TW211619B - A disk recording system and a method of controlling the rotation of a turntable in such a disk recording system - Google Patents

Abstract

A disk recording system for disks such as videodisks or compact disks has a turntable (2) on which the disk (1) is supported adjacent a recording head (10). A shaft (3) defining the axis of rotation of the turntable rotates in a bearing (4) and that bearing (4) is itself movable about an axis defined by another shaft (8). The bearing (9) of the shaft (8) is an air bearing and there is a damper unit (18) for damping that movement. There may be a sensor (14) for detecting the rate of rotation of the shaft (3) defining the axis of rotation of the turntable (2). The radial displacement of the head (10) relative to the axis of the turntable (2) may be determined on the basis of rotation of the other shaft (8), and the rotation of the turntable controlled on the basis of the product of signals representing the radial displacement and the rate of rotation of the shaft (3) respectively.

Description

A6 B6 211619 V. Description of the invention () The present invention is related to the recording system for recording a disc (such as a CD). The invention also relates to a method of controlling the rotation of a turntable relative to a recording head in a disc recording system. In many known systems, the information is recorded on a disc-shaped medium and can be played later. Usually the information is placed on the disc's circular ring or disc's continuous spiral track. The former device, such as a magnetic floppy disk or hard disk, in which the information is stored on the concentric magnetic tracks. The latter device includes, for example, a traditional record that stores analog audio information on a spiral groove on its surface, and an optically read video that stores analog video data in a series of spiral-shaped concave holes on the disc surface (or an interface boundary) Discs, Μ and Μ—optical spy for storing digital sound or other digital information in a series of spiral concave holes. Records, video discs, and CDs are media that consumers can use but usually cannot record; the method is to first record information on a disc, and then copy the disc in a different process, so that these are consumed The copy disc purchased by the user is similar to the main disc in shape and data content. The process of recording data on any such media usually has its commonality, that is, when the recording head (may be a magnetic head, a stylus, or a focused beam) Μ—the slower rate is within the disc H or the main disc When moving between the rim and the outer edge, the disc usually rotates at a speed between 16¾ rpm (for some records) and 1,800 rPm (or even higher for some video discs). One of the necessary conditions of the record system is that if the rotation of the disc changes, it can only be changed slowly; and this change can usually be easily determined by the inertia of the disc itself and the rotation of the disc. Institutional acquisition. However, the radial movement of the recording head on the disc is not so easy to control. The Chinese national standard (CNS> A4 specifications (210 X 297 gong)) is used for the paper size of the disk for notebooks --------------- J ------- ^ ------. 玎 ------ «**,--(Please read the precautions on the back before writing this page) Printed by the Staff Consumer Cooperative of the Central Standards Bureau of the Ministry of Economic Affairs 3 A6 211619 _-_ B6 5. Description of the invention () (Guess to read the precautions on the back before filling in this page) When recording, the recording head usually has to move in a discontinuous phase between different concentric tracks; as for singing Η, video discs or CDs are the same On the contrary, the recording head must be moved continuously in the radial direction of the disc in order to place the data on a spiral track. At the same time, the special feature of such discs is that the smoothness of radial movement is more important than the absolute accuracy of radial positioning. For example, for a record, when playing the last recorded copy, if any radial movement has the effective energy of the audio band, even if the movement is only a small part of the average slot pitch, it will also become one of the phonograms corresponding to the lateral direction Moving, the result is that the recorded audio sounds like a noise. As for video discs and CDs, it is not only recorded Any sudden radial movement of the head may prevent the player from moving along the track on the final disc, while the possibility of heavier weight is that such movements are dangerous because they will occur between successive rotations of the spiral track The pitch of the display is changed. Since this pitch is usually only 1. 6 ~ 1.7 Mm, and any reduction in pitch will increase the crosstalk between tracks (leading to the video disc's picture interference, or increase CD bit error is possible), so I hope that the track spacing should be maintained within a tolerance range of ± 0.13, and it is better to be smaller than this value. The printing is usually based on As soon as the recording head M is moved linearly (radially) through the disc shaft, the desired radial rail movement is obtained. When recording the master record, the radial movement is usually obtained by rotating a guide screw and a nut to move the installation The recording head on a linear slide or rolling fixture. Careful and reliable engineering technology can obtain satisfactory performance; the lead screw drive is hard enough to overcome the residual grinding force during installation. Record the main video disc and the main CD Can be used Similar technology, where the light that produces the focused beam moves above the rotating main disc. To avoid some of the light being movable and the rest must be fixed (due to the size of the light source, the paper size is applicable to the Chinese National Standard (CNS) A 4 specifications (210 X 297 mm) 211619 Ministry of Economic Affairs Central Standards Bureau Beigong Consumer Cooperative printed 5 clothes A6 B6 V. Description of invention () It is usually a laser), you can use a lead screw to move the entire value turntable ( Carrying the main disc) and its rotating bearings along a straight line, so that the recording head remains stationary. For long-playing optical video discs or discs used to store digital sounds or other digital data, first-class linear speeds are usually used The mode or recording method, because it can make the maximum recording time consistent with the lotus at the best linear speed (determining the bandwidth of the recordable signal) during the entire recording process. However, linear speed recording will increase the complexity of the system. Degree, because neither the rotational speed of the disc nor the radial movement speed of the recording head or playback head relative to the disc is constant. This is not a big problem for a system that can only play, because the rotation and radial movement are usually controlled by the server and managed by the data on the disc. The recording / playback system of pre-slotted discs (such as reading / writing data recording system) can also use this type of server to achieve constant speed recording. However, for a video disc or CD master record system (where there is no groove structure at the beginning of the master disc), there is a problem when generating the required motion according to the first rule. If the data is recorded at a linear velocity V on a spiral track with a pitch P, at the same time, the instantaneous radius at time t is R and the rotation speed is ω (radians / sec), ω = v Equation 1 Η and 5? Equation 2 This paper The scale is applicable to the Chinese National Standard (CNS) A 4 specifications (210 X 297 gong) 5 --------------- ^ -------- installed ------ Order ---- 1 -line (please read the notes on the back before filling in this page) A6 B6 Five 'Invention Description printed by the Employee Consumer Cooperative of the Central Standards Bureau of the Ministry of Economic Affairs () ⑴After substituting ⑵, welcome = Pv_ Equation 3

dt 2 ^ R EP-A-01 1495 shows that for a concentric data track with more than a circular value, a signal dependent on the radius β can be generated, and one of which is inversely proportional to the radius R The frequency of the AC signal obtains a device having the relationship of Equation 1. Then the angular rotation speed ❺ of the turntable is synchronized with the AC signal. A lead screw drive is used to control the radial velocity in Equation 2 with the same AC signal ^. A similar method is also described in EP-Α-011493, where the M-digit segmentation process generates an AC signal whose frequency is inversely proportional to the radius R. We can find that the methods disclosed by EP-Α-011495 and EP-Α-011493 both need to generate an AC signal, and the rotation of the turntable must be synchronized with it. As described above, either the recording head or the turntable bearing can be made as a moving element. However, no matter which one is a moving component, for a main video disc or a CD main disc, a large lead screw drive system is not completely satisfactory due to the large lotus smoothness required. Therefore, it is necessary to use a very precise ground lead screw. However, the sticking or sliding of the lead screw mechanism will cause significant problems. If a drive mechanism other than the lead screw is used, its hardness is usually lower than that of the lead screw. Then the smoothness of the radial rail movement mainly depends on whether the bearing reaches a minimum friction when the recording head or (in this case) the turntable bearing unit moves. According to a first aspect of the present invention, the mounting method of the recording head and the turntable is such that the shaft of the turntable can move according to the direction of movement defined by an air bearing. The paper size of the recording head is in accordance with the Chinese National Standard (CNS) A4 specification (210 297 mm) 6 (please read the notes on the back before writing this page) $ * 言 A6 A6 Printed 5 garments of the Beigong Consumer Cooperative of the Central Standards Bureau of the Ministry of Economic Affairs —_B6_ V. Description of invention () Move. The advantage of using this type of air bearing is that it can provide very low or substantially negligible friction in the direction of movement, while having greater rigidity in movement in other directions. In order to control the relative movement between the recording head and the turntable bearing assembly, it is not difficult to keep the maximum advantage of using a frictionless air bearing to support this movement (moving recording head or moving turntable bearing assembly) * The driving mechanism itself must not add friction . There are many frictionless devices that generate relative motion, such as the use of a motor with a current coil mounted in a magnetic field, or a movable permanent magnet with a variable magnetic field acting on it, or a moving alternating magnetic field on a movable Induction motors or hysteresis motors with conductive or ferromagnetic components. Usually such sensing devices have a common property, that is, they respond to a control signal by applying a controllable force to the movable element; however, when applying force to a movable component mounted on an air bearing, Since the mechanical properties of the moving element on the frictionless bearing are mainly affected by inertia, such a driving device does not make actions such as determining the position of the moving element *, but only determines its acceleration. This mechanical performance is the opposite of the lead screw mover, which is harder and directly determines the position of the movable element. Therefore, another suitable device needs to be used to control the position of the movable element. The position-sensing device detects movement, plus an amplifier that responds to both the wheel-out M of the position-sensing device and an externally supplied control signal. Controlling the relative movement between the two components is well known in the art The wheel output of the amplifier is sent to the control input of the generator or other drive device, so that the movement result can be limited according to the externally supplied control signal. In other words, this paper standard is applicable to China National Standard (CNS) A 4 specifications (210 X 297 public) ---------------- | -------- ------ book ---- J ^ «Μ (Jing first read the precautions on the back and then fill in this page) A6 211619-B6 V. Description of invention () (please read the precautions on the back and then fill in this page) ) Is an A feedback servo loop. The feature of this system is that there is an upper frequency limit (or bandwidth). The movement of the components mainly within this upper frequency limit is completely controlled by the feedback loop. As for the components mainly moving at higher frequencies, the feedback loop exerts a little control . In the above-mentioned device for controlling a large assembly mounted on a frictionless bearing, the choice of bandwidth (for example, it can be easily adjusted by changing the gain of an appropriate amplifier) will be a difficult compromise. Without feedback control, a system that includes large components mounted on a frictionless bearing is very susceptible to external vibrations, because the presence of such vibrations will cause the usually “fixed” system components to move, and usually Components that are considered to be "moving" tend to remain immobile due to inertia, resulting in a relatively large relative movement between the two. If the bearing is a rotating bearing, the sensitivity to linear vibration will be reduced by balancing the moving component. However, rotating components that rotate on the bearing shaft are still sensitive to vibration. To eliminate this relative movement, the feedback loop must have a large bandwidth, which includes all frequencies of possible external vibration. Printed by the Consumers ’Cooperative of the Central Bureau of Standards of the Ministry of Economic Affairs * 1 clothing with a large bandwidth can indeed reduce the effect of external vibration on the relative movement between the" movable "and" fixed "components, but is generated by the position sensing device The influence of any noise or other fluctuations contained in the signal will be greatly increased; because the role of the negative feedback loop is to attempt to maintain the position sensing device's number as a set value determined by an external control signal, Therefore, the fluctuation contained in the reading will show the opposite sign at the actual position of the movable element. Specifically, the embedded fluctuations that fall within the bandwidth of the negative feedback loop are imposed on the actual position of the movable element. Therefore, increase the frequency of 8. This paper is also applicable to the Chinese National Standard (CNS) A 4 specifications (210 X 297 mm) A6 B6 211619 V. Description of invention () (please read the precautions on the back before filling this page) Reduce external interference, but the influence of fluctuation on the position sensor will increase. As for recording a main video disc or a main CD, it is difficult to find a suitable bandwidth that is sufficient to remove external vibrations and at the same time the uncertainty caused by the internal fluctuations is acceptable. It should be noted that the above discussion is applicable to the following two situations, that is, the wheel-out of the position sensing device directly represents the relative position of the movable part and the fixed part (therefore, the function of the feedback loop is to make the external control signal control the Relative—install · position), or the output represents the relative speed between them (in this case, the external control signal controls their relative speed). In both cases, similar considerations dominate the choice of bandwidth. Therefore, it is necessary not to rely on a high-bandwidth greedy loop when reducing the effects of external vibration. " Printed by R Industrial Consumer Cooperative, Central Bureau of Standards, Ministry of Economic Affairs. According to the first aspect of the present invention, a passive passive damping (damping) of a movable element is provided. For example, a fluid-filled retarder is used. When punching, an outer element is fixed on a fixed element (or frame), for example, and an inner element is fixed on a movable component previously installed on a frictionless bearing. The movement of the movable element provides viscous impedance. Contrary to the inertial effect which is only used to stabilize the movement of these components to an external (inertial) frame, the effect of this cobalt impedance is used to stabilize the movement of the movable component to the frame of the machine itself, so the "movable" component Compared with the relative motion between the "fixed" elements, it can reduce rather than increase any vibration of the frame. In addition, this attenuation effect is only for the passive device, so it will not be added like the A return servo loop mentioned above. Noise or fluctuation. 9 This paper scale is compliant with China National Standards (CNS) Grade 4 (21U X 297 W). 211619 Printed by the Employee Consumer Cooperative of the Central Standards Bureau of the Ministry of Economic Affairs. 5. Description of Invention () It is necessary to explain the influence and stickiness of friction Resistance affects the main difference between the two. Friction occurs when two solid parts touch, and its characteristic is that if the two parts are to slide, no matter how slow the sliding is, a force exceeding a certain critical value must be applied. The viscous resistance produced by the punch is just the opposite. It will produce resistance to the relative movement. This resistance will decrease with the relative speed of the movement to the minimum speed. Therefore, the movement rate can be easily controlled by the change of the force. An object of the present invention is to use an air bearing to eliminate frictional force, and at the same time use a damping buffer to replace frictional force with viscous resistance. To control the lotus movement of this system, a negative feedback servo loop can be used. However, because the damping buffer provides a means to reduce the external vibration, and at the same time, because the constant linear velocity (CLV) recording, the required motion speed only gradually changes with the radius of the information recorded on the disc, while the constant angular velocity (CAV) recording The speed of the lotus will not be changed, so this servo loop can have a small bandwidth (ie, a long response time) to make the internal noise generated by the fluctuations in the lotus on the position sensing device unimportant. The applicant has found that a bandwidth corresponding to a response time of 5-10 seconds is suitable. According to one development of the first aspect of the present invention, a rotary bearing is used to support an arc-shaped relative movement between the recording head and the main disc shaft instead of a linear relative movement. In a preferred embodiment, the recording head remains stationary while the turntable bearing unit moves, while the arc-shaped relative motion can produce a position where the recording head is directly positioned on the main disc shaft. This will make the data to be recorded or visible marks as close as possible to the center of the last documentary. In addition, in the preferred embodiment, the shaft of the 1 turntable bearing and the shaft of the second rotary bearing supporting the turntable bearing are both vertical (please read the precautions on the back before writing this page) • Install. Order. Thread. The size of this paper is in accordance with Chinese National Standard (CNS) A4 specifications (210 X 297 mm) Α6 Β6 2116x9 V. Description of invention () (please read the precautions on the back before filling in this page), so there will be no cause The case where the gravity moves the turntable bearing unit to the side. Allowing the recording head to move in an arc rather than a linear motion on the disc shaft may be considered inferior to linear motion in function. In fact, when recording the main record%, since it is common to play the record with a needle mounted on the swing arm, if a main needle is also used when recording the main disc, its movement is similar to the curved movement of the playback head At that time, then the distortion of the trace (due to the change in the positioning between the play head and the recording slot during playback) will be lower than the distortion caused by the linear movement. When a focused light spot is used for optical recording of "laser image" type video discs H and CD, the recording process is not overly sensitive to the positioning of the recording head to the recording groove. In addition, at least when recording video discs and CDs at a rated constant linear speed (CLV), the linear recording speed of the arc-shaped lotus shadow is negligible, even if the arc-shaped movement has an angular lotus portion on the disc The copy exists because the curved lotus motion is very slow compared to the rotating lotus motion of the main disc. Therefore, the first idea of the present invention is to provide a viscous damper buffer M in a disc recording system where the relative motion must be a steady spiral shape to attenuate and control the diameter of the relative movement between the recording head and the main disc To the sports part. Printed by the Gonggong Consumer Cooperative of the Central Standards Bureau of the Ministry of Economic Affairs, it is best that the main disc rotates faster in a first bearing and the slower radial movement of the relative motion is supported by a second rotating bearing. The radial lotus part of the relative lotus is made into an arc shape. The force generating the relative motion is preferably provided by a direct drive motor using the principle of moving coils, moving magnets, induction or hysteresis. Or the effect of the relative lotus movement is provided by a spring. The size of the 11 papers is in accordance with the Chinese National Standard (C1SS) A 4 specifications (210 X 297 mm). The A6 Β6 is printed by the Consumer Cooperative of the Central Standards Bureau of the Ministry of Economy 5. Description of the invention () The other end of the spring can be controlled by a gear drive motor assembly. The first aspect of the present invention also includes a relative spiral motion supporting the smooth spiral between the recording head and the main disc in the disc recording system, wherein the main disc rotates faster on a first bearing, The slow radial radial part of the relative head movement of the recording head and the first bearing is supported by a second rotary bearing, so that the relative movement takes the form of a circular arc. The second rotating bearing is preferably an air bearing. The turntable and bearing of the entire main disc assembly are supported by a bracket mounted on the second rotating bearing rotating body. M and the recording head are fixed. The first aspect of the present invention also includes a device for sensing the relative motion of two parts, in which a group of movable conductive elements can perform lateral motion between two sets of fixed conductive elements with reversed AC voltages, At the same time, the capacitive induced voltage of the moving element forms a phase-sensitive detector, and the other reference wheel of the detector is the alternating voltage applied to a set of fixed conductive elements, so the phase-sensitive detector can be made The dc wheel output voltage represents the relative position between the fixed element and the moving element. The relative motion to be sensed is preferably a rotary motion, while the fixed element and the moving element have a circular shape. The other voltage representing the relative rate of movement between the fixed element and the moving element is preferably obtained from the representative voltage of the relative movement between the same element. The force for generating this relative movement is preferably controlled by a linear servo amplifier whose input is the representative voltage M of the above relative movement rate and a reference voltage representing the relative movement to be obtained. Now, a second aspect of the present invention will be discussed. This paper scale is applicable to the Chinese National Standard (CNS) A 4 specifications (2i0 X 297 mm) 12 --------------- 7 ------------ -• 玎 ---- j -line * ~ 0 (Please read the precautions on the back before filling in this page) 211619 A6 B6 V. Description of invention () In Equation 3, if at time U, R = 0 , Then the following equation is obtained: R = | pv (t-tc) Is Equation 4 The following equation can be obtained from Equation 4: E_ (t-tj Equation 5 Therefore, both R and ω are nonlinear time functions. Generated from a digital computer Such time functions are possible, and then these functions are sent to a digital-to-analog converter to obtain the voltages representing the required R and ω values. These voltages are then used to control the servo system M to manage radial and rotational motion. However, This device has its drawbacks, that the obtained R and ω values must be changed in a stepped manner, and the size of these steps depends on the resolution of the digital / analog converter. A digital computer can also be used to generate a radius The value of the rate of change of R is shown in Equation 6 below: dR dt

Pv s equation 6 ---------------- 'installed ------ order 7 lines «(Please read the precautions on the back before writing this page) 4n (Economy The Ministry of Standards and Technology ’s Employee Consumer Cooperative printed this value and the ω value derived in Equation 5 can be used to derive other values and then rounded off by the digital-to-analog converter and sent to the server M to control the radial and rotational speed. A single digital-to-analog converter can be used for the two values, because they have the same time-varying relationship. The advantage of this device is that R does not make a step change, only the change rate is a step change, so the recorded at disc The impact is less serious. However, the use of an appropriate computer system means that the paper standard is the General Chinese National Standard (CNS) A4 specification (21〇X 297 mm) A6 B6 V. Description of invention () (please read first (Notes on the back will be written on this page) The increase in complexity. Therefore, the second view of the present invention is to seek the M-analog device to obtain the required R and ω relationship. Therefore, the present invention proposes to generate signals related to R and 〇> ; Then use the product of the two signals, according to the difference between the product and a reference value Control the rotation of the turntable. Generate a signal VR corresponding to the radius R, M and a representative signal proportional to the rotation speed ω. The former is preferably a voltage signal, and the latter is preferably a frequency signal. This frequency signal can be It is generated by a slotted gating disc connected to the disc recording shaft, and it can be sensed by an optical device. The signal V and the frequency signal are then combined in a multiplier discriminator circuit to produce a and R ω The product is proportional to the appropriate signal. This product can be a voltage signal, which is then compared with a reference voltage V〇 representing the desired linear velocity. The difference between these two voltages is used to drive a servo amplifier. A motor that drives a turntable in a rotating disc recording system. Therefore, according to the second viewpoint of the present invention, a servo loop can be formed to maintain the product R < y at a constant value, while being equal to the required linear speed. It can be used A separate frequency discriminator circuit derives a voltage vc representing the quantity ZTX from the frequency signal, where ρ is the required track pitch, and then the voltage ve is derived from a voltage representing the quantity The voltage vs. comparison of vR. The Ministry of Economic Affairs, Central Standards Bureau, Negative Consumers Cooperative printed the clothes and then the difference between the voltage vc and Vs is used to drive a servo amplifier. The output of this servo amplifier will cause radial motion. Therefore, the second The role of the intermediary circuit is to hold Vs = vc, so maintain the radial velocity equal to the required value of pi at 2τχ. This disc recording system is best used for video discs or chimes or data CDs. The scale is applicable to the Chinese National Standard (CN'S) A4 specification (210 X 297 mm) A6 B6 211619 V. Description of the invention () Optical recording. Now, the M example mode refers to the drawings to explain in detail one embodiment of the present invention. It is a structural diagram of a disc recording system according to an embodiment of the present invention; FIG. 2 shows a linear damper buffer that can be used in the present invention; FIGS. 3a and 3b show a first rotation that can be used in the present invention. Damping buffer, Figure 3a is a cross-sectional view, and Figure 3b is a detailed view of the damping buffer mechanism; Figures 4a and 4b show a second rotary damping buffer that can be used in the present invention, Figure 4a is a cross-sectional view and Figure 4b is the resistance A detailed view of the damper mechanism; Figure 5 shows a device using a spring to apply torque to the main air bearing shaft in one embodiment of the present invention, and a monitoring spring rotating at the other end away from the bearing shaft Device; Figures 6a and 6b show another device using a duster spring to apply torque to the main air bearing shaft of an embodiment of the present invention, and a device to monitor the strain of the spring, Figure 6a is a perspective view of the device Figure 6, and Figure 6b is a detailed view of the device shown in Figure 6a; Figure 7 shows a local servo loop, which controls the motor device of the first embodiment of the present invention in Figure 5 or Figure 6a / 6b; Figures 8a and 8b show a capacitive sensing device used in an embodiment of the present invention. Figure 8a is a cross-sectional view, and Figure 8b is a decomposition of the disc of Figure 8a. The paper size is applicable to the Chinese National Standard (CNS) A 4 specifications (210 X 297 mm) ---------------_------- installed ------ TT ----- (please read first Note on the back and then write this page) A6 B6 211619 printed by the Employee Consumer Cooperative of the Central Bureau of Standards of the Ministry of Economy V. Description of invention () (Please read first (Notes to be written again on this page) Figure; Figure 9 is a block diagram of a circuit that processes the sensing device in Figures 8a and 8b; Figure 10 shows the output change of the circuit in Figure 9; The figure shows a distribution circuit that generates another output voltage from the output of the circuit in FIG. 9; FIG. 12 shows a servo amplifier used in the present invention; FIG. 13 shows the servo for the disc recording system in FIG. 1 Figure 14; and Figure 14 shows a multiplier discriminator that can be used in the Figure 13 servo system. Figure 1 shows the general structure of a disc recording system according to an embodiment of the present invention. The main disc 1 is supported by a turntable 2 mounted on the shaft 3. The shaft 3 is an internal component of a turntable bearing 4 (or an extension of an internal component). The turntable bearing 4 carrying the turntable 2 is mounted on a bracket 5 fixed to the arms 6, 7 and the arms 6, 7 are supported by the shaft 8 of the main bearing 9. The turntable bearing 4 and the main bearing 9 in this embodiment are rotary air bearings, and their axes are vertical. Printed by the Staff Consumer Cooperative of the Central Bureau of Standards of the Ministry of Economic Affairs In addition, a recording head 10 is installed so that it can be positioned above the turntable 2, that is, above the disc 1. In this embodiment, the recording head 10 is fixed, and the relative movement between the horizontal plane of the disc 1 and the recording head 10 can be obtained by rotating the turntable 2 and moving arms 6,7. The rotation of the turntable 2 to the shaft 3 is controlled by the turntable bearing 4, and the movement of the arms 6, 7 on the shaft 8 is controlled by the main bearing 9. The positioning of the arms 6, 7 is to make the recording head 10 do 16 to the axis of the turntable bearing 4 between the center of the disc 1 and the periphery. This paper size is applicable to the Chinese National Standard (CNS) A 4 specifications (210 X 297 mm). Printed by the Ministry of Central Standards Bureau Employee Consumer Cooperative 211619 V. Description of invention () A curved path moves. The rotation of the turntable 2 with respect to the shaft 3 is driven by a first motor 11, and the movement of the arms 6, 7 is driven by a second motor 12. In this embodiment, both engines are rectified engines with permanent magnet rotors; the rotors are mounted directly on shafts 3 and 8, so no additional bearings are required. A gate 13 with a slot is also mounted on the shaft 3, and the rotation of the gate 13 can be sensed by a light sensor 14. The sensor 14 generates a square wave wheel output signal with a two-value orthogonal relationship. These output signals are used in a servo system to control the rotation speed of the turntable 2. The main bearing 9 is supported by a vertical bracket 15, and the bracket 15 supports the bracket 15 from the inside of a horizontal mounting plate 16 by the bracket 17. A damper unit 18 is attached to the mounting plate 16 and will be described in detail later. In addition, a position sensing unit 19 is installed above or in the element 33 with a groove at the top from a bracket 19a, and this unit will also be described in detail later. As mentioned earlier, the present invention requires attenuation of the relative movement between the recording head and the turntable bearing. In an embodiment where the relative motion is linear, a linear damper as shown in Figure 2 can be used to attenuate the relative motion = for linear motion, such as when using a linear air bearing, a cylinder filled with fluid can be used The way in which the M piston moves is used as this type of damping buffer. It is important for the present invention to avoid all friction; therefore, traditional sealing devices cannot be used to prevent fluid from leaking around the piston rod; it is better to replace the device shown in Figure 2 (if it is horizontally moved), plus the cover device to Prevent dust from falling into the fluid. Therefore, Figure 2 shows a piston 20 installed in the container 21, and the paper size of the container is applicable to the Chinese National Standard (CNS) A 4 specifications (210 X 297 mm) 17 '----------- ---- ^ ------- Pretend ------, 玎 ----- j marry (please read the precautions on the back before writing this page) 211613 A6 B6 V. Description of invention ( ) (Please read the notes on the back before filling this page) 21 is filled with viscous fluid 22. The piston has a bracket 23 extending from the container 21 and is fixed to an object whose movement will be attenuated. The dust cover 24 is fixed on the bracket 23 and covers the opening 25 of the container to prevent dust from entering, and the bracket 23 is inserted through the cover. However, the damping shock absorber used in the present invention is preferably a rotary shock absorber and is used together with a rotating air bearing whose axis is vertical. Figure 3a shows the construction of a damping buffer including interleaved thin ring sheets. In Figure 3a, an annular device supports a fixed damping element 31. The fixed damping element 31 surrounds a shaft 32 (the shaft 32 corresponds to the shaft 8 in the first figure, for example, so that the damping buffer corresponds to the damper unit 18 in the first circle) and a moving damping element 33 is fixed to the On the shaft. The fixed damping element 31 is fixed to the device 30 by a pressing element 34 which is pressed by a spring (not shown in the figure). As shown in the detailed view shown in Fig. 3b, the stationary blade 35 in the fixed damping element 31 and the moving blade 36 fixed on the moving damping element 31 are staggered with each other. The viscous fluid 31 is filled into the damping buffer. Figures 4a and 41> Figure 4a and 41> show another damping cushion device with staggered concentric cylindrical sections. The reference numerals of the components in Figs. 4a and 4b are the same as the corresponding components in Figs. 3a and 3b. However, as can be seen from Figure 4b, the static cylindrical section 38 is perpendicular to the moving blade. Furthermore, if this damper is used in the embodiment of FIG. 1, the shaft 32 can correspond to the shaft 8 in FIG. 1 so that the damper forms the damper unit 18. The cylindrical shape of Figures 4a and 4b is better, because it allows the movable element to be adjusted freely in the vertical direction, and its structure is easier to inject fluid without producing 18. This paper scale is applicable to the Chinese National Standard (CNS) A4 specification (210 X 297mm) A6 B6 5. Description of the invention () Foam. There is a radial gap in a set of cylindrical segments to allow the fluid to be evenly distributed. Need to use a very high viscosity fluid M to control, for example, the very slow lotus speed required during CD recording, we can easily get a suitable fluid, such as the brand of Hy Hyvis sold by BP, there are also Different viscosity supplies. To inject fluid into the structure, the fluid can be heated to reduce its viscosity. According to the present embodiment of the invention, another feature of using a rotating bearing and a rotating damper is that if the pressing device 34 is raised to loosen the entire damper assembly, the outer damper element 31 is in its device 30 The rotation can make the rapid change of the position of the movable element affected by the shadow honey. As mentioned above, the driving force for the movement between the moving part and the fixed part can be a principle using a moving coil, moving magnet, induction or hysteresis. Produced by direct drive motor. According to the aforementioned principle, the motor cannot add any friction to relative motion; this will not be difficult to achieve, as long as the moving part of the motor does not have its own bearing but is directly mounted on the rotating air bearing shaft 8. If the drive current needs to be rectified (as in the traditional moving coil d.c. motor), it must be generated electronically by any known device, rather than using a mechanical switch. Printed by the Employee Consumer Cooperative of the Central Bureau of Standards of the Ministry of Economic Affairs. In addition, it was found to be possible to apply the required torque to a moving system with a spring. For example, the distal end of a coil spring is fixed to the output shaft of a gearbox, for example. The input shaft of the gearbox is driven by a traditional d.c. motor. Obviously, even if the output shaft is held in a fixed position, the spring will exert a torque that will only slowly change when the moving part of the air bearing and the damper assembly rotate; therefore this device has a pure M passive device Production 19 (Please read the precautions on the back before filling in this page) This paper is again applicable to the Chinese National Standard (CNS) A 4 specifications (210 X 297 public goods) A6 B6 2ii6i3 V. Description of invention () Health is roughly fixed The nature of the relative motion, at the same time, can drive the gearbox M in a relatively original way to make arbitrary adjustments relative to the moving speed. Therefore, FIG. 5 shows that the shaft 8 of the main bearing 9 in FIG. 1 is connected to a spring 40, and the spring 2 is connected to the output shaft 41 of a gearbox 42 which connects the shaft 41 to an electric motor 43. It was found that placing the generator / gearbox assembly into a servo loop with a shorter response time has its advantages. To make this possible, the shaft 41 also extends to a rotary potentiometer 44. Therefore, the output signal VP of the potentiometer 44 corresponds to the position of the shaft 44. Figures 6a and 6b show another device in which the strain of the sensing spring itself drives the inner servo loop, corresponding to the components in Figure 5 shown with the same reference numbers. In Fig. 6a, the spring 45 has a flat section, and the strain piece 46 is mounted thereon. As shown in detail in Figure 6b, the strain gauge is connected to a round-out amplifier 48 via a flexible connection, and this amplifier 48 generates an output signal V P. Figure 7 shows the above-mentioned servo loop. On Figure 7, the gearbox shaft position sensor (from Figure 5) or the spring torque sensor (from Figures 6a and 6b) is labeled 50. The round signal of this sensor is sent to a split amplifier 51. The drawdown amplifier 51 also receives a control voltage VQ and generates an output 52 that drives the gearbox motor 43. Therefore, this internal servo loop makes the sensor W? Out VP change with the control voltage VQ. The signal VQ is generated by another servo loop with a slower response (to be detailed later), so the position of the gearbox output shaft is so that the spring force K and the movable element (ie the main air bearing rotor, The movable part of the damping buffer and the entire turntable bearing assembly) The speed of the lotus is determined by comparing a paper standard to the Chinese National Standard (CNS) A 4 specifications (210 X 297 public goods) 丨 · ------ ------- ^ 丨 ..''-.------- installed ------ booking. ^-(Please read the notes on the back before writing this page) Ministry of Economic Affairs Printed by the Employees ’Cooperative of the Central Bureau of Standards A6 B6 211619 V. Description of the invention () It is controlled by an external control voltage Vc and a voltage Vs representing the movement speed obtained from a position sensing device such as described below. As for the device for sensing the position of the movable part (which may constitute the sensor unit 19 in Fig. 1), it is recommended to use a capacitive sensing device as shown in Figs. 8a and Sb. As shown, the shaft 8 of the main bearing 9 carries an insulating disc-shaped rotor 60. The rotor has conductive regions 61 occupying part of the surface on both sides. The rotating piece is installed between two insulating plates 62, 63 connected to the fixed frame, and each insulating plate carries a conductive area (Α, Β) separated by a narrow gap on its inwardly facing surface. The number of these conductive areas depends on the range of rotation angle to be sensed, but the device shown in the figure has 8 conductive areas that allow a maximum rotation of 45 °. The rotor 60 carries four conductive areas on each surface, and each conductive area is 45 ° in the center, and the interval between them is the same so that the interval between the conductive areas is also 45 °. The conductive areas 61 on both sides of the rotary piece 60 are arranged together and all are connected to a conductive cylinder 65 and a flexible wire. The conductive areas on the two fixed plates 62, 63 are arranged in pairs relative to each other, and the pair of conductive areas are electrically connected. In addition, the conductive areas spaced apart from each other on the insulating plate are also electrically connected. Therefore, on the two fixed plates 62, 63 There are two groups of alternating conductive regions (Α and Β) formed on each, and each group shares an identical electrical connection. For those skilled in the art, other construction methods with equivalent functions are obvious. For example, instead of using a method of forming a conductive area on the surface of an insulating material, a fixed conductive area is formed from a metal material, or a conductive area is moved, or two In particular, a free-standing metal block is formed for all moving conductive areas. Then apply equal and inverted AC voltages (VA and VB) to the two sets of fixed conductive areas. These voltages are preferably square wave amplitudes. For example, the paper size between the two peaks is applicable to the Chinese National Standard (CNS) Grade 4 (210 X 297 mm). · -------------- J ------- ^ ------, 玎 ----- 'Wei * V (Please read the precautions on the back before filling out this page) Printed by Beigong Consumer Cooperative, Central Bureau of Standards, Ministry of Economic Affairs A6 B6 printed by the Employee Consumer Cooperative of the Central Bureau of Standards of the Ministry of Economy V. Description of the invention () The amplitude value is 30 volts. Due to the capacitance between the conductive areas on the rotating disc 60 and the conductive areas on the fixed plates 62, 63, an AC voltage is generated in the conductive areas on the disc 60, and its waveform is applied to the fixed plates 62, 63. The voltage waveforms of the conductive areas are similar, and the size and phase depend on the azimuth positions of the conductive areas on the rotating disc 60 and the conductive areas on the fixed plates 62, 63. This voltage can be buffered by, for example, a low gain and high input impedance lotus amplifier connected by flexible wire 64 (with optional amplification) and generated to a phase sensitive detector (mainly by a multiplier and Followed by a low-pass filter), and the reference input of this detector is the waveform shown in Figure 9 applied to a set of fixed conductive areas. Thus the phase-sensitive detector can get a d.c. output, which represents the orientation of the moving conductive area relative to the fixed conductive area (0). It is easy to display d.c. The voltage is proportional to CA + cb, where cA & cB is the capacitance between the movable conductive area and the two sets of fixed conductive areas. If the disc and the fixed plate are always flat and parallel, these capacitances will be proportional to the heavy day area between the movable conductive area and each fixed conductive area. If these conductive areas have circular inner and outer edges, then these areas are linear functions of the azimuth angle θ, and CA + CB is a constant. Then we can see that d.c. voltage V, except at the approach points (ΘΑ and ΘΒ) (where the rotating conductive area is aligned with the two sets of fixed conductive areas) is roughly a linear function of zero. Figure 10 shows the relationship between the conductive area and Θ when the center is at 45 °. Due to its symmetrical structure, the sensing device shown in Figures Sa and 8b conforms to the Chinese National Standard (CNS) A4 specification (210 X 297 mm). -^ ------- install ------ order ----- ^ line (please read the notes on the back before writing this page) Printed by Employee Consumer Cooperative of Central Bureau of Standards, Ministry of Economic Affairs 2. Description of the invention () It can tolerate the situation where the rotating plate 60 is not completely equidistant or parallel to the fixing plates 62, 63. It is obvious to those skilled in the art that the rotation sensing device can be modified in various ways. For example, the number of conductive areas can be increased to make the corresponding angle less than 45. : This can increase the sensitivity, ie the rate of change with 0, but the linear operating range (θΒ-θΑ) will decrease. When the rotation sensing device is used to measure the azimuth position of a turntable bearing assembly swinging in an arc shape in the embodiment of the present invention shown in FIG. 1, although the voltage is roughly a linear function of Θ, but It is not a linear function of the distance between the recording head and the center of the main disc, so it may be opposed. This distance can be expressed as

2RC sin (Θ-θ „I where Rc is the turning radius of the turntable bearing assembly on its swing arm, but the Θ value of the recording head above the center of the main disc (assuming this system is aligned, so this position exists) At the same time, sin 1j is not a linear function of Θ. However, a geometric shape can be selected to make it linear for this purpose. For example, if Rc = 200 rara and the CD with a radius of 60 mm is recorded at the same time, then the maximum (Θ-Θ.) The value is 17 °, and at this maximum offset value, the voltage is only 0.4% different from the value obtained by the linear extrapolation of some smaller values of (θ-θ.). If necessary, the circuit can correct this Error. Usually we will find it necessary to position the rotation sensing device so that the value of% = 0 does not correspond to a zero recording radius (ie the position of the recording head directly above the turntable axis). We can add as shown in Figure 9 Appropriately select a fixed reference voltage (vQFFSET) to obtain the voltage VR with the above corresponding relationship. The paper size is universal Chinese National Standard (CNS) A 4 specification (210 X 297 gong) ----------- ---'-- „------- install ------ order ----- ^ line (please read first (Notes will be written on this page.) A6 _ B6 printed by the Beigong Consumer Cooperative of the Central Bureau of Standards of the Ministry of Economy V. Description of the invention () It has been found through experiments that using this device can obtain a very good signal-to-noise ratio, especially A second output voltage Vs can be obtained, which can suitably represent the change rate of% to be used in a servo loop to control the radial motion (in other words, represents the radial motion speed, the recording head relative to the main disc 35) dt. The second output voltage vs can be obtained by a split circuit as shown in Figure 11. Just like the vff discussed above, vs has a small error affected by the radius (this is due to the fact that in Figure 1 The shape of the swing arm of the embodiment), if necessary, the circuit can correct this error. The withdrawal performance of this circuit is mainly determined by (^ and ^, optional components {^ and (: 2, they are μ time constant is And the first-order low-pass response of RtC2 limits the high-frequency response of the circuit, so it can reduce the high-frequency noise appearing at the output. It is found in a record CD system that the radial motion is controlled in the manner described now The speed is possible. The speed is only a few microns per second. Figure 12 shows the structure of a suitable servo amplifier to control radial motion. The voltage Vs representing the radial speed is compared with a control voltage Vc representing the desired speed. The phase difference value (vs-vc) produces an ingress of the amplifier. The outgoing VQ of the amplifier controls the radial motion, such as controlling the torque applied to a rotating bearing system, which is buffered by a damping buffer For example, controlling a direct drive motor or rotating one end of a coil spring (the other end is connected to a movable element). The role of the servo system tends to maintain Vs and Vc equal. The servo amplifier shown in Figure 12 has an integral response. At the same time, by adjusting the values of resistor r and capacitor C, the total response time of the servo system can be set to an appropriate value> For example, 5 to 10 seconds. One is between the long response time and the paper standard General Chinese National Standard (CNS) A 4 specifications (2i0 X 297 mm) 24 --------------- 1 ------- -Buttons ------, 玎 ---- ^ A-V One (please read the precautions on the back and then 塡. ¾ this page), A6 B6 __ V. Description of invention () Short reaction time is good Compromise, because long reaction time will make the system stable too slow, and short reaction time will add excessive noise generated by the rotating sensor to the radial motion. Fig. 13 shows a control system for recording the system of the first CD. In the 13th circle > a radius sensor 108 generates a radius voltage VR and a radius velocity voltage Vs. Therefore, the sensor 108 can be based on information from the position sensing device 19 in FIG. 1 (already discussed in detail with reference to FIGS. 8, 9, 10, and 11). Similarly, the rotation of the turntable 2 in Figure 1 is monitored by the turntable gate 13 and the sensor 14, and the sensor 14 generates a pulse signal 102 (preferably a square wave) M representing ω and a delayed pulse signal 104. These signals 102, 104 are sent to two-value multiplier discriminators 110, 112. The first frequency discriminator also receives the radius voltage signal VR from the radius sensor 108. From the 11 and the signals 102, 104, the frequency discriminator 110 generates a voltage V, proportional to νκω. The voltage Δ1 is compared with a voltage VOH representing the required linear speed. The comparison is performed by a servo amplifier 111, and then it generates a round signal as the DC drive of the motor 11 of the rotary turntable 2. Similarly, the second frequency discriminator 112 receives the signal from the sensor 14 and also receives a reference voltage 113. The frequency discriminator 112 can generate a voltage Ve proportional only to ω from the pulse, and then compare this voltage with the representative voltage Vs approximately proportional to ^.

The difference between Vc and Vs can drive a servo amplifier 114, and the output of the amplifier 114 leads to radial motion. Therefore, the role of the second servo loop is to make Vs equal to Vc. If the sensitivity of the discriminator is carefully selected according to the ratio of the required track pitch P, then Vc can be represented as the number, so this second service loop

Ⅹ IX This paper scale is in accordance with the Chinese National Standard (CNS) A 4 specifications (210 X 297 Gongchu) ---------------'------------ -. 玎 ---- γ $ * f-(Please read the precautions on the back before writing this page) Employee Cooperative Printed by the Ministry of Economic Affairs, Central Standard Bureau Printed by the Employee Consumer Cooperative of the Central Bureau of Standards, Economy 21161 ^ 5. Description of the invention () The function is to make the radial velocity | equal to the required value. at 2n In the device of Figure 13, proper adjustment of the gain and frequency response of the servo amplifiers in and 114 is usually required. The method well known to those skilled in the art is to ensure an appropriate and correct overall response consistent with stability . In particular, the amplifier 114 may have the persistence of Figure 12 discussed above. Figure 14 shows a structure that can be used as a frequency discriminator 110. The structure of the frequency discriminator 112 is similar, in which the reference voltage 113 replaces the signal V. In FIG. 14, the electronic switch 101 is controlled by the pulse 102 from the sensor 14. The switch 101 generates a voltage signal 103 that alternates between the radius voltage VR and the ground voltage. The frequency of this signal is the frequency of the pulse 102 . The voltage transition of the signal 103 waveform causes a current pulse to flow through the capacitor 105 to a second electronic switch 106, which is controlled by the delayed gating signal 104 from the turntable gating. This delay must be less than half a cycle. The delayed gating signal 104 can be generated by a second optical sensor acting on the gating disc 13, but can also be generated by electrically delaying the gating signal 102. As a result, the delayed gating signal 104 passes the current pulse from the capacitor 105, and the gate turns alternately between the ground voltage and the input of the amplifier 107. Therefore, the average voltage h appearing at the output of the amplifier 107 is proportional to the repetition rate of VR and the strobe signal 102, so MVimVRG; is proportional to. The capacitor 115 is used to reduce the transition of the voltage ¥ 1 waveform due to the current pulse from the capacitor 105. In addition to using a reference voltage 113 instead of VR, the M frequency converter 112 is the same as in FIG. 14, the reference voltage 113 will not change with the radius, but it will be set to be proportional to the required track pitch P to obtain a representative Voltage. The size of this paper is in accordance with China National Standard (CNS) A4 specifications (210 X 297 public) ----------------------- $ ------ . 玎 ------ I „-*. (Please read the notes on the back before writing this page)

Claims (1)

21Λ⑽ Α7 Β7 C7 D7 Printed by the Central Bureau of Standards of the Ministry of Economic Affairs of the Decline Industry Consumer Cooperative 6. Patent Application No. 821 d〇573 Patent Application Application Amendment of Patent Scope Amendment Date: June 1982 1-one disc recording system, It includes a recording head (10) and a turntable (2) that can rotate on a first axis. The turntable (2) supports a disc (1) close to the recording head (10) in a rotatable manner; its characteristics are: The installation of the head (10) and the turntable (2) enables the first axis to move the recording head (10), and the movement direction of the first axis relative to the recording head (10) is defined by an air bearing (9) , And the device (18) is used to slow down the movement. 2. The disc recording system according to item 1 of the patent application scope, wherein the damping device (18) is a viscous damping buffer. 3. According to the disc recording system described in item 1 or 2 of the patent application scope, wherein the recording head (10) and the turntable (2) can move relative to each other on a second axis, which is usually One axis is parallel and has a certain distance. 4. According to the disc recording system described in item 3 of the patent application scope, where the recording head (10) is fixed, and the turntable (2) is mounted on at least one arm (6, 7), the second axis is Go through the at least one arm (6, 7) further away from the turntable (2). 5. According to the disc recording system described in item 3 of the patent application scope, wherein the air bearing (9) is a rotating air bearing and defines a second axis. 6. According to the disc recording system described in item 1 of the patent application scope, where the movement is controlled by a motor (12, 43). 7. According to the disc recording system described in item 6 of the patent application scope, (read the note on the first side ^ matters before writing this page), install. Order ·-line · this paper ^ degree is applicable National Standards (CNS) A 4 specifications (210 X 297 public goods) 211613 Α7 Β7 C7 D7 Printed by the Central Bureau of Standards of the Ministry of Economy Ｍ 工 Consumer Cooperatives-ii 6. Applying for patents to enclose the ^ motivation (12,43) through a spring (40,45) Connect with air bearing. 8. According to the disc recording flaw mentioned in item 1 of the patent application scope, there is a device for sensing the relative movement between the recording head and the turntable. The device includes a set of conductive objects connected to one of the recording head and the turntable. Elements; the second and third sets of conductive elements are connected to another object, the first set of elements can act on the second and third sets of elements; apply a first AC voltage to some of the second and third sets of conductive elements Μ and apply a second AC voltage to the remaining second and third sets of conductive elements, so that adjacent devices receive different voltages, and the first and second voltages are reversed; K and detect the first set of elements Induced voltage of the capacitor and compare the voltage with the first or second AC voltage to determine the relative position between the first set of elements and the second and third sets of elements by M to determine the relative position between the recording head and the turntable之 装置。 The device. 9. A method for controlling the rotation of a turntable (2) to a recording head (10) in a disc recording system, this method includes: generating a first corresponding to the radial movement of the recording head (10> to the turntable shaft) The signal generates a second signal corresponding to the rotation rate of the turntable (2>), generates the product of the first and second signals, and controls the rotation of the turntable (2) according to the difference between the product and a reference value. 10 · According to the method described in item 9 of the patent application scope, wherein the first signal is a voltage signal and the second signal is a frequency signal. ('Please read the notes on the business side before writing this page )-Installed. Ordered • Line. This paper scale is applicable to the Chinese National Standard (CNS) A 4 specifications (210 X 297 mm) 211613 Α7 Β7 C7 D7 Printed by S Industrial and Consumer Cooperative of the Central Bureau of Standards of the Ministry of Economy Park 11 · The method according to item 9 or 10 of the patent application scope, wherein the product is a voltage signal. 12. The method according to item 9 of the patent application scope, wherein the product of the first and second signals is generated Including generating a magnitude that is positive with the first signal The ratio M and the frequency depend on the pulse wave of the second signal. 13. According to the method described in item 12 of the patent application range, at least part of the pulse wave passes through an amplifier (107), which generates these averages representing the product Amplitude pulse wave 14. According to the method described in item 9 of the patent application scope, in which a signal corresponding to the radial velocity of the recording head is compared with the second signal, Μ controls the recording head (10) to the turntable (2 ) Radial movement. 15.-Disc recording system includes: a recording head (10), a turntable (2) supporting a disc (1) close to the recording head (10), the turntable (2) can Rotate the recording head (10); move the recording head (10) to the axis of the turntable (2). The device that generates a first signal corresponding to the radial movement of the recording head against the turntable shaft generates a signal corresponding to the turntable. Device for the second signal of the rotation rate * Device for generating the product of the first and second signals, M and the device for controlling the rotation of the turntable according to the difference between the product and a reference value. 16. According to item 15 of the patent application scope The disc recording system mentioned above, one includes (1〇5> Connected first and second gates (1〇1, 1〇6) (· Please read the notes on the ridge surface before writing this page) · —Installation · Order · Line · This paper The standard is applicable to China National Standard (CNS) A4 (210 X 297 mm). A7 B7 C7 D7 6. Patent application gate network, the first gate (101) and capacitor (105) are arranged to produce a size A pulse wave proportional to the first signal and a frequency proportional to the second signal, and the second gate is arranged to pass at least part of the pulse wave. 17. Disc recording according to item 16 of the patent application In general, the second gate (106) is controlled by the second signal, so as to pass only the unipolar pulse wave. 18. According to the disc recording system described in item 15 or 16 of the patent application scope, there is an amplifier (107) connected to the second sink (106), which generates a pulse wave with an average amplitude passing through the second gate. 19. The disc recording system according to item 15 of the scope of the patent application further includes a device for comparing a signal corresponding to the radial velocity of the recording head with the second signal, and controlling the recording head moving device based on the comparison result . (Please read the decent phonetic note ^^ before writing this page) Printed by the Employee Consumer Cooperative of the Central Standards Bureau of the Ministry of Economic Affairs This paper scale is applicable to the Chinese National Standard (CNS) Grade 4 (210 X 297 conversion)