EP0734570A1 - Dispositif d'enregistrement et/ou de reproduction comprenant une boucle d'asservissement - Google Patents

Dispositif d'enregistrement et/ou de reproduction comprenant une boucle d'asservissement

Info

Publication number
EP0734570A1
EP0734570A1 EP95929985A EP95929985A EP0734570A1 EP 0734570 A1 EP0734570 A1 EP 0734570A1 EP 95929985 A EP95929985 A EP 95929985A EP 95929985 A EP95929985 A EP 95929985A EP 0734570 A1 EP0734570 A1 EP 0734570A1
Authority
EP
European Patent Office
Prior art keywords
signal
detection signal
record carrier
detection
reel
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP95929985A
Other languages
German (de)
English (en)
Inventor
Meindert Lambertus Norg
Maarten Steinbuch
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Koninklijke Philips NV
Original Assignee
Koninklijke Philips Electronics NV
Philips Electronics NV
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Koninklijke Philips Electronics NV, Philips Electronics NV filed Critical Koninklijke Philips Electronics NV
Publication of EP0734570A1 publication Critical patent/EP0734570A1/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B15/00—Driving, starting or stopping record carriers of filamentary or web form; Driving both such record carriers and heads; Guiding such record carriers or containers therefor; Control thereof; Control of operating function
    • G11B15/18—Driving; Starting; Stopping; Arrangements for control or regulation thereof
    • G11B15/46—Controlling, regulating, or indicating speed
    • G11B15/54—Controlling, regulating, or indicating speed by stroboscope; by tachometer

Definitions

  • Recording and/or reproducing apparatus including a servo control loop.
  • the invention relates to a recording and/or reproducing apparatus for recording/reproducing an information signal in a track on a longitudinal record carrier, comprising:
  • - reel driving means including a motor for driving a reel to rotate to effect a feeding operation of the record carrier in its longitudinal direction
  • - record carrier speed detection means for generating a first detection signal in relation to the speed of the record carrier during said feeding operation
  • - signal combination means for combining said first and second detection signal and a predetermined signal which is representative of a predetermined speed of the record carrier so as to obtain a servo control signal, such that the feeding speed of the record carrier may be equal to the predetermined speed.
  • the apparatus shown in figure 46 of this publication includes an outer (or first) servo control loop which serves as a speed control loop, in which the first detection signal, which relates to the actual speed of the record carrier, is compared to the predetermined signal, which relates to the required speed of the record carrier. Further, an inner (or second) servo control loop is present in which the rotational velocity is measured and used as a second feedback signal, so as to improve the speed control of the motor.
  • the resultant servo control signal is used to supply the motor with a supply signal so as to rotate the take up reel.
  • the known apparatus is however subject to irregularities in the record carrier speed that can not be suppressed sufficiently by the known servo system.
  • the invention has for its object to provide an improved recording and/or reproducing apparatus with a better suppression capability for variations in the record carrier speed.
  • the apparatus in accordance with the invention is characterized in that said second detection means is adapted to generate a second detection signal having a relation to the radius of the amount of record carrier being wound on said reel, and that said signal combination means is adapted to generate said servo control signal such that it is equivalen to calculating a deviation between said predetermined signal and said first detection signal, and non-linearly combining said deviation with said second detection signal.
  • the invention is based on the recognition that during feeding the record carri onto the reel that is driven by the motor, the radius of the amount of record carrier wound on the said reel will change gradually from a low value to a higher value. Because of this, the servo gain changes. One would require a speed controller for the whole operating rang of the servo system. The varying gain however limits the achievable performance of the servo system.
  • the servo system can be made substantially independent of this variation, resulting in better performance of the servo system.
  • the second detection may be adapted to generate said second detection signal response to the rotational velocity of a reel.
  • Said reel may be the take up reel, but may alternatively be the supply reel, as the radius on the take up reel may be determined from radius of the supply reel when knowing the total length of the record carrier.
  • the apparatus may be further characterized in that, said second detection me is adapted to generate said second detection signal such that said second detection signal is proportional to 1 over said radius, and that said signal combination means is adapted to generate said servo control signal such that it is equivalent to calculating a deviation betwe said predetermined signal and said first detection signal, and multiplying said deviation wi said second detection signal and in that said signal combination means comprises - deviation calculation means for calculating said deviation, and
  • the second detection signal can be derived fro detection means for detecting the rotational velocity of a reel alone.
  • said signal combination means further comprises
  • - combining means for non-linearly combining said third detection signal by said first detection signal so as to obtain said second detection signal.
  • the outer loop is not capable of substantially keeping the record speed consta the first detection signal is also needed so as to obtain the second detection signal.
  • said reel rotational velocity detection means is adapted to generate the third detection signal which is proportional to the rotational velocity of said reel, and that the combining means is adapted to divide said third detection signal by said first detection signal.
  • said speed detection means include a rotatable member for contacting the record carrier so as to be rotated thereby when the record carrier is fed.
  • An embodiment of the rotating member can be as described in European patent application no. 94.201.618.9 (PHN 14,875).
  • Another realisation of the speed detecting means makes use of an additional control track on the record carrier having pulses recorded in the track. Using a reading head, the pulses can be read out and used for obtaining the first detection signal.
  • the invention is particularly applicable in an apparatus of the capstanless type as, without the servo control in accordance with the present invention, variations in the record carrier speed will be much larger in such apparatuses than in apparatuses provided with a capstan.
  • figure 1 shows an embodiment of the apparatus
  • figure 2 shows an embodiment of the servo control circuit of figure 1
  • figure 3 shows another embodiment of the servo control circuit
  • figure 4 shows a further elaboration of the servo control circuit of figure 2.
  • Figure 1 shows an embodiment of the apparatus for recording and/or reproducing an information signal on/from a record carrier 2.
  • the record carrier is a tape ⁇ like record carrier that is transported from a supply reel 8 via guide rollers 13 and 14 to a take up reel 9 with a velocity v t .
  • the direction of transport is indicated by the arrow in the figure.
  • the tape transport is realized by means of a reel motor 11 that is coupled to the take up reel 9.
  • the present embodiment is of the capstanless type. That means that no capstan and no pinch roller are available to realize the transport of the tape with the velocity v t .
  • a magnetic head 1 is present for recording and/or reproducing the information signal, such as an audio signal, on/from a track on the record carrier 2.
  • a signal processing unit 5 is available for processing the information signal applied to a terminal 6, so as to enable the recording of the information signal on the record carrier. When in a reproductio mode, the signal processing unit 5 processes the signal read from the record carrier by the head 1 so as to regenerate the information signal and to supply the regenerated information signal to the terminal 6.
  • a rotating member 21 is provided, which is in mechanical contact with the ta 2 and is rotated by the tape, as the tape is fed in one of its two longitudinal directions.
  • a tacho generator 20 is coupled to the rotating member and supplies pulses with a pulse frequency dictated by the rotational velocity of the rotating member. The number of pulses per unit of time, supplied by the tacho generator 20 is thus a measure for the transport velocity of the tape 2.
  • a tacho generator 18 is coupled to the take up reel 9 and supplies pulses wit pulse frequency dictated by the rotational velocity of the take up reel 9.
  • the apparatus is further provided with a servo control unit 22.
  • the servo control unit 22 has a first input 24 for receiving a predetermined signal v r . This predetermined signal relates to the required transport velocity of the record carrier 2. Further, the unit 22 has inputs 26 and 28 for receiving the pulses generated by the tacho generators 20 and 18 respectively.
  • the unit has an output 32 for supplying a control signal so as to control the rotational velocity of the motor 11 such that the tape 2 is transported with the required velocity.
  • FIG. 2 A further elaboration of the servo control unit 22 is shown in figure 2.
  • the u 22' of figure 2 comprises an outer loop 52 and an inner loop 54.
  • the outer control loop 5 comprises a converter 56 which converts the pulses supplied by the tacho generator 20 int first detection signal that is representative of the actual velocity v t of the tape 2. This is indicated in figure 2 by the ' ⁇ v t ' sign.
  • This first detection signal is supplied to a first inp of a signal combination unit 58, which is in the present situation in the form of a subtracto circuit.
  • the terminal 24 is coupled to a second input of the combination unit 58.
  • the inner control loop 54 comprises a converter 60 which converts the pulses supplied by the tacho generator 18 into a detection signal which is representative of the rotational velocity of the take up reel. This is indicated in figure 2 by the ' ⁇ ⁇ ' sign.
  • This detection signal is supplied via a loop amplifier 62 to a first input 69 of a second signal combination unit 64, which is in the present situation in the form of a multiplier circuit.
  • a output of the combination unit 58 is coupled to a second input 68 of the combination unit via a control unit 66 which may be a PH) controller.
  • the control system is based on the following rules.
  • the transfer function v ⁇ U, of the system to be controlled that is the system formed by the apparatus between the terminal 32 and the output of the converter 56, equals C j .R.
  • the actual value for R varies as a function of time. Therefore, the transfer function of the system varies as a function of time. Further, the actual value of R is not known.
  • the invention is based on the measure to multiply the transfer function by another transfer function which is related to 1/R, so that the total transfer function of the system to be controlled by the outer control loop 52 becomes independent of R.
  • This is realized by the multiplier circuit 64.
  • This circuit multiplies the signal applied to its input 68 with the signal applied to its input 69.
  • the signal applied to the input 69 has a relation to
  • Figure 3 shows a second embodiment. If the outer control loop 52 is not capable of keeping v t substantially constant, the formula (5) remains valid. In that case, the inner control loop 54' requires an additional signal combination unit 70 in the form of a divider. Outputs of both converters 56 and 60 are coupled to corresponding inputs of the divider 70. The divider realizes the division given by formula (5), so that the output signal the divider is related to 1/R.
  • Figure 4 shows a further elaboration of the servo control circuit of figure 2.
  • the loop filter 62 comprises the unit 7 which gives a minimum output for small input signals and has an output signal proportion to the input signal for large input signals.
  • the assumption that the tape speed is controlled correctly by the oute loop does not take into account small and relatively fast variations of ⁇ .
  • These (unwanted) variations can be filtered out by a lowpass filter 77, also included in the loop filter 62.
  • the cutoff frequency of the filter 77 is such that it does not have a disturbing effect on the loop gain in the inner loop 54.
  • the unit 62' in figure 3 comprises the filter 77 and the divider 70 must be reconditioned so as to avoid the problems explained above during start-up, so as to provide an output signal at the output of divider 70 when the input signals are zero.
  • the tacho generator 18 described above is coupled to the take up reel so as to obtain the detection signal which is related to the rotational velocity of the take up reel. It may however be possible to couple the tacho generator 18 to the take up reel motor 11. Account should be taken in this situation for the ratio between the motor rotational velocity and the reel rotational velocity.
  • the tacho generator 18 may be coupled to the supply reel. This for the reason that when having information relating to the radius of the amount of record carrier on the supply reel, it is possible to derive therefrom information relating to the radius of the amount of record carrier on the take up reel, when knowing the total length of the record carrier.
  • the divider 70 in figure 3 realizes the division ⁇ / v t .
  • the multiplier 64 should be replaced by a divider so as to realize the multiplication by 1/R.
  • the second detection signal applied to the input 69 of the combination unit 64 has been obtained from a measurement of the rotational velocity of the reel 9. It may however be possible to measure the radius R of the amount of tape wound on the reel 9 in another way, such as directly by optical means.
  • the signal combination unit 64 in the embodiments described can be moved from the position where it is shown in the figures to a position between the terminal 24 and the combination unit 58. This further requires an additional combination unit, such as the unit 64, in the outer loop 52, before the combination unit 58.
  • the total signal combination circuit of the combination units that is the units 58 and 64 and the additional unit 64, to generate said servo control signal such that it is equivalent to calculating a deviation between said predetermined signal v r and said first detection signal (which is the signal applied to the minus-input of the unit 58 in figure 2), and non-linearly combining said deviation with said second detection signal (which is the signal applied to the input 69 of unit 64 in figure 2).
  • the invention is applicable to recording/reproducing apparatuses of the helical scan type and the linear recording/reproducing type.

Landscapes

  • Control Of Electric Motors In General (AREA)

Abstract

Ce dispositif, destiné à enregistrer et/ou à reproduire un signal porteur d'information sur une piste d'un support (2) d'enregistrement longitudinal, comprend des moyens d'entraînement de bobine comportant un moteur (11) servant à faire tourner une bobine (9), afin d'effectuer une opération d'alimentation du support d'enregistrement dans la direction longitudinale de celui-ci. Des moyens (20, 21, 56) de détection de la vitesse du support d'enregistrement sont conçus pour produire un premier signal de détection en rapport avec la vitesse du support d'enregistrement lors de l'opération d'alimentation. Des seconds moyens (18, 60) de détection sont conçus pour produire un second signal de détection en rapport avec le rayon de la quantité du support d'enregistrement en cours d'enroulement sur ladite bobine. En outre, des moyens (58, 64) de combinaison de signaux sont destinés à combiner ces premier et second signaux de détection et un signal prédéterminé représentant une vitesse prédéterminée du support d'enregistrement, de manière à obtenir un signal de servocommande tel que la vitesse d'alimentation du support puisse être égale à la vitesse prédéterminée. Les moyens de combinaison de signaux sont conçus pour produire un signal de servocommande tel que celui-ci soit équivalent au calcul d'un écart entre le signal prédéterminé et le premier signal de détection, et à la combinaison non linéaire de cet écart avec le second signal de détection.
EP95929985A 1994-09-26 1995-09-15 Dispositif d'enregistrement et/ou de reproduction comprenant une boucle d'asservissement Withdrawn EP0734570A1 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
NL9420276 1994-09-26
NL9420276 1994-09-26
PCT/IB1995/000764 WO1996010252A1 (fr) 1994-09-26 1995-09-15 Dispositif d'enregistrement et/ou de reproduction comprenant une boucle d'asservissement

Publications (1)

Publication Number Publication Date
EP0734570A1 true EP0734570A1 (fr) 1996-10-02

Family

ID=19865182

Family Applications (1)

Application Number Title Priority Date Filing Date
EP95929985A Withdrawn EP0734570A1 (fr) 1994-09-26 1995-09-15 Dispositif d'enregistrement et/ou de reproduction comprenant une boucle d'asservissement

Country Status (3)

Country Link
EP (1) EP0734570A1 (fr)
JP (1) JPH09505929A (fr)
WO (1) WO1996010252A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2018235011A1 (fr) * 2017-06-23 2018-12-27 International Business Machines Corporation Commande de transport de bande avec suppression de perturbations de tension variant dans le temps

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6622113B2 (en) 2001-06-21 2003-09-16 International Business Machines Corporation Method and apparatus for detecting and computing tape reel radius using low-resolution angular position sensors
US8767335B2 (en) 2012-08-30 2014-07-01 International Business Machines Corporation Accurate radius and velocity measurement of tape transports

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5222684A (en) * 1990-03-19 1993-06-29 Matsushita Electric Industrial Co., Ltd. Tape driving apparatus for tape medium record reproducing apparatus
US5330118A (en) * 1990-11-27 1994-07-19 Matsushita Electric Industrial Co., Ltd. Tape driving apparatus
JP2615518B2 (ja) * 1991-08-13 1997-05-28 富士通株式会社 磁気テープ装置の電流供給回路及び電流供給制御方法

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO9610252A1 *

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2018235011A1 (fr) * 2017-06-23 2018-12-27 International Business Machines Corporation Commande de transport de bande avec suppression de perturbations de tension variant dans le temps
GB2578076A (en) * 2017-06-23 2020-04-15 Ibm Tape transport control with suppression of time-varying tension disturbances
GB2578076B (en) * 2017-06-23 2021-05-26 Ibm Tape transport control with suppression of time-varying tension disturbances
DE112018002025B4 (de) 2017-06-23 2023-06-15 International Business Machines Corporation Bandtransportregelung mit Unterdrückung von zeitvariablen Spannungsstörgrössen

Also Published As

Publication number Publication date
JPH09505929A (ja) 1997-06-10
WO1996010252A1 (fr) 1996-04-04

Similar Documents

Publication Publication Date Title
EP0570956B1 (fr) Appareil d'enregistrement/reproduction magnétique
EP0532238B1 (fr) Appareil de régulation de vitesse de bande
US5860610A (en) Magnetic tape tension control device
US4777413A (en) Tape speed control device
WO1996010252A1 (fr) Dispositif d'enregistrement et/ou de reproduction comprenant une boucle d'asservissement
EP0810597B1 (fr) Méthode de commande de la vitesse de la bande d'un enregistreur sans cabestan et galet presseur
EP0691641B1 (fr) Appareil de traitement de signal audio et appareil d'enregistrement et/ou de reproduction pour un support d'enregistrement en forme de bande
GB2042223A (en) Motor speed control circuits
US4095146A (en) Reel-to-reel drive with speed control
JPH0580738B2 (fr)
US4238720A (en) Equipment for the electronic speed control of an induction type motor, especially for use with data store motors
US4471272A (en) Circuit for controlling the speeds of two capstans
KR920009773B1 (ko) 테이프의 고배속, 정배속 주행용 릴모터 제어방법 및 회로
JP4130710B2 (ja) 磁気テープ装置およびその制御方法
JP2810136B2 (ja) テープ速度制御装置
EP0740302B1 (fr) Appareil magnétique d'enregistrement/de reproduction
US6301069B1 (en) Servo control apparatus utilizing clock signal and control data
JP2910396B2 (ja) 記録再生装置
JP2827508B2 (ja) モータ制御装置
KR910003016B1 (ko) Dat의 릴모우터 제어장치
EP0427530A2 (fr) Appareil d'enregistrement et de reproduction magnétique d'image
JP2810212B2 (ja) テープ速度制御装置
JP2586519B2 (ja) テープ速度制御装置
JPH03207075A (ja) テープ残量表示装置
JPH08185602A (ja) 磁気記録再生装置

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): AT DE FR GB

17P Request for examination filed

Effective date: 19961004

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION HAS BEEN WITHDRAWN

18W Application withdrawn

Withdrawal date: 19961125