JP3271248B2 - Tracking control device for signal recording / reproducing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tracking control device for controlling the tracking of a rotary magnetic head on an oblique track of a recording medium of a signal recording / reproducing apparatus.

[0002]

2. Description of the Related Art In a helical scan type signal recording / reproducing apparatus, a CTL signal is recorded on a track in a longitudinal direction of a magnetic tape, and a phase servo is performed by a time difference between a reference signal and a reproduced CTL signal during reproduction. In the above method, the physical distance between the oblique track to be reproduced and the CTL signal recorded in the longitudinal direction changes due to expansion and contraction of the magnetic tape over time, variations in tape tension during recording and reproduction, changes in the tape running system, etc. Resulting in. For this reason, there has been a problem that the video head cannot accurately scan an oblique track even if the time difference between the reference signal and the reproduced CTL signal is detected during reproduction and controlled to be constant.

In a control method in which a pilot signal is recorded on an oblique track and a leak signal from an adjacent track is minimized at the time of reproduction, the recording and reproduction efficiency of a head used at the time of recording and reproduction may vary. Since the minimum point of the leakage signal and the optimum point of the oblique track scanning are shifted, there has been a problem that accurate scanning cannot be performed.

[0004]

SUMMARY OF THE INVENTION In view of the above problems, the present invention provides a video head which can be used even if the magnetic tape expands and contracts due to aging, the tape tension varies during recording and reproduction, and the tape running system changes. It is another object of the present invention to provide a tracking control device of a signal recording / reproducing device capable of accurately scanning an oblique track.

[0005]

According to the present invention, there is provided a recording medium having a plurality of recording media.
In the tracking control apparatus for controlling a plurality of rotary magnetic head-tracking to reproduce the number of slant tracks, respectively, and reproducing means for reproducing a slope signal recorded by frequency modulation or phase modulation at a predetermined position of said plurality of slant tracks Sampling means for sampling the slope signal reproduced by the reproducing means with a pulse signal indicating a rotational phase of the rotary magnetic head; and a sampling value sampled by the sampling means and a predetermined level. , And control means for controlling the transfer of the recording medium based on the comparison result of the comparing means.

[0006]

FIG. 3 shows a sawtooth wave signal as a slope signal used for tracking control of the tracking control device of the present invention.
1 shows a tape format in which a signal is recorded on an oblique track of a magnetic tape. As shown in FIG. 3, a slope signal described below is recorded on a track on the tape 22 which is recorded in an oblique direction. In FIG. 3, 3A,
Reference numerals 3B and 3C denote operation trajectories of the rotating magnetic head for reproducing recorded signals, and also show signals synchronized with the rotation of the rotating drum (hereinafter, referred to as PG signals).

FIG. 5 shows the operation trajectories 3A, 3B and 3C of the rotary magnetic head showing the principle of the present invention, a slope signal reproduced in each case, and a PG signal mounted on a rotary drum. A PG signal from the generator and the PG signal
A waveform diagram shows a relationship between a sampling timing signal for sampling the slope signal and a sampling level (Sa, Sb, Sc) when the signal is delayed by a predetermined time (T) from the signal.

Assuming that the ideal operation trajectory of the rotary magnetic head is 3C in FIG. 3, the sampling level is Sc (median level of the slope signal) as shown in FIG. 5C. In each of the operation trajectories 3A and 3B, a slope signal is sampled after a predetermined time T from the PG signal as shown in FIGS.
By measuring the levels Sa and Sb, it is possible to detect the shift amount and the direction of the operation track relative to the recording track.

[0009] Here, the description is made using a PG signal as a signal synchronized with the rotation of the rotating magnetic drum.
A signal synchronized with the rotation of the rotary head is mounted drum, limited to obtain long as it can measure the time relationship between the reproduced waveforms of the timing signals have greens.

FIG. 4 is a plan view of a main part of a general helical scan type recording / reproducing apparatus. 4, the rotary heads 4A to 4D of the A to D channels are arranged on the rotary drum 4 as shown in FIG. 1 and 2 are tape guides for keeping the tape running constant, 3 is a magnetic tape, 4 is a cylindrical rotating drum, and each of the heads 4A to 4A
4D is fixed on the rotating drum 4. The rotation speed of the rotary drum and the tape running are controlled so that recording tracks as shown in FIG. 3 are formed on the magnetic tape 3 wound on the rotary drum 4.

FIG. 1 is a block diagram of a recording system according to the present invention for recording the slope signal for tracking control. In FIG. 1, 5 is a slope signal generation circuit for recording, 6 is a slope signal recording timing control circuit for controlling the recording timing of the slope signal, and 7A to 7A.
D is a switch means for switching between a recording signal and a slope signal based on the control signal output of the slope signal recording timing control circuit 6, and 8A to 8D are Ach to Dch
A recording circuit including a circuit for modulating and amplifying a recording signal and supplying a recording current; 9A to 9D
This is a rotary transformer for transmitting a recording signal to each of the heads 4A to 4D.

The recording timing control circuit 6 controls the switch means 7A to 7D so that the slope signal is recorded at a fixed position of each track by each of the heads 4A to 4D by the recording system thus constructed, and the recording circuit 8A The frequency modulation or the phase modulation is performed at .about.8D, a slope signal is supplied to each head, and recorded on a magnetic tape together with a recording signal.

FIG. 2 shows a reproducing system according to the present invention when reproducing a tape recorded in the recording system. FIG.
, 10 is a video head for reproduction, 11 is a reproduction circuit including an amplification circuit for demodulating and amplifying a reproduction signal, 1
2 is a signal processing circuit for a video signal, 13 is a sample timing signal generation circuit that receives a PG signal as a reference signal and generates a sample timing signal, 14 is a sample and hold circuit, 15 is a reference level generation circuit, and 16 is a comparison level generator. Circuit, 17 an adder, 18 a speed control circuit, 19 a motor drive circuit, 20 an FG signal waveform shaping circuit, 21 an FG signal amplifying circuit, 22 a magnetic tape on which the slope wave is recorded together with a recording signal, 23 is a capstan motor,
24 is a pinch roller.

The operation of the thus-constructed reproducing system of the present invention will be described. The slope signal reproduced by the video head 10 is sampled and held by the sample and hold circuit 14.
Sampling is performed using the sampling signal from the sample timing signal generation circuit 13, the sample value level of the slope signal is input to the comparison circuit 16, and the reference level generation circuit 15
Is compared with the median level of the slope signal serving as the reference signal generated in step (1). Then, the difference output of the comparison circuit 16 is controlled by the adder 17 to control the tape feed speed.
The output of the capstan motor 23 is added to the output of the capstan motor drive circuit 19 to control the rotation speed of the capstan motor 23.

Here, the sampling output level of the reproduced slope signal in the sample and hold circuit 14 has a known value when the video head 10 has correctly scanned the recording track. That is, when the video head 10 correctly scans the recording track, the output level of the reference level generating circuit 15 is set so that the level of the median value of the slope signal becomes a known level. By making the comparison, it is possible to detect the shift amount and the direction of the scanning track of the video head 10 with respect to the recording track.

Further, by adding this detection result to the speed control system of the capstan motor 23, the deviation of the scanning locus of the reproduction video head 10 from the recording track can be corrected. That is, the relative deviation (off-track amount) in the vertical direction with respect to the scanning locus of the rotary head can be detected and the deviation can be corrected.

[0017]

By recording the slope signal together with the recording signal at the time of tape recording, even if there is expansion and contraction due to aging of the tape, variations in the tape tension during recording and reproduction, changes in the tape running system, etc. The track information necessary for the head to scan the helical track can be detected. Further, since negligible influence of variations between the channels of the reproduction signal level, never or shift the optimum point of the helical tracks scanned by variations in the recording and reproducing efficiency of the f head to be used for recording and reproduction.

Furthermore, since it is not necessary to record the CTL signal on the track in the longitudinal direction, a fixed head is not required and the mechanism can be simplified, and at the same time, a recording circuit dedicated to the fixed head is not required, so that the circuit can be simplified. Becomes

[Brief description of the drawings]

FIG. 1 is a block diagram of a recording system according to the present invention.

FIG. 2 is a block diagram of a reproduction system of the present invention.

FIG. 3 is a diagram showing a head traveling locus.

FIG. 4 is a plan view of a main part of a general rotary head.

FIG. 5 is a waveform diagram illustrating the operation of the present invention.

[Explanation of symbols]

 4A to 4D Recording head 5 Slope signal generation circuit 6 Recording timing control circuit 7A to 7D switch 13 Sample timing generation circuit 14 Sample and hold circuit 15 Standard level generation circuit 16 Comparison circuit

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-62-202349 (JP, A) JP-A-61-110358 (JP, A) JP-A-57-173281 (JP, A) 8827 (JP, B1) (58) Field surveyed (Int. Cl. ⁷ , DB name) G11B 15/467

Claims (4)

(57) [Claims] A plurality of oblique tracks of claim 1. A recording medium which
Is in the tracking control device for controlling the tracking of a plurality of rotary magnetic heads for reproducing, reproducing means for reproducing the respective slope signal recorded in the predetermined position of said plurality of slant tracks, the slope reproduced by the reproducing means comparing means for comparing a sampling means for sampling the signal at the pulse signal indicating the rotational phase of the rotary magnetic head, a sample value sampled by said sampling means with a predetermined level,
A control unit for controlling the phase of the recording medium based on the comparison result of the comparison unit. 2. The tracking control device according to claim 1, wherein the slope signal is frequency-modulated and recorded on the diagonal track. 3. The tracking control apparatus according to claim 1, wherein the slope signal is phase-modulated and recorded on the oblique track. 4. The tracking control device for a signal recording / reproducing device according to claim 1 , wherein the slope signal is a sawtooth signal .