JPH0430357A - Magnetic tape reproducing device - Google Patents

Abstract

PURPOSE:To improve the playability by giving an output of a tracking error signal control means to a tape drive means for controlling a tape feed so as to make a control variable of a tracking error signal by plural tracking signals equal to each other. CONSTITUTION:A counter 67 is counted up by an FG pulse (i) generated from a cylinder drive speed detector 11, reset by a PG pulse (j) generated from a cylinder drive speed detector 12 and the count (k) is fed to a logic circuit 68. The circuit 68 outputs a switching signal (f) and a storage command (h) in response to the count (k). A storage circuit 64 stores a tracking error signal (e) according to the command (h) and sends storage information to changeover circuit 65. The circuit 65 switches the signal (e) and the storage information of the circuit 64 according to the signal(f) to output a new tracking error signal (g) corrected. Thus, the control variable of a tracking error signal by plural tracking error signals is made equal and the playability is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a magnetic tape playback device that can be used in digital audio tape recorders, video tape recorders, and the like.

Conventional technology: In digital audio tape recorders that use a rotating head to perform recording and playback, a head tracking detection signal is recorded at a predetermined location on a track formed on a magnetic tape, and this tracking detection signal is used during playback. A method has been used in which the head is caused to travel correctly on the track using the following method (for example, Japanese Patent Application No. 62-9304).

An example of the above-mentioned conventional magnetic tape reproducing device will be described below with reference to the drawings.

Fig. 2 is a pattern diagram of tracks on which tracking detection signals are recorded, Fig. 5 is a block diagram of a conventional magnetic tape playback device, Fig. 6 is a timing chart showing its operation timing, and Fig. 7 is a diagram of the track pattern on which tracking detection signals are recorded. FIG. 3 is a relationship diagram showing the relationship between the tracks on the magnetic tape shown in the figure and the head locus.

In FIG. 5, ■ is a rotating cylinder, 11 is a cylinder rotational speed detector (FG), 12 is a cylinder rotational position detector (PG), 13 is a cylinder control circuit, 14 is a cylinder drive circuit, 1avlb is a head, and 2 is a Magnetic tape, 3 is a capstan motor, 31 is a capstan rotation speed detector (FG), 32 is a capstan control circuit, 33 is a capstan drive circuit, 4 is a synchronous signal detection circuit, 5 is a detection circuit, 61.62 is a sample circuit, 63 is a subtracter, 66 is an adder, 7 is a delay circuit, a is a head output, and b is a detection circuit 5
C is a sample pulse output from the synchronization signal detection circuit 4, d is a sample pulse output from the delay circuit 7, and e is a tracking error signal output from the subtracter 63.

In FIG. 2 and FIG. 7, 21 is a truck, 21A
is the center line of the track, 21B is the center point of the track (center point in the length direction of the track center line 21A), 22a, 2
2b is the recording position of the tracking signal, 23 is the head trajectory, and 23A is the center line of the head trajectory.

Regarding the magnetic tape playback device configured as above,
The operation will be explained below with reference to the drawings.

In FIG. 5, when reproducing a signal recorded on the magnetic tape 2, the capstan 3 is connected to a capstan rotation speed detector 11. Capstan control circuit 12. The magnetic tape 2 is fed by being rotated at a substantially constant speed by the capstan drive circuit 13. The rotating cylinder 1 also has a cylinder rotation speed detector 11. cylinder rotational position detector 12, cylinder control circuit 13. /Under drive circuit 1
4, it is rotating at a predetermined speed, and the rotation / speed / da 1
The heads la and Ib attached to the magnetic tape 2
The signal recorded on the upper track 21 is reproduced. At this time, the output a of the heads 1a and 1b is output from the synchronization signal detection circuit 4.
When a synchronizing signal is detected, a pull/pull pulse C is generated.

The delay circuit 7 to which the sample pulse C is input generates the sample pulse d after a certain period of time. At the same time head la, l
Output a of b is input to the detection circuit 5, and head la, lb
A tracking signal proportional to the amount of crosstalk between the track being reproduced and both adjacent tracks is selected and detected. The output of this detection circuit 5 is input to sample circuits 61 and 62, and sampled and held at the timing of the two sample pulses c and d. Next, a subtracter 63 calculates the difference between these two sample and hold values to create a tracking error signal e. This tracking error signal e is added to the control signal output from the capstan control circuit 32 and inputted to the capstan drive circuit 33, whereby the tape speed is tracked, and the tracking error amount approaches zero and the heads 1a and 1b It works to correctly on-track the track 21.

Here, the output timing of the tracking error signal e is explained using FIG. 6. In FIG. 6, the tracking error signal e is
is a tracking error signal due to the tracking signal 22b output from the head 1a, and section B is a tracking error signal due to the tracking signal 22a output from the head 1a. Similarly, section A1 is a tracking error signal based on tracking signal 22b output from head 1b, and section B1 is a tracking error signal based on tracking signal 22b output from head 1b.
2a, and the following relationship holds true.

A: B=5: 2=A1: Bl This means that the tracking error signal due to the first half tracking signal 22b of one track is higher than the tracking error signal due to the second half tracking signal 22a.
Because it is output for a long time compared to that by
This indicates that the control amount is increasing.

Next, the actual head trajectory will be explained using FIG. 7.

In FIG. 7, when the inclination of the track 21 on the magnetic tape 2 and the inclination of the head locus 23 on the magnetic tape 2 caused by the heads 1a and 1b attached to the rotary cylinder 1 are different from each other, a tracking error signal is generated by the tracking signal 22b. Since the control amount is more dominant than the control amount of the tracking error signal by the tracking signal 22a, the center line 23A of the head trajectory 23 does not pass through the track center point 21B.

Problem to be Solved by the Invention However, in the above conventional configuration, the tracking signal 2 recorded at a plurality of predetermined positions on the track 21 is
If the control amounts by 2a and 22b are not equal (particularly if the inclination of the track 21 and the inclination of the head trajectory 23 are different, then the heads la and lb will be correctly aligned to the center point 21 of the track).
B is not traced, and important information recorded in a portion near the center of the track 21 cannot be correctly reproduced, resulting in poor playability.

The present invention solves the above conventional problems, and even when the inclination of the track 21 and the inclination of the head locus 23 are different from each other, the heads la and lb are traced so as to pass through the center point 21B of the track. It is an object of the present invention to provide a magnetic tape reproducing device capable of reliably reproducing important information recorded in a portion near a center point 21B and improving playability.

Means for Solving the Problems To achieve this object, the magnetic tape reproducing apparatus of the present invention has a magnetic tape reproducing apparatus in which tracking signals for detecting the tracking position by crosstalk from adjacent tracks are recorded at a plurality of predetermined positions on the track. a rotary cylinder to which a magnetic tape is attached; a rotary cylinder control means for controlling the rotation of the rotary cylinder; a magnetic tape running means for running the magnetic tape; detecting the tracking signal; tracking error detection means for obtaining a tracking error signal indicating the relative position between the track and the track, and holding the value until the next tracking error signal is obtained; a reference signal generating means for providing a timing for dividing the interval with the tracking signal at the same position in one track almost equally by the number of tracking signals recorded on one track; and an output timing of the tracking error detecting means and the reference signal generating means. storage means for storing the tracking error signal in a time lag period with respect to the generated reference signal; and when the output of the tracking error detection means and the command of the reference signal generation means match, the tracking error detection means; and trunking error signal control means for outputting the output as is, and outputting the contents of the storage means if they do not match, and controlling tape feeding by applying the output of the tracking error signal control means to the tape running means. do.

Effect of the Invention With the above-described configuration, the amount of control of the tracking error signal by the plurality of tracking signals on one track is equalized, and even if the inclination of the track and the inclination of the head trajectory deviate, the head can be kept at the center point of the track. By tracing and reliably reproducing important information recorded near the center point of the track, playability can be greatly improved.

Embodiment Hereinafter, a magnetic tape reproducing apparatus according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of a magnetic tape reproducing device according to an embodiment of the present invention, FIG. 2 is a pattern diagram of tracks on which tracking detection signals are recorded, and FIG.
4 is a timing chart showing the operation timing, and FIG. 4 is a relationship diagram showing the relationship between the tracks on the magnetic tape shown in FIG. 2 and the head locus.

In FIG. 1, 1 is a rotating cylinder, 11 is a cylinder rotational speed detector (FG), 12 is a cylinder rotational position detector (PG), 13 is a cylinder control circuit, 14 is a cylinder drive circuit, la+1b is a head, and 2 is a Magnetic tape, 3 is a capstan motor, 31 is a capstan rotation speed detector (FG), 32 is a capstan control circuit, 33 is a capstan drive circuit, 4 is a synchronous signal detection circuit, 5 is a detection circuit, 61.62 is a sample circuit, 63 is a subtracter, 64 is a storage circuit, 65 is a switching circuit, 66 is an adder, 67 is a counter, 68 is a logic circuit, 7 is a delay circuit, a is a head output,
b is the tracking signal detected by the detection circuit 5, C is the sample pulse output from the synchronization signal detection circuit 4, d is the sample pulse output from the delay circuit 7, e is the tracking error signal output from the subtracter 63, and f is the sample pulse output from the delay circuit 7. The switching control signal that controls the switching circuit 65, g is the corrected tracking error signal output from the switching circuit 7, h is the storage command signal, 1 is the FG pulse output from the cylinder rotation speed detector 11, and J is the switching control signal that controls the switching circuit 65.
is the PG pulse output by the cylinder rotation position detector 12,
k is the counter value of the counter 67.

In FIGS. 2 and 4, 21 is a truck, 21A
is the center line of the track, 21B is the center point of the track (center point in the length direction of the track center line 21A), 22a, 2
2b is the recording position of the tracking signal, 24 is the head trajectory, and 24A is the center line of the head trajectory.

The operation of the magnetic tape reproducing apparatus of this embodiment configured as described above will be described below with reference to the drawings.

In FIG. 1, when reproducing a signal recorded on a magnetic tape 2, a capstan 3 is connected to a capstan rotation speed detector 11. Capstan control circuit 12. The magnetic tape 2 is fed by being rotated at a substantially constant speed by the capstan drive circuit 13. The rotating cylinder 1 also has a cylinder rotation speed pressure detector 11. The cylinder rotation position detector 12 and the cylinder control circuit 131/IJ cylinder drive circuit 14 rotate the cylinder at a predetermined speed.
Heads la and Ib attached to the renoder 1 reproduce signals recorded on tracks 21 on the magnetic tape 2. At this time, the outputs a of the heads la and lb are input to a synchronization signal detection circuit 4, which generates a sample pulse C when a synchronization signal is detected. The delay circuit 7 to which the sample pulse C is input generates the sample pulse d after a certain period of time. At the same time, the outputs a of the heads la and lb are input to the detection circuit 5, which selects and detects a tracking signal proportional to the amount of crosstalk with both adjacent tracks of the track being reproduced by the heads la and lb. The output of this detection circuit 5 is input to sample circuits 61 and 62, and sampled and held at the timing of the two sample pulses c and d. Next, a subtracter 63 calculates the difference between these two number hold values to create a tracking error signal e, which is input to a storage circuit 64 and a switching circuit 65. On the other hand, counter 67
is the FG pulse j generated by the cylinder rotation speed detector 11
The count is increased by the cylinder rotation position detector 1.
2 is reset by the generated PG pulse j, and sends the count value k to the logic circuit 68. logic circuit 6
8 outputs a switching signal f and a storage command according to the count value k.

The storage circuit 64 stores the tracking error signal e according to the storage command signal of the logic circuit 68, and the switching circuit 65
Send navel memory information. The switching circuit 65 converts the tracking error signal e directly sent from the subtracter 63 and the storage circuit 6 in accordance with the switching signal f inputted from the logic circuit 68.
4 and the tracking signal 22b.
A new tracking error signal g is corrected so that the amount of control of the tracking error signal by the tracking error signal 22a is almost the same as the amount of control of the tracking error signal by the tracking signal 22a. This corrected tracking error signal g is added to the control signal output from the capstan control circuit 32 and inputted to the capstan drive circuit 33, whereby the tape speed is controlled, the amount of tracking error approaches zero, and the head 1a , 1b work to correctly on-track the track 21.

Here, the output timing of the storage command signal h1, the switching signal f1, and the corrected tracking error signal g is explained using FIG. 3. In FIG. The storage circuit 64 stores the tracking signal 2 of the latter half on the track 21.
2a is stored. Next, the switching signal ``selects the output of the storage circuit 64 during a period when the counter value k is within a certain range, and otherwise selects the output of the subtracter 64.
It is input to the switching circuit 65 as a command to select the output of No. 3. As a result, in the corrected tracking error signal g output by the switching circuit 65, the section C is a tracking error signal due to the trunking signal 22b output from the head 1a, and the section C is a tracking error signal due to the tracking signal 22a output from the head 1a. It's a signal. Similarly, the section C1 is a tracking error signal based on the tracking signal 22b output from the head 1b, and the section D1 is a tracking error signal based on the tracking signal 22b output from the head 1b.
This is a tracking error signal based on the tracking signal 22a of output b, and the following relationship holds true.

C: D=1: 1=C1: Di This is the tracking signal 2 of the first half of one track 21
Since the tracking error signal by 2b and that by the latter half trunking signal 22a are output for almost the same time, this shows that their control amounts are almost equal.

Next, the actual head trajectory will be explained using FIG. 4.

In FIG. 4, even if the inclination of the track 21 on the magnetic tape 2 and the inclination of the head locus 24 on the magnetic tape 2 caused by the heads la and lb attached to the rotary cylinder 1 are different from each other, a tracking error due to the tracking signal 22b occurs. Since the control amount of the signal and the control amount of the tracking error signal by the trunking signal 22a are kept almost the same, the center line 24A of the head trajectory 24 passes almost directly above the center point 21B of the track.

As described above, according to the present embodiment, the counter 67 is incremented by the FG pulse L generated by the cylinder rotational speed detector 11 and reset by the PG pulse J generated by the cylinder rotational position detector 12. value k
a logic circuit 68 that outputs a switching signal f and a storage command signal in response to the command signal;
By providing a switching circuit 65 that switches between the tracking error signal stored in 4 and the tracking error signal e output from the subtracter according to the switching signal f,
It is possible to control the tracking error signal by the first half of the track and the king signal so that the control amount of the tracking error signal by the second half of the track and the king signal is almost the same, so that the head can be correctly centered on the track. You can dramatically improve playability by tracing.

Furthermore, according to this embodiment, commands to the switching circuit 65 and the memory circuit 64 are sent to the FG used for controlling the cylinder.
Since it is created based on the count value k of the counter 67 using the pulse i and the PG pulse j, there is no need to newly supply a reference signal from the outside, and a large effect can be obtained with an extremely small number of additional circuits. can.

In this embodiment, the counter 67 is configured to count up in response to the cylinder FG pulse i generated by the cylinder rotational speed detector 11, but it may be configured to count down in response to the cylinder FG pulse i.

Furthermore, in this embodiment, if the processing shown in the block diagram of FIG. 1 is performed by software, it can be realized with only extremely small changes in software.

Effects of the Invention As described above, the present invention provides a magnetic tape on which tracking signals are recorded at a plurality of predetermined positions on a track for detecting a tracking position based on crosstalk from adjacent tracks, and a rotating cylinder to which a head is attached. a cylinder control means for controlling the rotation of the rotary cylinder; a magnetic tape running means for running the magnetic tape; detecting the tracking signal and obtaining a tracking error signal indicating the relative position of the head and the track; tracking error detection means that holds the value until the next tracking error signal is obtained; and tracking that records in one track an interval between one predetermined tracking signal of the track and a tracking signal at the same position of the next track. a reference signal generating means for providing timings that are approximately equally divided by the number of signals, and storing the tracking error signal in a time difference period between the output timing of the tracking error detecting means and the reference signal generated by the reference signal generating means. If the output of the tracking error detection means matches the command of the reference signal generation means, the output of the tracking error detection means is output as is, and if they do not match, the contents of the storage means are outputted. and a tracking error signal control means for controlling the tape feeding by applying the output of the tracking error signal control means to the tape transport means, thereby controlling the tracking error signal due to a plurality of tracking signals on one track. The control amount becomes equal, and even if the track inclination and the head trajectory inclination deviate, the head traces the center point of the track, ensuring that important information recorded near the center point of the track is recorded. Playability can be greatly improved by regenerating it, and its practical effects are great.

[Brief explanation of drawings]

FIG. 3 is a timing chart showing the operation timing of the same embodiment, and FIG. 4 is a pattern diagram of the tracks on which a signal for locking detection is recorded, and FIG. 4 shows the tracks on the magnetic tape shown in FIG. 2 in the same embodiment. A relational diagram showing the relationship with the Herad locus, FIG. 5 is a block diagram of a conventional magnetic tape playback device, and FIG. 6 is a timing chart showing the operation timing of the conventional example.
FIG. 7 is a relationship diagram showing the relationship between the tracks on the magnetic tape shown in FIG. 2 and the head locus in the conventional example. 1...Rotating cylinder, la, lb...head,
2... Magnetic tape, 3... Capstan motor, 4... Synchronous signal detection circuit, 5... Detection circuit,
7... Delay circuit, 11... Cylinder rotation speed detector, 12... Cylinder rotation position detector, 13.
... Nylinder control circuit, 14... Ninda drive circuit, 31... Capstan rotation speed detector, 32
...capstan control circuit, 33...capstan drive circuit, 61.62...sample circuit,
63...Subtractor, 64...Storage circuit, 6
5...Switching circuit, 66...Adder, 67...
Counter, 68...Logic circuit.

Claims (2)

[Claims] (1) A magnetic tape on which tracking signals are recorded at a plurality of predetermined positions on the track for detecting the tracking position by crosstalk from adjacent tracks, a rotating cylinder to which a head is attached, and rotation control of the rotating cylinder. a cylinder control means for running the magnetic tape; a magnetic tape running means for running the magnetic tape; detecting the tracking signal and obtaining a tracking error signal indicating a relative position between the head and the track, thereby obtaining a next tracking error signal. tracking error detection means for retaining the value up to a certain point; and dividing an interval between a predetermined one tracking signal on the track and a tracking signal at the same position on the next track approximately equally by the number of tracking signals recorded on one track. reference signal generation means for providing timing; storage means for storing the tracking error signal in a time difference section between the output timing of the tracking error detection means and the reference signal generated by the reference signal generation means; tracking error signal control means for outputting the output of the tracking error detection means as is when the output of the detection means and the command of the reference signal generation means match, and outputting the contents of the storage means when they do not match; A magnetic tape playback device, comprising: applying an output of the tracking error signal control means to the tape running means to control tape feeding. (2) The cylinder control means includes: rotational speed detection means that generates a pulse proportional to the rotational speed of the rotating cylinder; rotational position detection means that generates a pulse once per rotation of the rotating cylinder; and the rotational speed detection means. and a cylinder driving means for driving the rotary cylinder using pulses output from the rotational position detection means, and the reference signal generation means counts up or down using the pulses generated by the rotational speed detection means; 2. The magnetic tape reproducing apparatus according to claim 1, comprising: a counting means that is reset by a pulse generated by the rotational position detecting means; and a reference signal generating means that generates the reference signal according to a count value of the counting means.