# US 5,703,854 A · Disc recording/reproduction apparatus and method for resetting an address control circuit to maximize an address margin of the memory > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,703,854 A - Document ID: US5703854A - Status: Granted - Kind: A - Application number: 08/493,368 - Filed: 1995-06-21 - Granted: 1997-12-30 - Earliest claimed: 1994-06-29 - Assignees: Sony Corporation - Inventors: Hirokazu Kuroda; Ryo Ando - Web page: https://patentgrep.com/patent/US5703854A ## CPC - G11B 27/105: {of operating discs} - G11B 19/28: Speed controlling, regulating, or indicating (G11B19/24 takes precedence) - G11B 7/0037: with discs - G11B 11/10595: {Control of operating function} - G11B 20/1217: {on discs} - G11B 2220/2529: Mini-discs - G11B: INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER (recording measured values in a way that does not require playback through a transducer G01D9/00; recording or playback apparatus using mechanically marked tape, e.g. punched paper tape, or using unit records, e.g. punched or magnetically marked cards G06K; transferring data from one type of record carrier to another G06K1/18; circuits for coupling output of reproducer to radio receiver H04B1/20; gramophone pick-ups or like acoustic electromechanical transducers or circuits therefor H04R) ## Abstract A spindle servo circuit controls the rotation of a disc-driving spindle motor based on absolute address information taken from a disc. Reproduction digital data is written to and read from a RAM. An address control circuit generates a write address of the RAM by counting clocks synchronized with the reproduction digital data by a first counter, and generates a read address of the RAM by counting reference clocks by a second counter. A jitter correction circuit produces jitter-removed reproduction digital data from the RAM. The address control circuit is reset so that the address margin of the RAM is maximized when the spindle servo circuit is locked. ## Claims ### Claim 1 A disc recording/reproduction apparatus for recording and reproducing data onto and from a disc on which control information is written in advance, comprising: a spindle servo circuit for controlling, based on the control information taken from the disc, rotation of a spindle motor that drives the disc; a memory to and from which reproduction digital data is written and read; an address control circuit for generating a write address of the memory by counting clocks synchronized with the reproduction digital data by a first counter, and for generating a read address of the memory by counting reference clocks by a second counter; a jitter correction circuit for producing jitter-removed reproduction digital data from the memory; and reset means for resetting the address control circuit so as to maximize an address margin of the memory when the spindle servo circuit changes from an unlocked state to a locked state. ### Claim 2 (depends on 1) The disc recording/reproduction apparatus according to claim 1, wherein the reset means resets the first and second counters when a difference between the write address and the read address of the memory exceeds a predetermined value. ### Claim 3 (depends on 2) The disc recording/reproduction apparatus according to claim 2, wherein spindle servo circuit controls the spindle motor so that the disc is rotated at a constant linear velocity. ### Claim 4 (depends on 3) The disc recording/reproduction apparatus according to claim 3, wherein the spindle servo circuit performs rough spindle servo in a first control mode and normal spindle servo in a second control mode after completion of the first control mode. ### Claim 5 (depends on 4) The disc recording/reproduction apparatus according to claim 4, wherein a judgment of the completion of the first control mode is made based on whether a phase-locked loop of the clocks has been locked. ### Claim 6 (depends on 5) The disc recording/reproduction apparatus according to claim 5, wherein a judgment of completion of the second control mode is made based on whether the spindle servo circuit has been locked. ### Claim 7 A recording/reproduction method for recording and reproducing data onto and from a disc on which control information is written in advance, comprising the steps of: controlling, based on the control information taken from the disc, a spindle servo circuit of a spindle motor that drives the disc; generating a write address of a memory to and from which reproduction digital data is written and read by counting clocks synchronized with the reproduction digital data by a first counter, and a read address of the memory by counting reference clocks by a second counter; correcting jitters by producing jitter-removed reproduction digital data from the memory; and resetting the address control so as to maximize an address margin of the memory when the spindle servo circuit changes from an unlocked state to a locked state. ### Claim 8 (depends on 7) The disc recording/reproduction method according to claim 7, further comprising the step of resetting the first and second counters when a difference between the write address and the read address of the memory exceeds a predetermined value. ### Claim 9 (depends on 8) The disc recording/reproduction method according to claim 8, further comprising the step of controlling the spindle servo circuit so that the disc is rotated at a constant linear velocity. ### Claim 10 (depends on 9) The disc recording/reproduction method according to claim 9, further comprising the step of operating in a first control mode, wherein the spindle servo comprises rough spindle servo and operating in a second control mode after completion of the first control mode, wherein the spindle servo comprises normal spindle servo. ### Claim 11 (depends on 10) The disc recording/reproduction method according to claim 10, further comprising the step of determining whether the first control mode is completed based on whether a phase-locked loop of the clocks has been locked. ### Claim 12 (depends on 11) The disc recording/reproduction method according to claim 11, further comprising the step of determining whether the second control mode is completed based on whether the spindle servo circuit has been locked. ### Claim 13 A disc recording/reproducing apparatus for recording or reproducing data onto or from a disc on which address information is recorded in advance, comprising: reproducing means for reproducing signals recorded on the disc as a reproduced signal; address information extraction means for extracting the address information from the reproduced signal; clock extraction means for extracting a clock component from the reproduced signal; memory means for temporarily storing the reproduced signal; spindle servo means for controlling a rotation speed of the disc in accordance with the extracted address information; reference clock generating means for generating a reference clock; memory control means for controlling a write address to the memory means and a read address from the memory means, and including counter means for counting the extracted clock component from the clock extraction means; address generating means for generating a write address to the memory means in accordance with the extracted clock components counted by the counter means and a read address of the memory means in accordance with the reference clock; and reset means for resetting the counter means so as to maximize an address margin of the memory means when the spindle servo means changes from an unlocked state to a locked state. ### Claim 14 A disc recording/reproduction apparatus for recording and reproducing data onto and from a disc on which control information is written in advance, comprising: a spindle servo circuit for controlling, based on the control information taken from the disc, rotation of a spindle motor that drives the disc; a memory to and from which reproduction digital data is written and read; an address control circuit for generating a write address of the memory by counting clocks synchronized with the reproduction digital data by a first counter, and for generating a read address of the memory by counting reference clocks by a second counter; a jitter correction circuit for producing jitter-removed reproduction digital data from the memory; and reset means for resetting the address control circuit so that the write address of the memory and the read address of the memory are reset to a same value so as to maximize an address margin of the memory when the spindle servo circuit changes from an unlocked state to a locked state.