公开(公告)号：DE3583110D1

公开(公告)日：1991-07-11

申请号：DE3583110

申请日：1985-10-22

Applicant: IBM

Inventor： BALTADEN GLENN D ,  BAXTER DUANE W ,  DAVIE NEIL R

IPC: G11B7/00 ,  G11B7/0045 ,  G11B7/125 ,  G11B7/13 ,  G11B19/04 ,  G11B27/36

Abstract: @ An optical file system in which a command to store data results in a write operation in the next available storage position. A single optical path is used for both reading and writing. By dividing the detector (10) in two equal parts (10A, 10B) along the direction of relative movement, it is possible to determine whether data has been written at a position which is in advance of the center of the area viewed by the detector. The write operation is conditioned on the output of the first part of the detector. Since the first part of the detector gives advance warning on the status of the oncoming data position, it is possible to switch from reading to writing without the requirement for a wasted revolution or wasted space. By dividing the signal resulting from a change of reflectance sensed during a write operation by a measure of the intensity of the write laser a read signal free of the write modulation is obtained.

公开(公告)号：CA1291561C

公开(公告)日：1991-10-29

申请号：CA535983

申请日：1987-04-29

Applicant: IBM

Inventor： DAVIE NEIL R

IPC: H03M7/14 ,  G06T9/00 ,  G11B20/14 ,  H03M5/14

Abstract: ASYMMETRIC RLL CODING Method and apparatus for generating asymmetrically constrained run-length-limited encoded data from a serialized binary string of 1's and 0's. The method comprises the steps of encoding the input data bits using a run-length-limited-encoding constraint in the form of M/N (d,k), where M is the number of input data bits, N is the number of output bits associated therewith, d is the minimum number of 0 data bits between adjacent data bit 1's and k is the maximum number of 0 data bits between adjacent 1's; and adjusting the values of d and k, so as to alternate between a value d1 and d2 and a value k1 and k2 respectively where d1 ? d2, The apparatus comprises means for generating N output data bits in response to M input data bits and for generating data bit 0's between data bit 1's based upon a run-length-limited d,k coding constraint and means for adjusting d and k as used by said means for generating output data bits to alternate between a value d1 and d2 and a value k1 and k2 respectively, where d1 ? d2. Fractional numerical values for d1 and d2 can be employed in the method or apparatus.

公开(公告)号：CA1087675A

公开(公告)日：1980-10-14

申请号：CA268526

申请日：1976-12-22

Applicant: IBM

Inventor： DAVIE NEIL R ,  LAMBIOTTE JOSEPH C

IPC: H04N1/23 ,  B41J2/44 ,  G03G15/04 ,  G06K15/12 ,  H04N1/053 ,  H04N1/113 ,  H04N1/12 ,  H04N1/29 ,  H04N1/407

Abstract: FEEDBACK CONTROL FOR LASER DISCHARGE SYSTEM In a xerographic printer wherein an acousto-optic modulator is used to derive a deflected first-order beam of electromagnetic power which raster scans a charged photoconductor to leave a selectively discharged latent image area bordered by a discharged border area; power contents of said first order beam is maintained constant by adjusting the efficiency of the acousto-optic modulator with a closed loop electrical control system. The efficiency of the acousto-optic modulator is adjusted only when the beam is scanning the discharged border area of the photoconductor. By providing a means which allows the power contents of the first order beam to be constant the quality of copies are significantly improved.

公开(公告)号：FR2336715A1

公开(公告)日：1977-07-22

申请号：FR7636138

申请日：1976-11-22

Applicant: IBM

Inventor： DAVIE NEIL R ,  LAMBIOTT JOSEPH C

IPC: H04N1/23 ,  B41J2/44 ,  G03G15/04 ,  G06K15/12 ,  H04N1/053 ,  H04N1/113 ,  H04N1/12 ,  H04N1/29 ,  H04N1/407 ,  G03G15/052

Abstract: In a xerographic printer wherein an acousto-optic modulator is used to derive a deflected first order beam of electromagnetic power which raster scans a charged photoconductor to leave a selectively discharged latent image area bordered by a discharged border area; power contents of said first order beam is maintained constant by adjusting the efficiency of the acousto-optic modulator with a closed loop electrical control system. The efficiency of the acousto-optic modulator is adjusted only when the beam is scanning the border area of the photoconductor.

公开(公告)号：CA1285651C

公开(公告)日：1991-07-02

申请号：CA532449

申请日：1987-03-19

Applicant: IBM

Inventor： DAVIE NEIL R

IPC: H03K5/00 ,  G11B5/09 ,  G11B7/00 ,  G11B7/004 ,  G11B7/0045 ,  G11B7/005 ,  G11B20/10 ,  G11B20/14 ,  G11B20/18 ,  H03M5/08 ,  H04L7/033 ,  H04L7/02

Abstract: RESTORING AND CLOCKING PULSE WIDTH MODULATED DATA Width restoring to eliminate unintended width variations in pulse width modulated data in combination with a phase lock loop allows pulse width modulated data in high density optical recordings. The width restoration is accomplished by detecting the timing relationship of the leading and trailing edges of pulses relative to expected timing for the leading and trailing edges. Expected time is derived from a phase locked loop or the original write signal. The detected timing is compared to the expected timing and the timing of the leading and trailing edge signals is corrected. Either analog or digital width correction techniques are used. width restoration may be used while reading data or while writing the data.