JPH06205350A - Automatic tracking control method and magnetic recording and reproducing device using the method - Google Patents

Abstract

PURPOSE:To obtain a reproduced video image with best picture quality at all times by adjusting tracking so as to minimize the sum of a noise level of a horizontal synchronizing signal and a crosstalk component of a chroma signal. CONSTITUTION:Upon the receipt of a command of reproduction, a microcomputer 8 designates a predetermined tracking phase to a servo circuit 9. In this case, a reproduction signal picked up by rotary heads 2,3 is given to a head amplifier 5 or the like, and a horizontal synchronizing signal of the video signal via the amplifier 5 is given to an envelope detection circuit 20, in which the signal is converted into a DC voltage signal and it is inputted to an A/D converter circuit 7. On the other hand, a chroma signal reproduced via the head amplifier 5 or the like becomes a crosstalk component and it is converted into digital data signal at an A/D converter 7 via a detection circuit 24 and the data are stored in a computer 8. Then the computer 8 stores a level of the horizontal synchronizing signal and the level of the crosstalk component and controls a servo circuit 9 based on a tracking phase minimizing the level.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic tracking control method and a magnetic recording / reproducing apparatus using this method, in which a reproduced image of the best image quality can be obtained particularly during slow reproduction (hereinafter referred to as "EP reproduction").

[0002]

2. Description of the Related Art FIG. 3 is a block circuit diagram of an automatic tracking control system of a conventional magnetic recording / reproducing apparatus, in which 1 is a rotary drum, 2 and 3 are rotary heads attached to the rotary drum 1, and Scans a recording track recorded on the magnetic tape 4 and picks up a reproduction signal. A head amplifier circuit 5 amplifies a reproduction signal picked up by the rotary heads 2 and 3. A detection circuit 6 detects the amplified reproduction signal and converts it into a DC voltage. An A-D conversion circuit 7 converts the DC voltage into a digital signal and inputs the digital signal to the microcomputer 8. Reference numeral 9 denotes a servo circuit which drives a capstan motor 11 through a capstan drive circuit 10 and a drum motor drive circuit 1
2, the drum motor 13 is controlled so as to have a predetermined speed and phase, and a command of a reference tracking phase value is received from the micro computer 8, and the control pulse picked up by the control head 14 and the output of the PG head 15 are output. Based on the above, so-called tracking adjustment for adjusting the phase of the rotary drum 1 is automatically performed.

Next, the operation of this conventional example will be described with reference to the flowchart of FIG. When the micro computer 8 receives the command of the reproducing operation, the reproducing operation is started in S1,
2 designates a predetermined tracking phase value to the servo circuit 9, and in S3, the reproduced signals picked up by the rotary heads 2 and 3 and inputted through the head amplifier 5, the detection circuit 6 and the AD conversion circuit 7 The level is stored in the memory of the micro computer 8.

Next, the micro-computer 8 designates a tracking phase value shifted by a predetermined amount from the initially designated tracking phase value to the servo circuit 9 in S4, and after the servo system becomes stable in S5, the tracking is performed. The level of the reproduction signal corresponding to the phase value is stored in the memory of the micro computer 8. Next, the operations of S4 and S5 are repeated until the range of the tracking phase value designated in S6 covers the entire range of the predetermined tracking fixed range from point A to point B shown in FIG.

Next, in S7, the tracking phase value (point C) at or near the maximum value of the levels of the reproduction signal stored in the memory is detected, and in S8, the detected tracking phase value is used as a reference value for the servo circuit. 9 and then enters the monitoring system in S9, the level E of the reproduction signal is S
When it falls below the level D at the point C defined by 8 by a predetermined tracking error allowable amount α, the operation returns to S4 and the operation of resetting the tracking phase value is restarted.

FIG. 5 is a characteristic diagram showing the relationship between the level of the reproduced signal during EP reproduction and the tracking phase value. During normal reproduction, the level of the reproduced signal exhibiting a single-peak characteristic is trapezoidal, and the maximum value cannot be detected. Therefore, at the time of EP reproduction, in S7, from the tracking phase values of the points A and B, AC:
The tracking phase value at the point C at which the BC ratio is 2: 6 for VHS recording tape and 3: 5 for S-VHS recording is calculated and given to the servo circuit as a reference value.

However, in the case of EP reproduction, the positions of the points A and B become unstable due to the crosstalk component and the like, so that the position of the calculated point C also fluctuates.

[0008]

Since the conventional automatic tracking adjustment system is configured as described above,
Since the level of the reproduced signal fluctuates due to the crosstalk component or the like during the EP reproduction, the tracking phase value given as the reference value fluctuates, and the tracking phase is not fixed to the best point of the image quality, so that the image quality of the reproduced video deteriorates. there were.

The present invention has been made to solve the above-mentioned problems, and automatic tracking adjustment can be performed so that the image quality of a reproduced image becomes the best even during SP reproduction and EP reproduction. An object of the present invention is to obtain a tracking control method and a magnetic recording / reproducing apparatus using the method.

[0010]

An automatic tracking control method according to the present invention detects a tracking phase value that minimizes the sum of the noise level of a horizontal synchronizing signal of a reproduced video signal and the level of a crosstalk component of a chroma signal. Then, the reference value is given to the tracking servo system.

In the magnetic recording / reproducing apparatus according to the present invention, the means for detecting the noise level of the horizontal synchronizing signal of the reproduced signal and the level of the crosstalk component of the chroma signal, and the sum of the levels of these signals are minimized. And a means for giving a tracking phase value to the tracking servo system as a reference value.

[0012]

According to the present invention, the tracking adjustment is automatically performed so that the sum of the noise level of the horizontal synchronizing signal of the video signal and the level of the crosstalk component of the chroma signal is minimized. The tracking phase can be fixed at the best point of the image quality of the video signal.

[0013]

EXAMPLES Example 1. 1 is a block circuit diagram of an automatic tracking control system of a magnetic recording / reproducing apparatus according to a first embodiment of the present invention. The same parts as those in FIG. In FIG. 1, 17 is an FM demodulator for returning a reproduced signal from an FM signal to a video signal, 18 is a sync separation circuit for separating a horizontal sync signal from the video signal, 19 is an amplifier, 20 is an envelope detection circuit, and is amplified by an amplifier 19. Envelope detection is performed on the generated horizontal synchronization signal, and DC voltage conversion that changes depending on the amount of noise in the horizontal synchronization signal portion is performed. Reference numeral 21 is a chroma circuit that obtains a chroma signal by performing processing such as frequency conversion on the reproduction signal of the low frequency range input from the head amplifier 5, 22
Is a 1H delay device, 23 is a subtractor, 24 is a detection circuit for detecting the crosstalk component of the clock signal output from the subtractor 23, and the output signals of the envelope detection circuit 20 and the detection circuit 24 are AD conversion signals. The data is converted into digital data by the circuit 7 and stored in the memory of the micro computer 8.

Next, the operation of the first embodiment will be described with reference to the flow chart of FIG. Micro computer 8
When a playback operation command is received, the playback operation is started in S10, and then a predetermined tracking phase value is designated for the servo circuit 9 in S11. At this time, the rotary head 2,
The reproduced signal picked up by 3 is passed through a head amplifier 5, an FM demodulator 17, a sync separation circuit 18 and an amplifier 19, and a horizontal sync signal of a video signal is converted into an envelope detection circuit 2
It is input to 0, converted into a DC voltage, and input to the AD conversion circuit 7.

On the other hand, the head amplifier 5 and the chroma circuit 2
The chroma signal reproduced through 1 is set to 1 by the 1H delay unit 22.
The crosstalk component is delayed by H, subtracted from the chroma signal after 1H by the subtractor 23 to remove the normal chroma signal, becomes a crosstalk component, is detected by the detection circuit 24, is converted into a DC voltage, and is converted into an AD converter 7. Is entered. A-D conversion circuit 7
Converts the input signals into digital data, inputs them to the micro computer 8, and stores them in the memory in S12.

Next, the micro-computer 8 operates at S13.
Then, the servo circuit 9 is shifted by a predetermined amount from the first tracking phase value and the tracking phase value is designated.
After the servo system becomes stable at 4, the level of the horizontal synchronizing signal and the level of the crosstalk component of the cross signal corresponding to the tracking phase value are stored in the memory. Next, S15
The range of the tracking phase value specified by is A shown in FIG.
The operations of S13 and S14 are repeated until the entire tracking fixed range from the point to the point B is covered.

Next, in S16, the tracking phase value at which the sum A of the noise level of the horizontal synchronizing signal and the level of the crosstalk component of the chroma signal at each tracking phase value stored in the memory is the minimum value is detected, and in S17. The detected tracking phase value is given to the servo circuit 9 as a reference value, and then the monitoring mode is entered in S18, and the sum B of the noise level of the horizontal synchronizing signal of the reproduction signal and the level of the crosstalk component of the chroma signal is set as above. If the tracking error allowable value α exceeds the sum A, the process returns to S13 to restart the reference value resetting operation.

As described above, according to the first embodiment, since an appropriate tracking phase value is always given as the reference value of the tracking servo system, the best tracking phase value is obtained not only during normal reproduction (SP mode) but also during EP reproduction. A reproduced image of high image quality can be obtained, and particularly a great effect can be obtained during EP reproduction.

[0019]

As described above, according to the present invention, the tracking adjustment is automatically performed so that the sum of the noise level of the horizontal synchronizing signal and the level of the crosstalk component of the chroma signal is minimized. There is an effect that a reproduced image of the image quality of is obtained.

[Brief description of drawings]

FIG. 1 is a block circuit diagram of an automatic tracking control system of a magnetic recording / reproducing apparatus according to a first embodiment of the present invention.

FIG. 2 is a flowchart of a first embodiment.

FIG. 3 is a block circuit diagram of an automatic tracking control system of a conventional magnetic recording / reproducing apparatus.

FIG. 4 is a flowchart of a conventional example.

FIG. 5 is a characteristic diagram showing a relationship between a reproduction signal level and a tracking phase value.

[Explanation of symbols]

 7 A-D conversion circuit 8 Micro computer 9 Servo circuit 12 Drum motor drive circuit 17 FM demodulator 18 Sync separation circuit 20 Envelope detection circuit 21 Chroma circuit 22 1H delay device 23 Subtractor

[Procedure amendment]

[Submission date] January 10, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0001

[Correction method] Change

[Correction content]

[0001]

BACKGROUND OF THE INVENTION The present invention is particularly suitable for EP reproduction.
The present invention relates to an automatic tracking control method for obtaining a reproduced image of the best image quality and a magnetic recording / reproducing apparatus using this method.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] 0002

[Correction method] Change

[Correction content]

[0002]

2. Description of the Related Art FIG. 3 is a block circuit diagram of an automatic tracking control system of a conventional magnetic recording / reproducing apparatus, in which 1 is a rotary drum, 2 and 3 are rotary heads attached to the rotary drum 1, and Scans a recording track recorded on the magnetic tape 4 and picks up a reproduction signal. A head amplifier circuit 5 amplifies a reproduction signal picked up by the rotary heads 2 and 3. A detection circuit 6 detects the amplified reproduction signal and converts it into a DC voltage. An A-D conversion circuit 7 converts the DC voltage into a digital signal and inputs the digital signal to the microcomputer 8. Reference numeral 9 denotes a servo circuit which drives a capstan motor 11 through a capstan drive circuit 10 and a drum motor drive circuit 1
The drum motor 13 through 2, and controls so that each becomes a predetermined speed and phase, microcontroller Manipulator over data 8
Then, a so-called tracking adjustment for automatically adjusting the phase of the rotary drum 1 is automatically performed based on the control pulse picked up by the control head 14 and the output of the PG head 15 in response to a command for a reference tracking phase value.

[Procedure 3]

[Document name to be amended] Statement

[Name of item to be corrected] 0003

[Correction method] Change

[Correction content]

Next, the operation of this conventional example will be described with reference to the flowchart of FIG. Microcontroller Publicis over data 8,
When receiving the command of the reproducing operation, the reproducing operation is started in S1,
In S2, a predetermined tracking phase value is designated for the servo circuit 9, and in S3, the reproduced signal picked up by the rotary heads 2 and 3 and input through the head amplifier 5, the detection circuit 6, and the AD conversion circuit 7 is selected. the level is stored in the memory of the micro <br/> con Manipulator over data 8.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0004

[Correction method] Change

[Correction content]

[0004] Next, microcontroller Publicis over data 8, S4
At the servo circuit 9, a tracking phase value shifted from the initially specified tracking phase value by a predetermined amount is specified, and after the servo system is stabilized at S5, the level of the reproduction signal corresponding to the tracking phase value is set to a micro level. Con pin
It is stored in the memory of the-menu data 8. Next, the operations of S4 and S5 are repeated until the range of the tracking phase value designated in S6 covers the entire range of the predetermined tracking fixed range from point A to point B shown in FIG.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0013

[Correction method] Change

[Correction content]

[0013]

EXAMPLES Example 1. 1 is a block circuit diagram of an automatic tracking control system of a magnetic recording / reproducing apparatus according to a first embodiment of the present invention. The same parts as those in FIG. In FIG. 1, 17 is an FM demodulator for returning a reproduced signal from an FM signal to a video signal, 18 is a sync separation circuit for separating a horizontal sync signal from the video signal, 19 is an amplifier, 20 is an envelope detection circuit, and is amplified by an amplifier 19. Envelope detection is performed on the generated horizontal synchronization signal, and DC voltage conversion that changes depending on the amount of noise in the horizontal synchronization signal portion is performed. Reference numeral 21 is a chroma circuit that obtains a chroma signal by performing processing such as frequency conversion on the reproduction signal of the low frequency range input from the head amplifier 5, 22
Is a 1H delay device, 23 is a subtractor, 24 is a detection circuit for detecting the crosstalk component of the clock signal output from the subtractor 23, and the output signals of the envelope detection circuit 20 and the detection circuit 24 are AD conversion signals. respectively circuit 7 is converted into digital data and stored in the memory of the microcontroller Manipulator over data 8.

[Procedure correction 6]

[Document name to be amended] Statement

[Correction target item name] 0014

[Correction method] Change

[Correction content]

Next, the operation of the first embodiment will be described with reference to the flow chart of FIG. Microcontroller Publicis over data 8
When receiving the command of the reproducing operation, the reproducing operation is started in S10, and then a predetermined tracking phase value is designated to the servo circuit 9 in S11. At this time, the reproduction signal picked up by the rotary heads 2 and 3 is passed through the head amplifier 5, the FM demodulator 17, the sync separation circuit 18 and the amplifier 19, and the horizontal sync signal of the video signal is input to the envelope detection circuit 20 to generate a direct current. It is converted into a voltage and input to the AD conversion circuit 7.

[Procedure Amendment 7]

[Document name to be amended] Statement

[Name of item to be corrected] 0015

[Correction method] Change

[Correction content]

On the other hand, the head amplifier 5 and the chroma circuit 2
The chroma signal reproduced through 1 is set to 1 by the 1H delay unit 22.
The crosstalk component is delayed by H, subtracted from the chroma signal after 1H by the subtractor 23 to remove the normal chroma signal, becomes a crosstalk component, is detected by the detection circuit 24, is converted into a DC voltage, and is converted into an AD converter 7. Is entered. A-D conversion circuit 7
Converts the input signals respectively to the digital data input to the microcontroller Manipulator over data 8 is stored into the memory at S12.

[Procedure Amendment 8]

[Document name to be amended] Statement

[Correction target item name] 0016

[Correction method] Change

[Correction content]

[0016] Next, microcontroller Publicis over data 8, S1
In step 3, the servo circuit 9 is shifted by a predetermined amount from the first tracking phase value and the tracking phase value is designated.
After the servo system is stabilized at 14, the level of the horizontal synchronizing signal corresponding to the tracking phase value and the level of the crosstalk component of the cross signal are stored in the memory. Next, S1
The operations of S13 and S14 are repeated until the range of the tracking phase value designated by 5 covers the entire tracking fixed range from point A to point B shown in FIG.

[Procedure Amendment 9]

[Document name to be amended] Statement

[Correction target item name] 0018

[Correction method] Change

[Correction content]

As described above, according to the first embodiment, since an appropriate tracking phase value is always given as the reference value of the tracking servo system, the reproduced image with the best image quality is obtained not only during SP reproduction but also during EP reproduction. Is obtained, and in particular, a great effect is obtained during EP reproduction.

[Procedure Amendment 10]

[Document name to be amended] Statement

[Correction target item name] Explanation of code

[Correction method] Change

[Correction content]

[EXPLANATION OF SYMBOLS] 7 A-D converter circuit 8 microcontroller Manipulator over data 9 servo circuit 12 the drum motor drive circuit 17 FM demodulator 18 sync separator 20 envelope detector circuit 21 chroma circuit 22 IH delayer 23 subtractor

Claims (2)

[Claims] 1. A tracking phase value shifted by a predetermined value within a predetermined tracking fixed range is given to a tracking servo system as a reference value, and a noise level of a horizontal synchronizing signal of a reproduction signal and a chroma signal of a tracking signal at each tracking phase value. An automatic tracking control method in which a tracking phase value that minimizes the sum of the levels of crosstalk components is detected and the tracking servo system is controlled using the detected tracking phase value as a reference value. 2. A plurality of tracking phase values shifted by a predetermined value within a predetermined tracking fixed range are successively given to a tracking servo system as reference values and included in a horizontal synchronizing signal of a reproduced signal at each tracking phase value. Means for detecting the noise level and the level of the crosstalk component of the chroma signal, a means for detecting the tracking phase value at which the sum of the noise level and the level of the crosstalk component at each tracking phase value is the minimum, and this detected A magnetic recording / reproducing apparatus comprising: means for giving a tracking phase value to the tracking servo system as a reference value.