JPH03162708A - Scanning locus controller - Google Patents

Abstract

PURPOSE:To secure the linearity of a tape pattern at the time of recording to improve the tap exchangeablity and to narrow the track by providing a head which can be displaced in the direction orthogonal to its plane of revolution and correcting the bend of the track. CONSTITUTION:A reference signal recording means 32 which records a reference signal with a prescribed certain period in the scanning time and a fixed detecting means 24 which detects the reference signal in the detection mode are included. Further, a detection operating means 40 which calculates the extent of displacement of the track bend based on period intervals of respective reference signals detected by the fixed detecting means 24, a driving means 44 which drives the mobile rotary head, and a storage means 42 which stores the calculation result of the detection operating means 40 and outputs the calculation result to the driving means 44 as the controlled variable of displacement correction driving in the recording mode are included to constitute a device. The reference signal is periodically recorded by the rotary head, and the extent of track displacement is detected by the change of intervals of the reference signal, and the track bend is corrected by the mobile head. Thus, the track pattern for recording is secured to improve the magnetic medium exchangeability and narrow the track.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to the control of the scanning trajectory of a head in a video tape recorder, etc., and in particular, the invention relates to the control of the scanning trajectory of a head in a video tape recorder, etc. desired pattern. For example, it relates to a scanning trajectory control device that makes a straight line. It is about improvement. [Prior Art] An example of a device 6 having a movable rotary head that can control the height of the head during recording on a record carrier is shown in FIG. This conventional example performs such head height position control to maintain a constant track width by a plurality of heads. The same figure (B) is the same figure (Al
The main parts of the image have been enlarged. In these figures, the track TA. T.B. T.C.・・・
In the predetermined interval IA of . And the rotating head H
When A scans the section IB adjacent to the predetermined section IA of the next track, the recording mode is switched to the playback mode, and the section IB adjacent to the section IA of the next track is switched from the recording mode to the playback mode.
Reproduction. That is, the crosstalk of the pilot signal recorded in section IA is reproduced. Then, the height of the head is controlled in step 1 so that the crosstalk level is always constant, and signals are recorded on a predetermined track based on this. [Problems to be Solved by the Invention] ] By the way, the linearity of a tape pattern or track during recording has conventionally depended on the accuracy and stability of the running system.Therefore, the accuracy and stability of the running system may be insufficient, or there may be problems with the head. If there is a disturbance, track bending will occur. To correct this track bending,
This is an important issue, especially when narrowing tracks is used to increase recording density. However, in the above-mentioned conventional technology, the head height control signal is obtained based on the detection result of only a certain section corresponding to a part of the vertical planking period of the recording signal, and this control signal is... It is not changed during one track scan. In other words, although it is possible to correct the position of the vertical movement of the entire track, it is almost impossible to compensate for the bending of the track, and it cannot be corrected. The present invention has been made in view of the above points, and one of its purposes is to improve tape compatibility by ensuring linearity of a tape pattern during recording. It is possible to achieve narrower tracks and to perform stable and good tracking during playback. Another purpose is to perform scanning trajectory control with a cost-effective configuration by reducing the influence of head processing accuracy and mounting accuracy on trajectory control. [Means for Solving the Problem] The present invention applies to a rotating body. By providing a head that can be displaced in a direction perpendicular to the rotating surface, the height of the movable rotating head is controlled to control the scanning locus, and a scanning method that forms an oblique track on the magnetic carrier is performed. The trajectory control device includes a reference signal recording means for recording a reference signal intermittently at a predetermined constant cycle within a scanning period while diagonally scanning the magnetic carrier, and a reference signal recording means for recording a reference signal intermittently at a predetermined constant period within a scanning period, and a reference signal recording means for recording a reference signal intermittently at a predetermined constant period during a scanning period; fixed detection means for detecting each of the reference signals; detection and calculation means for calculating the amount of displacement of track bending based on the cycle interval of each reference signal detected by the fixed detection means; It stores the driving means to carry out the operation and the calculation results by the detection calculation means. The apparatus is characterized by comprising a storage means for outputting the calculation result to the drive means as a displacement correction drive control amount in the recording mode. [Operation] According to the present invention, a reference signal is recorded on the magnetic carrier at regular intervals while the rotating head is scanning. This reference signal is detected by a fixed detection means, and the amount of head displacement is calculated from the periodic interval. Then, the movable head is displaced with a control amount corresponding to the calculated result, and the original signal is recorded. [Example] An example of the present invention will be described below with reference to the accompanying drawings. Configuration of this embodiment> First, the configuration of this embodiment will be explained. Figure 1 shows the arrangement of the head section, and Figure 2 shows the connections of the signal processing section. In FIGS. 1 and 2, a full erase head 12 is fixedly disposed on the supply side of the table 10 traveling as indicated by an arrow Fl.
The tape 10 that has passed through this is configured to be sent via a pole l4 to a drum 16 rotating in the direction of arrow F2. The drum l6 is provided with a fixed head 18 and a movable head 20 adjacent thereto, each having 62 channels. The table 10 that has passed through the drum 16 passes through the ball 22
The material is transferred to the take-up side via the . Furthermore,
On the winding side of the table 10, a detection head 24. A control/audio erasing head 26 and an audio recording B/playback head 28 are fixedly arranged in this order. Next, the erase signal output side of the erase signal output circuit 30 is connected to the full erase head 12, and the fixed head l
8 is connected to the reference signal output side of the reference signal output circuit 32. Further, the output side of a recording signal output circuit 34 is connected to the movable head 20. Furthermore, the output side of the detection head 24 is connected to the input side of a detection circuit 38 via an amplifier 36, and an example of the output of this detection circuit 38 is as follows.
It is connected to the input side of the arithmetic circuit 40.

The output side of this arithmetic circuit 40 is connected to the input side of a memory circuit 42, and the output side of this memory circuit 42 is connected to the input side of a drive circuit 44. Movable head 2
0, as indicated by the arrow F3, based on the command from the drive circuit 44, the Pymoful. It is driven by means such as a voice coil. Of the above-mentioned parts, the full erase head l2 is for erasing the entire width of the table 10. next,
The fixed head l8 is fixed to the drum l6 and rotates to record a reference signal on the tape 10. As the reference signal, for example, a sine wave signal having a frequency at which normal recording is performed on tape IO is used. The movable head 22 is movable in the height direction. In other words, it is configured to allow minute movements in the direction perpendicular to the recording track. Also,
The detection head 24 is a single gap head with a width close to a full track. Next, the detection circuit 38 performs peak detection or envelope detection on the output signal of the detection head 24, and the calculation circuit 40 uses this detection signal to calculate the interval between each intermittent signal. It is. Details will be explained later. Further, the memory circuit 42 is for storing the calculation results, and the drive circuit 44 is for driving the movable head 20 based on data output from the memory circuit 42 at an appropriate timing. ．． <Operation of the Embodiment> Next, the overall operation of the embodiment configured as described above will be explained with reference to FIGS. 3 to 5. First, full-width erasure is performed on the table lO by the full erase head l2 based on the erase signal output from the erase signal output circuit 30. After this, the following two modes of operation are performed in sequence. a. Track bend detection mode Operation in this mode is performed in advance before normal recording. After full-width erasure by the full erase head l2 described above, a reference signal is recorded by, for example, the channel CHI (7) fixed head 18 based on the output of the reference signal output circuit 32. At this time, the reference signal is transmitted intermittently at an arbitrary fixed period as shown in FIG. As a result, the table 10 has a fixed head l.
Intermittent signals a and a4 are recorded on the 8 scanning tracks 18L, respectively. Next, as the tape runs, the intermittent signals a1 to a
4 is the detection head 24 a4. a s +a. ,a,
They are detected in this order. Here, assuming that there is no bend in the track 18L, the output detection signal of the detection head 24 is
It will look like Figure TAI. As shown in the figure, since the detection head 24 crosses the intermittent signals 81 to a4 at equal times, the time interval between the centers of the intermittent signals a + ""' a4 is as follows.
Both become equal at Δt0. Therefore, no particular calculation is performed in the calculation circuit 40, and the movable head 20 is not displaced by the drive circuit 44. On the other hand, if track 18L has a bend,
The timing at which the detection head 24 crosses the intermittent signals a, ~a4 is different from the above case, and the timing at which the detection head 24 crosses the intermittent signals a, ~a4 is different from the above case, and the detection head 24 crosses the intermittent signals a, ~a4 quickly.
Cross slowly. Therefore, the intermittent signals a1 to a4
For example, as shown in FIG. 4(B), the time interval between the centers of Δt. Δts. Δt. The operations of recording such intermittent signals and detecting their time intervals are repeated multiple times as necessary, and the time intervals Δtl. Δ11. Δt,
The average value of is used in the following calculations. Next, the arithmetic circuit 40 performs a calculation to determine the amount of head displacement with respect to the normal position from this time interval. This calculation is performed, for example, as shown in FIG. In the figure, the intermittent signal al. a2 center CI. Let the interval of C2 be ΔC. Also, the relative speed between each head and the tape in the trajectory TRA is set to v1 (for example, 5 in VHS system).
8m/sec). The relative velocity on the trajectory TRB is expressed as Vi.
The angle between the trajectory TRA and the tape running direction is θ (e.g., t and V
In the Hs method, it is 5°58'9.9-). Then, on the trajectory TRA, the time required to move the head between the center points P1 and P2 is Δ as shown in FIG. 4 (Al).
to, the distance between them is ■1ΔL0. Similarly, on the trajectory TRB, the center point P1. P
Since the time required for the head movement between s and s is Δts as shown in FIG. 4(B), the distance between them is 1Δt. In addition, the time at the conventional location in the direction perpendicular to the uncurved trajectory TRA. For example, P. Assuming that the times of P and P are the same, on the trajectory TRA, P. ．． P. Since the time required to move the head between the two positions is Δt0-Δt3, the distance between them is vl(ΔL0-Δts). From these numbers, the amount of head displacement from the normal position is
, then in FIG. 5, the triangle Δp. p. p. and Δp,p. p. Since they have a similar relationship, it becomes:
Calculating the displacement i1x from this, x1= (ΔC/cosθl・{l−(Δts/Δt.l }−
It becomes f21. Xs, etc. can also be determined by similar calculations. These calculation outputs are interpolated by approximating the track bending with a straight line, for example, to obtain the result as shown by the solid line in FIG. 4(C). A control signal is generated to move the movable head 20 in a direction opposite to the displacement. The above operation is performed on channel CHI of drum l6. CH2
This is performed using each fixed head l8, and the displacement amount x7 for each is determined. The calculation result X of such calculation circuit 40. The control signal corresponding to . is temporarily stored in the memory circuit 42. After this operation, it automatically shifts to the next operation mode. b. Curvature correction recording mode In this operation mode, first, the recording of the reference signal by the fixed head 18 is stopped, and after the table lO is rewound by the amount transferred by the operation of the track bending detection mode described above, the recording by the movable head 20 is started. Recording of the signal begins. First, when there is no track bend, signals are recorded without any particular drive control being performed on the movable head 20. Unless special drive control is performed, the movable head 20 traces the same trajectory as the fixed head 18 with a slight delay. Therefore, the movable head 20 also draws a straight track like the fixed head l8, and the recording signal output from the recording signal output circuit 34 is recorded on the straight track. Next, when there is a track bend, the control amount corresponding to the track displacement position Xn stored in the storage circuit 42 is
The data is read out corresponding to the corresponding channel and track position of the movable head 20, and is further input to the drive circuit 44.
In the drive circuit 44, the movable head 20 is displaced in accordance with this control amount, and track curvature is corrected. <Other Examples> Note that the present invention is not limited to the above-mentioned embodiments, and includes, for example, the following examples. (11 In the above embodiment, the fixed head 18 provided on the drum l6 was used to perform intermittent recording of the reference signal, but the recording may be performed with the movable head 20 in a fixed state. (2) Track pattern Since the linearity of each channel of the movable head 20 exhibits almost the same characteristic, the displacement amount described above is detected only for the movable head 20 of one channel, and the same track bending correction is performed for the other channel. In addition, if similar displacement correction is to be made to the movable heads 20 of both channels, the track bending detection operation may be performed on a frame-by-frame basis. (3) Fixed head If the recording track by l8 is a very narrow track, the detection gain by the detection head 24 will be small.For this reason, in the track bend detection mode, several consecutive fields corresponding to the track width of fixed head l8 ( or several frames), the reference signals are recorded in row 11, and these are shown in Figure 4 (
It is better to obtain a detection signal like Al or (B). (4) In the above embodiment, the drive control signal for the movable head based on the calculation result is approximated by a straight line, but it may be approximated by a high-order curve such as a polynomial. Furthermore, the number of intermittent signals may be increased by shortening the intermittent period of the reference signal. Furthermore, the signal processing circuit configuration can be modified in various ways to achieve the same effect, and these are also included in the present invention. [Effects of the Invention] As explained above, the present invention has the following effects. (1) We decided to record a predetermined reference signal with a rotating head at a constant cycle, detect the amount of track displacement from the change in the interval, and perform track bending correction based on this, so the track pattern at the time of recording can be adjusted. Ensuring improved magnetic carrier compatibility. It is possible to achieve narrower tracks and to achieve stable and good tracking performance during playback. f21 f! Since we decided to record the reference signal for the i-air carrier intermittently with a rotating head and detect it with a fixed head over the entire width, the influence of the machining accuracy and mounting accuracy of those heads on trajectory control is reduced. It is also advantageous in terms of cost.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the head arrangement of an embodiment of the scanning trajectory control device according to the present invention, FIG. 2 is a circuit diagram showing the signal processing part of the embodiment, and FIG. FIG. 4 is a time chart showing the operation of the above embodiment. FIG. 5 is an explanatory diagram showing an example of the method of calculating the amount of head displacement in the embodiment. FIG. 6 is a diagram showing the conventional technique. This is an explanatory diagram. lO...Tape (magnetic carrier), 12...Full erase head, 16...Drum, l8...Fixed head (
reference signal recording means), 20... movable head (movable rotating head), 24... detection head (fixed detection means), 3
0... Erasing signal output circuit, 32... Reference signal output circuit, 34... Recording signal output circuit, 38... Detection circuit (detection calculation means), 40... Calculation time B (detection calculation means) ), 42... memory circuit (storage means), 44... drive circuit (drive means). TRA. TRB--Truck, X
n... Track displacement amount.

Claims (1)

[Claims] A rotating body is provided with a head that can be displaced in a direction perpendicular to the rotating surface thereof, and the height of this movable rotating head is controlled to control the scanning locus. A scanning trajectory control device that forms a diagonal track includes a reference signal recording means for recording a reference signal intermittently at a predetermined constant period within a scanning period while diagonally scanning the magnetic carrier; fixed detection means for detecting each of the reference signals along the running direction of the carrier; detection calculation means for calculating the displacement amount of track bending based on the period interval of each reference signal detected by the fixed detection means; The apparatus is characterized by comprising a driving means for driving the movable rotary head, and a storage means for storing the calculation result by the detection calculation means and outputting the calculation result to the driving means as a displacement correction drive control amount in the recording mode. A scanning trajectory control device.