FR2532460A1 - DISC PLAYER FOR REPRODUCING INFORMATION FROM A DISC HAVING A SPIRAL RECORD TRACK - Google Patents

Abstract

THE INVENTION RELATES TO A DISC DRIVE FOR REPRODUCING INFORMATION FROM A DISC BEARING A SPIRAL RECORDING TRACK. THE DISC READER ACCORDING TO THE INVENTION INCLUDES A READ HEAD 2 DRIVEN BY A STEP MOTOR 5. THIS STEP MOTOR IS CONTROLLED BY PULSES WHICH COME FROM A CONTROL CIRCUIT 7 AND OF WHICH THE NUMBER IS DETERMINED FROM OF DEPOSITION DATA OF THE START OF THE TRACK AND OF DATA OF THE REAL POSITION OF THE READING HEAD. THE INVENTION APPLIES IN PARTICULAR TO DIGITAL SOUND DISC PLAYERS.

Description

The present invention relates generally to an apparatus for

  reproduce information from a disc-shaped recording medium, for example a digital sound disc, and more particularly relates to a disc player for reproducing

  information from a disk on which is recorded

  recorded a modulated signal in response to the information in one

  spiral recording spire, and in which a

  Playback function intended to play the recorded signal from the spiral track on the disc moves in the direction of the disc radius to follow the track

spiral recording.

  A digital sound disc, which is a rotating disc carrying a spiral recording track on

  which a modulated digital signal in response to data

  born of a sound signal as information

  program and other digital information is recorded.

  for example in an optical readable manner, is used

  The digital data by which the digital signal recorded on the digital sound disk is modulated is formed, for example, into a disk drive to obtain a reproduced sound signal.

  a data format containing segments of trane suc-

  The duration of each frame segment is 136.1 microseconds, therefore the repetition frequency of a frame segment is, for example, 7.35 kHz. Each frame segment has a synchronization portion containing synchronization information. frame, part of scus-coding and part of datao Each subcoding part is used in eight channels containing channels P to W and contains in the Q-channel address information accompanying program information in the data portion and forming a unit

  in each block segment that includes ninety-

  eight frame segments The duration of each block segment is 13.3 milliseconds and therefore, the frequency of

  repetition of a block segment is 75 Hz.

  Each address information unit which is formed with the generated address information at the Q channel in each frame segment forming a block segment

  and therefore appearing every 13.3 milliseconds

  des, contains data representing a number for

  each section of program information, data

  presenting a number for each part of a section of information

  program formations, time address information representing reproduction time in each section

  of program information, expressed in mirrors and

  counts, and data representing a number for each

  block segment in each second of reproduction time

  The aforementioned duration of the frame segment, the duration of the block segment and the reproduction time are measured when the disk drive on which the disk is placed.

  digital sound works in its normal mode of reproduction.

  duction. Moreover, in a digital sound disc, the inner coil of the spiral recording track is usually used as the starting end of the reproduction

  and the outer turn of the spiral track serves as the

  end of reproduction Therefore, the sig-

  Digital audio recorded on the digital audio disc is played along the spiral recording track, in the direction from the inner turn to the outer turn when the disc drive on which the digital sound disc is mn normal mode

  In the inner turn of the runway

  spiral recording on the digital disc of his,

  time information representing the reproduction time

  in each reproduction distance from the start end, for reproduction to the beginning of each section of program information recorded on the spiral recording track are recorded

  in the form of a table, materials.

  The disk drive adapted to reproduce the program information from the digital disc of

  mentioned above is carried out in the same way as

  see selectively reproduce the pro-

  gram from any desired position on the disc using the address information and the recorded table of contents, and is therefore arranged to

  selectively kill a search operation in the-

  what a desired position on the disk is sought

  and the reading position defined by a read head

  ture is moved to the desired position

sought.

  In the search operation performed by a

  previous disc player, the playback position of.

  the reading head is moved rapidly a distance in the direction perpendicular to the spiral recording track on the discs and is

  then ordered to follow this track in order to reproduce

  derive the address information therein in the normal reproduction mode so that the reading position in which the playhead is at that time is detected from the reproduced address information, and the distance between position

  detected and the desired position on the disk is deter-

  This movement of the reading position of the playhead is repeated until its position is the desired position. In other words, the reading position

  of the head of reading is ordered to move ra-

  a certain distance in the trans-

  of the spiral recording track and for

  follow this track in normal alternate

  natively to quickly reach the desired position

  on the disk during the search operation.

  But since this earlier disc player

  which is designed to selectively perform the operation

  The above-mentioned search pattern must reproduce the address information to detect the current head position and set the distance between the detected position and the desired position during the rapid movement of the head position. reading to the desired position in the search operation, and that it takes a certain fixed time, which is not extremely short, to reproduce the address information and detect the position in which the t 4 is located. If you are currently reading and set the distance between the detected position and the desired position, this earlier disc player raises a problem that the duration of a search period can not be very short. Additionally, this earlier disc player raises another problem in that there is a relatively large difference in the time required for the search operation between the case where the distance between the position or

  find the playhead at the beginning of the replay operation.

  search and the desired position is relatively short and the case where the distance between the position o is the read head at the beginning of a search operation

  and the desired position is relatively long.

  a disadvantage in the actual use of this

previous disc player.

  An object of the invention is therefore to provide a disk player for reproducing information from a disk having a recording track.

  spiral, this reader being arranged to perform selective

  a research operation and avoids

  aforementioned problems of the prior art.

  Another object of the invention is to propose a disk player for reproducing information

  from a disc with a recording track

  spiral, this reader being able to perform an opera-

  research in a relatively short time.

  Another object of the invention is to

  propose a disk player to reproduce

  from a disc with a recording track.

  spiral recording, this player being able to perform a

  search operation in a relatively short time.

  and an almost constant time regardless of the dis-

  between the position of the disk where the playhead is at the beginning of the search operation, and the

  desired position on the disc until the posi-

  the reading head must be moved

  Another object of the invention is to

  setting a disk drive to reproduce information from a disk carrying a spiral recording track, which player performs a retry operation in which the read position is set to

  the disc by a playhead is moved with

  decision to reach a desired position on the disc.

  The invention thus relates to a disk player for reproducing information from a disc carrying a spiral recording track 9 this disc player having a read head for reading a signal recorded on the spiral recording track a stepper motor controlled by pulses applied to it so that the read head is animated with successive stepwise movements according to the radius of the disk in response to the pulses provided 9 a counter

  set to zero when the reading head is set to the

  starting end of the spiral recording track

  and producing first position data representative

  both the position of the reading head on the disk by counting the pulses used to drive the motor

  not pass and a commnrde circuit that produces se-

  position data, representing a position on

  the disk specified by a position designation signal.

  reading, which determines the resulting data

  corresponding to the difference between the first

  position and the second position data and which produces the pulses used to rotate

  the stepper motor in response to the resulting data.

  In a search operation carried out by such a reader

  drive, the stepper motor is controlled in

253 Z 460

  response to the impulses produced by the

  and therefore, the position of the head of

  ture on the disc is moved to approach the

  specified by the position designation signal.

  reading position, and after having approached the position specified by the read position designation signal the position of the read head is moved in a detailed manner by a precise command using

  address information reproduced from the

  that in order to reach the position specified by the signal

  of reading position designation.

  Thanks to the arrangement described above, the disk drive according to the invention is not obliged to reproduce the address information from the disk and to perform operations according to the address information reproduced during the period. in which the

  position of the read head is moved by the mo-.

  step to approach the position specified by the read position naming sig nal in the search operation and therefore

  this approach period can be made very short.

  As a result, the time required for the search operation becomes relatively short.

  given that the movement of the position of the head of

  the stepping motor is done at high speed and

  that the duration of the approach period is almost constant

  regardless of the distance between the position o

  find the playhead at the beginning of the replay operation.

  search and the position specified by the designating

  playback position, the search operation can

  be carried out in a relatively short time and

  constant regardless of the distance between the posi-

  reading head and the specific position of the

  linked by the read position designation signal.

  Other features and advantages of the

  will be better understood when reading the description of

  following statement of an example of achievement and

  FIG. 1 is a simplified diagram of an embodiment of a disk drive according to the invention, and FIG. 2 is a flowchart used to explain the operation of the embodiment of FIG.

Figure 1.

  FIG. 1 represents an essential part of an example of a disk drive according to the invention,

  lo constituted as an optical disk drive for reproducing

  information from a digital sound disk According to Figure 1, a disk 1 is placed on the

  optical disk drive, which, like the nimble disk,

  its mentioned above carries program information including sections saved with

  address information in a recording track.

  in a spiral with a predefined recording format

  completed, and a table of contents recorded in the

  turn inside the track, this disc being set

  The spiral track on the disk 1 is formed for example by the alignment of small cavities formed in response to a digital signal modulated by the program information and the information of the address, so that the digital signal is optically read in the spiral recording track by an optical head 2 functioning as a reado head

  The optical head 2 projects a light beam, for example

  of laser light on disk 1 which receives the

  light intensity modulated beam in response to the spiral recording track of disk 1 and reflected by this disk, on a photodetector which is in the

  head to produce a digital output signal read over-

  Thus, the position of the disk 1, which receives the light beam from the optical head 2, constitutes the reading position formed on the disk 1 by the optical head 2. The optical head 2 also contains a tracking device. intended to maintain the light beam directed on the disc 1 in correct alignment relation with the spiral recording track followed This tracking device is controlled by a tracking control circuit 4 connected to the output of a circuit 3, in which a tracking error signal is produced at the output of a photodetector which is in the optical head 2, so that a slave tracking is

performed.

  The optical head 2 is moved by a motor not

  step 5 in the direction of the disc radius 1, that is,

  say the direction perpendicular to the recording track

  The stepping motor 5 is arranged to

  be driven by impulses and, from a cir-

  motor control furnace 7 to which a pulsed signal P s and a direction control signal Pd are applied

  from the output terminals t e t 2 of a communication circuit

  1 t 2 control 6 respectively, a drive signal whose polarity is determined according to the polarity of the direction control signal, is applied to the stepper motor 5, when each pulse forming the signal

  pulsed Ps is applied to the motor control circuit 7.

  This means that the motor 5 operates step by step under the effect of the pulses of the pulsed signal P to turn s

  in the direction determined by the control command signal

  Pd 'Under the effect of the stepwise rotation of the motor, the optical head 2 performs successive steps following the ravon of the disk 1, in the direction of the inner turn of

  the spiral recording track to the outside

  of this track, or vice versa, depending on

  the positive or negative polarity of the control signal

  In this case, the optical head 2

  this from a constant distance with each step on the disc 1

  and moves from the inner turn to the outer turn

  or vice versa, for example by four thousand successive steps

  An up-down counter 8 with a clock terminal

  CK box, a counting terminal and U / D decounter a standby terminal CR and a CO output terminal is provided and the pulsed signal Ps and the signal co: mnande

  direction Pd from the control circuit d 9

  seems 6 are also applied to the clock terminal

  CK and at the U / D counting and down counting terminal

  In addition, the output of an end detector 9

  tee of reproduction start is applied to the terminal

  of resting CR The detector 9 of the end of de-

  The reproduction portion detects the optical step 2 located at the start end for reproducing the disk 1, for example by mechanical or optical contact with an engagement portion mounted on the optical head and producing the detection output signal. With this arrangement, the up-down counter 8 is set to

  rest by the crimp signal of the detector 9 d 1

  playback start tee when the optical head 2 is located at the start end to reproduce the disc 1 and then counts or counts down the positive or negative polarity of the direction control signal Pd each time a pulse forming the pulsed signal

  P is applied to it, the stepping motor 5 being

  it is processed by the pulsed signal Ps and the direction control signal Pd so that the optical head 2 effec-c kills successive steps. Therefore, the counting output at the output terminal CO of the counter-counter 8 represents the distance between the end starting of the reproduction of the disc 1 and a position of this disc which is currently the optical head 2 in

  the direction of the disc radius and this count is used

  as position data dp representing the posi-

  Optical head 2 on the disk 1 The dp position data thus obtained at the CO output terminal

  of the up-down counter 8 are supplied to a terminal of

  nl of the overall control circuit 6.

  The output signal of the photodetector

  located in the optical head 2 is applied to a cir-

  cooked 10 rumen signal detection and the digital signal read on the spiral recording track of the disc 1 appears at its output terminal This signal

  digital is applied to a decoder 11 and the information

  reproduced program statements Sp, the reproduced output information of the address contained in the Q-channel

  mentioned above, ie the address information re-

  produced and the table of contents reproduced

  decoder II when the disk drive

  in the normal reproduction mode The reproduced program information S is supplied to a program processing circuit 12 and

  a reproduced sound signal A appears at its output terminal.

  The replicated address information Q 'is

  plotted to a decryption circuit 13 and data from

  time TQ corresponding to the time represented by

  time address formations which are in the reproduced address information Q 'are obtained at

  decryption circuit 13 and applied to a terminal of

  N 2 of the overall control circuit 6 In addition, the table of contents reproceded is provided at a terminal

  input N 3 and it is stored.

3:

  The output t 3 of the control circuit 6 is

  connected to an input end of a circuit 14 genera-

  jump pulse generator and a jump pulse PJ produced by the jump pulse generator 14 is applied to the tracking control circuit 4 when

  the jump pulse P is applied to the circuit 4 of com-

  In pursuit, the tracking device in the optical head is controlled in response to

  the jump pulse Tj to move the position of iec-

  on the disk 1 by the optical head 2, rapidly along a path transverse to each turn of the

  spiral recording track, so that the posi-

  reading of the optical head 2 performs an operation

  In this track skip operation, the number of turns of the spiral recording track that are skipped by the reading position of the optical head 2 and the direction of the jump movement are determined respectively. by the duration of imapulsions and the polarity of the jump pulse Pj The output of the tracking control circuit 4 is also used

  by a low-pass filter 15 to an input N 4 of the circuit

Cooked Set Control 6.

  In addition, a control signal generating circuit 16 is connected to an input N 5 of the set control circuit 6 and a given control signal is applied to the input N of the control circuit 6 by the generator circuit. command signal 16 when this

last works.

  When the runway reader made

  written above performs a search operation 9 a read position designation signal I, which is

  one of the control signals from the general circuit

  16, is applied to the input 5 of the overall control circuit 6. The signal I of

  reading position designation is arranged to spe-

  specify a position on disk 1 with for example a

  section number of program and data information

time.

  The operation of the doenn control circuit appears to be 6, in the case where the read position designation signal I for the search operation is applied thereto is described with the operation

  other circuits and parts connected with the cir-

  command line 6, referring to the organization chart of the

Figure 2

  If we assume that the position on the disc 1

  is defined by the information section rumorp

  gram representing the same section of information and that the time address information representing x minutes

  and y seconds are designated by the sign I

  reading position, first at phase C 1, time data Ti representing the elapsed time in the reprocession distance from the starting end to reproduce the position specified in the normal reproduction mode are In these calculations, the reproduction time of x 0 minutes and YO

  seconds that must be passed in the distance of repro-

  duction after the starting end to reproduce

  For the purpose of the same program information section recorded on the spiral recording track in normal playback mode, is obtained using the reproduced table of contents which has been previously supplied to the control circuit 6. together by the input terminal N 3 and which has been memorized and the time of

  X minutes and Y seconds that must pass in the dis-

  Reproduction rate from the start end for reproduction to the specified position in: normal reproduction mode is obtained by adding x minutes and v seconds to x min and yo sec. The data

  representing the time of X minutes and Y seconds are used

as time data Ti.

  Then, in phase C 2, the time data Ti is converted into position data di of the same type as the position data dp obtained at the output.

  O O of the up-down counter 8 In general, the time T-

  elapsed in the breeding distance from the former

* starting point for reproduction up to a certain

  position on disk 1 in the reproduction mode

  normal and distance L from the extremity of de-

  part for reproduction up to a certain position on disk 1 along the radius of this dic satisfy the relation expressed by the equation: Lx = f (T x) + kof (Tx) is a function of Tx and k is a constant

  * and therefore the distance Li corresponding to the

  Time equations T are obtained according to this equation, and the position data di are obtained by representing the distance Li by data of the same type as the data.

db position.

  In phase C 39 the position data di is compared with the position data dp supplied by the input terminal N 1 from the up-down counter 8

  to produce the resulting data of correspon-

  1-p dant to the difference between the position data di

  and dp The resulting data di p represent the dis-

  from the position of optical head 2 on disk 1 and the specified position in the direction of

  radius on disk 1 In phase 04, the number of

  pulses forming the pulsed signal Ps supplied to the circuit of

  motor control 7 and the polarized control signal

  of direction Pd also applied to the com-

  motor 7, necessary to move the head op-

  2 to the specified position are calculated on the value of the resulting data di-po A'la phase C 5,

  the pulsed signal P containing pulses the name of which

  s bre was calculated at phase T 4 and the direction control signal Pd having the calculated polarity at phase C 4

  are produced and applied to the control circuit of the

  7 and down-counter 8, from the terminals of

output t 1 and t 2 respectively.

  With the pulsed signal Ps and the signal of com-

  Pd direction command thus applied to the motor control circuit 7 and up-down counter 8 from the overall control circuit 6, the stepper motor operates and rotates the number of steps corresponding to the number of impulsions of the pulsed signal Ps in the direction of rotation determined as a function of the polarity of the direction control signal Pdi therefore, at the phase M1, the optical head 2 is moved by a number of steps

  successive numbers corresponding to the number of pulses of the

  pulsed pulse Ps according to the radius of disk 1, in the di-

  from the starting end for reproduc-

  to the terminal end for reproduction of the disk 1 or reciprocally in response to the polarity of the steering control signal P so as to

  Approach the position specified for DIC 1. At the same time, the meter-depressor 8

  count or count according to positive or negative polarity

  the direction control signal Pd each law that a pulse of the pulsed signal ps is applied to it to produce the position data d representing P the position of the optical head 2 on the disk 1, position now reached after the movements not at not successive. Then the disk drive is placed in the

  normal reproduction mode and, in phase C 6, the

  times of time Ti for the position specified on disk 1 are compared with the QC time data provided

  input terminal N 2 to produce the resulting data.

  corresponding to the difference between the data

  Ti and TQ time data The resulting data Ti Q re-

  show the difference between the reading position of the optical head 2 and the position specified on the disc 1 1. The decision phase D 1 checks if the time Ui Q represented by the resultant data Ti Q is shorter or equal to a predetermined time U 1, for example one minute If the time Ui Q represented by the

  resulting data Ti Q is greater than the predefined time

  completed Q 1, the number of pulses forming the signal

  pulsed P and the polarity of the control command signal

s

  which are necessary to move the optical head

  that 2 up to the specified position are again calculated

  based on the resulting Ti-QS data at phase C 7 and then the pulsed signal Ps containing the number

  of pulses calculated in phase C and the signal of com-

  Pd direction command having the calculated polarity at phase C 7 are produced and applied to both the motor control circuit 7 and the C-phase 8 up-down counter 8

  With the signal P and the control signal

s

  management team Pd again applied to the com-

  motor 7 and the down-counter 8 by the cir-

  cook of assembly control 6, the stepper motor 5

1.5

  by turning step by step, a number of steps corresponding to

  for the pulses of the pulsed signal P in the direction of rotation determined in response to the polarity of the direction control signal Pd and consequently, in the phase M 2, the optical head 2 is again displaced

  several additional steps, the names of which

  corresponds to that of the pulses of the pulsed signal P s according to the radius of the disk 1, in the direction from the starting end for the reproduction until the terminal end of the reproduction on the disk 1, o

  reciprocally, in response to the polarity of the

  direction command Pd so as to approach the posi-

  specified on disk 1 In addition, and simultaneously

  the down-counter 8 counts or counts down according to

  the positive or negative polarity of the position control signal Pd is applied each time a pulse of the pulsed signal PS is applied thereto to produce at position data d representing the position of the optical head P on the disk 1, after successive steps

additional.

  In phase C 9 1 the time data Ti p r the

  position specified on dic 1 are compared again

  calf with time data TQ to produce data

  resultant Ti Q corresponding to the difference between time data Ti and T Qo

  Then in phase Cd the amplitude and the

  tracking operation of the read position of the optical head 2, which are necessary for

  that this reading position of t 4 te 2 reaches the po-

  the desired section are calculated on the basis of

  tents Ti Q and a control signal J representing the am-

  plitude and direction of the jump operation

  runway is applied to the pulse generator circuit 14

  jumping from the output terminal t 3.

  Moreover, if the time Ui Q represented by the resultant data Ti-Q is shorter than or equal to the predetermined time U 1 as a result of the control of the phase

  decision D 1, phases C 7, C 6 and C 9 are skipped.

  With the control signal J supplied by the cir-

  6, the jumper pulse generator circuit 14 produces the jump pulse PJ and applies it to the tracking control circuit 4 and therefore the reading position of the optical probe 9. 2 is controlled to perform the jump operation of the determined amplitude and direction and in response to the control signal J so as to approach

  more closely to the position specified on disk 1.

  In this case, the output signal of the tracking control circuit 4 is also applied by the filter

  low pass 15 at the input N 4 of the drive control circuit

  seems 6 and therefore the stepper motor 5 is

  to make the optical head 2 perform the stepwise movements necessary for the operation of the track

  the reading position of the optical head 2.

  In phase C 11, the time data Ti for

  the position specified on disk 1 are again

  trimmed with the time data TQ to produce the resulting data Ti Q corresponding to the difference iQ between the time data Ti and TQ Then, the decision phase D 2 checks the time if the time Ui Q represented by the data of resulting time Ti Q is shorter or equal to a predetermined time of permissible error UO If the time Ui Q represented by the resulting time data Ti Q

  is shorter or equal to the predetermined time of error

  On the contrary, if the time Qi Q is greater than the predetermined time of permissible error UO, the operation of the phase C 10 and that of the phase Cil and the control 8 of the decision phase D 2 are repeated until the time Ui Q is shorter or equal to the predetermined time

permissible error T 0.

  As has been described above, when a position on the disk 1 is specified by the read position designation signal I, first of all the

  position data for the position specified in the

  1 are compared with the position data of the optical head 2 and the stepping motor 5 is controlled in response to the difference between these position data.

  for the optical head 2 to move quickly and to

  close to the specified position Then, the difference between the specified position and the 'reading position of

  the optical head 2 after its rapid movement is de-

  tected and the reading position of the optical head 2 is controlled to perform 11 track jump operation

  in response to the detected difference so as to approach

  closer to the specified position O After the track skip operation of the playback position of optical tape 2, the search operation is complete

  when the reading position of the optical head 2 has

  colors the specified position with a permissible error

  An embodiment of the invention adapted

  to be used with a digital sound disc was de-

  writing; above with regard to the drawings but it is well

  tense that various modifications can be made by those skilled in the art without departing from the frame or the spirit

  inventions and that a disk drive according to 1 linven-

  may also be adapted to reproduce information

  from any record-bearing record track.

  spiral recording, other than a digital sound disc.

Claims (4)

  1 Disk drive to reproduce   infonrmations from a disc bearing a   spiral recording S comprising a reading device   to read a signal recorded in the recording track.   spiral recording on the disk, characterized in that it comprises a reading position displacement device comprising a reading device (5, 7) driven by pulses provided to it so that said reading device (2) performs successive stepwise movements according to the radius of the disk in response to the pulses provided, a counter (8) which is quiescent when said reading device (2) is located at the starting end of the   spiral recording track on the disc and produces   first position data representing a position of said reading device (2) on the disk by counting pulses used to drive said reading device (5, 7) and an overall control circuit (6). comprising a device for producing second position data representing a position on the disk specified by a   reading position designation signal, a   tif to obtain resultant data corresponding to the difference between the first position data and the second position data, and a device for producing the pulses used to drive said reading device displacement device (5, 7) in response to resulting data, said circuit of   overall control (6) providing the pulses pro-   said device (5, 7) for displacing   reading to train it and thus shift the posi-   said reading device (2), with the movements   step by step so as to approach the posi-   on the disk specified by the designation signal reading position.   Disk reader according to claim 1, characterized in that said set control circuit (6) further comprises a device for producing a direction control signal which determines the direction of successive stepwise movements of said reading device. (2), and which applies to said reading device (5, 7). Disk drive according to claim 2,   characterized in that said device (5, 7) for displacing   reading device includes a motor   (5) which causes the said movements not to succeed   if Is udit device 'reading (2) and a circuit of com   command (7) which controls said step motor (5) in response to   impulse and control command signal   provided by the said control circuit overall (6).   Disk drive according to claim 1,   characterized in that said control circuit of Iven-   (6) further comprises a device for producing   a control signal used to trigger an operation   track jump required to move the position   reading device (2) so as to reach   the position specified by the designation signal of   reading position after the step-by-step movements   cessives of said reading device (2) have been executed.