Method and apparatus for data recording and reproducing with error reduction
AssigneePioneer Electronic Corporation
InventorsFumihiko Yokogawa, Hiroyuki Hirano
Life of this patent
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Abstract
An optical disk data recording and reproducing apparatus includes variable delay circuits in the recording and reproducing sections of the apparatus. The delay of the reproducing section delay circuit is adjusted when the error ratio determined for a reproduced data signal corresponding to a recorded data signal is greater than a predetermined value. When the error ratio is less than the predetermined value after adjustment of the delay circuit, the delay of the delay circuit in the recording section is adjusted to match the adjusted delay of the reproducing section delay circuit and the delay of the latter circuit is retured to its original value.
Claims5
A method of data recording and reproducing for use with a recording and reproducing apparatus which includes a pickup for recording on or reading from a recorded medium, a reproducing section which includes a first delay circuit for delaying a signal representing the data signals read from the recording medium, and a recording section which includes a second delay circuit which delays a modulated signal whose modulation represents the data to be recorded comprising the steps of:
- (a) modulating a data signal which is to be recorded by a recording/reproducing clock signal which has been delayed by said first delay circuit,
- (b) recording said modulated data signal with a time delay provided by said second delay circuit,
- (c) reproducing the data signal recorded in step (b) using the recording/reproducing clock signal delayed by said first delay circuit,
- (d) calculating the error ratio from said reproduced data signal,
- (e) determining if the calculated error ratio is greater than a predetermined maximum allowable value,
- (f) adjusting the delay interval provided by said first delay means if the error ratio is greater than said allowable value,
- (g) repeating steps (b) through (e), and
- (h) again adjusting the delay interval provided by said first delay circuit if the error ratio is still greater than said allowable value.
An apparatus for recording and reproducing data signals stored on a recording medium, said apparatus including a pickup head, a reproducing section and a recording section,
- said reproducing section comprising;
- amplifier means for amplifying an RF signal from said pickup head representing the data read from the recording medium, derivative pulse edge detecting means for detecting an edge of a signal which is the derivative of said RF signal, a first variable delay circuit responsive to the detected pulse edge, a phased locked loop receiving the delayed pulse edge for producing a reproduced clock signal, an analog to digital converter receiving the amplified RF signal and an output from said phase locked loop for providing a digital signal representing said RF signal, a demodulator means for demodulating the digital signal, and an error calculating circuit for calculating the error ratio of said demodulated signal;
- said recording section comprising;
- means for receiving data to be recorded, modulator means for modulating said received data with the clock signal reproduced by said phase locked loop, a second variable delay circuit receiving said modulated data signals, and recording means for controlling said pickup head to record data signals on said recording medium in accordance with the modulated data signal.
Dependencies are inferred from the claim text.