatus where an electron beam is scanned on the face of a fiber optic cathode-ray tube (FOCRT) in synchronization with a movable recharging medium. The compensation circuit includes a charge pump circuit, an integrator circuit, and a current source. The charge pump circuit draws a constant charge from the integrator circuit in response to a repetitive series of stepper pulse corresponding to the velocity changes in the recording medium. The current source generates a constant current that flows into the integrator circuit and is equal to the average DC current flowing out of the integrator circuit via the charge pump circuit. The output voltage of the integrator circuit is used for controlling the vertical displacement of the electron beam of the FOCRT in synchronization with the movable recording medium. A DC stabilization circuit and a sample-and-hold circuit may be included for stabilizing the average DC voltage level of the integrator output voltage and for removing the sweep and recovery noise from the integrator output voltage respectively.

Compensation circuit for synchronizing image motion with a movable

A circuit is described for automatically controlling an input current to a current translating device having an output current functionally related to the input current. A sensing circuit detects the output current of the device and produces a control signal representative of the output current. The control signal is coupled to a control circuit that varies the input current to the device. In the preferred embodiment of the invention, the dynamic range of the sensing circuit is increased by coupling a constant current generator to its input.

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Tualatin, OR, United States of America

Judd L Sirotiak