JPS63119059A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To attain the high speed tape traveling control of constant speed by detecting the number of tracks scanning a head and controlling the revolution of a reel motor driving a reel base so that the number can be a required value. CONSTITUTION:Since a tape is traveled from one-fold to 100-fold from a tape traveling speed detecting means, a control signal eT is outputted. On the other hand, for the revolution of a cylinder, the reference voltage ES of a driving amplifier is supplied by the output eT of the tape speed detecting means, and the number is set so as to lock to 2,000rpm by a voltage ET1 at the time of the usual reproduction and to 2,500rpm by a voltage ET3 when the tape speed is 100-fold. Namely, the number is set so that a point N1, in which f-V converter outputs ES1 and ET1 come to be equal, is equivalent to 2,000rpm, and a point N2, in which ES2 and ET3 are equal, is equivalent to 2,500rpm. Thus, since the tape speed rises and eT is successively decreased from the ET1, it is coincident with the rising curve of the tape speed and a follow-up change is automatically executed.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a rotary head type digital audio tape recorder (hereinafter referred to as DAT), and in particular, the present invention relates to a rotary head type digital audio tape recorder (hereinafter referred to as DAT). Concerning a number control device.

[Conventional technology]

Digitalization of audio, as exemplified by CD (compact disc) players, is progressing rapidly, and rotary head fJiDAT recorders will soon be commercialized for tape recorders.

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

By the way, when a tape is run at a high speed different from that during normal recording and playback, the scanning trajectory of the head crosses multiple signal tracks recorded on the tape. The speed will change.

On the other hand, in DAT, a data punching (data strobe) circuit is used as a circuit to reproduce a digital signal from the signal reproduced from the head, but the input transmission rate of this circuit usually has a margin for speed deviation and jitter in the tape running system. is about the overlay percentage, and the relative speed with the head changes due to the high-speed running of the 7''-p, and if the transmission rate of the input signal deviates from the overlay percentage range, data reproduction becomes impossible.

For this reason, with DAT, when the tape is running at high speed, the cylinder rotation speed cannot be the same as during normal recording and playback, and the relative speed between the head and tape is always constant or within the permissible jitter of the data strobe circuit. It is essential to perform variable control according to the running speed of the tape.

Examples of conventional techniques for running a tape at a constant high speed include:
As shown in Japanese Patent Laid-Open No. 57-12448, in addition to the helical scanning of the head, another track is provided in the running direction of the tape, and tracking control signals (control signals) are recorded at constant intervals on the tape. A method of reading the tape during high-speed running and detecting and controlling the tape speed from the frequency, or as shown in JP-A-54-156506, it corresponds to the rotational speed of both reel stands on the tape supply side and winding side. A means for generating a signal is provided.

There is a method of controlling the tape speed at a constant rate by processing the signal.

However, the former example cannot be applied to a DAT without a control signal track, and the latter example is inconvenient due to large errors due to the overall tape length, tape thickness, reel hub diameter, etc.

[Problem that the invention seeks to solve]

By the way, the above-mentioned conventional technology is related to high-speed running control of the tape, and does not give any consideration to the rotational speed control of the cylinder.

In other words, even if it were possible to stably achieve high-speed running of the tape at a constant desired speed, and also achieve a cylinder rotation speed so that the relative speed of the head was constant with respect to the tape speed, the high-speed running from the normal playback state would not be possible. During the transition period, the rise characteristics of the tape running system and the cylinder motor do not match, so there is a problem that a deviation occurs in the relative speed during this period, and a timing at which data reproduction becomes impossible occurs.

Another disadvantage is that even if the tape running speed changes due to load fluctuations in the tape running system under high-speed running conditions where the relative speed is constant, the tape speed state is not fed back to the cylinder rotation speed control system, resulting in a deviation in the relative speed. be.

The purpose of the present invention is to solve the problems of the prior art described above,
In a DAT without a control signal, the tape can be run at high speed and accurately at a constant speed, and at the same time the relative speed of the head is constant depending on the tape running speed, or does not exceed the permissible jitter of the data strobe circuit described above. It is an object of the present invention to provide a magnetic recording and reproducing device that continuously and continuously variablely controls the number of cylinder rotations so that data can be read within a range.

[Means for solving problems]

For the above purpose, first, the cylinder rotation speed according to the tape running speed is controlled by the reference voltage value of the motor drive amplifier,
In other words, this is achieved by changing the reference value of the servo control in accordance with the tape running speed instead of fixing it.

That is, in a motor rotation speed servo system having an fV converter, the lock point of the motor rotation speed can be changed by setting the reference voltage of the drive amplifier. The configuration is such that follow-up control is performed in relation to the speed signal so that relative speeds between the tape and the head do not occur.

In addition, for high-speed and stable tape running, when the head crosses tracks, there is a one-to-one correspondence between the tape speed and the number of tracks that the head crosses, so this can be determined by counting the number of tracks that the head crosses. This is achieved by controlling the rotation speed of a motor (reel motor) that drives the reel stand so that it reaches a predetermined value.

Therefore, in the present invention, the envelope of the output of the regenerative amplifier that amplifies the head reproduction signal (when the head crosses multiple tracks, the reproduction signal becomes an uneven AM modulated wave) is detected, the number of envelopes is counted, and a predetermined standard is determined. A servo configuration is provided in which a tape speed-to-voltage converter is provided that generates a control signal in accordance with the error from the value, and this control signal is fed back to the reel motor drive circuit to control the rotational speed of the reel motor.

[Effect]

The cylinder rotation speed control means inputs the cylinder motor's FG (frequency generator) signal and controls the rotation speed, but the reference voltage of the drive amplifier that determines the one rotation speed is t as described below.
- When the reference voltage is high, the cylinder rotation speed is increased, and as the reference voltage decreases, the cylinder rotation speed is decreased.

On the other hand, the tape speed detection means in the high-speed tape running system counts the number of tracks that the head crosses during high-speed tape running, and outputs a control signal according to the tape speed. That is, it works to output a control signal that is at its maximum when the tape running speed is normal during recording and reproduction, and decreases as the tape running speed increases.

In addition, the tape high-speed running means drives the reel stand for high-speed tape running and controls the rotation speed of the motor, and the reference voltage that is the rotation speed control target value corresponds to the tape high-speed running target value. The voltage level is set to the output voltage level of the tape speed detecting means. That is, the tape speed detection means and the tape high-speed running means constitute a negative feedback loop that controls the number of rotations of the reel motor, and the number of rotations of the reel motor is controlled so that the tape running speed is constant.

That is, when the tape running speed is slower than the target value, that is, when the number of track crossings reproduced by the head is less than the reference value, the control signal of the tape speed detecting means becomes greater than the reference voltage of the tape high-speed running means, and the reel motor is The applied control voltage increases, and the rotational speed of the reel motor increases accordingly, increasing the tape speed and increasing the number of track crossings, and the control operates so that the error in this number with respect to the reference value becomes zero. and others<.

Furthermore, when the tape running speed is faster than the target value, the operation is the opposite to the above.

In the above configuration, in the normal recording/reproducing state, the cylinder rotation speed is controlled by a control signal from the tape speed detecting means. At this time, of course, the reference voltage of the cylinder drive amplifier, ie, the control signal of the tape speed detection means, is set so that the cylinder rotational speed matches that during normal recording and reproduction.

Next, when the tape is running at high speed, the tape speed detecting means and the tape high speed running means operate, and the tape speed gradually increases toward the control target value.

At this time, the control signal output from the tape speed detection means decreases as the tape speed increases, as described above.
Cylinder rotation speed varies in relation to tape speed. In other words, the characteristics of the control signal output from the tape speed detection means are set such that when the tape speed is normal recording/playback, the cylinder rotational speed is the same as normal recording/playback, and when the tape speed is the target high-speed running, the cylinder rotational speed is the same as that of the head. If the cylinder rotation speed is set to a predetermined speed without any relative speed difference, the relative speed with the head will remain constant depending on the tape speed while the tape speed is increasing toward the target value. Since the data is automatically followed, it is possible to solve the problem of inability to reproduce data due to discrepancies in the start-up speed of the tape running system and cylinder motor rotation.

〔Example〕

Hereinafter, specific embodiments of the present invention will be described based on the drawings.

FIG. 1 shows an embodiment of the present invention.

In the figure, 1 is the cylinder, 2α and 2h are the magnetic heads, 3 is the tape, 4 is the cylinder motor, and FG5 is f-
V converter 10. Cylinder rotation speed control means comprising a drive amplifier 11; 6 a cylinder drive motor having an FG 4; 7 a tape speed detection means; 8 a tape high-speed running means; 9 driving a reel stand for winding the tape 3. This shows the reel motor.

In the embodiment shown in FIG. 1, the tape speed is sequentially detected during tape O high-speed running control as described above, and the cylinder is rotated so that the relative speed with the head is constant according to the O speed detection signal, that is, the tape running speed. This is to follow-up control of the number.

The operation will be described below with reference to specific examples, operation waveforms, etc. of each part.

FIG. 2 shows the operating characteristics of the fV converter 10 in FIG. 1. As is well known, the f-V converter converts the cylinder motor rotation number wave number f into voltage.
As shown in the figure, the converted voltage − is inversely proportional to the input signal frequency f.
It is configured to output f.

It can be inferred from the percentages shown in FIG. 2 that the rotational speed of the cylinder motor 6 can be easily changed by changing the reference voltage εS of the driving amplifier 110. That is, in the cylinder motor servo system shown in FIG. 1, negative feedback is applied so that the fV converter output 6/ matches the reference voltage of the drive amplifier, so the reference voltage Es
If it is changed to Es, ~Es due to the characteristics of the fV converter, the cylinder motor rotational speed can be arbitrarily changed from N1 to N3 in response to this change.

FIG. 3 shows the tape speed detecting means 7, f' in FIG.
- It shows a specific circuit example of the driver R8,
In the figure, 12 is a regenerative amplifier that amplifies the head reproduced signal, and 15 is an envelope detection circuit for the reproduced signal e%1.
4 is a counting circuit that counts the number of envelope detection signals hO, and 15 is a tape speed detection circuit that compares the counting data with a reference value of the number of envelopes corresponding to the target speed of high-speed tape running and outputs a control signal gl proportional to the comparison error. , 16
indicates a drive amplifier for the reel motor 9, and 17 indicates a reference voltage.

In FIG. 3, first, the operation of the tape speed detection subactor 70 will be explained.

If tape 3 is run at a higher speed than the normal recording/playback speed,
An amplifier 12 that amplifies the reproduced signals of the heads 2α and 2b.
The output -1 of is as shown in FIG. 4 (α).

In other words, the reproduced signal from head 2α has a large amplitude when scanning over tracks with the same azimuth angle because the tape runs at high speed and the head crosses multiple tracks with different azimuth angles. If different tracks are scanned, the waveform will be modulated in an uneven manner such that the amplitude becomes smaller. The same applies to the head 2b, and in the case of DAT, the tape is wound around the cylinder at a angle of 90° and the head is opposed at 180°, so the amplitude modulated wave group is 1/4 per rotation of the cylinder.
It becomes cyclical.

The envelope detection circuit 15 performs envelope detection of the amplitude modulated wave e1, and although the details are omitted, it is composed of a well-known Emiho quad detector or a diode detector, as shown in FIG. 4(A). Envelope waveform C of amplitude modulated wave C1
Outputs 3.

The counting circuit 14 counts the number of envelopes -2 within a predetermined period, for example, every rotation of the cylinder, and outputs the result to the tape speed detection circuit 15 at the next stage.

The tape speed detection circuit 15 compares the result of the counting circuit with a reference value of the number of envelope lines corresponding to the tape high speed running target value. Assuming that the setting is 100 times that during playback (assuming the f-p speed is 1x), as shown in Fig. 5, when the f-p speed is 100 times, ET, , maximum Er at 1x, ,
The control signal 87 is configured to output a minimum ET at 200 times, and a linear characteristic between the tape speed and envelope number since there is a proportional relationship between the tape speed and envelope number.

Specifically, the speed detection circuit 15 includes a PWM converter that compares the result of the counting circuit with a reference value and generates, for example, a p'rx wave according to the error, and integrates the PWM wave. However, these are well-known techniques and are easy to configure, so the details will be omitted.

Next is the tape high speed running means 8, which controls the rotation speed of the reel drive motor 9 so that the tape runs at a constant target high speed.In other words, the reference voltage 17 of the drive amplifier 16 is - If the high-speed target value of the drive is 100 times that during normal recording and playback, then according to the characteristics shown in Figure 5, E
The tape running speed is set to 5, for example, the tape running speed is 1.
When it is lower than 00 times, the tape speed is compared with the control signal gl output from the tape speed detection circuit, and depending on the error, the drive voltage applied to the reel motor 9 is increased to increase the rotation speed of the reel motor and the tape speed is set to the control target value. In the region where the tape speed is higher than 100 times, conversely, the motor drive voltage is reduced to lower the reel motor rotation speed, and a negative feedback loop is configured so that the tape speed becomes 100 times as much. Therefore, the traveling speed of the y''-plane is controlled by CLr (constant linear velocity) regardless of the winding diameter and the like.

The configuration and operation of each part of the embodiment shown in FIG. 1 has been described above with reference to FIGS. 2 to 5.

The control of the rotational speed of the cylinder motor according to the tape running speed, which is the gist of the present invention, will be described below.

In DAT, the cylinder rotation speed during normal recording and playback is 2000.
The tape running speed is 8.15/S, and the tape running is controlled by a dedicated drive unit, not shown in FIG. 1, like a conventional VTR.

Now, when running the tape at high speed, in order to maintain the relative speed with the head constant as during normal recording and playback, the cylinder rotation speed should be controlled to the relationship (theoretical value) shown in Figure 6 with respect to the tape speed. Must. In other words, if the tape running speed is set to 100 times the normal recording and playback speed,
For running in the FF direction, set 2000 rpm to 250 Or
pm and 2000 for traveling in the RETF' direction.
O control is required from rpm to 150 rpm.

Below, regarding the FF direction, the tape high speed running target value is set to 10.
The control operation when set to 0 times will be explained.

FIG. 7 (When a high-speed search (tape high-speed running control) operation is started at time t0 from the normal playback state as shown in at, the tape speed becomes the normal playback speed (1x) as shown in <br.
It gradually rises from t, depending on the start-up characteristics of the running system, and
At the point in time, the target speed is locked to 100 times.

In addition, since the tape runs from 1x to 100x as shown in (α) from the tape running speed detection means, the control signal shown in (c), which is just the reverse of (b), is obtained from the characteristics shown in Fig. 5. is output.

On the other hand, the cylinder rotation speed is determined by the reference voltage Es of the drive amplifier being supplied by the output of the tape speed detection means, and due to the characteristics shown in FIG.
pm, and when the tape speed is 100 times faster, it is set to be locked to 2500 rpm by Ea. In other words, in Fig. 2, the f-V converter outputs E, 1 and E
The point N1 where rI is equal is 2000rpyx, and E
8. The point N where and Era are equal is set to correspond to 250 Orpm. Specifically, once the characteristics shown in Fig. 5 are determined, E
□ and ET, cylinder rotation speed is 2000 rp
This can be easily achieved by setting the f-V converter characteristics so as to provide nh and 2500 ypm, or by appropriately amplifying the characteristics shown in FIG. 5 in accordance with the f-V converter characteristics.

In such a configuration, when a high-speed search operation is started, the cylinder rotation speed increases to 1.0 as shown in FIG. 7(d). Then, the speed is set to 200 Orpm, which is the same as during normal playback, and 2500 rpm after t1 when the tape speed is locked at 100 times (EarEi).
rpni, and in that process, as the tape speed increases, the elongation decreases sequentially from Ea to Ea as shown in (1), so it automatically follows the tape speed increase curve shown in (h). Become something to do.

In addition, the waveforms after t in FIG. 7 may be different from the standard value due to, for example, mechanical load fluctuations in the tape running speed.
It shows the operation of each part when the change is 50 times or 150 times from 0 times. Even if the tape speed fluctuates above or below the reference value, g7 is detected according to the speed as shown in Figure 5, and f-V conversion is performed as shown in Figure 2 depending on the magnitude of the g7. Since the reference voltage based on the device characteristics automatically moves, the cylinder rotation speed can be automatically controlled to follow the tape speed in one-to-one correspondence.

The control operation in the FF direction has been described above.

Control in the REW' direction can be similarly achieved by, for example, switching the f-V converter from the OK characteristic shown in Figure 2 to one with characteristics that are symmetrical on the frequency axis around point A. This is possible, and the control operation is also the same as in the FF direction, so details will be omitted.

〔Effect of the invention〕

As described above, according to the present invention, the number of tracks scanned by the head is detected and the number of rotations of the reel motor that drives the reel stand is controlled so that this number becomes a required value, thereby controlling high-speed tape running at a constant speed. becomes possible.

Furthermore, since the rotation speed of the cylinder motor can be automatically controlled so that the relative speed with the head is constant according to the tape running speed, for example, when starting up high-speed tape running, or when the load on the running system changes during high-speed running, etc. Therefore, even if the tape speed fluctuates from the reference value, it is possible to solve the problem of inability to reproduce data due to mismatch in relative speed.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of one embodiment of the present invention, and FIG. 2 is a characteristic diagram for explaining the operation of the f-V converter shown in FIG. 1. FIG. 3 is a tape speed detecting means 7 of the circuit shown in FIG. 4 and 5 are waveforms and characteristic diagrams for explaining the operation of the circuit shown in FIG. 3, and FIG. 6 is a diagram showing the correction of the cylinder rotational speed with respect to the tape running speed. Figure 7 is the first
FIG. 6 is a diagram showing operation waveforms (timing charts) of various parts during tape high-speed running control in the illustrated embodiment. 1...Cylinder 2...Head 5...Tape 5...・Cylinder rotation speed control means 6...
−・−・・・Cylinder motor 7・・−・−・・・・
・Tape speed detection means 8...--Tape running at high speed 1st Figure 2 Figure 3 Figure 4 b) ez Figure 5 Figure 60 (bao)

Claims (1)

[Claims] 1. A rotating head type PC that performs recording and reproduction by scanning a magnetic tape with a head mounted on a rotating cylinder.
In an M recorder or VTR, a rotational speed control means for controlling the rotational speed of the cylinder, a high-speed running means for driving a reel shaft to run the magnetic tape at a speed higher than a normal recording and reproduction speed, and a running speed of the tape. and a running speed detecting means for detecting the running speed of the tape and controlling the high-speed running means of the tape, and the tape running speed detecting means controls the rotational speed control means to control the rotational speed of the cylinder in relation to the running speed of the tape. A magnetic recording/reproducing device characterized in that it is configured to control. 2. The rotation speed control means includes an f-V converter attached to a motor that drives the cylinder and converts an FG signal into a voltage, and an output of the f-V converter and an output of the tape running speed detecting means. The magnetism according to claim 1, characterized in that it is constituted by a motor drive amplifier configured to perform a comparison and generate a control signal according to the comparison error to control the rotational speed of the cylinder motor. Recording and playback device. 3. The magnetic tape running speed detection means includes a detection circuit that brings the head into contact with the magnetic tape and detects the envelope of the playback output of the head, and a detection circuit that detects the envelope of the playback output of the head, and a detection circuit that detects the envelope of the playback output of the head, and a detection circuit that detects a plurality of recording tracks on the magnetic tape when the head runs at high speed. It consists of a counting circuit that counts the number of peaks and/or troughs in the output of the detection circuit caused by cross-scanning, and a speed detection circuit that outputs a control signal according to the count value of the counting circuit. A magnetic recording and reproducing apparatus according to claim 1, characterized in that: