JPH01165058A - Automatic tracking controller for magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To execute a tracking control for driving a tracking value to a best point in a short time and to reproduce a picture good in S/N by detecting the level of a reproduced signal at every 2XN (N>=1) rotation of a rotating head. CONSTITUTION:At the time of starting a reproduction, the reproduced signal detected by the rotary heads 2, 3 in a head amplifying circuit 13 is amplified, detected, converted to a digital signal by an A/D converting circuit 15 and inputted to a microcomputer 16. At this time, a timing for detecting the digital signal once for every 2XN rotation of the rotating heads 2, 3. The microcomputer 16 inputs a tracking control pulse signal to a servo circuit 12 by a reference formed in a 1/2 frequency dividing vertical reference generating circuit 17. The servo circuit 12 outputs a speed control signal and a phase control signal to a capstan motor 9 and a drum motor 4 to control a speed and a phase. In a tape recorded by the four rotary heads, a detection is executed by the head having no mounting error nor the difference of an electromagnetic converting efficiency to reproduce the screen good in the S/N.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides automatic tracking control for a magnetic recording/reproducing device configured to detect a reproduced signal while tracing a track recorded on a magnetic tape with a rotating head. It is related to the device.

[Prior Art] FIG. 3 is a block diagram showing an automatic tracking control device for a conventional magnetic recording/reproducing device, in which ('1)
is a rotating drum, (2) and (3) are one-turn heads attached to the rotating drum (1), and these rotating heads (
2) and (3) detect playback signals while tracing the tracks recorded on the magnetic tape (7). (13) is a head amplifier circuit that amplifies the reproduction signal detected by the rotating heads (2) and (3). (14) A detection circuit detects the amplified reproduction signal output from the head amplifier circuit (13) and converts it into a DC voltage. (15) is an A/D conversion circuit which converts the above DC voltage into a digital signal and inputs it to the microcomputer (16).

(12) is a servo circuit, and a capstan drive circuit (
controlling the speed and phase of the capstan motor (9) through the tram motor drive circuit (11) and the speed and phase of the drum motor (4) through the tram motor drive circuit (11);
The rotating drum (1
) is adjusted relative to the PG pulse corresponding to the phase. That is, tracking adjustment is automatically performed.

Next, the operation of the above configuration will be explained.

At the start of playback, the microphone computer (16) specifies an initial tracking value for the servo circuit (12). At this time, the rotary head rotates once to adjust the reproduction signal level picked up by the rotary heads (2) and (3).
Head amplifier (13), detection circuit (14)
, and is input to the microcomputer (16) through the A/D conversion circuit (15) and stored in memory.

Next, the microcomputer (16) connects the servo circuit (1
For 2), specify a tracking value that differs by a predetermined amount from the initial tracking value described above, and once the servo system has stabilized, adjust the playback signal level using the microcomputer (
16).

By repeating the above operations, the tracking value is increased/decreased to detect the optimal tracking value at which the reproduced signal level is maximum, and then fixed at the optimal tracking value.

[Problems to be Solved by the Invention] Since the conventional automatic tracking control device for a magnetic recording/reproducing device was configured as described above, the purpose of predetermined tracking control was achieved to some extent. However, in conventional automatic tracking control, it takes a long time for tracking to converge.

In addition, as shown in Fig. 5, 4-head 270'' winding is performed by using a cassette adapter or the like to record a magnetic tape recorded with a magnetic recording device using the rolling method. When playing on a playback device, there are 4 rotating heads (LID).

In order to alternately detect the playback signal level of the tracks recorded in (RIG), (L20), and (R20),
There is a problem in that the tracking value and the playback signal level cannot correspond to each other, resulting in a playback screen with a poor S/N ratio.

After considering this problem, we found that even if the rotating heads (Lip) and (L20) have the same azimuth angle,
Between the re-rotating head (LIO) and (L20), there are differences in mounting to the rotating cylinder and differences in electromagnetic conversion efficiency.
Two rotating heads (LIO) with such differences
, (L20), as shown in FIG.
21) and -(L23), there is a slight difference in recording width, etc.
It was found that this is because hunting or the like occurs in the control in the width direction (W) of (R11), which makes it impossible to perform good control.

Here, the above rotating head (Lt, o), (L20)
It would be good if the difference in level and electromagnetic conversion efficiency could be eliminated, but this is practically impossible due to the dead point in manufacturing.

This invention was made to solve the above-mentioned problems, and allows a magnetic recording device having four rotary heads to record data within a short time after the start of reproduction. An object of the present invention is to provide an automatic tracking control device for a magnetic recording and reproducing device that can obtain a reproduced screen with a good S/N ratio even when a magnetic tape that has been recorded is reproduced by a reproducing device having two rotating heads. .

[Means for Solving the Problems] An automatic tracking control device for a magnetic recording and reproducing device according to the present invention adjusts the reproduction signal level to 2XN (N
≧1) 2xN (N≧1) of the rotating head detected every rotation.
) It is characterized by being configured so that tracking control is performed for each rotation.

[Function] According to the present invention, the level of the reproduced signal is adjusted to two levels of the rotating head.
By detecting every XN (N≧1) rotation, tracking control that drives the tracking value to the best point in a short time becomes possible. Therefore, even if a magnetic tape recorded with a magnetic recording device with four rotating heads is played back with a magnetic recording/reproducing device with two heads,
It becomes possible to establish a correspondence between the tracking value and the reproduction signal level, and it is possible to obtain a reproduction screen with a good S/N ratio.

[Embodiment of the Invention] Hereinafter, an embodiment of the present invention will be described based on the drawings.

FIG. 1 is a block diagram showing an automatic tracking control device for a magnetic recording/reproducing device according to an embodiment of the present invention. In the figure, (1) to (16) are the same as the conventional example shown in FIG. Therefore, the same reference numerals are given and detailed explanations are omitted.

In FIG. 1, (17) is a 1/2 frequency division vertical reference signal generation circuit, which generates a 1/2 frequency division vertical reference signal based on a delayed signal created by delaying the drum phase comparison reference signal. , and this 1/2 frequency divided vertical reference signal generation circuit (17
A tracking control pulse signal is created based on, for example, a 30H2 frequency-divided vertical reference signal generated by 172.

Figure 2 shows each operation waveform diagram when performing the above operations (
Shown in a), (b), and (c). This figure 2(a).

The operation waveforms shown in (b) and (C) correspond to A, B, and C shown in the configuration diagram of FIG. 1.

Next, the operation of the above configuration will be explained.

When playback starts, the head amplifier circuit (13) amplifies the playback signals detected by the rotating heads (2) and (3), and the playback increases! Detect @ signal and A/D
It is converted into a digital signal by a conversion circuit (15) and input to a microcomputer (16). At this time, the timing of detecting this digital signal is 1 every time the rotating heads (2) and (3) rotate 2XN (N≧1).
It is something that is detected twice. Then, the microcomputer (16) to which this digital signal is input is generated by the 1/2 frequency division/frequency division vertical reference generation circuit (17) as shown in FIG.
b) A tracking control pulse signal as shown in FIG. 2(C) is created based on the l/2 frequency-divided vertical reference signal as shown in FIG. 2(C) and inputted to the servo circuit (12).

The servo circuit (12) to which this tracking control pulse signal is input sends the speed control signal to the capstan drive circuit (12).
0), and also outputs the phase control signal to the drum drive circuit (1
1) to control the speed and phase of the capstan motor (9) and tram motor (4), and rotate with the control pulse picked up by the control head (6) and the output of the PG head (5). drum(
Adjust the relative position with the PG pulse corresponding to the phase of 1). If a digital signal is detected every 2XN rotations of the rotating video head in this way, on a tape recorded by a magnetic recording device having four rotating heads, (LL
), (R1).

(L2), (R2). Therefore, the tracking value and the reproduction signal level can be matched, and a screen with a good S/N ratio can be reproduced.

It should be noted that the same effect as in the above embodiment can be obtained by using an envelope signal of a high frequency output from a rotating video head instead of the reproduction signal level explained in the above embodiment.

[Effects of the Invention] As described above, according to the present invention, the level of the reproduced signal is detected every 2XN (N≧1) rotations of the rotary head, so that tracking (a to the best point) can be achieved in a short time. Therefore, even if a magnetic tape recorded by a magnetic recording device having four rotary heads is reproduced by a magnetic recording and reproducing device having two rotary heads, This has the effect of being able to reproduce a screen with a good S/N ratio.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram showing an automatic tracking control device for a magnetic recording/reproducing device according to an embodiment of the present invention, FIG. 2 is a signal waveform diagram for explaining the present invention in detail, and FIG. 3 is a conventional magnetic recording system. FIG. 4 is a schematic diagram showing an example of a 2-head magnetic recording/reproducing device; FIG. 5 is a schematic diagram showing an example of a 4-head magnetic recording device; FIG. 6 is a diagram showing a scanning locus during conventional reproduction, and FIG. 7 is a diagram showing a flowchart of a program. (1)--Rotating drum, (2), (:l)--Rotating head, (10)--Capstan drive circuit, (1
1)--Drum drive circuit, (12)--Servo circuit, (14)--Detection circuit, (15)-A/D
Conversion circuit, (16)--Microcomputer, (1
7) -, -1/2 frequency division vertical reference value generation circuit. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (3)

[Claims] (1) A tracking amount variable means for changing the tracking amount of the servo circuit by an arbitrary unit amount in the forward and reverse directions, a reproduced signal level detecting means for detecting the level of the reproduced signal reproduced by the rotary head, and the reproduced signal level detecting means reproduction signal level holding means for temporarily holding the output signal of the
a reproduction signal level comparison means for comparing the reproduction signal level before and after a change in the tracking amount in the tracking amount variable means; and a tracking amount control means for automatically controlling and fixing the tracking amount so that the reproduction level signal is the best. In an automatic tracking control device for a magnetic recording/reproducing device, the output signal of the reproduction signal level detection means is detected by a rotating head of 2×N (N is any integer greater than or equal to 1).
A magnetism characterized in that the reproduction signal level is held by the reproduction signal level holding means every rotation, and the tracking control is performed every 2×N rotations of the rotary head by the reproduction signal level retention means and the reproduction signal level comparison means. Automatic tracking control device for recording and reproducing equipment. (2) The automatic tracking control device for a magnetic recording/reproducing apparatus according to claim 1, wherein the reproduction signal level detection means detects the reproduction signal level from an envelope signal of a high frequency output from a rotary head. (3) Claim 1 or 2, wherein the reproduction signal level holding means is configured to store the reproduction signal level in a digital storage device using an A/D converter. automatic tracking control device for magnetic recording and reproducing devices.