JPS583130A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To simplify the overall constitution and to easily realize non-adjustment, by mechanically shifting a rotary magnetic head almost toward the rotary shaft direction, and automatically performing tracking control. CONSTITUTION:A pulse signal PFG is applied to the 1st counter circuit as a count input signal. Further, a switching pulse Psw is applied to the 1st and 2nd counter circuits 41 and 42 as a reset signal. Next, an output of an oscillator 43 is applied to the 2nd counter circuit 42 as a count input signal. A count output from the circuits 41 and 42 is applied to an adder/subtractor 44 to select either addition or subtraction in response to a tape direction discriminating signal F/R inverted depending on the forward or reverse direction of tape run. A slope correction signal is obtained by converting a digital output signal from the circuit 44 into an analog voltage signal.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic recording/reproducing device such as a video tape recorder using a rotating magnetic head, and in particular, the present invention relates to a magnetic recording/reproducing device such as a video tape recorder using a rotating magnetic head. The present invention relates to a magnetic recording/reproducing device that performs control.

In a rotating head type video tape recorder (hereinafter referred to as VTR), which is a type of magnetic recording and reproducing device using a rotating magnetic head, a magnetic tape (so-called video tape) is used.
A so-called helical scan type is common, in which the magnetic head is wound obliquely around a rotating magnetic head so as to form part of a spiral and guided.

An example is shown in FIG. In this FIG. 1, a rotary head device 1 consists of upper and lower drums 2 and 3.
is fixed to the chassis of the VTR or the like, and the upper drum 2 is driven to rotate, for example, in the direction of the arrow by a motor 4 or the like. This rotating upper drum 2 (also referred to as a rotating drum) has
One or more video heads 5 are attached. On the outer peripheral surfaces of the upper and lower drums 2 and 3, a magnetic tape (videotape) 6 is wound diagonally, for example, around the tape guide step 7 of the fixed lower drum 3, and is guided in the direction of arrow B, for example. Traveling is driven.

Next, FIG. 2 shows an example of a video track pattern recorded and formed on the magnetic tape 6, in which the tape running direction is in the direction of arrow B, and the moving direction of the rotating video head 5 on the magnetic tape is in the direction of the arrow. In this case, the video track is, for example, track T1.

T2, T3, T4, etc. are sequentially recorded at a constant pitch p while drawing a diagonal pattern from the bottom end of the tape to the upper left corner of the figure. In addition, corresponding to these track TKs, control pulses (CTL pulses)
Pet is recorded.

By the way, in order to accurately trace (scan) the video head 5 with respect to the recording track T during reproduction, the head 5 is connected via an electro-mechanical conversion element such as a bimorph plate 8, as shown in FIG. The video head 5 is attached to the rotating upper drum 2 and supplies drive signals to the electrodes attached to both sides of the bimorph plate 8 during playback.
An automatic tracking restaurant is being used in which the rotational axis is shifted in the track width direction, that is, in the rotational axis direction (direction of arrow C) perpendicular to the rotational scanning direction.

An example of this automatic tracking control will be explained with reference to FIG. 4.

In FIG. 4, the configuration of the control circuit system can be roughly divided into:
Dynamic tracking control circuit section 11, jumping control circuit section 12, and tilt correction circuit section 13
It consists of three blocks.

First, the dynamic tracking control circuit section 11 is designed to correct poor linearity of the recorded video track T itself, minute head deviations caused by mechanical disturbance of the head, etc. The position of the video head 5 with respect to the track T is determined by the reproduced video signal RF from the video head 5.
The correction operation is performed while constantly detecting the error.

That is, the output from the oscillator 14 is transmitted to the bimorph plate 8.
The video head 5 is forcibly vibrated to perform a so-called wobbling operation by supplying a
sent to the envelope detector 16 via the input terminal 15;
The obtained envelope waveform signal (level detection signal) is sent to a balanced modulator 17, for example. This balanced modulator 1
7 is supplied with an excitation signal for wobbling operation from the oscillator 14, and by balanced modulating this signal and the envelope waveform signal, the deviation of the video head with respect to the video track T is calculated. Error signal according to direction and amount of deviation (track deviation detection signal)
is obtained. This error signal is added and synthesized with the signal from the oscillator 14 by an adder 18, and sent to the adder 19 as an output signal of the dynamic tracking control circuit 11. is the contact start position on the magnetic tape 6 when the head 5 contacts the magnetic tape 6 during reproduction and starts the above-mentioned tracing operation,
Control is performed to match the starting end position of the video trunk T. Further, the inclination correction circuit section 13 is for making the inclination angle of the head trajectory coincide with the video track T. These controls are mainly used to control the recorded video track T when playing back at a tape speed different from the tape running speed at the time of recording, for example, during so-called slow motion playback, quick motion playback, or still playback. This control is performed to correct the deviation of the trace locus of the head 5 in a certain relationship.

For example, the broken line in FIG. 2 shows the head trajectory U during 1/2 slot playback.
The pitch in the tape running direction B is the pitch in the tape running direction B of the video track T.
The pitch p is 1/2, and the head trajectory U moves in the opposite direction to the tape running direction by p/2 every time one head trace is performed, so the ratio is once for every two traces. Therefore, it is necessary to correct the jumping of the head 5. Also, with respect to the inclination angle of the video track T, the head trajectory U
Since the inclination angles of the traces are different, it is also necessary to correct the inclination angle by shifting the head 5 in proportion to the trace length. For this reason, the jumping control circuit section 12 outputs a jumping control signal whose voltage level is switched every time τ for tracing one track, as shown in FIG. , as shown in FIG. 5B, outputs a sawtooth waveform slope correction signal that increases the head deviation amount in proportion to time within one trace time τ. And these jumping control signals,
The tilt correction signal and the output signal from the dynamic tracking control circuit 11 are added by an adder 19 and sent to the bimorph plate 8 via the bimorph drive circuit 20, thereby moving the head 5 in the direction of arrow C ( (track width direction), so that the head trajectory U coincides with the center of the video track T.

Here, the information required for the jumping control and tilt correction is obtained from the tape running system shown in FIG. 4.

That is, in the running system of the magnetic tape 6, with the rotary head device 1 as a reference position, a full erase head 21 for erasing the full width of the tape is located upstream in the tape running direction BK, and an audio head 22 and a control head (CTL) are located downstream. Audio/C integrated with head) 23
A TL head device 24 is arranged, and a capstan 25 and a pinch roller 26 are arranged further downstream of the head device 24 to drive the magnetic tape 6 to run. To detect the rotational position of the rotating upper drum 2 of the rotary head device 1, especially the position where the video head 5 starts contacting with the tape, or to detect the head switching rotational position when two or more video heads are used. , a rotation detection pulse generator 28 is provided. Further, in order to detect the tape running speed, a kind of rotation detector 29 is provided which generates a pulse having a frequency corresponding to, for example, the rotational speed of the capstan 25 or the rotational speed of the pinch roller 26. For example, a switching pulse signal Psw, which is a head switching signal, from the rotation detection pulse generator 28, a CTL pulse Pet from the CTL head 23,
A pulse signal PFG having a frequency proportional to the tape running speed from the rotation detector 29 is supplied to the jumping control circuit section 12 and the tilt correction circuit section 13, respectively.

Incidentally, the tilt correction circuit section 13 is configured as shown in FIG. 6, for example. First, the pulse signal P has a frequency proportional to the rotational speed of the capstan 25 for driving the tape running, and therefore proportional to the tape running speed.
The FG has a constant pulse width in a monomulti (vibrator) circuit 32, is integrated in an integrating circuit 33, and is subjected to a type of frequency-voltage conversion process. The voltage output from the integrating circuit 33 is supplied to one terminal f of the changeover switch 34 and to the other terminal r of the changeover switch 34 via an inverter 35, respectively. This changeover switch 34 is controlled by a tape direction changeover signal F/H indicating whether the tape running direction is the forward direction or the reverse direction, and is connected to the terminal f side when the tape is running in the forward direction, for example.

The output signal from the changeover switch 384 is sent via the voltage shift circuit 1 to the integration circuit 36 for forming the sawtooth wave described above. FIG. 6 shows an example in which two integrating circuits 36a and 36b are provided corresponding to a rotary head device using two video heads. The integration circuits 36a and 36b are reset to zero in response to the switching pulses Psw for these two video heads. In this case, the pulse Psw is sent as is to one integrating circuit 36a, and the pulse Psw is sent to the other integrating circuit 36b.
A pulse Psw which is inverted by an inverter 37 is sent. These integrating circuits 36a and 36b each output a slope correction signal as shown in FIG. 5B, for example. In this FIG. 5B, two integrating circuits 36 a
Signals from t 36 b are collectively displayed.

In the conventional slope correction circuit section 13 as described above, since an analog circuit is used in the main part of the circuit configuration, it is troublesome to adjust the time constants of the integrating circuits 33, 36a, 36b, etc. It is difficult to integrate circuits (■C) and LSI.

The present invention has been made in view of such conventional circumstances, and it forms the above-mentioned slope correction signal through digital arithmetic processing, simplifies or eliminates circuit adjustment, and facilitates integration into ICs, especially LSIs. The object of the present invention is to provide a magnetic recording/reproducing device equipped with a tracking control circuit system that facilitates the tracking control circuit system.

That is, the feature of the magnetic recording/reproducing apparatus according to the present invention is that the magnetic head is attached to a rotating body of a rotating magnetic head via an electro-mechanical conversion element, and a control signal to the electro-mechanical conversion element is used to control the rotation of the magnetic head. In a magnetic recording/reproducing device configured to control the position of the magnetic head in the in-track direction with respect to a recording track on a magnetic tape guided and guided while being wrapped around a head device, means for outputting a first pulse signal of a frequency corresponding to the standard tape speed; an oscillator for outputting a second pulse signal of a frequency corresponding to the standard tape speed; a processing circuit unit that outputs a signal for correcting the inclination angle of the scanning locus of the magnetic head with respect to the recording track, and converts the output signal from the processing circuit unit into, for example, an analog voltage signal, and converts the output signal from the processing circuit unit into an analog voltage signal, and converts the output signal from the processing circuit unit into an analog voltage signal, and converts the output signal from the processing circuit unit into an analog voltage signal. The purpose is to perform tilt correction by supplying the

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

FIG. 7 shows the basic configuration of a slope correction circuit section 40 as a main part of an embodiment of the present invention, and the slope correction circuit section 1 of FIG.
3 and configure the other parts in the same way as in FIG. 4. In this FIG. 7, the pulse signal PFG is generated by detecting the rotation of the capstan etc.
The signal has a frequency corresponding to the tape speed and is supplied to the first counter circuit 41 as a count input signal.

Further, a switching pulse PSW having timing information at the time when the head starts contacting the tape by detecting the rotational position of the rotating drum is supplied as a reset signal (zero clear signal) to the first counter circuit 41 and the second counter circuit 42, respectively. has been done. Next, the oscillator 43
The above P at standard tape speed, so-called normal speed
It generates a pulse signal PN having a frequency equal to FG, and is supplied to the second counter circuit 42 as a count input signal. Furthermore, the count outputs from these first and second counter circuits 41 and 42 are supplied to an addition/subtraction circuit 44, and a tape direction determination signal F/RK is inverted depending on whether the tape running direction is forward or backward. Depending on the operation, either addition or subtraction is selected.

Then, by converting the digital output signal from the addition/subtraction circuit 44 into an analog voltage signal by a digital-to-analog converter (DA converter) 45, the above-mentioned slope correction signal can be obtained.

Here, in the time chart of FIG. 8, the first counter circuit 41 counts the pulse signal PFG with a cycle wave number corresponding to the tape speed, and the first count data signal C
FG is obtained, and the second counter circuit 42 counts the pulse signal PN having a frequency corresponding to the standard speed to obtain the second count data signal CN. For example, by subtracting these count data signals CFG1CN in the addition/subtraction circuit 44, a digital signal D for tilt correction is obtained.
8L is obtained. Therefore, in the case of normal playback that does not require tilt correction, the subtracted digital signal D
SL is always 0, and the above-mentioned tilt angle correction is not performed. It goes without saying that the counting operation is cleared to zero (reset) by the switching pulse signal PSW.

Next, FIG. 9 shows an example of a circuit that embodies such a basic configuration. In this FIG. 9, the high frequency oscillator 43
A second counter circuit 42 that divides the oscillation output from a frequency divider 46 and counts a pulse signal PN having a frequency corresponding to the normal speed (for example, 900 Hz) outputs, for example, 4 bits of QO to Q3. Count data is being output.

The first counter circuit 41 outputs, for example, 6-bit count data QO to Q5, and each of these bits is processed by an exclusive OR circuit (exclusive OR circuit).
(Sibu-OR circuit) E is supplied to the BO-B5 terminal of the adding/subtracting circuit 47 with the jumping data via ORO to EOR5. These EORO to EOR5 are supplied with a signal F obtained by inverting the tape direction determination signal F/R by an inverter 49.
This signal F/R is also supplied to the addition/subtraction switching terminal C of the addition/subtraction circuit 47. The input terminals AO-A4 of the addition/subtraction circuit 47 are supplied with, for example, a 5-pit jumping control data signal JO-J4 from the jumping control circuit section 12 described above. Here, the addition/subtraction circuit 44 in FIG. 7 is as follows:
In FIG. 9, an addition/subtraction circuit 47 and a subtraction circuit 48 are shown separately. Then, the output terminal SO~ of the addition/subtraction circuit 47
The 6-bit data from S5 is input to the input terminal A of the subtraction circuit 48.
The 4-bit data from the output terminals QO to Q3 of the second counter circuit 42 is supplied to the input terminals BO to B3 of the subtraction circuit 48, and the difference between them is sent to the DA converter 45. I am sending it to

Various other specific circuit configurations are possible.

As is clear from the above description, according to the present invention, since the slope correction circuit section is configured with a digital circuit, it can be relatively easily integrated into an LSI, and when applied to an automatic tracking control circuit system, it can be used in common. The above signal P FG ,
Psw etc. can be used, the overall configuration is simplified ((), no adjustment can be easily achieved, and the influence of temperature characteristics is extremely small compared to analog circuits.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing an example of a rotary head device, FIG. 2 is a front view of a magnetic tape showing recorded video tracks and CTL pulses, and FIG. 3 is a partially cutaway perspective view showing an example of how the video head is installed. , FIG. 4 is a block diagram showing an example of the configuration of the tracking control system, FIG. 5 is a time chart for explaining each operation of jumping control and tilt correction, and FIG. 6 is a block diagram showing an example of the tilt correction circuit section. It is a circuit diagram. 7 to 9 show embodiments of the present invention, "7
8 is a block circuit diagram showing the basic configuration, FIG. 8 is a time chart for explaining the operation, and FIG. 9 is a block circuit diagram showing a more specific example of the circuit configuration. 1... Rotating head device 2... Rotating upper drum 5... Video head 6... Magnetic tape 40... Tilt correction circuit 41... First counter circuit 42... Second counter Circuit 43... Oscillator 44... Addition/subtraction circuit 45... D-A converter Patent applicant Sony Corporation representative Patent attorney Kodo Koike 1) Sakae Mura - No. 1
Figure 3

Claims (1)

[Claims] The track width of the magnetic head relative to the recording trunk on the magnetic tape that is attached via a mechanical transducer and guided by a control signal to the electro-mechanical transducer is wound around the rotary head device. In a magnetic recording and reproducing apparatus configured to control a position in a direction, the device includes means for outputting a first pulse signal having a frequency corresponding to an actual tape running speed, and a second pulse signal having a frequency corresponding to a standard tape speed. an oscillator outputting a signal;
a processing circuit unit that performs a counting operation on the second pulse signal and outputs a signal for correcting the inclination angle of the scanning locus of the magnetic head with respect to the recording track; A magnetic recording/reproducing device characterized by supplying a signal to a mechanical transducer.