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Abstract

An optical data recording system in which during recording the image of the acoustic pulse at the writing surface is made to move at the same relative velocity with respect to the recording medium whereby motion blur is minimized or reduced. The writing beam, such as that generated by a laser, is incident on acousto-optic device (such as a Bragg cell) and may be diffracted (deflected) at an angle determined by the frequency of a source applied to the device. By selecting the system magnification between the device and the recording medium such that the magnification, in one embodiment, is substantially equal to the ratio of the velocity of the recording medium to the velocity of the sound wave in the acousto-optic device; the image of the acoustic pulse follows the surface of the recording medium and permits imaging of the video signal to the recording medium without blurring. In a second embodiment wherein the writing beam is scanned across the surface of the recording medium, the system magnification is selected to be substantially equal to the ratio of the velocity of the writing beam to the velocity of the sound wave in the acousto-optic device. System resolution is substantially improved by reversing the video digital bit stream which is applied to a balanced diode mixer in the modulator driver electronics thereby shifting the acoustic carrier signal phase by 180.degree. which in turn induces a 180.degree. phase shift in the light scattered by that video pulse. The present invention also allows a glass modulator to be utilized at relatively high video rates (i.e., in the range of 55 M bit/sec.) rather than currently utilized TeO.sub.2 modulators which are much more expensive.

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First Claim