WO1997033282A1

WO1997033282A1 - Device and method of controlling the playback speed of a compact disc (cd) inserted into a cd player

Info

Publication number: WO1997033282A1
Application number: PCT/DE1997/000337
Authority: WO
Inventors: Ralf Pretz; Egon SCHÜTT; Jorge Lloveras-Taschka
Original assignee: Ralf Pretz; Schuett Egon; Lloveras Taschka Jorge
Priority date: 1996-03-08
Filing date: 1997-02-26
Publication date: 1997-09-12
Also published as: DE19608958A1

Abstract

The invention relates to a device and a method for controlling the playback speed of a compact disc inserted into a CD player. To have any particular effect on the revolution speed, including reverse-order playing of the frames of a CD, it is proposed to connect the CD player to a record player (16) having a motor-driven turntable (17) in such a manner that the instantaneous turntable speed or the revolution speed of a disc (10, 18) arranged on the turntable (17) delivers the correcting variable for the CD playback speed.

Description

description

Device and method for controlling the playback speed of a compact disc (CD) inserted in a playback device

The invention relates to a device and a method for controlling the playback speed of a compact disc inserted in a playback device.

For a long time, so-called records, which consist of the unbreakable plastic polyvinyl chloride-polyvinyl acetate copolymer (PVCA), served as the carrier of mechanically stored sound information. The information lies in the deflection of a groove that runs in a spiral from outside to inside. The deflection of the groove is followed by a sapphire or diamond needle when playing. In the case of single-channel or monophonic recording, the groove is only deflected in the horizontal direction, in the case of two-channel or stereophonic recording, in each case at 45 ° to the horizontal. Magnetic systems are used as pickups in which a small magnet, moved by a scanning needle, oscillates between two fixed pairs of coils for the left and right channels. Simple turntables have pickups with piezoceramic transducers; electrodynamic pickups are used for higher demands. The record has recently been displaced to a considerable extent by the so-called compact disc, in which the sound information is stored as a digital signal that can be scanned by a laser without contact. The contactless scanning enables wear-free playback, in which disturbances such as those caused by scratches or dust on records are eliminated, as is the noise or distortion of frequency responses. In addition, the storage capacity of a CD is considerably larger than in the case of the aforementioned records, so that the recorded sound information, in particular pieces of music etc., can be accommodated on a low-volume disc. Despite the relieved Handling the compact discs has the record in the disc and transmitter area advantages that are not available with the commercially available CD players. For this reason, record players are still used in the discotheque area. However, many new music releases are no longer released as a record. Professional operators of record players replace the rubber mat usually arranged on the turntable with a felt mat in order to create a slidable surface for the record to be played. This makes it possible to change the playback speed of the record by briefly rotating or holding the record by hand against or in the direction of rotation of the turntable. On the one hand, this serves to generate deliberately distorted sound reproductions which can be carried out individually at any time. On the other hand, it enables precise manipulations which, in conjunction with the pitch control of the turntable, allow the playback to be controlled in such a way that the piece played is clock-synchronized with a piece of music reproduced from another sound source. Such manipulation possibilities are missing in the CD players, since the CD has to be inserted into a corresponding receiving compartment, which was then pushed back into the starting position before the laser installed on the device scans and processes the information stored on the CD. The playback speed of a CD can only be manipulated to the extent that the so-called "pitch" controller and "pitch bend" controller can be used to indirectly change the CD rotation speed, albeit within a narrow range.

It is an object of the present invention to provide a device of the type mentioned at the outset, with which the rotational speed, including the playback of the frames, can be influenced as desired in the reverse order of a CD. The device in question should be of simple construction and easy to handle. It is also an object of the present invention to provide a corresponding method for controlling the playback speed of a compact disc, which the operator can carry out with little effort.

This object is achieved with the device mentioned at the outset in that the CD player is connected to a turntable having a motor-driven turntable in such a way that the instantaneous turntable speed or the speed of rotation of a disk arranged on the turntable constitutes the manipulated variable for the CD player. Playback speed delivers. With this device, it is possible to use the turntable previously known from record players, which is motor-driven at a constant rotational speed, either the turntable itself or a disk located thereon in the manner known from records due to the professional operator is slowed down, accelerated or moved in the opposite direction. The changed manipulated rotation speed is transferred to the CD playback speed via a synchronization device, so that the high playback quality of the CD is used without restriction and, in addition, the manipulations previously possible with records and their playback can be carried out. Since the manipulations in question can be carried out on a turntable arranged separately from the CD player or on a disk placed thereon, the CD (like the record in the past) is not affected by the manipulations in question. The device according to the invention also includes such turntable arrangements which are integrated in the CD player with the proviso that the turntable or the disk located thereon are easily accessible by hand. However, preferred embodiments are those in which the turntable is arranged separately, because then no additional vibration-damping measures for the CD playback system have to be taken for impacts and vibrations generated by manipulations. When synchronizing the rotational speeds of the turntable or the disk arranged thereon with the CD rotational speed, it is possible to fall back on synchronization devices known in principle from the prior art. In each case, the instantaneous rotation speed of the turntable or the disc placed thereon must be measured, the deviation from the nominal value determined and this deviation converted into an electrical signal which, in a corresponding manner, reverses the rotation speed of the CD including the playback of the frames Order changes analogously.

An advantage of this type of detection is that the functionality of a turntable is in no way reduced by the installation. For example, an operator can use a turntable alternately to play a record and control a CD player without any modifications or the like. Care has been taken to ensure that the slide mat is used exactly like a conventional slide mat, that is, it is equally suitable for the use of records as well as for information transfer.

Further developments of the device according to the invention are described in claims 2 to 7.

For example, the instantaneous turntable or disc rotation speed is preferably measured and determined optically, optoelectronically, electromagnetically or electronically.

Manipulation of the rotational speed of a motor-driven turntable presupposes that the turntable is driven by a belt or a roller which can "slip" when braking or counter-rotating. However, the wear of the relevant transmission means is accepted. These and other refined slip clutches also have the disadvantage that they only delay the desired one Can set the nominal rotation speed of the turntable according to its inertia. The same applies to turntables with direct drive: if the turntable is stopped, the motor is permanently affected. It is therefore preferable to use a disk arranged on the turntable, which can be manipulated without or with only slight influence on the turntable. In order to keep the friction between the disk and the turntable as low as possible, the disk is preferably coated on both sides with slidable material, such as felt, and the turntable has a polished, smooth surface. Felt has the advantage that it is just as slippery on a smooth metal surface as the turntable surface, as it enables the disc to have a good grip on the manipulation side. The disk itself preferably consists of plastic, hard rubber or metal, such as in particular aluminum.

A determination of the instantaneous speed of rotation of the turntable or of the disk, which is as simple as it is practicable, can be achieved by the relevant markings which are scanned optically or optoelectronically. As an alternative to this, it is possible to select the disk or the turntable from electrically conductive material, a toothing, the movement of which can be electromagnetically scanned, preferably being provided on the peripheral edge over a rotation angle of 360 °. In both cases, the marking movements can easily be determined by infrared, laser or other optical transmitting and receiving devices or a Hall IC. The respective speeds of rotation are then compared with the nominal speeds of rotation, the respective manipulated variable for the CD playback speed being determined from the difference.

The advantage of the device described is that CD players that are available on the market can also be retrofitted. In this case, a corresponding control device, which is connected to the motor-driven turntable, is connected upstream of the respective CD electronics, which then controls the motor. According to a further embodiment of the invention, the turntable of the turntable is connected to a measuring device for the current rotational speed. The instantaneous values obtained from the measuring device are passed on as a manipulated variable to the rotational speed control of the CD player. This further development serves in particular to control the speed of rotation of the CD player in addition to the pitch controller present on the turntable, also by external manipulation of the turntable.

The pitch controller present in higher quality turntables according to the state of the art serves to set the turntable rotation speed to a desired value (deviating from the standard rotation speed). Such a function is always useful if the rhythm of two successive pieces is to be brought into line. In principle, the same manipulation can thus be carried out with the pitch controller as can be achieved externally by manipulation on the turntable turntable, but the controller setting in question is sometimes very tedious. The quartz control present in record players can also be used to control the rotational speed of the CD player according to the invention. The internal control loop signals of the rotational speed are passed on in the form of frequency signals, converted to binary codes which can be used as a manipulated variable for the rotational speed control in such a way that the output playback speed is accelerated or braked in each case. The control is preferably implemented in such a way that the percentage change in the speed of rotation of the turntable serves as a manipulated variable for a percentage change in the playback speed of the CD. A microcontroller is preferably used for control. The last-mentioned measure serves in particular for the purpose of achieving the synchronization of two pieces of music to be played or faded in succession. As previously described, you can either use the pitch control or manually by influencing the turntable externally, its rotational speed can be influenced. The relevant brief decelerations or accelerations lead to a frequency influencing of the reproduced sound material, commonly referred to as "lyre". In order to enable the manipulations described without "lyre", a digital signal processor known in the prior art is used, which is usually used in studio technology and which transposes an audio signal up or down on the scale by a user-adjustable value. The data taken from the turntable are forwarded to the microcontroller, which converts the transmitted data and forwards it to the signal processor as an inversely proportional manipulated variable. The signal processor is coupled to the audio output of the turntable or CD player and uses the data coming in from the microcontroller to process the audio material in real time. If the operator brakes the turntable, for example by 3%, this value is transmitted to the signal processor, which accordingly raises the frequency response of the audio signal by 3%, so that no or only a minimal, ie barely audible fluctuation in the Pitch occurs. In addition, the signal processor can transpose an output signal by means of a controller (pitch shifter) present on the device as a percentage increase or decrease, and, if necessary, correct it for this set value in the event of manipulation.

Finally, the above-mentioned microcontroller is connected to a chip for recognizing the key of the input signal. The smoothest possible transition between two successive pieces of music also presupposes that the respective keys of the successive pieces of music "match" each other. In order to avoid generally perceived disharmonies, a chip is used which is able to recognize the key of the piece of music. This chip analyzes the keys of the music pieces present as an input signal and passes this data on to the microcon- troller on. Possibly. can be carried out by the microcontroller via corresponding control commands to the digital signal processor. A display of the respective actual keys is preferably triggered. In the form of a recommendation list which is also shown on a display, the operator has the option of selecting a desired key to which the subsequent piece of music is to be transposed.

The method mentioned at the outset is carried out according to the invention in such a way that the speed of rotation of a motor-driven turntable or of a disk arranged thereon is manipulated, this change in the speed of rotation being carried out by manipulation being used as a manipulated variable for the CD playback speed. The means described above are used to carry out this method.

The control commands can be transmitted not only for CD players, but in principle for all electronic storage media, provided that they have a correspondingly short access time, e.g. RAMs, ROMs, PROMs, EPROMs, floppy disks, hard disk drives etc.

Further details and embodiments of the invention are explained with reference to the drawings. Show it

1 and 2 each schematically cross sections through a

Disk with the corresponding measuring devices for determining the rotational speed,

3 to 5 are schematic representations of a turntable connected to a CD player.

A motor-driven turntable is to be understood as a device which is known as a so-called record player according to the prior art. Is on the turntable in question a disk coated on the top and bottom with felt or similar lubricious material is arranged, which has circumferential markings which run past a measuring device during the rotating operation of the plate or turntable and the correspondingly moved, possibly manipulated disk.

In the embodiment shown in FIG. 1, the disk 10 has black and white fields 11, 12 of equal size on the circumference. A transceiver 13 emits optical or infrared signals 14, which are reflected by the fields 11 and 12 in accordance with their reflective properties and are fed as signals 15 to the receiver. From the characteristics of the reflected signals 15 and their frequency, the rotational speed and possibly the direction of rotation of the disk 10 can be determined as a function of time using methods known in the prior art. Likewise, it is possible via an electronic evaluation to determine the deviation of the rotational speed from the constant rotational speed of the turntable and to process it as a manipulated variable for the rotational speed of the CD playback speed. Rotating movements of the disk directed against the direction of rotation of the turntable can be processed in the form of negative signals compared to other positive signals with the same direction of rotation. The order in which the CD frames are played can be changed in a corresponding manner.

In an alternative embodiment according to FIG. 2, in which the turntable chassis 16 is additionally shown with the turntable designed as a turntable 17, the rotational speed of a disk 18 designed as a slip mat, which is changed compared to the turntable rotation, is determined by sensors 19, which are arranged in a corresponding holder 20. The slip mat has on its edge-side circumference 21 the markings already described, the sensors 19 corresponding to the transceiver 13. Alternatively, it is possible to electrically separate the disk 18 with the exception of the upper and lower felt pads 22 Form conductive material, such as a metal body, which has notches on the edge, which can be scanned electromagnetically, for example by a Hall IC. The notches arranged equidistantly on the peripheral edge 21, for example in the form of grooves which are rectangular in cross section, lead to different induction voltages such as the "increases" between them, so that from the voltage sequence of the voltages induced in each case to the rotational speed of the disk 18 or whose change in the speed of rotation allows conclusions to be drawn in relation to the turntable speed of rotation.

However, any other embodiments are also possible within the scope of the present invention which are suitable for determining the change in the rotational speed of a manipulated platter or a manipulated disk with respect to a nominal rotational speed and, depending on the extent of the rotational speed change which has been determined, the rotational speed ¬ control including the order in which the CD frames are played. A frame is a storage unit for the respective sound information (comparable to individual images in a film). A complete sound recording results from the entirety or the sequence of the frames, e.g. a piece of music.

FIG. 3 shows a first application which serves to eliminate pitch fluctuations caused by manipulations on the turntable or pitch controller. The turntable 30 is connected to the device 31 for equalizing the pitch via two lines 32 and 33. The line 33 serves as a "phono" line, via which the signals picked up by a pickup system of the turntable 30 are transmitted. Line 32 serves as a signal line for frequency signals which correspond to the respective current turntable speed. These signals are sent to a microcontroller 34, which is also connected to a digital signal processor 35 is like the phono line 33. A percentage change in the speed of rotation of the turntable serves in the manner described as a manipulated variable for an inverse percentage change in the frequency of the information played from the record. The correspondingly converted phono signal is given on line 36.

4 shows a further variant for controlling the CD player from the turntable, in which frequency signals output to the microcontroller 34 via a line 37 are output to a CD player 39 via an output line 38. With this variant it is possible to "manually" influence pieces of music played from an inserted CD by manipulating the speed of rotation on the turntable as a manipulated variable for the "playing speed" of the CD.

FIG. 5 shows a combination of the application examples shown in FIGS. 3 and 4, to which the same applies. In addition to the line 33, a line 40 is provided between the digital signal processor 34 and the CD player 39. Turntable (turntable) manipulations, which lead to a change in the turntable rotation speed, use line 40 as a manipulated variable for the CD playback speed.

Claims

claims

1. Device for controlling the playback speed of a compact disc (CD) inserted in a playback device, characterized in that the CD playback device is connected to a turntable (16) having a motor-driven turntable (17) in such a way that the current turntable speed or the rotation speed a disc (10, 18) arranged on the turntable (17) provides the manipulated variable for the CD playback speed.

2. Device according to claim 1, characterized by an optical, optoelectronic, electromagnetic or elek¬ tronic measuring device (13, 19) for determining the instantaneous turntable speed or the disk rotation speed and / or the direction of rotation.

3. Device according to claim 1 or 2, characterized gekennzeich¬ net that the disc (10, 18) on both sides with lubricious material (22), such as felt, is coated.

4. Device according to one of claims 1 to 3, characterized in that the disc (10, 18) made of plastic, hard rubber or metal, preferably aluminum.

5. Device according to one of claims 1 to 4, characterized in that the turntable (17) or the disc (10, 18) has markings (11, 12) which can be optically or optoelectronically scanned to determine the instantaneous rotational speed.

6. Device according to one of claims 1 to 4, characterized in that the disc (10, 18) or the Drehtel¬ ler (17) consists of electrically conductive material and Has a toothing over a rotation angle of 360 °, preferably on the circumferential rank (21), the movement of which can be scanned electromagnetically.

7. The device according to claim 5 or 6, characterized gekennzeich¬ net that an infrared, laser or other optical transmitting and receiving device (13) or a Hall IC is provided as a scanning device.

8. Device according to one of claims 1 to 4, characterized in that the turntable (17) of the Plattenspie¬ lers (16) is connected to a measuring device for the current speed of rotation and that the instantaneous values obtained from the measuring device as a manipulated variable the speed control of the CD player are passed on.

9. Device according to one of claims 1 to 8, characterized in that the percentage change in the rotational speed of the turntable serves as a manipulated variable for an inverse percentage change in the frequency of the information played from the CD or record.

10. The device according to claim 9, characterized in that a digital signal processor is used for changing the frequency.

11. The device according to any one of claims l to 10, characterized in that a chip is provided for detecting the key of the sound material present as an input signal and that a further control for signal processing, namely the key, is provided, with which optionally the next piece played is changed in the playback.

12. A method for controlling the playback speed of a compact disc (CD) inserted in a playback device, characterized in that the speed of rotation of a motor-driven turntable or of a disk arranged thereon is manipulated, this being done by manipulation of the rotation speed change and / or change in the direction of rotation is used as a manipulated variable for the CD playback speed.

13. A method for compensating for the pitch fluctuations resulting from manipulations on the turntable when playing a sound carrier (disk or CD), characterized in that the rotational speed of the turntable serves as a manipulated variable for an inversely proportional change in pitch.