JP2539499B2 - Magnetic recording / reproducing device - Google Patents

Description

TECHNICAL FIELD The present invention relates to a rotary head type digital audio tape recorder (hereinafter referred to as DAT), and in particular, keeps the relative speed between the head and tape constant during random access such as music selection. The present invention relates to a magnetic recording / reproducing device suitable for keeping.

[Conventional technology]

In the rotating head type DAT, in order to perform high-speed random music selection (cueing of music) at a speed of several tens to several hundred times the normal playback speed, a signal indicating the start of the music recorded in the track, It is necessary to accurately read the control signal recorded at the same recording density as the music PCM signal such as a signal for displaying the time and the music number information signal when the tape is running at high speed.

By the way, when the tape is run at a speed different from that during normal recording / playback, the running path of the head crosses a plurality of signal tracks recorded on the tape, and if the cylinder rotation speed is constant, the head and tape will move relative to each other. The speed changes.

On the other hand, in the DAT, a data punching (data strobe) circuit is used as a circuit for reproducing a digital signal from a signal reproduced from a head. Normally, the input transmission rate of this circuit has a margin for speed deviation and jitter of the tape running system. It is around 10%, the relative speed with the head changes due to the high-speed running of the tape, and the transmission rate of the input signal is ± 10.
If it deviates from the range of around%, data reproduction is impossible, that is, random access cannot be performed.

For this reason, in DAT, when the tape is running at high speed, the cylinder rotation speed cannot be the same as during normal recording / reproduction, and the tape must be kept at a constant relative speed between the head and the tape or within the allowable jitter of the data strobe circuit. It is essential to control according to the traveling speed of the vehicle.

Hereinafter, the relationship between the tape running speed and the cylinder speed for keeping the relative speed of the tape and the head constant will be described.

FIG. 7 shows scanning of the head during normal recording and reproduction. In the figure, 1 is a head, 2 is a tape, and 3 is a signal track on the tape. The relative velocity V ₀ between the tape and the head at this time is expressed by the equation (1).

Here, V _H0 is the head or cylinder rotation speed during normal recording / reproducing, θ is the tilt angle of the track, and V _T is the tape running speed during normal recording / reproducing.

On the other hand, the relative speed V when the tape is run at n times the normal recording / playback is as shown in formula (2) when the tape is run in the FF (fast forward) direction, and in the REW (rewind) direction. In this case, each of them is represented by the equation (3).

The relationship between the cylinder speed and the tape running speed n is shown when the relative speed V in the equations (2) and (3) is set equal to the relative speed V ₀ in the normal recording and reproduction of the equation (1). It is FIG. To maintain the same relative speed as during normal recording and playback, for example, when the tape is run at a high speed of 200 times, F
It is necessary to control the cylinder speed to 3000 rpm in the F direction and 1000 rpm in the REW direction.

Japanese Patent Application Laid-Open No. Sho 61-214164 discloses an apparatus for controlling the relative speed between the tape and the head by changing the number of rotations of the cylinder according to the running speed of the tape. These devices control the number of cylinder revolutions so that the reproduction clock frequency obtained as a cycle of the reproduction signal in the data strobe circuit becomes a predetermined fixed frequency.

Further, as a conventional technique related to this type of device for controlling the tape running at a constant high speed, there is, for example, JP-A-54-136306.

[Problems to be Solved by the Invention]

However, in the above-mentioned prior art, since the relative speed between the tape and the head is detected by using the reproduction signal from the head, for example, signal dropout occurs, or reproduction is performed due to defective tape touch of the head caused by the tape running system. If the signal is lost, the control of the cylinder rotational speed is lost, and if the signal is once lost and returned again, there is a problem that it is difficult to control the pulling-in of the cylinder rotational speed.

An object of the present invention is to solve the above drawbacks and provide a magnetic recording / reproducing apparatus capable of maintaining a constant relative speed between a head and a tape during a high speed search without being affected by the state of a reproduction signal. is there.

[Means for solving the problem]

The above-mentioned purpose indirectly detects the running speed of the tape by detecting the reel base rotation speed on the tape supply side and the winding side,
This is achieved by controlling the cylinder speed so that the relative speed to the head becomes constant with respect to the tape running speed.

It should be noted that in order to detect the tape running speed from the rotation speed of both reel stands, it is necessary to know the length of the tape. Regarding this point, the tape is running at a predetermined speed in the normal playback state, for example. This is possible by detecting the rotational speeds of both the reel side on the supply side and the reel side on the winding side.

[Action]

The tape reproducing means runs the tape at a normal reproduction speed or an arbitrary predetermined speed n times the normal reproduction speed.

The tape length discriminating means detects the rotational speeds of both the reel bases on the tape supply side and the winding side when the tape is traveling at a predetermined speed by the tape reproducing means, and discriminates the absolute length of the mounted tape. Do.

The tape high speed running control means is, for example, the above-mentioned Japanese Patent Laid-Open No. 54-
As described in Japanese Patent No. 136306, the rotation speed of the reel shaft on the take-up side is controlled according to the running direction of the tape so that the sum of the numbers of rotations of the reel bases on the tape supply side and the take-up side is constant. Drive at high speed.

The tape running speed detecting means detects the rotating speeds of the two reel stands, calculates the running speed of the tape based on the result of the tape length identification by the tape length determining means, and determines the predetermined tape running speed. The control signal of is output.

Further, the cylinder rotation speed control means receives the control signal of the tape running speed detection means and operates to variably control the rotation speed of the cylinder according to the control signal.

With such a configuration, if the cylinder speed controlled by the control signal of the tape running speed detecting means is set to satisfy the relationship shown in FIG. 8, the relative speed between the head and the tape is constant regardless of the reproduction signal from the head. Can be kept at

〔Example〕

Hereinafter, specific examples of the present invention will be described with reference to the drawings.

FIG. 1 shows an embodiment of the present invention. In the figure, 4 is a cylinder, 1a and 1b are a pair of rotating magnetic heads having different azimuth angles (corresponding to head 1 in FIG. 1), 5 is a tape supply side reel stand, and 6 is a tape winding side. The reel stand 7 is a tape supply side reel stand fG16, the tape winding side reel stand fG17, fv converters 18 and 19, and an adder 2
0, a tape high speed running control means composed of a drive circuit 21 and a reel motor 22 for driving the reel stand 5 or 6, 8 is a tape length determining means, 9 is a tape running speed detecting means, 1
0 is cylinder rotation speed control means, 11 is a cylinder motor, 12 is a capstan motor 13, tape playback means comprising a capstan servo circuit 14 and a system control microprocessor 25, 23 is a capstan, and 24 is a pinch roller. 7 and other parts denoted by the same reference numerals as those in FIG. 7 indicate the same things.

 The configuration and operation of each unit will be described below.

As the tape high speed running control means 7, an example equivalent to that of Japanese Patent Laid-Open No. 54-136306 is shown. The f-v converters 18 and 19 are composed of, for example, a well-known monostable multivibrator and an integrating circuit, and are reel fG signals obtained in synchronization with the rotations of the tape take-up reel stand 6 and the tape supply reel stand 5, respectively.
Converts 17 and 16 frequency signals to voltage. The adder 20 is composed of, for example, an adder circuit using a resistor, and is an fv converter.
The output signals of 18 and 19 are added. The drive circuit 21 is composed of a comparator for comparing a predetermined reference voltage with the output signal of the adder 20 and an amplifier, etc., and the reel stand 5 or so that the comparison error between the reference voltage and the output of the adder 20 becomes zero. The rotation speed of the reel motor 22 that drives 6 is controlled. With such a configuration, the adder 20 can be set according to the setting of the reference voltage of the drive circuit 21.
The output of the tape is adjusted to this value, that is, the rotation control of the reel motor 22 works so that the sum of the rotation speeds of the tape take-up side and the supply-side reel stand becomes equal to the reference voltage. Depending on the speed, it will be driven at high speed. During high-speed running of the tape, the pinch roller 24 is opened by mechanism control.

The tape length discriminating means 8 detects the rotational speeds of the reel bases 5 and 6 on the tape supply side and the winding side when the tape is run at a predetermined speed, and discriminates the length of the mounted tape from this result. To do. That is, for example, when the tape is run at the normal reproduction speed, the length of the tape is identified from the following relationship by detecting the rotation speed of the reel bases 5 and 6 on the supply side and the winding side.

Assuming that the tape playback time position is f, the tape thickness is μ, the hub radius of the reel stand is r ₀ , and the playback speed is V _T , the tape diameter r _t of the take-up reel stand is π (r _t ² −r ₀ ² ) = From μV _T t Further, the tape diameter r _S on the supply side is π (r _t ² −r ₀ ² ) = π (r max ² −, from the condition that the tape amount on the take-up reel stand at time t is equal to the tape amount sent out. r _S ² ) (5) On the other hand, the original total amount of tape is μV _T · T _MAX = π (r max ² −r ₀ ² ) (6) From formulas (5) and (6) Accordingly, when the rotation frequencies of the supply-side reel base and the take-up reel base at time t are f _T and f _S , respectively. From equations (4) to (8) Therefore, from equation (9), f _T , f _S, that is, the rotation periods Tt and Ts
Is detected, the tape length T _MAX can be identified by calculation.

FIG. 2 shows a reel table fG as a specific example in DAT.
It shows the relationship of the repetition frequency of the reel base fG with respect to the reproduction position of the tape obtained from the equation (8) when Hz / revolution. The tape length determining means 8 is specifically composed of a microprocessor or the like, and has both reels fG shown in FIG.
Based on the measured value of the frequency, the tape length is calculated by the equation (9) and the identification signal e _S is output. For the output method of e _S ,
The arithmetic result is output in parallel or serially output by a decoding process, but these techniques are well known and will not be described in detail.

The tape reproducing means 12 starts the operation of the capstan servo circuit 14 by the control signal of the system controlling microprocessor 25 when the reproducing operation command key is operated while the cassette is attached to the device. , Capstan motor
The capstan 23 directly connected to the cap 13 and the tape take-up side reel stand 6 connected via gears and the like are driven in the tape take-up direction, and the tape is run at the rotational speed of the capstan 23. The tape running speed during this normal playback is 8.
It is 15 mm / S. Of course, at the same time as the operation of the capstan servo circuit 14, the pinch roller 24 is pressed onto the capstan 23 by mechanical control.

The tape running speed detecting means 9 is a reel fG on the tape supply side.
The repetition period of both 16 and the reel fG17 on the tape winding side is measured, and the tape running speed is calculated from this result, and the control signal e _V corresponding to this is output. That is, if the length (T _MAX ) of the loaded tape is known by the tape length determination means 8, both reels will be in accordance with the following relationship.
By measuring the repetition period of fG, the absolute running speed of the tape can be calculated.

If the tape speed at any tape position is V, the radius of the tape diameter of the take-up reel is rt, and the supply side is rs, the tape amount on the take-up side is equal to the tape amount sent from the supply side, so π (rt ² −r ₀ ² ) = π (r max ² −rs ² ) ... (10) On the other hand, since the original total tape amount is expressed by the equation (6),
From equations (6) and (10) At this time, the reel base rotation frequencies f _T and fs on the tape winding side and the feeding side are From equations (11) and (12) Here, Tt and Ts are reels fG on the tape winding side and the supply side.
Cycle 8 Hz / rotation The tape running speed detection means 9 is configured by using, for example, a microprocessor, measures the repetition cycle Tt and Ts of both reel fG signals, and based on this result, formula (14) is used. The calculation shown is performed to detect the tape traveling speed V. Then, depending on the value of V, for example, as shown in FIG. 3, e _V0 is used when the tape speed is in the normal reproduction, and when the tape running is in the FF (fast forward) direction with this as a _sakai , the tape speed is set. A control signal e _V that has a substantially linear characteristic that decreases according to the tape speed and increases according to the tape speed in the REW (rewinding) direction is output. Regarding the concrete output method of e _V , for example, it is easy to output the result of tape speed calculation by a microprocessor as a few bit data and convert it to an analog value via a well-known D / A converter. Since this is realized, and details thereof are known, description thereof will be omitted. The system control microprocessor 25 determines the key operation of the device to determine whether the tape running is in the FF direction or the REW direction, and a control signal corresponding to the direction is input to the tape running speed detecting means 9. It is done by doing.

The cylinder rotation speed control means 10 controls the rotation speed of the cylinder motor 11 according to the control signal e _V output from the tape running speed detecting means 9, that is, the running speed of the tape.

FIG. 4 shows a concrete configuration example of the cylinder speed control means 10. In the figure, 26 is fG of the cylinder motor 11, 27 is f
The -v converter, 28 represents a comparison amplifier. The f-v converter 27 is f
The input signal frequency f of G26 is converted into a voltage. Comparator amplifier 2
Reference numeral 8 compares and amplifies the control signal e _V output from the tape running speed detecting means 9 of FIG. 1 and the output signal ef of the fv converter 27, and the number of revolutions of the cylinder motor 11 so that the comparison error becomes zero. Control. With such a configuration, the tape running speed detecting means 9 to
Since the control signal e _V having the characteristic shown in the figure is input, the rotation speed of the cylinder motor 11 is changed as shown in FIG.
The input / output characteristics of 27 are controlled according to the value of e _V. Therefore, for example, when configuring a high-speed search of 200 times, the cylinder speed is FF as shown in FIG.
Direction is 3000 rpm, and REW direction is 1000 rpm, the cylinder speed is 3000 rp due to the characteristics of the fv converter in FIG.
m and 1000 rpm, and f at 2000 rpm during normal playback
Assuming that the -v conversion output ef is ef _F , ef _R , ef ₀ , the characteristics of the tape running speed detecting means 9 are adjusted so that these values and e _VF , e _V0 , e _VR shown in FIG. By setting, the cylinder rotation speed according to the tape running speed is such that the relative speeds of the tape and the head always match.

The configuration and operation of each part in the embodiment of FIG. 1 have been described above. With such a configuration, when the playback operation command key is operated while the tape is loaded in the playback device,
The tape is run at normal playback speed. At this time, the tape length determining means 8 operates to determine the length of the mounted tape.

Next, when the search operation command key is operated and the tape is driven by the tape high-speed running control means 7, the tape running speed detecting means 9 measures the rotation speeds of both the tape supply side and the winding side reel bases. And tape length determining means 8
The tape running speed is calculated on the basis of the result of the determination, and a predetermined control signal corresponding to the tape speed and the running direction is output. The cylinder rotation speed control means 10 controls the rotation speed of the cylinder motor 11, that is, the cylinder 4 according to the control signal of the tape running speed detection means 9 so that the relative speed of the heads 1a and 1b with respect to the tape is always constant. , The high speed search control operation is performed regardless of the state of the reproduction signal from the head.

The discrimination of the tape length by the tape length discriminating means 8 is as follows.
As long as the tape is kept mounted on the apparatus only when the first reproducing operation is performed, it is not necessary to perform the operation each time the reproducing operation is repeated. Specifically, after the tape is loaded in the apparatus, the length of the tape is determined when the first reproducing operation is performed, and thereafter, the result may be stored until the tape is removed.

By the way, after the tape is loaded in the device, the reproducing operation is not always performed first, and the high-speed search operation may be performed immediately.

In this case, since the length of the tape is unknown, the tape running speed cannot be calculated, and the cylinder rotation speed cannot be controlled.

FIG. 6 shows another embodiment according to the present invention in consideration of the above points. In the figure, 29 is a capstan servo circuit for running the tape at n times the normal reproduction speed, and other parts designated by the same reference numerals as those in FIG. 1 are the same or equivalent.

In FIG. 6, when the cassette is mounted on the apparatus and the tape 2 is loaded on the cylinder 4, the tape reproducing means 12 first loads the tape to the n-times speed capstan servo circuit 29.
Therefore, it operates so as to run for a predetermined time. Although not shown, mounting of the cassette, completion of loading of the tape, and the like are performed by the system control microprocessor 25 detecting the state of the mechanical sensor.

The control signal from the system control microprocessor 25 starts the operation of the n-times speed capstan servo circuit 25, the capstan motor 13 rotates, and the tape rotates at the capstan 23 rotation speed as in the case of FIG. To start running. This tape running speed is the capstan servo circuit 29
If the double speed ratio is set to, for example, three times the normal reproduction speed, it is 24.45 mm / S.

The time required for the tape length determination means 8 to determine the tape length is approximately 0.6 Hz when the reel fG frequency in the case of a 120-minute longest tape in the DAT is the normal reproduction speed as shown in FIG. In the case of triple-speed playback, since the frequency is approximately 1.8 Hz, at least about 0.6 seconds is required. In response to this, the tape playback time is set to an appropriate value, for example, 1 second. Is performed by the system control microprocessor 25.

With such a configuration, when the cassette is mounted on the reproducing apparatus, the tape is once reproduced at the speed three times the normal reproduction speed for the above-mentioned predetermined time. At this time, the tape length discriminating means 8 is operated to measure the rotational speeds of both reel bases. Based on the result, the length of the attached tape is calculated, and the tape length is identified. Of course, this calculation is performed based on the equation (9), but the tape speed V _T used for the calculation is set to a value three times the normal reproduction speed.

Therefore, according to this embodiment, each time the cassette is newly installed, the tape is first run at a predetermined speed for a predetermined time and the length of the tape is identified during this time. Even if the immediate high-speed search operation command key is operated, it is possible to shift to the high-speed search operation after the identification of the length of the tape is completed (processed by the microprocessor 25 for system control), and the tape runs at high speed. It is possible to accurately calculate the speed and control the cylinder rotational speed according to the tape speed.

In the above example, the tape speed by the n-times speed capstan servo circuit 29 is set to 3 times speed, but this is not particularly limited. For example, in order to complete the operation identification of the tape length in a short time, the reproduction speed may be increased such as 4 × speed or 5 × speed, and if the operation identification time is allowed, the capstan servo circuit 14 is commonly used. It is also possible to determine the tape length in the reproduction state.

In the embodiment shown in FIG. 2, the tape is run at a predetermined speed for a predetermined time every time the cassette is mounted to identify its length. Therefore, when the normal reproduction operation key is operated after the cassette is mounted. On the contrary, there is a drawback that the time required to reach the reproduction operation state is extended. In order to solve this, the embodiment of FIG. 1 is also used. For example, when the reproducing operation key is operated after the cassette is mounted, the immediate reproducing operation is conducted to identify the length of the tape in this state.
It is also effective to apply the embodiment of FIG. 2 only when the high speed search operation key is operated after the cassette is mounted.

The embodiments of the present invention have been described above. In the embodiment of FIGS. 1 and 2, an example in which the tape length discriminating means and the tape running speed detecting means are provided independently has been shown, but this is not particularly limited, and for example, one microprocessor is used. It can also be shared. Also, the tape high speed running control means is described as an example of the one described in JP-A-54-136306, but is not particularly limited. Further, as for the cylinder rotation speed control means, an example in which the reference voltage of the comparison amplifier is variably controlled by a control signal according to the tape running speed is shown, but this is not particularly limited and is constituted by, for example, a digital. For the servo circuit, the clock frequency of the servo circuit can be variably controlled by a control signal corresponding to the tape running speed.

Further, in FIG. 2, the capstan servo circuit is provided for two systems for normal reproduction and n-times speed reproduction, but this is not particularly limited, and for example, for a servo circuit composed of a digital circuit, The operating clock frequency can be shared by switching control, and various modifications can be easily made without changing the gist of the present invention.

〔The invention's effect〕

As described above, according to the present invention, the relative speed between the tape and the head is constant without using the reproduction signal from the head and without the length of the tape being left or right with respect to the high speed running of the tape. Since the cylinder speed can be controlled as described above, it is possible to realize a high-speed search system that is not affected by the state of the reproduction signal such as signal dropout.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a diagram showing the relationship between the position of the tape and the fG frequencies of the supply side and take-up side reel bases during normal reproduction, and FIG. Is the first
Of the control signal output from the tape running speed detecting means of FIG. 4, FIG. 4 is a block diagram showing a concrete configuration example of the cylinder speed control means of FIG. 1, and FIG. 5 is f of FIG.
6 is a characteristic diagram showing input / output characteristics of the -v converter, FIG. 6 is a configuration diagram showing an embodiment of the present invention, FIG. 7 is a schematic diagram showing a scanning locus of a head in a normal reproduction state, and FIG. FIG. 6 is a diagram showing the relationship between the tape running speed and the cylinder rotational velocity when the relative speed of the tape is the same as during normal reproduction. DESCRIPTION OF SYMBOLS 1 ... Head 2 ... Tape 4 ... Cylinder 7 ... Tape high speed running control means 8 ... Tape length determination means 9 ... Tape running speed detection means 10 ... Cylinder rotation speed control means 12 ... Tape playback means 29 ... n speed capstan servo circuit

Claims (4)

(57) [Claims] 1. A magnetic recording / reproducing apparatus for recording / reproducing information by scanning a magnetic tape by a head mounted on a rotary cylinder, and normally drives a reel shaft on a supply side or a winding side of the magnetic tape. The tape high speed running control means for running the magnetic tape at a speed faster than the recording / playback speed, the tape playing means for running the magnetic tape at a predetermined speed, and the tape running control by the tape playing means,
Tape length discriminating means for discriminating the length of the magnetic tape by measuring the rotational speeds of the magnetic tape supply side and the take-up side reel stand, and calculating based on these measurement results; The rotation speed of the reel stand on the winding side is measured, and the traveling speed of the magnetic tape during high speed traveling by the tape high speed traveling control means is based on the measurement results and the tape length determination result by the tape length determination means. And a tape running speed detecting means for outputting a control signal according to the running direction and running speed of the magnetic tape, and controlling the number of revolutions of the rotary cylinder in relation to the control signal of the tape running speed detecting means. A cylinder rotation speed control means is provided, and the rotation speed of the cylinder is controlled so that the relative speed between the tape and the head becomes constant during high speed running of the magnetic tape without being influenced by the length of the tape or the like. Magnetic recording and reproducing apparatus, characterized in that it forms a Gosuru as. 2. The tape reproducing means is configured to run the magnetic tape at a normal reproducing speed, and the tape length discriminating means determines the length of the magnetic tape during normal reproduction of the magnetic tape by the tape reproducing means. 2. The magnetic recording / reproducing apparatus according to claim 1, wherein 3. The tape reproducing means is configured to run the magnetic tape at a normal reproducing speed or at an arbitrary high speed n times the normal reproducing speed, and the magnetic tape is mounted on the magnetic recording / reproducing apparatus. At this time, the magnetic tape is run for a predetermined time by the tape reproducing means, and the length of the magnetic tape is judged by the tape length judging means while the magnetic tape is running. The magnetic recording / reproducing apparatus described. 4. The tape reproducing means comprises two means for running the magnetic tape at a normal reproduction speed and at an arbitrarily high speed n times the normal reproduction speed, and the magnetic tape is mounted on the magnetic recording / reproducing apparatus. When the reproducing operation key is operated, the running of the magnetic tape by the tape reproducing means is set to the normal reproducing speed, and at the same time, the length of the magnetic tape is judged by the tape length judging means, and the magnetic recording is performed. When the magnetic tape is mounted on the reproducing apparatus and the high-speed access operation key is operated, the tape reproducing means temporarily runs the magnetic tape at a speed n times the normal reproducing speed for a predetermined time, and at the same time, the tape length determination is performed. 2. The magnet according to claim 1, wherein the length of the magnetic tape is discriminated by means and a high speed access operation is performed after a predetermined time has elapsed. Recording and reproducing apparatus.