JPH09161360A - Tape reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain stable operation without being affected by a drop-out of a signal by controlling the number of revolution of a drum so that a relative speed between a tape and a head becomes a fixed level from a speed detection value from a period of a regenerative control signal and a number of revolution detection value from an output pulse period of the drum FG. SOLUTION: A tape running speed detection means 118 measures the period of the control signal regenerated by a control head 116 to output the speed detection value to a relative speed deviation detection means 122. A number of revolution detection means 121 measures the period of the output pulse of the drum FG 120 to output a drum number of revolution detection value to the relative speed deviation detection means 122. The means 122 outputs an answering number of revolution error signal to a data number of revolution control means 123 from both speed deviation, and controls a drum motor 119 of a rotary drum 101 so that the relative speed between the tape and the head becomes the fixed level according to a tape speed. Thus, the stable operation without being affected by the drop-out of the signal is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital VTR in which a control signal is used as a tracking control signal and a rotary magnetic head is used to reproduce a digital video signal.
In particular, the present invention relates to a control method and a reproducing apparatus capable of keeping a relative speed of a rotary magnetic head and a tape constant in a high speed search operation.

[0002]

2. Description of the Related Art A conventional V widely used for consumer use
A digital VHS (hereinafter referred to as DVHS) that ensures compatibility with the HS system VTR and records and reproduces a compressed digital signal.
Has been developed and is about to be put into practical use as a digital recording medium compatible with broadcasting and communication using future digital signals.

In DVHS, moving picture data is compressed by the MPEG (Moving Picture Experts Group) compression technique, and sub information signals such as time information and data addresses are recorded at the beginning of each track as sub codes. An example of the recording pattern is shown in FIG.

In FIG. 7, 103 is a magnetic tape, 701 and 702 are scanning loci during normal reproduction of a magnetic head having a positive azimuth angle and a negative azimuth angle, respectively, and normal reproduction image data is recorded in a blank portion of 703. Area, 7
The shaded portion of 04 is a subcode data area in which subinformation such as time information and data address is recorded, and 705 is a signal for tracking control of the rotary magnetic head, as in the conventional analog VHS / VTR. Is a control track on which a control signal is recorded.

In the DVHS, several tens of normal reproduction speeds are used.
In order to perform high-speed random access at a speed of several hundred times,
The subcode data 704 recorded at the head of the track must be accurately read when the high-speed tape is running.

By the way, when the tape is run at a high speed different from normal recording / reproducing, the scanning locus of the head traverses a plurality of signal tracks recorded on the tape, and thus the drum on which the magnetic head is mounted. If the number of rotations remains constant, the relative speed between the head and tape changes.

On the other hand, in the DVHS, 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 transmission rate at the input of this circuit is the speed deviation of the tape running system,
The margin for jitter is about ± 10%, the relative speed with the head changes due to the high speed running of the tape, and if the transmission rate of the input signal deviates from the range of about ± 10%, data reproduction is impossible, that is, random access cannot be performed. The inconvenience occurs.

For this reason, in the DVHS, when the tape is running at a high speed, the drum rotation speed cannot be the same as that during normal recording and reproduction, and the relative speed between the head and the tape is always constant.
Alternatively, it is indispensable to perform follow-up control according to the running speed of the tape so that it falls within the allowable jitter of the data strobe circuit.

FIG. 8 shows the relationship between the tape running speed and the drum speed for keeping the relative speed of the tape and head constant in the DVHS standard mode (tape speed of 16.675 mm / s). Is. The drum rotation speed for normal recording / reproduction is 1800 rpm, but in order to maintain the relative speed constant, for example, when the tape is run at a high speed of 200 times, the drum rotation speed is 2800 in the FF direction.
It must be controlled to rpm and 800 rpm in the REW direction.

As a method / apparatus of this kind for controlling the relative speed of the tape and the head to be constant by changing the number of rotations of the drum in accordance with the tape running speed, for example, Japanese Patent Laid-Open No. 61-2141.
Some are disclosed in Japanese Patent Laid-Open No. 64. This device is
The data strobe circuit controls the number of rotations of the drum so that a reproduction clock obtained as a frequency synchronized with the reproduction signal always has a predetermined frequency. For example, a conventional DAT (digital audio tape) which is a digital recording / reproducing apparatus of the same kind. Recorders) used this type of method.

Further, as a conventional technique for controlling a constant high speed running of a tape in relation to this type of device, for example, Japanese Patent Laid-Open No.
The thing disclosed by 4-136306 gazette is mentioned.

[0012]

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 rotary head, for example, signal dropout occurs, or the tape is dropped. If the reproduction signal is lost due to a defective tape touch on the head due to the traveling system or the like, there is a problem that the drum rotation speed is out of control.

Furthermore, in the case where the signal is once lost and then restored again, the data strobe circuit (PLL) is used.
Since the circuit itself does not have the self-recovery capability, it is possible to control re-drawing of the drum rotation speed by, for example, Japanese Patent Laid-Open No. 62-
The auxiliary control as disclosed in Japanese Patent No. 8354 is indispensable, and it has a drawback that the control is complicated.

The object of the present invention is to solve the above-mentioned drawbacks of the prior art, to keep the relative speed between the head and the tape constant in a high speed search operation, simply, without being influenced by the signal reproduction state of the rotary head. It is to provide a tape reproducing device capable of

[0015]

[Means for Solving the Problems] As described above, the DVHS
Is an upper compatible system of the conventional analog VHS, and a control signal is used for head tracking control as in the case of VHS.

Therefore, the object is to detect the tape speed at the time of high-speed search from the frequency of the reproduction control signal and control the drum rotation speed so that the relative speed of the head becomes constant with respect to this tape speed. To be achieved.

In the first aspect of the invention, the tape high speed running control means has a constant sum of the rotational speeds of the reel bases on both the tape supply side and the winding side as disclosed in, for example, Japanese Patent Laid-Open No. 54-136306. As described above, the rotational speed of the reel shaft on the winding side is controlled according to the tape running direction, and the tape is run at high speed.

The tape running speed detecting means works to detect the running speed of the tape based on the frequency of the control signal reproduced in the high speed running state of the tape.

The relative speed deviation detecting means detects the relative speed deviation between the tape and the head from the speed detection result from the tape running speed detecting means and the corresponding drum rotation speed detection result, and the relative speed deviation is detected. A control signal corresponding to the amount / direction is output.

Further, the drum rotation speed control means receives the control signal of the relative speed deviation detection means, variably controls the rotation speed of the drum according to the control signal, and the output control signal from the relative speed deviation detection means is predetermined. The reference value, that is, the relative velocity deviation between the tape and the head becomes zero.

Further, in the second invention, the servo means functions to change and control the number of rotations of the drum in accordance with the speed detection result from the tape running speed detection means.

With this configuration, the negative feedback control is performed so that the drum rotation speed satisfies the relationship shown in FIG. 8 in accordance with the tape running speed. Therefore, the relative speed between the head and the tape is irrespective of the reproduction signal from the rotary magnetic head. It can be controlled to be constant.

[0023]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of a tape reproducing apparatus according to the first invention.

101 is a rotary drum, and 102a and 102
Reference numeral b is a pair of rotary magnetic heads mounted on the rotary drum 101 and having mutually opposite azimuth angles.
It is assumed that a has a positive azimuth angle and 102b has a negative azimuth angle. Reference numeral 103 is a tape, 104 is a tape supply side reel stand, 105 is a tape winding side reel stand, 113 is fV converters 108 and 109 of a tape supply side reel stand FG106 and a tape winding side reel stand FG107, and an adder 11
0, a drive circuit 111, and a reel high-speed running control means composed of a reel motor 112 for driving the reel base 104 or 105, 114 a capstan for running the tape 103, 115 a pinch roller, and 116 a control signal reproduction. A control head 117 is an amplifier for amplifying a reproduced control signal, 118 is a tape running speed detecting means, 119 is a drum motor for rotating the rotary drum 101, 120 is a drum FG, 121 is a rotational speed detecting means, and 122 is a relative speed. Deviation detection means, 123 is a motor rotation speed control means, and 124 is a system control circuit.

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

The tape high speed running control means 113 is equivalent to that disclosed in Japanese Patent Laid-Open No. 54-136306.

The fV converters 108 and 109 are composed of, for example, a well-known monostable multivibrator and an integrating circuit, and are obtained in synchronization with the rotations of the tape supply reel base 104 and the tape take-up reel base 105, respectively. FG
The frequency signals of signals 106 and 107 are converted to voltages.
The adder 110 is composed of, for example, an adder circuit using resistors, and adds the output signals of the fV converters 108 and 109. The drive circuit 111 uses a predetermined reference voltage and the adder 110.
Comprised of a comparator and an amplifier for comparing the output signal of
The rotation speed of the reel motor 112 that drives the reel base 104 or 105 is controlled so that the comparison error between the reference voltage and the output signal of the adder 110 becomes zero.

In the above structure, first, at the start of high-speed running, the system control circuit 124 gives a speed instruction value n for instructing a predetermined tape speed and FF / R for instructing the tape running direction.
The EW signal is output. First, on the basis of the FF / REW signal, the reel stand on the take-up side is switched by mechanism control (not shown) such that the reel stand 105 is in the FF direction and the supply reel stand 104 is in the REW direction. The reference voltage of the drive circuit 111 is set based on the speed instruction value n. According to the set reference voltage, the adder 110
Output signal of the reel motor 112 is controlled 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, so that the tape 103 operates at a predetermined speed. Is driven at high speed. It should be noted that the pinch roller 115 is in the released state by the mechanism control during high-speed tape running.

The tape running speed detecting means 118 measures the period of the control signal reproduced by the control head 116, obtains the tape speed from the measurement result, and determines the speed detection value V _t which is the identification result corresponding thereto. It is output to the speed deviation detecting means 122.

The tape traveling speed detecting means 118 is composed of, for example, a dedicated period measuring counter, a microprocessor or the like, and outputs the detected speed detection value V _t as, for example, several bits of digital data.

The rotation speed detecting means 121 is a drum FG12.
The period of the output pulse of 0 is measured, the drum rotation speed is obtained from this measurement result, and the rotation speed detection value N, which is the identification result corresponding to this, is output to the relative speed deviation detecting means 122.

The rotation speed detecting means 121 is composed of, for example, a dedicated cycle measuring counter, a microprocessor, or the like, and outputs the detected rotation speed detection value N as, for example, several bits of digital data.

The relative speed deviation detecting means 122 obtains a predetermined drum speed N ₀ from the characteristic shown in FIG. 8 based on the speed detection value V _t which is the identification result of the tape running speed detecting means 118, and the drum rotation The speed deviation of the drum rotation speed is calculated from the number N ₀ and the rotation speed detection value N which is the identification result of the rotation speed detecting means 121, and as shown in FIG. 2 according to the deviation amount of the drum rotation speed and the direction of the deviation. The rotation speed error signal e _N having the characteristic is output to the data rotation speed control means 123.

The relative speed deviation detecting means 122 is constituted by using, for example, a microprocessor or the like, and regarding the concrete output method of the rotation speed error signal e _N , for example, the relative speed according to the tape speed by the microprocessor is used. The calculation result of the amount of deviation of the drum rotation speed from a certain condition is output as digital data of several bits, and this is output by a known D /
Since it is easily realized by converting into an analog value via an A converter or the like, the details are omitted because it is publicly known.

Note that the control direction of the drum rotation speed differs as shown in FIG. 8 depending on whether the tape running direction is the FF direction or the REW direction. For this reason, the calculation of the relative speed deviation must be performed by identifying the tape running direction. In this respect, the system control circuit 124 identifies the key operation (not shown) of the device and determines the selected direction. The control signal FF / REW is the relative speed deviation detecting means 122.
It is done by being output to.

The motor speed control means 123 controls the speed error signal e _N output by the relative speed deviation detection means 122.
Is a predetermined value, that is, the drum motor 1 that outputs the rotation speed control signal e _s so that the relative speed between the tape and the head becomes constant according to the tape speed and controls the rotation of the rotating drum 101.
The control of 19 is performed.

FIG. 3 is a diagram showing an example of a specific configuration of the motor rotation speed control means 123, and 301 is a rotation speed error signal e _N , 30 output by the relative speed deviation detection means 122.
Reference numeral 2 is a reference voltage V _r , 303 is a comparison amplifier, and 304 is a rotation speed control signal e _s .

The comparison amplifier 303 has a rotation speed error signal 301.
And a reference voltage 302 are comparatively amplified to output a rotation speed control signal e _s so that the comparison error becomes zero.
Controls the rotation speed of. The reference voltage 302 is set to a central value of the control signal of the relative speed deviation detecting means 122 shown in FIG. 2, that is, a value at which the relative speed of the tape and drum rotation speed (rotation speed of the head) is constant (deviation is zero). It

As described above, the configuration of each part in the embodiment of FIG.
The operation has been described. With such a configuration, when the high speed search key is operated and the tape 103 is running at high speed by the tape high speed running control means 113, the tape running speed detecting means 118 is based on the frequency of the control signal reproduced from the control head 116. The tape speed is detected by the speed detection value V _t and the relative speed deviation detection means 1
22. The relative speed deviation detecting means 122 calculates how much the drum rotation speed deviates from the characteristic shown in FIG. 8 based on the tape running speed data V _t and the rotation speed detection value N output by the rotation speed detecting means 121. It outputs a rotation speed error signal e _N according to the deviation amount of the drum rotation speed and the direction of the deviation as shown in FIG. Then, the motor rotation speed control means 1
Reference numeral 23 is a rotation speed error signal of the relative speed deviation detecting means 122.
The drum motor 119 is feedback-controlled so that e _N matches the reference voltage V _r , that is, the rotation of the rotating drum 101 is controlled so that the relative speed is always constant.

As a result, the magnetic head 1
It is possible to control the relative speed of the tape and the head to be constant regardless of the state of the reproduction signal from 02a and 102b.

The first embodiment of the present invention has been described above with reference to FIG.

In the embodiment shown in FIG. 1, the tape traveling speed detecting means 118, the rotation speed detecting means 121, the relative speed deviation detecting means 122, and the motor rotation speed controlling means 123 are independently provided. The number is not particularly limited, and can be shared by using, for example, one microprocessor.

FIG. 4 is a block diagram showing an embodiment of the tape reproducing apparatus according to the second present invention.
Is a servo means, the other parts denoted by the same reference numerals as those in FIG. 1 indicate the same things, and their operations are also the same.

FIG. 5 is a block diagram showing a concrete configuration example of the servo means 125. Reference numeral 501 is a drum FG signal input from the drum FG 120, 502 is an fV converter, which corresponds to the drum FG signal 501. It functions to output the fV converted signal 503 having the characteristic shown in (1) of FIG.
504 is a speed detection value V _t input from the tape running speed detection means 118, 505 is an FF / REW signal input from the system control circuit 124, and 506 is an offset voltage generation circuit, which is output from the system control circuit 124. FF / REW signal 505 and tape running speed detection means 11
The offset voltage 507 is generated in accordance with the speed detection value 504 output from the control unit 8. 508 is the fV conversion signal 50
3 and the offset voltage 507 are added and an adder signal 509 is output, 510 indicates a reference voltage V _r , 511 indicates a comparison amplifier, and 512 indicates a rotation speed control signal e _s .

In FIG. 5, the fV converter 502 is composed of, for example, a dedicated period measuring counter, a microprocessor, or the like, measures the period of the drum FG signal 501, and outputs a frequency detection value of, for example, several bits. Output as digital data.

The offset voltage generation circuit 506 is composed of, for example, a microprocessor, and the FF / REW signal 505 input from the system control circuit 124 and the speed detection value 5 output from the tape running speed detection means 118.
According to 04, an offset voltage 507 for changing and controlling to a predetermined drum rotation speed determined by the characteristic shown in FIG. 8 is generated.

That is, in the FF direction search, a positive offset voltage V ₁ proportional to the tape speed is calculated, and conversely, in the REW direction search, a negative offset voltage V ₂ is calculated and output, whereby the adder 508 is operated. The f-V conversion characteristic is in the direction of characteristic (2) according to the tape speed in the FF direction search, and in the direction of characteristic (3) in the REW direction search, in contrast to the characteristic (1) of FIG. It is sequentially shifted.

The offset voltage is calculated by the fV conversion sensitivity _Kf (V / rpm) which is the slope of the characteristic (1) shown in FIG.
Is determined based on That is, _if the tape speed is 200 times and the FF direction search is performed, the V _r point is 2 based on the known K _f.
The offset voltage is calculated to be 800 rpm, and in the case of the REW direction search, the offset voltage is calculated and output so that the V _r point matches 800 rpm.

Further, the comparison amplifier 511 and the addition signal 509
The reference voltage 510 of V _r is compared, and feedback control of the drum motor 119 is performed so that the comparison error becomes zero.

With such a configuration, the tape speed is detected in the high speed search operation, and the offset voltage output from the offset voltage generation circuit 506 in proportion to this is used to detect the characteristic (2) in the FF direction search as shown in FIG. ), Or in the direction of (3) in the REW direction search f-
The V conversion curve is shift-controlled. As a result, the lock point of the drum rotation moves with respect to the reference voltage V _r , which is the control center, according to the tape speed, so that the relative speed of the tape and the head can be controlled to be constant.

The second embodiment of the present invention has been described above with reference to FIG.

In the embodiment shown in FIG. 4, the tape running speed detecting means 118 and the servo means 125 are provided independently, but this is not particularly limited, and for example, one microprocessor or the like is used. It can also be shared.

Furthermore, in the embodiment of the present invention shown in FIGS. 1 and 4, the tape high-speed running control means 113 uses the reel motor 112 to drive the reel shaft of the reel stand on the tape winding side. However, this is not particularly limited, and for example, by driving a capstan motor (not shown) that controls the rotation of the capstan 114,
It is possible to drive the tape at a high speed by driving the reel shaft on the winding side by using a transmission means such as a belt or a gear to rotate the rotation of the capstan motor, within a range not changing the gist of the present invention. Various modifications are easy.

[0055]

As described above, according to the present invention,
The tape running speed is detected from the frequency of the playback control signal, and the drum rotation speed is controlled so that the relative speed between the tape and the rotary magnetic head becomes constant accordingly. It is possible to realize a tape reproducing device capable of stable high-speed search operation that is not affected by.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of a tape reproducing apparatus according to the first present invention.

FIG. 2 is a diagram showing characteristics of an output signal of a relative speed deviation detecting means in the embodiment of FIG.

FIG. 3 is a block diagram showing a specific configuration of motor rotation speed control means in the embodiment of FIG.

FIG. 4 is a block diagram showing an embodiment of a tape reproducing apparatus according to the second present invention.

FIG. 5 is a block diagram showing a specific configuration of servo means in the embodiment of FIG.

FIG. 6 is a diagram for explaining the operation of the servo means in the embodiment of FIG.

FIG. 7 is a diagram showing a recording pattern on a magnetic tape according to the present invention.

FIG. 8 is a diagram showing a relationship between a tape running speed and a drum rotation speed for keeping a relative speed between a head and a tape constant.

[Explanation of symbols]

101 ... Rotating drum, 102a, 102b ... Rotating magnetic head, 103 ... Magnetic tape, 104 ... Supply side reel stand,
Reference numeral 105 ... Winding side reel stand, 113 ... Tape high speed running control means, 114 ... Capstan, 116 ... Control head, 118 ... Tape running speed detecting means, 119 ... Drum motor, 121 ... Rotation speed detecting means, 122 ... Relative speed Deviation detecting means, 123 ... Motor speed control means, 12
5 ... Servo means.

Claims (2)

[Claims] 1. A tape reproducing apparatus which is a helical scan system having a rotary magnetic head, wherein a control signal is used for tracking control, and the rotary magnetic head scans a magnetic tape to reproduce information. A tape high speed running control means for driving the reel shaft on the supply side or the winding side of the magnetic tape to run the magnetic tape at a speed faster than a normal playback speed; a control head for playing back the control signal; A tape running speed detecting means for detecting the running speed of the magnetic tape during high speed running control by identifying the frequency of a control signal reproduced by the control head, a rotating speed detecting means for the rotating magnetic head, and the tape running speed. Relative speed between the rotary magnetic head and the magnetic tape based on the detection results from the detection means and the rotation speed detection means. It is provided with a relative speed deviation detecting means for detecting a difference and outputting a predetermined control signal, and a motor rotation speed controlling means for receiving the output of the relative speed deviation detecting means and controlling the rotation speed of the rotary magnetic head drive motor. The rotational speed of the rotary magnetic head is controlled so that the relative speed between the magnetic tape and the rotary magnetic head is always constant irrespective of the tape running speed during the high speed running / playback operation of the magnetic tape. A tape reproducing device characterized by the above. 2. A magnetic tape reproducing apparatus having a rotating magnetic head, wherein a control signal is used for tracking control, and the rotating magnetic head scans a magnetic tape to reproduce information. A tape high-speed running control means for driving the reel shaft on the supply side or the winding side of the magnetic tape to run the magnetic tape at a speed faster than a normal playback speed; and a control head for playing back the control signal. A tape traveling speed detecting means for identifying the frequency of a control signal reproduced by the control head to detect a traveling speed of the magnetic tape during high speed traveling control, and a tape traveling speed detecting means for detecting the tape traveling speed. And a servo means for changing and controlling the number of rotations of the rotary magnetic head. A tape reproduction characterized by controlling the number of revolutions of the rotary magnetic head so that the relative speed between the magnetic tape and the rotary magnetic head is always constant regardless of the tape running speed during the line reproduction operation. apparatus.