Recording system for recording information on record medium by using energy beam
AssigneeMitsubishi Denki Kabushiki Kaisha
InventorsOsamu Ito, Isao Watanabe
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Abstract
A recording light beam from an argon laser is modulated with an electrical recording signal and then recorded on a rotating disc-shaped record medium. Immediately after this recording, a recorded signal on the record medium is reproduced with a light beam from a helium-argon laser and converted into an electrical signal. Duty cycles of both signals are sensed by respective duty cycle sensors. A differential amplifier produces a differential signal between the sensed duty cycles and supplies it to an optical modulator arranged to control the output of the recording laser. The modulator controls the recording light beam to its optimum light level for recording in response to the differential signal which was detected just before its modulation.
Claims6
A recording system for recording information on a record medium by using an energy beam, comprising an input terminal which is supplied with an electrical recording signal, a recording source of an energy beam for generating an energy beam for recording information on said record medium, a modulator means for modulating said energy beam with said electrical recording signal, a recording means for recording said information on said record medium with said modulated energy beam, a reproducing means for reproducing information recorded on said record medium substantially simultaneously with the recording of said information to produce a reproduced signal converted to an electrical signal, a first duty cycle sensor means connected to said reproducing means to sense a duty cycle of said reproduced signal from said reproducing means, a second duty cycle sensor means connected to said input terminal to sense a duty cycle of said recording signal, a differential amplifier means connected to said first and second duty cycle sensor means to generate a difference between output signals from said first and second duty cycle sensor means to produce a differential signal, and a control means connected to said differential amplifier means to control the power of said energy beam entered into said modulator means from said source of said energy beam in response to said differential signal from said differential amplifier means.
Dependencies are inferred from the claim text.