Magnetic field modulation magnet-optical recording apparatus in which an FM modulator and a magnetic head driving circuit are used in common
AssigneeSharp Kabushiki Kaisha
InventorHiroshi Fuji
Life of this patent
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Abstract
A positive direction current source is connected to a magnetic head coil via a multiplier and a switching device, and a negative direction current source is connected to the magnetic head coil via the switching device. The output current of the positive direction current source is controlled to a level appropriate for generating a magnetic field forming a magnet-optical recording mark based on the amplitude of an information signal by the multiplier. The switching device is turned on/off by a carrier signal. As a result, a magnetic head driving signal can be obtained having the positive direction current value modulated based on the amplitude of the information signal.
Claims14
A magnetic field modulation magnet-optical recording apparatus having magnetic head means for applying to a magnet-optical recording medium a magnetic field modulated according to information to be recorded, and which forms a magnet-optical recording mark having the direction of magnetization specified in binary on said magnet-optical recording medium comprising:
- AM modulation means for AM modulating a first recording signal having a first frequency based on a second recording signal having a second frequency lower than said first frequency, and then providing an AM modulation signal,
- magnetic head driving means for converting the current value of said provided AM modulation signal into a current value appropriate for generation of said magnetic field by said magnetic head means, and providing a magnetic head driving current of said appropriate current value to said magnetic head means,
- wherein the mark length of said magnet-optical recording mark is FM modulated based on at least said second recording signal.
A magnetic field modulation magnet-optical recording apparatus having magnetic head means for applying a magnetic field modulated according to information to be recorded to a magnet-optical recording medium, and which forms on said magnet-optical recording medium a magnet-optical recording mark having the direction of magnetization specified in binary, comprising:
- Am modulation means for AM modulating a first recording signal having a first frequency based on a second recording signal having a second frequency lower than said first frequency, and then providing an AM modulation signal,
- magnetic head driving means for converting the current value of said provided AM modulated signal into a current value appropriate for generation of said magnetic field by said magnetic head means,
- clip means for clipping as a clip level said provided signal with a predetermined negative direction current value in the output signal of said magnetic head driving means to provide the same to said magnetic head means,
- wherein the mark length of said magnet-optical recording mark is FM modulated based on at least said second recording signal.
A magnetic field modulation magnet-optical recording apparatus having magnetic head means for applying to a magnet-optical recording medium a magnetic field modulated according to information to be recorded, and which forms on said magnet-optical recording medium a magnet-optical recording mark having the direction of magnetization specified in binary, comprising:
- adding means for adding a first recording signal having a first frequency and a second recording signal having a second frequency lower than said first frequency to provide an added signal,
- magnetic head driving means for converting the current value of said provided added signal into a current value appropriate for generation of said magnetic field by said magnetic head means to provide a magnetic head driving current of said appropriate current value to said magnetic head means,
- wherein the mark length of said magnetic recording mark is FM modulated based on at least said second frequency.
A magnetic field modulation magnet-optical recording apparatus having a magnetic head for applying to a magnet-optical recording medium a magnetic field modulated according to information to be recorded, and which forms on said magnet-optical recording medium a magnet-optical recording mark having the direction of magnetization specified in binary, comprising:
- a first current source for conducting a flow of positive direction current to said magnetic head means,
- a second current source for conducting a flow of negative direction current to said magnetic head means,
- switching means for alternately turning on/off said first current source and said second current source by a first recording signal having a first frequency,
- first current control means connected to said first current source for controlling the magnitude of the output current of said first current source based on the amplitude of a second recording signal having a second frequency lower than said first frequency to generate a magnetic head driving current for said magnetic head means to generate said magnetic field,
- wherein the mark length of said magnet-optical recording mark is FM modulated based on at least said second frequency.
Dependencies are inferred from the claim text.