JPH0973603A - Recording signal current setting method, signal recording device, and magnetic recording medium - Google Patents

Abstract

The present invention relates to a recording signal current setting method, a signal recording device, and a magnetic recording medium, the reproduction output of which is maximized even if a magnetic recording medium having an arbitrary recording characteristic and a recording / reproducing head are combined. Therefore, the magnitude of the signal current is set so as to be accurately recorded in a short time. SOLUTION: A signal current having a constant value at which the recording is almost saturated is applied to a second head to perform pre-recording at the second azimuth angle to overwrite and erase the signal recorded up to that point, and then the same. The first head that tracks on the scanning locus is given a signal current that changes stepwise below a certain value for each measurement step, and is overwritten and recorded at the first azimuth angle, and recorded by the second head. The signal is erased in proportion to the recording depth of the signal recorded at the first head. Therefore, the reproduction output level of the signal recorded at the first head can be accurately measured.

Description

Detailed Description of the Invention

[0001]

[Table of Contents] The present invention will be described in the following order. BACKGROUND OF THE INVENTION Technical Field of the Invention Conventional Technology (FIGS. 14 to 18) Problems to be Solved by the Invention (FIGS. 14 and 19 to 2)
2) Means for Solving the Problems (FIG. 3) Embodiments of the Invention (FIGS. 1 to 13)

[0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording signal current setting method, a signal recording device and a magnetic recording medium, and for setting an optimum value of a recording signal current for obtaining a reproduction signal of maximum amplitude in a magnetic head in a video tape recorder, for example. Can be applied to.

[0003]

2. Description of the Related Art Conventionally, a video tape recorder generally records a high frequency signal obtained by frequency-modulating a carrier wave with a video signal on a magnetic tape by a rotary head. The high frequency signal is strongly recorded on the magnetic layer of the magnetic tape as the current of the recording signal applied to the head increases. The remanent magnetization of the magnetic layer increases as the magnetomotive force increases, and is a concept of the recording process of the recording wavelength unit in the magnetic layer, which is a magnetization region of a wavelength unit corresponding to a recording signal wavelength (hereinafter referred to as a magnetization region). Becomes deeper. The magnetic flux generated on the surface of the magnetic tape increases due to the residual magnetization, and the reproduction signal increases.

However, when the magnetomotive force becomes stronger when the recording signal exceeds a certain optimum strength, the magnetized region becomes too deep.
That is, the center of the magnetized region inside the magnetic layer becomes too deep.
This phenomenon is equivalent to forming a magnetized region that is thicker (thicker) and shorter than the magnetized region when the same recording signal is recorded with a certain optimum intensity. As a result, when the recording signal exceeds a certain optimum intensity, the demagnetizing field acting on the magnetized region itself causes the magnetomotive force to form a closed loop in the magnetized region. Therefore, when the recording current exceeds a certain value, the magnetic flux generated on the surface of the magnetic tape is rather reduced.

In order to maximize the magnetic flux emitted on the surface of the tape and to obtain the maximum output signal level at the head during reproduction, it is possible to set a current value for generating a magnetomotive force at the recording head, which is an optimum signal recording strength. This is the setting of the optimum value of the recording current. The characteristic curve representing the relationship between the recording current value and the reproduction output level at this time is called the optimum recording current characteristic curve. Saturation recording refers to signal recording with a strength at which a signal recorded on a magnetic material that is a recording medium is newly magnetized by a recording signal that is stronger than the magnetization signal at the time of recording and is almost erased. Say.

To obtain an optimum recording current characteristic curve in a conventional video tape recorder having a relatively long recording wavelength, using an iron oxide tape having a 1/2 ″ width in which the coercive force Hc of the magnetic powder applied to the recording medium is low. In the first method, the magnetic tape is run and erased by the preceding erasing head, and a plurality of measurement recording steps are sequentially recorded by changing the level of the recording signal for a certain period of time. After that, the magnetic tape is run to measure the reproduction output level of the reproduction signal for a plurality of corresponding reproduction measurement steps sequentially for a fixed period of time. Then, the reproduction output level is measured by overwriting and recording every measurement step.

As shown in FIGS. 14 and 15, in both the first and second methods, the recording current is increased stepwise at each recording measurement step and applied to the head to be measured, and the reproduction output is obtained. The level is sequentially detected and measured at each regeneration measurement stage,
The maximum value of the reproduction output level, that is, the optimum recording current value that is the maximum value is measured and detected and set. Incidentally, FIG.
In the first method, the rotating drum is provided with a pair of heads, for example, first and second channels, and each head travels a different track.
Further, FIG. 15 shows that different heads record and reproduce in the same track at different times in the second method.

On the other hand, as shown in FIG. 16, an audio head 1 for recording an audio signal is provided on a rotating drum 3 separately from an image head 2, and the audio signal is FM recorded in a deep magnetic layer of a magnetic tape. There is a video tape recorder. A third method is conceivable in this type of video tape recorder. As shown in FIG. 17, in the third method, the audio signal is FM-recorded in the deep layer by the audio head 1 and then the image signal is overwritten and recorded in the surface layer by the image head 2. After this,
The erasing level of the audio signal FM recorded in the deep layer is measured.

For example, as shown in FIG. 18, when the characteristic curve 4 of the reproduction output level with respect to the recording current of the image signal to be overwritten and recorded does not show a clear single maximum value but shows a substantially flat maximum value. Also, the increase in the recording depth corresponding to the recording signal strength of the image head 2 can be judged by the characteristic curve 5 showing the erasing level by the overwriting recording of the previously recorded audio signal. Therefore, it was thought that the strength of the recording signal could be judged more correctly and the recording current for always recording at the optimum depth could be set together with the first method.

[0010]

However, the above-mentioned first problem
In the above method, the measurement is performed while the magnetic tape is running. For this reason, the first method has a problem that the measurement time is longer than that of the second method (measurement in a stationary state) because recording, rewinding, and reproduction traveling operations are required. . That is, in the first method, in addition to the recording time, rewinding time, and reproduction measuring time required for measurement, the state transition time from recording, rewinding, and rewinding to reproduction of the mechanical structure system that runs the magnetic tape is Will be needed. Further, the software for controlling the mechanical structure system also requires the time for the synchronous control for precisely adjusting the traveling position for each track for measurement.

For this reason, as shown in FIG. 14, it is conceivable to record in a plurality of tracks including the measurement track and prepare for insufficient control accuracy for rewinding to the measurement recording start point. At this time, for example, the recording current, which is measured stepwise as in the signal recording of the normal use, is applied to the heads forming a pair in the first and second channels at substantially the same level. Even in this case, the recording time will be longer because the recording is performed in the extra track. Incidentally, if the control error is ± 2 tracks or more, it is necessary to record the same signal for 5 or more tracks including the above-mentioned track to be measured and the preliminary measurement track when a control error occurs.

Further, the first method is such that, when the magnetic tape runs, friction and vibration of the tape running support system, increase in fluctuation of the thickness of the air layer formed between the magnetic tape and the head and drum, and dropout. Due to the frequent occurrence of, the measured value of the reproduction output level fluctuates and the interference noise increases. Therefore, as shown in FIG.
The first method requires reproducing many observing points recorded at the same level, averaging, calculating and estimating to remove the influence of this obstacle, which results in a long measurement time. It was

Next, in the above-mentioned second method (measurement with the magnetic tape stationary), for example, first and second heads paired with the first and second channels are provided on the rotary drum. Therefore, consider the case where each head records and reproduces at the first or second inclined azimuth angle. At this time, the first head having the first azimuth angle and the second head having the second azimuth angle have the first and second recording currents measured at each measurement step as in the normal signal recording. Were recorded at the same level on the heads of the river. In this case, if the coercive force Hc of the magnetic powder is low, the recording of the first head of the first azimuth angle recorded in the previous measurement step is performed by recording the second head of the second azimuth angle of this measurement step. Most of the signals have been overwritten and erased.
Even if the first head of the channel is overwritten every time, the residual signal level of the same first azimuth angle reproduced on the same track by the previous recording signal is relatively weak. As a result, the problem of the influence of the previous recording signal on the reproduction level of the recording signal in the latter stage was reduced.

On the other hand, when the coercive force Hc of the magnetic powder is sufficiently high, such as a high-quality iron oxide tape for high image quality and a metal powder tape, which are magnetic recording media compatible with high-density recording of short-wavelength signals, the magnetic layer is overlaid. After writing, the residual signal level at the same azimuth angle due to the previous recording signal became stronger, and there was a problem that the reproduction level of the recording signal in the later stage was significantly affected by the residual signal level. As shown in FIG. 19, particularly when recording, reproducing, and measuring at a stage where the recording current is small, the previous record overwritten for each measurement stage is not sufficiently erased,
The residual signal of the same azimuth angle of the previous recording signal is reproduced together with the current recording signal.

For this reason, as shown by the solid curve 6 in the upper part of FIG. 20, the measured level of the reproduced current recording signal interferes with the residual signal, and especially when the recording current is small. There is an error in the measurement of the signal output level. Therefore, there is a problem that an error remains even if processing is performed by averaging or calculation, and accurate measurement cannot be performed. Therefore, as in the case of the above-mentioned third conventional method, the strength of recording is superposed by the first head of the signal recorded at the other second head which is paired with the first head to be measured. It is conceivable to know the recording depth, which is the recording signal strength of the first head, by knowing the amount of erasure that has undergone writing and erasing, and to measure it more accurately.

However, as shown by the broken line characteristic curve 7 in FIG. 20, the reproduction output level of the second head at the second azimuth angle depends on the first head at the first azimuth angle of the original measurement object. When the recording strength is smaller than or substantially equal to that of the second head, overwrite erasing cannot be sufficiently performed. Therefore, it is interfered with the residual signal of the recording signal of the second head of the second azimuth angle recorded at the time of the previous measurement, and particularly the reproduction of the second head which is overwritten and erased at the stage where the recording current is small. There is an error in the measurement of the signal output level. If the original recording strength of the first head is always higher than that of the other second head, the recording strength of the other second head is small.
By the subsequent overwriting and erasing by the first head, the recording signal of the second head is almost erased, and the recording signal is always erased to be in the state of the minute signal level. Therefore, as shown by the solid curve 8 on the lower side of FIG. 20, the reproduction output by the other second head has little relation to the recording strength by the first head to be measured. Therefore, the method of measuring the recording strength of the first head to be measured with the other second head cannot be used for the quantitative measurement in the conventional second method. .

By the way, as described above, as the recording signal level by the head increases, the center of the magnetized region in wavelength units becomes deeper, and the self-demagnetizing force generated inside the tape magnetic layer increases, and in general, the recording signal is increased. When the level exceeds a certain optimum intensity, the reproduction output level will decrease. However, when the coercive force Hc of the magnetic powder is high, or when the magnetic substance is oriented obliquely or vertically and densely stands up and the magnetic layer is thin, such as the magnetic substance structure of the vapor deposition tape, the demagnetization force increases. Can be difficult. Therefore, it may be difficult for the reproduction output level to decrease even when the recording signal level exceeds a certain optimum intensity.

On the other hand, in the head recorded on the metal powder tape, a high magnetic permeability film which generates a strong magnetomotive force on the inner wall surface of the headgear is used to generate a magnetomotive force of optimum strength at an optimum recording current almost exactly. Some are formed to the thickness of. With a head having this structure, it is difficult to record even deeper because it is difficult to generate a magnetic field in the gear that saturates to generate an excessively strong magnetomotive force even when a stronger recording current is applied. Therefore, even if the recording current is increased to exceed the optimum recording current and recording is performed, it may be difficult for the reproduction output level to decrease. Incidentally, if the high-permeability film is made thick, a large amount of the high-speed magnetic-permeability film material is used, and it is difficult to process the head, so that the cost is increased.

This means that, as shown in FIG. 21, the characteristic curve 9 obtained by measuring the recording current by increasing it stepwise shifts to a substantially flat characteristic before the optimum recording current is reached. To do. Especially, when recording with a head of the above structure on a vapor deposition type tape whose magnetic layer structure and magnetic characteristics are different from the coating type tape, even if the recording exceeds the optimum recording current value, the playback output level detected by the head May not decrease at all.

Further, in the flat characteristic, the residual measurement signal in the previous measurement result causes interference between the signals having the same azimuth angle as the recorded reproduction measurement signal of this time, and the reproduction output level due to a slight reproduction output fluctuation. Multiple maximum values may appear. In this way, when the reproduction output level near the optimum recording current value is almost flat, or when multiple maximum values appear, high observation accuracy is required and the measured values are numerically processed and estimated. Therefore, there is a problem that the measurement becomes complicated. This has been a great obstacle in setting the optimum recording current.

Next, in the above-mentioned third method, as shown in FIG.
As shown in FIG. 2, between the lower edge of the audio head 1 and the lower edge of the image head 2, there is a mounting step in the rotational axis direction of the rotary drum 3. This is because the audio head 1 and the image head 2 are several degrees to several tens in the rotation direction of the drum 3.
° This is because it is necessary to record on the same track of the running magnetic tape that is installed in advance.

Therefore, when the magnetic tape is statically recorded and reproduced by the third method, the track loci of the audio head 1 and the image head 2 do not match. Therefore, in the third method, it is necessary to run the magnetic tape without fail, and to record, rewind, and reproduce the data, and to measure the time, as compared with the conventional method in the stationary state. It takes a long time, and since an audio head that is different from the image head that is the measurement target is used, the measurement result of an indirect signal that has characteristics different from the recorded signal of the measurement target is used. There are drawbacks that errors are likely to occur and the mechanism control becomes complicated.

The present invention has been made in consideration of the above points. Even if a magnetic recording medium having arbitrary recording characteristics and a recording / reproducing head are combined, the magnitude of the recording signal current that maximizes the reproducing output level can be obtained. A recording signal current setting method capable of accurately setting and recording in a short time and a signal recording apparatus using the method are disclosed, and the signal recording apparatus records with an optimum recording signal current to obtain a higher output power. It is intended to propose to obtain a magnetic recording medium on which soft recording has been performed such as a video signal having a balanced quality.

[0024]

In order to solve the above problems, the present invention controls the value of a recording signal current to record a recording signal on a magnetic recording medium at a first azimuth angle, and reproduces and outputs the recording signal. In the recording signal current setting method for setting the value of the recording signal current that maximizes the reproduction output level based on the first measurement result obtained by measuring the level, in the first process, the value of the recording signal current is set. The recording signal is controlled to a constant value, and the recording signal is almost saturated-recorded on the magnetic recording medium at a second azimuth angle different from the first azimuth angle at each measurement step. Second
In the process of 1, the value of the recording signal current is controlled to be a value equal to or lower than a certain value, and the recording signal is recorded at the first azimuth angle at each measurement step so as to be superposed on the recording signal which is almost saturated and recorded by the first process. To do.

A recording signal current of a constant value at which the recording is almost saturated is applied to the second head to perform prerecording at the second azimuth angle, and the signals recorded up to that point are overwritten and erased.
After that, a recording signal current that changes stepwise below a certain value for each measurement step is applied to the first head that tracks on the same scanning locus to perform overwriting recording at the first azimuth angle. The signal recorded in the first head is erased in proportion to the recording depth of the signal recorded in the first head. Therefore, the reproduction output level of the signal recorded at the first head can be accurately measured. As a result, even if a magnetic recording medium having an arbitrary recording characteristic and a recording / reproducing head are combined, the magnitude of the recording signal current that maximizes the reproducing output can be accurately recorded in a short time.

According to the present invention, the first recording / reproducing head for recording / reproducing at the first azimuth angle and the first recording signal for adjusting the value of the recording signal current corresponding to the first recording / reproducing head. A current value adjusting means, a first recording means for recording a recording signal on the magnetic recording medium by the first recording / reproducing head, and a recording signal recorded on the magnetic recording medium by the first recording / reproducing head. A first reproducing means for reproducing, a reproducing output level measuring means for outputting a first measurement result obtained by measuring a reproducing output level of a recording signal recorded at a first azimuth angle on the magnetic recording medium, and a first measurement Measurement result storage means for storing the result, control means for controlling the first recording signal current value adjusting means, the first recording means, the first reproducing means, and the reproduction output level measuring means, and the control contents of the control means. Is stored in the control means A control content storage means for supplying a control procedure signal and setting the value of the recording signal current that maximizes the reproduction output level on the basis of the first measurement result. A second recording / reproducing head for recording and reproducing at a different second azimuth angle;
Second recording signal current value adjusting means for adjusting the value of the recording signal current corresponding to the second recording / reproducing head, and second recording means for recording the recording signal on the magnetic recording medium by the second recording / reproducing head. Recording means is provided. Further, when setting the value of the recording signal current that maximizes the reproduction output level, first, the value of the recording signal current is controlled to a constant value, and the recording signal is almost always recorded on the magnetic recording medium at the second azimuth angle at each measurement step. Record saturation.
Next, control the value of the recording signal current to a value below a certain value,
The recording signal is recorded at the first azimuth angle for each measurement step so as to be superposed on the recording signal which is almost saturated.

Further, in the present invention, the value of the recording signal current that maximizes the reproduction output level is set based on the measurement result of the reproduction output level of the recording signal recorded by controlling the value of the recording signal current. Recording at a first azimuth angle on a magnetic recording medium on which a recording signal is recorded by a signal recording device that records at a second azimuth angle different from the first azimuth angle and the second azimuth angle. When setting the value of the signal current, first, the value of the recording signal current is controlled to a constant value, and the recording signal is almost saturated-recorded on the magnetic recording medium at the second azimuth angle at each measurement step. Next, the value of the recording signal current is controlled to a value equal to or lower than a certain value, and the recording signal is superposed on the recording signal almost saturated and recorded, and the recording signal is set to the first value at each measurement step.
Record at the azimuth angle of.

[0028]

An embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 generally shows an 8 mm video tape recorder 10. 8mm video tape recorder 10
Prior to the recording of the image signal, the recording paused state on the magnetic tape 11 is maintained and the pair of heads 12 and 13 is
The recording current characteristic of is measured. Subsequently, the 8 mm video tape recorder 10 sets the optimum recording signal current, for example, the recording current value, which maximizes the reproduction output, in the heads 12 and 13, respectively, and records the image signal.

When measuring the recording current characteristic, the control block 14 of the 8 mm video tape recorder 10 cuts off the input signal S1 to the recording signal processing block 15, and the FM modulator 16 of the recording signal processing block 15 causes the carrier wave to pass through the carrier wave. Only the first and second channel gain control amplifiers (in the figure, GCA
Indicated by 17) and 18). The control block 14 is
The gain control amplifiers 17 and 18 are controlled to control the carrier wave signals S2 and S3 whose current values are controlled to the recording signal processing block 1.
5 to the mechanical block 22.

Heads 12 and 13 of mechanism block 22
Generates a magnetomotive force corresponding to each recording current value of the carrier signals S2 and S3 at each azimuth angle (± 10 °). As a result, the carrier signals S2 and S3 are recorded on the same track of the stopped magnetic tape 11 as a magnetized area having a depth and an azimuth angle according to the magnetomotive force.

One of the heads 12 and 13 as the first head having the first azimuth angle is shown in FIG.
As shown in (A), a signal (indicated by a white bar in the figure) by the recording current that increases at each measurement step j is given, and as a second head of the second azimuth angle to be scanned prior to this, As shown in FIG. 2B, the other head is provided with a signal (indicated by a white bar in the figure) by a constant maximum recording current as a constant value level at each measurement step. As a result, as shown by the arrow, the signal recorded in one head is completely overwritten and erased by the signal in the other head, and the signal recorded in the other head that precedes scanning is recorded in one head. Only the signal strength is overwritten and erased. After this, the heads 12 and 13 are attached to the magnetic tape 11 which is stopped.
The same track is tracked and reproduced signals S4 and S5 corresponding to the respective azimuth angles are given to the reproduced signal processing block 23.

Incidentally, when all the measurement steps j are completed, as shown in FIG. 3 (A), before the recording current intensity of one head (indicated by a white bar in the figure) reaches the maximum value, The reproduction output level of one head (indicated by the shaded bar in the figure) is
Reach the maximum value. Further, as shown in FIG. 3B, the reproduction output level (indicated by a shaded bar in the figure) of the other head that scans prior to this is overwritten and erased, so that the reproduction output level decreases. It will decrease gradually.

The reproduction signal processing block 23 reproduces the reproduction signal S.
The reproduction output level detector 24 detects the levels 4 and S5, respectively, and supplies the detection signal S6 to the control block 14. In the control block 14, data S7 in which the recording current value and the levels of the reproduction signals S4 and S5 indicated by the detection signal S6 are associated with each other is stored in the work data storage unit 27. When the measurement is completed, the control block 14 detects the optimum recording current value based on the data S7, and controls the recording signal processing block 15 to record at this current value.

The control block 14 has a control unit 29 including a microcomputer, an optimum recording current measurement setting program storage unit 28, and a work data storage unit 27, and reads out a program from the optimum recording current measurement setting program storage unit 28. The measurement data calculation result is read from the data storage unit 27, the recording current characteristic is measured by the control unit 29 including a microcomputer, and the optimum recording current is set. As shown in FIG. 4, when recording the carrier signals S2 and S3, the control unit 29 including the microcomputer in the control block 14 controls the optimum recording current measurement setting program storage unit 2
The recording program 30 is read from 8 to control the gains of the gain control amplifiers 17 and 18, and the mechanical block 2
The mechanism drive system 31 in 2 is controlled to maintain the recording paused state.

When the data S7 is fetched, the control unit 29 including a microcomputer reads the reproduction measurement program 32 from the optimum recording current measurement setting program storage unit 28 and controls the mechanism drive system 31 and the reproduction output level detection unit 24. When setting the optimum recording current, the control unit 29 including the microcomputer reads the reproduction calculation program 33 from the optimum recording current measurement setting program storage unit 28, reads the data S7 from the work data storage unit 27,
The optimum recording current value is detected by the reproduction calculation program 33.
Then, the control unit 29 including the microcomputer reads the recording program 30 again to read the gain control amplifier 17.
By controlling 18 and 18, the detected optimum recording current value is set.

Here, when measuring the recording current characteristic, the control unit 29 including the microcomputer measures the recording current characteristic according to the measurement procedure shown in FIG. That is, the control unit 29 including the micro computer, starts the start step SP0.
In step SP1, the mechanism drive system 31 is used to set the recording temporary stop state, and the process proceeds to step SP2. At step SP2, the control unit 29 including the microcomputer synchronizes the switching timings of the heads 12 and 13 for the same recording track, and proceeds to step SP3.

At step SP3, the control unit 29 including the microcomputer initializes the parameter i to 0, sets the parameters E and F to 2 and 1, respectively, and proceeds to step SP4. (This means that the second head has been set to the Eth head and the first head 12 has been set to the Fth head.) At step SP4, the control unit 29 including the microcomputer is operated at the Fth head.
The carrier signal S3 of the E-th head (here, the second head 13) that makes a pair with the head (here, the first head 12)
Set the recording current strength of to a maximum constant value, and
Move to P5.

At step SP5, the control unit 29 including the microcomputer initializes the parameter j to 0 and proceeds to step SP6. At step SP6,
The control unit 29 including the microcomputer determines whether the parameter j is smaller than n + 1, where n is an arbitrary number of repeated measurements, and when a negative result is obtained, determines that the parameter j is smaller than n + 1. Then, the process proceeds to step SP7. In step SP7, the control unit 29 including the microcomputer sets the recording current strength of the Fth head to the jth head.
The stage (here, the 0th stage) is set and the process proceeds to step SP8.

At step SP8, the control unit 29 including the microcomputer is operated by the E-th head (the second head in this case).
At the head 13), the carrier signal S3 is recorded once in the same track, and the process proceeds to step SP9. In step SP9, the control unit 29 including the microcomputer records once the carrier signal S2 having the recording current intensity of the jth step in the same track at the Fth head (here, the first head), and proceeds to step SP10. .

At step SP10, the control unit 29 including the microcomputer reproduces the residual recording signal of the carrier signal S3 which has been overwritten and erased at the Fth head by the Eth head. The control unit 29, which includes a microcomputer, sets the reproduction output level at this time to the data Data (i,
E, j) is stored in the work data storage unit 27, and the process proceeds to step SP11. At step SP11, the control unit 29 including the microcomputer reproduces the carrier signal S2 recorded at the Fth head. The control unit 29 including the microcomputer stores the reproduction output level at this time as the data Data (i, F, j) in the work data storage unit 27, and proceeds to step SP12.

At step SP12, the control unit 29 including the microcomputer increments the parameter j to j + 1 and repeats the processing at step SP6 and thereafter. Eventually, if a positive result is obtained in step SP6, the control unit 29 including the micro computer,
When it is judged that the parameter j is equal to n + 1, step SP
Move to 13. As a result, as shown in FIG. 6A, for example, characteristic curves 34 and 35 showing the reproduction output levels of the first and second heads 12 and 13 when the recording current of the first head 12 is changed are displayed. Obtainable.

At step SP13, the control unit 29 including the microcomputer judges whether the parameter i is equal to 1 or not, and if a negative result is obtained, only the recording current characteristic of one head (here, the first head 12) is obtained. When it is determined that the measurement is performed, the process proceeds to step SP14. In step SP14, the control unit 29 including the microcomputer sets the parameters i, E and F to 1, 1 and 2, respectively, and proceeds to step SP15. (This is the first head 12
Means that the E-th head has been set and the second head has been set to the F-th head. )

In step SP15, the control unit 29 including the microcomputer switches in synchronization with the scanning timing of the head to be recorded / reproduced next, so that the switching timing of the rotary head is 180 [°] which is the corresponding timing angle. ] Shift is performed, and the processing from step SP4 onward is repeated. Eventually, if a positive result is obtained in step SP13, the control unit 29 including the microcomputer determines that the recording current characteristics of both heads have been measured and moves to step SP16 to end the recording current characteristic measurement.

As a result, as shown in FIG. 6B, for example, the characteristic curve 36 showing the reproduction output levels of the second and first heads 13 and 12 when the recording current of the second head 13 is changed. And 37 can be obtained. By the way,
The characteristic curve 37 shows the case where the magnetomotive force of the first head 12 is smaller than that of the second head 12 and the reproduction output level near the maximum value is larger than that of the characteristic curve 35.

Next, when setting the optimum recording current value, the control unit 29 including the microcomputer detects and sets the optimum recording current value according to the detection and setting procedure shown in FIG. That is, the control unit 29 including the microcomputer is
The process enters from the start step SP17, and at step SP18, the parameter i of the data to be read is initialized to 0, the parameters E and F are set to 2 and 1, respectively, and the process proceeds to step SP19.

In step SP19, the control unit 29 including the micro computer, among the data Data (i, F, j) in which the parameter j is 0 to n, according to the above-mentioned setting, the parameter i = 0 and F = The data that is 1 is read. As shown in FIG. 8, a control unit 2 including a microcomputer
9 is the maximum value max and the minimum value min from the read data
If it is detected, the process proceeds to step SP20. Step SP
20, a control unit 29 including a microcomputer
Sets a reproduction output level lower than the maximum value max by a specified amount as the threshold value TH, and proceeds to step SP21.

Incidentally, the threshold value TH is, for example, the maximum value ma.
It is set from x to -0.5 [dB] (= 0.944 × max). Also, as another setting method, the maximum value max and the minimum value mi
If the difference from m is Δ, this difference is almost 4 [d] in the normal variable range of the magnetic recording current of the video tape recorder.
Since B] to 8 [dB], TH = max− (Δ / 8) is set to set the threshold TH using the difference. The threshold TH in this case is (0.925 to 0.954) × max, which is almost equivalent to setting the threshold value to 0.94 times the maximum value max. You can

In step SP21, the control unit 29 including the microcomputer compares the threshold value TH with the data Data (i, F, j) read in step SP19, and compares the data exceeding the threshold value TH. Peak (i, F, j) are extracted in ascending order and the process proceeds to step SP22. In step SP22, the control unit 29 including the micro computer judges whether or not the extracted data Peak (i, F, j) is one, and if a negative result is obtained, the plurality of data Peak (i. ,
F, j) is determined to exist, and the process proceeds to step SP23.

In step SP23, the control unit 29 including the microcomputer sets the threshold value TH among the parameters i = 0 and E = 2 data Data (i, E, j) according to the above-mentioned setting. The data corresponding to the parameter j of the exceeded data Data (i, E, j) is extracted, and the process proceeds to step SP24. In step SP24, the control unit 29 including the microcomputer detects the start data Data (i, E, k) in ascending order of the data Data (i, E, j) extracted in step SP23, and detects the start data Data (i, A value that becomes, for example, −3 [dB] from E, k) is calculated as the threshold value Depth.

A control unit 29 including a microcomputer
Compares the threshold Depth with the data Data (i, E, j) extracted in step SP23, and the data immediately before Data (i, E, j) which is smaller than the threshold Depth. To detect. The control unit including the microcomputer obtains the measurement stage j at this time as a set value, and proceeds to step SP25. In step SP25, the control unit 29 including the microcomputer stores the data Data (i, F, j) of the measurement step j obtained in step SP24 in the Fth head (here, the first head 1).
As the set value of the recording current in 2), the process proceeds to step SP26.

On the other hand, if a positive result is obtained in step SP22, the control unit 29 including the microcomputer will
It is judged that there is only one data Peak (i, F, j) that exceeds the threshold value TH, and the process proceeds to step SP27. Step S
In P27, the control unit 2 including the microcomputer
9 is the data Peak of the measurement stage j obtained at step SP21
(i, F, j) is set as the set value of the recording current of the Fth head (the first head 12 in this case), and the process proceeds to step SP26.

At step SP26, the control unit 29 including the microcomputer judges whether or not the parameter i is 1, and if a negative result is obtained, only the set value of one head (here, the first head 12) is set. Judging that I got it,
Move to step SP28. At step SP28,
The control unit 29 including the microcomputer sets the parameters i, E and F of the data to be read to 1, 1 and 2 respectively.
Is set, and the processing from step SP19 onward is repeated. Eventually, when a positive result is obtained in step SP26, the control unit 29 including the microcomputer determines that both head set values have been obtained, and then step SP28
Then, the detection and setting procedure is completed.

As shown in FIG. 9, the mechanical block 22 is
The rotary drum 38 once rotates counterclockwise toward the paper surface. The rotating drum 38 has heads 12 and 13 arranged 180 ° apart from each other. The magnetic tape 11 runs from left to right on the front side of the peripheral side surface of the rotating drum 38. As shown in FIG. 10 (A), in the rotary drum 38, the rotary shaft 39 is inclined with respect to the traveling direction of the magnetic tape 11. As a result, the heads 12 and 13 obliquely scan the magnetic tape 11 from the lower edge side of the magnetic tape 11.

As shown in FIG. 10 (B), 180 ° from each other
The separated heads 12 and 13 have no mounting step on the rotating drum 38. (Here, the head is viewed from the side of the magnetic layer of the magnetic tape 11 which is in contact with the head). FIG.
As shown in (C), when the magnetic tape 11 is in the recording suspended state, the heads 12 and 13 alternately record on the same track 40 on the magnetic tape 11 (here, the track 40 on the magnetic tape 11). Is viewed from the head side in contact with the magnetic layer).

By the way, when the magnetic tape 11 is in a normal running state, the heads 12 and 13 are 1 track / track respectively.
Record times. In the case of an analog video tape recorder, an image signal of one vertical section is recorded in each track in the signal of the standard video system such as the NTSC system and the PAL system. At this time, the rotary drum 38 records on one track by half rotation and records on two tracks by one rotation.

As a result, in the case of the 2-head analog FM system video tape recorder, the rotary drum 38 records an image of two vertical sections (one frame section) by one rotation.
Therefore, as shown in FIG. 10D, the recording format on the magnetic tape 11 viewed from the side of the magnetic layer with which the head is in contact has the tracks 41 and 42 corresponding to the first and second channels alternately formed. It

In the above configuration, when setting the optimum recording current, first, the tape to be recorded is controlled in the stopped state waiting for the start of recording. The maximum recording current at which the recording is almost saturated is, for example, the second azimuth of the second channel.
Is applied to the head 13 which is the recording / reproducing head, and is recorded on the track 40 only once (half-round rotation of the drum). Then, by rotating the rotary drum 38 by a half turn, a recording current that is changed stepwise at each measurement step is applied to the head 12 of the first channel, and the track 40 is overwritten and recorded only once.

By the above-mentioned procedure, 1 is set for each track 40.
Overwrite recording one by one and record one recording section (rotary drum 38
1 rotation). As a result, the track 40 has a recording signal which is saturatedly recorded by the head 13 and subsequently left overwritten and erased by the head 12, and a recording signal which is overwritten and recorded by the head 12.

Then, the respective recording signals are recorded in the head 12
Then, the reproduction output level of each recording signal is measured. The respective measured values are stored in the work data storage unit 27. Thereafter, the recording signal strength level of the head 12 is increased by one step, and the above procedure is repeated to measure the respective reproduction output levels corresponding to this recording signal strength level.

When this procedure is repeated at all measurement steps of the recording signal strength level, the data sequence of the head 12 is used, for example, as shown in FIG.
The optimum recording current characteristic curve shown in 1 (A) is given. Then, the maximum value max of the reproduction output level is obtained, and
Data Peak (i, F, j) exceeding the threshold TH shown in (B) are searched in ascending order. As a result, the data Peak (i, F, j) becomes 1
At this time, this is set as a set value that gives the optimum recording current of the head 12.

Next, the recording order of the heads 12 and 13 is exchanged back and forth in order to switch in synchronization with the scanning timing of the head to be recorded / reproduced and measured, the measurement object is changed, and the measurement is performed in the same procedure as described above. This leaves the remaining head 1
It is possible to obtain the optimum recording current characteristic curve of No. 3 and the current setting value that gives this maximum value. This is the set value that gives the optimum recording current for the head of this channel. As a result, the optimum set value of the recording current can be obtained for each of the heads 12 and 13 forming a pair.

On the other hand, a characteristic in which the portion giving the maximum value of the characteristic curve becomes almost flat even when the optimum recording current value is exceeded (for example, when the recording current is excessively set, the reproduction output level decreases by -0.5 [. In the case of a tape or head having a value of [dB] or less), a plurality of data Peak (i, F, j) are obtained in the above procedure, and the optimum recording current value to the tape cannot be known. In this case, the optimum recording current value is set using the measured data sequence of the reproduction output level after overwriting and erasing obtained from the pair Eth head.

That is, the recording current value when the characteristic curve of the Fth head begins to become flat and the reproduction signal output level of the Eth head corresponding to this recording current value are determined. FIG.
As shown in (C), the recording current when the E-th reproduction output level is attenuated by, for example, -3 [dB] as compared with this level is set as a set value for giving the optimum current value to the F-th head.

By observing the reproduction output level of the E-th head in this way, even after the characteristic of the reproduction output level of the F-th head changes from the increasing state to the flat state,
The head recording depth information can be obtained with high sensitivity. In addition, the error in the measurement stage where the recording current applied to the F-th head is still small is particularly small, and the measurement can be performed with higher accuracy.

Therefore, as the composition and structure of the head and tape are diversified, the characteristics may be uneven or different, and even if the overcurrent recording exceeds the maximum value, the characteristics become flat and the maximum value is difficult to obtain. Or, even in the case where the residual signal of the previous measurement interferes and a plurality of maximum values appear in the conventional method, according to the present invention, the recording signal strength given to the head is not affected by them. It is possible to accurately set the optimum recording current value that prevents the occurrence of excessive or shortage in a short time. In addition, it is possible to easily correct the unevenness of the recording characteristics at the beginning of use of the head and the change of the recording characteristics during the period until the service life is exhausted. Further, even in a conventional video tape recorder using a magnetic tape having a low coercive force H _C , since the residual signal of the previous recording is almost erased, the adverse effect of the signal interference due to it is not exerted and the optimum recording current can be accurately obtained. Can be set.

According to the above structure, the same track 40 is attached to the heads 12 and 13 having different azimuth angles.
And the measurement step j on the other head mentioned above.
The recording current is given at a constant and maximum value so that the recording is saturated every time, and the preceding recording is performed to erase the signal recorded in the track 40 before that. By supplying a recording current that increases in a recording manner and recording, the carrier wave signal S3 recorded in the other head is erased substantially in proportion to the recording depth of the carrier wave signal S2 recorded in the one head. Therefore, since the reproduction output level and the accurate recording depth of the carrier signal S2 overwritten on the carrier signal S3 can be measured, even if a magnetic tape and a head having arbitrary recording characteristics are combined, the optimum reproduction output is obtained. It is possible to accurately set the desired recording current value to the head in a short time and with high accuracy.

In the above-described embodiment, the case where the reproduction is performed once in one measurement stage and the measurement is performed is described, but the present invention is not limited to this, and the influence of measurement noise mixed in at the time of measurement is removed. Therefore, the measurement data obtained by measuring a plurality of times may be averaged to reduce the influence of the mixed noise. Recording, reproduction and measurement may be repeated a plurality of times for the same recording signal strength given to the head in the same procedure. In this case, the results stored in the memory may be averaged and used as the measurement value. In this case, the same effect as described above can be obtained.

In the above-described embodiment, the case where the rotating drum 38 is provided with the pair of heads 12 and 13 has been described, but the present invention is not limited to this, and as shown in FIG. 43 has two pairs of heads 44 to 47, which are used alternately for recording,
The present invention can also be applied to a case in which heads forming a pair for each type of recording signal are separately provided on the drum, and the same measurement is performed for each head pair. Incidentally, as shown in FIG. 13, two pairs of heads 4
4 to 47 scan different tracks 48 to 51 when the magnetic tape is running, and scan the same track 53 when the recording is temporarily stopped.

The two pairs of heads 44 to 47 are, for example, 4
4 is the first head of the first azimuth angle, 45 is the second head of the second azimuth angle, 46 is the third head of the first azimuth angle, and 47 is the fourth head of the second azimuth angle. In the case of the head arrangement, when the magnetic tape is in the running state, the different tracks 48 to 51 are sequentially scanned and recorded, and if the track which is the scanning locus of the first head 44 is set to 48, The second head 45 has 49 tracks, and the third head 46 has 5 tracks.
0, the track by the fourth head 47 becomes 51 so that one track is head-scanned, the head is arranged and the head is switched to the head to scan the next 270 °, and the next track is sequentially recorded on the tape. Recording and reproduction are performed by scanning. Further, in the recording paused state, the heads 44 to 47 scan the same scanning locus without any step on the head mounting surface, so that the same track 53 is sequentially scanned while switching the heads as described above. Becomes

In this case, the present invention is carried out in accordance with the above embodiment, but in the case of the recording and reproducing measurement of the first head 44, the second scanning is performed immediately before. Since the head of the azimuth angle of is the fourth head 47, almost saturated recording is performed by the fourth head 47 at the maximum recording current which is a constant value even in each measurement step, and then the first head continues.
Recording is performed at the head 44 with a recording current that is equal to or less than a certain value in the measurement stage. In this case, the fourth of the second azimuth angle
Head 47 corresponds to the second head 13 of the second azimuth angle in the above embodiment, and the first head 44 of the first azimuth angle corresponds to the first head of the first azimuth angle in the above embodiment.
It corresponds to the head 12 of the above, but during recording and reproduction measurement, recording is performed in synchronization with the head switching order by the above-mentioned head arrangement, and in the other second head 45 and third head 46, during normal running. Unlike the case of recording, the recording program is read out and synchronously controlled so that recording is not performed.

For reproduction measurement, the reproduction measurement program is read so that the head used for recording is used, the measurement data is fetched under synchronous control, and the measurement data is stored in the work data storage unit 27. . further,
The reproduction calculation program is read out, the recording current set value is calculated, and the control unit 2 including the microcomputer
When setting this set value in the GCA which is the recording signal current value adjusting means 9, the first to fourth corresponding to the GCA 17 and 18 which are the recording signal current value adjusting means in the above embodiment.
Of the four recording signal current value adjusting means and set to the first recording signal current value adjusting means corresponding to the first head 44 of the four recording signal current value adjusting means. I decided to.

Here, for reproduction measurement, it is desirable to use the head used for recording in terms of head measurement, and when recording is performed using the first head 44, the third head 46 having the same azimuth angle is used. If playing, the third head 46
If there is any abnormality in the
Although the recording and reproduction could be performed without any problem by using, the third head 46 was used for reproduction measurement, and therefore the first head 4
Since there is an inconvenience of not knowing which one of the fourth head 3 and the third head 46 is abnormal, it should be noted in the implementation.
This means that the second head 45 is different from the fourth head 47.
The same applies to. Of course, for these things, a head switching order separate from the head switching order at the time of normal recording / reproducing is prepared separately, and the first head 44
It is not excluded that the second head 45 having the same azimuth angle as that of the fourth head 47 is used for the pre-recording at the time of the measurement, and the head used for this recording is reproduced if desired. Needless to say.

The recording program 3 in the above embodiment
0, reproduction measurement program 32, reproduction calculation program 33
In the two pairs of heads, the Fth head, which is the target of recording, reproduction measurement, and the setting of the recording signal current, and the Eth head that performs almost saturated recording prior to that, are the Fth heads. Is the first head 44, the Eth head is the fourth head 47, the Fth head is the second head 45, the Eth head is the first head 44, and the Fth head is the fourth head 47. When the third head is the third head 46, the Eth head is the second head 45, and when the Fth head is the fourth head 47, the Eth head is the third head.
May be implemented as the head 46 of the above.

Further, in the above-described embodiment, the case where the pair of heads 12 and 13 provided on the rotary drum 38 are respectively measured and the respective recording currents are set has been described, but the present invention is not limited to this. However, the set value obtained by measuring one head may be used as the set value for the other head when the head processing accuracy is high and the recording characteristics of the pair of heads are not uneven. Further, in the above-described embodiment, the method of measuring even when the reproduction output level is hard to decrease even when the recording signal strength level becomes equal to or higher than the optimum strength is described, but the present invention is not limited to this, and the iron oxide tape is not limited thereto. In the case of a recording medium such that the reproduction output level always decreases above the optimum strength such as a metal coated tape or the like, the signal recorded in the previous measurement stage and remaining in the track and recorded is recorded as the second signal. Since the head has an azimuth angle and has the effect of erasing by nearly saturated recording, the maximum read output data of the head for which the second azimuth angle is set is measured without measuring the read output level of the head. The value may be obtained.

Further, in the above-mentioned embodiment, the case where the present invention is applied to the video tape recorder 10 for recording an analog signal has been described, but the present invention is not limited to this.
A recording signal reproducing apparatus that records and reproduces with a digital signal can be applied as long as it is effective to make the recording signal amplitude substantially constant and to know the recording characteristics with a specific periodic signal.

Further, in the above embodiment, the head 1
The case where the recording current of the carrier signal S2 given to one of 2 and 13 is increased from the minimum value to the maximum value in each measurement step has been described, but the present invention is not limited to this, and the recording is performed in the previous measurement step. However, since it has the effect of erasing the signal remaining and recorded in the track by substantially saturated recording, it can be applied to the case where the recording current is decreased from the maximum value to the minimum value at each measurement step. Start the measurement from the optimum recording current predicted value that is the most predictable recording current, decrease direction,
It is also possible to apply the method for finding the optimum recording current more efficiently with a smaller number of times of measurement, by sequentially increasing or decreasing the measured recording current in the increasing direction.

Further, in the above-mentioned embodiment, the case where the recording currents of the carrier signals S2 and S3 which are modulated by the image signal are set has been described, but the present invention is not limited to this, and is modulated by an arbitrary signal, for example, an audio signal. It can also be applied to the case of setting a recording signal of an arbitrary carrier wave signal and audio digital signal to be used.

Furthermore, in the above-mentioned embodiment, the case where the present invention is applied to the 8 mm video tape recorder 10 has been described, but the present invention is not limited to this, and it can be applied to other types of video tape recorders for recording image signals. Can also be applied. And the resulting video soft videotape recorded by this can get good quality

Further, in the above embodiment, the case of recording on the magnetic tape 11 has been described, but the present invention is not limited to this, and the tilted azimuth loss is applied to the same track of the recording medium where the recording depth influences as a residual magnetic flux. As long as it is a recording / reproducing system in which a signal is magnetically recorded by utilizing, it can be applied to the case of recording / reproducing on an arbitrary magnetic recording medium, for example, a disc-shaped recording medium. The video soft magnetic recording disk obtained as a result of recording by this can obtain good quality.

As the magnetic recording medium, a magnetic recording tape,
Disk-shaped magnetic recording discs, etc., generally used iron oxide tapes as magnetic recording tapes, S-VHS tapes, which are high Hc magnetic recording media with strong coercive force compatible with short wavelength high density recording, metal. Coating tapes, metal deposition tapes, etc. can be used. Especially in the 8 mm video tape recorder, high Hc metal coating tapes and metal deposition tapes as well as multilayer metal coating tapes and multilayer deposition tapes can be used.

The recording / reproducing head having the first azimuth angle and the recording / reproducing head having the second azimuth angle are recording / reproducing heads capable of magnetic recording at the respective azimuth angles. For example, a ferrite head as a ring type head having an azimuth angle in the headgear, a head in which a high-permeability material is formed in the head magnetic path, a film of a high-permeability material such as a spatula around the gearup of another head material such as ferrite. Use a film-forming head to strengthen the magnetomotive force generated by the gear, and a head that reduces noise during tape sliding due to the orientation of the crystal orientation with respect to the head scanning direction and the size of the crystal structure. Is also good.

As the recording signal current value adjusting means,
Those that receive an analog signal to change the gain, those that receive a digital signal to change its signal amplitude in an analog manner, those that are input in a digital signal state, such as multiplication / division of coefficients or bit shift in digital signal processing. The gain is varied by the signal amplitude varying means, and then the signal is converted to analog by the DA converter and output. Further, the variable gain is switched in a time division manner in synchronization with the scanning timing of the corresponding recording medium. One that sets the recording signal current of the head, and one that has a built-in storage memory that sets the recording signal current value to the corresponding head and that receives the control signal of the control means and sets the predetermined setting value of the storage memory You may use it.

As the recording means and the reproducing means, there are a case where the recording means and the reproducing means are arranged independently, and a case where the recording means and the reproducing means are one and the recording and reproducing functions are switched by a control signal. is there. Specifically, the case where the recording amplifier and the reproducing amplifier circuit or the integrated circuit have different configurations, the case where the recording amplifier and the reproducing amplifier circuit are partially or completely used in common, and the case where the recording amplifier and the reproducing amplifier circuit are used in the integrated circuit are performed. For example, when it is connected. Further, in the case where a plurality of amplifier circuits as recording / reproducing means are arranged corresponding to the number of heads, such as two or four, a method of reducing the interference of the amplifier circuit signals with each other by switching the externally supplied bias, the miute switch or the like. Can be used depending on the measurement case of the present invention.

The detection method used in the reproduction output level measuring means for measuring the reproduction output level may be detection by analog signal processing or digital signal processing.
In analog signal processing, diode detection, detection using the non-linear portion characteristic of the internal resistance of the emitter by the transistor, envelope detection, peak detection, effective value detection, etc. by using the clamp circuit together to increase the detection efficiency, etc. When converting to a digital signal and inputting and performing the detection, the absolute value processing of the digital signal processing and the digital detection processing which performs the dropout detection processing at the same time when the reproduced FM signal is digitally FM demodulated are used. Is also good. Here, as the control means for receiving the analog detection signal output, a microcomputer having a built-in AD converter may be used.

The control means is a control section including a micro computer, and the micro computer or the central signal processing device is an input / output means such as an AD converter, a DA converter, an input / output interface buffer, and a reference clock of the micro computer. Internal or external control unit, additionally ROM, EEPR
It may be a control unit having storage means such as OM and RAM inside or outside.

The measurement result storage means is a work data storage means for performing processing such as measurement data and measurement calculation, and is a RAM as a memory, a RAM capable of continuously holding measurement contents by a backup, a rewritable EEPROM, a flash memory. Can be used. This memory may be internal or external to the control means, may be a memory that communicates externally with a control unit including a microcomputer by a control bus signal, or may be removable by a socket through an interface. Can be used as a memory for performing processing such as storage and measurement calculation, and when those measurement data can be continuously stored and stored, the control content storage means for confirming the history of head characteristics is the storage of the recording current setting method. Means for storing the control content for controlling the operation of each component as a program, receiving a read control signal from the control means, and storing the control signal by the recording, reproducing measurement, and reproducing calculation program for setting the recording signal current. It is a storage means for supplying.

The storage content is a storage memory which is an optimum recording current measurement setting program storage section having a measurement recording program, a measurement reproducing program, and a measurement data calculation program as storage contents, and is a ROM, a one-time ROM, or an EEPROM. , A flash memory or the like capable of holding stored contents, which may be built in the control means, and which is externally communicated with a control unit including a microcomputer by a control bus signal of wiring. Also, it may be an internal memory, an external memory, or an attachable / detachable memory that has an interface and is detachable by a socket.These are contents such as program threshold values by communication or memory exchange, The operation parameter may be changed appropriately.

The recording signal for performing these recordings may be a single carrier signal, and scanning of the preceding recording / reproducing head in order to increase the recording depth of the recording signal of the preceding recording / reproducing head. Even if the recording signal frequency is lowered in synchronism with, if the frequency is within the range of the frequency band used when the actual input signal is converted to the recording signal by the recording signal processing block, the range of the single carrier modulation It is inside and you may use it.

[0090]

As described above, according to the present invention, the head of the second azimuth angle is supplied with the recording signal current of a constant value at which the recording is almost saturated, and the preceding recording is performed at the second azimuth angle. The signal recorded in is overwritten and erased, and after this,
The head of the first azimuth angle that tracks on the same scanning locus is provided with a recording signal current that changes stepwise below a certain value for each measurement step, and overwrite recording is performed at the first azimuth angle. The signal recorded with the head with the azimuth angle of 1 is erased in proportion to the recording depth of the signal recorded with the head with the first azimuth angle. Therefore, the reproduction output level of the signal recorded at the head of the first azimuth angle can be accurately measured. As a result, even if a magnetic recording medium having an arbitrary recording characteristic and a recording / reproducing head are combined, the recording signal current can be set to the recording / reproducing head with a high accuracy in a short time so that the magnitude of the recording signal current that maximizes the reproducing output. The method, the signal recording device, and the magnetic recording medium recorded with the optimum recording signal current can be realized.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a video tape recorder according to an embodiment of a recording signal current setting method according to the present invention.

FIG. 2 is a timing chart showing an initial recording level and reproduction output level and timing at the measurement stage.

FIG. 3 is a timing diagram showing recording levels and reproduction output levels and timings at all measurement stages.

FIG. 4 is a block diagram showing routes of recording, reproduction measurement, and optimum recording current setting.

FIG. 5 is a flowchart showing a recording current characteristic measurement procedure according to the embodiment.

FIG. 6 is a characteristic curve diagram showing a reproduction output with respect to a recording current of a tape having a high coercive force.

FIG. 7 is a flow chart showing a procedure for detecting and setting an optimum recording current according to the embodiment.

FIG. 8 is a characteristic curve diagram showing a reproduction output with respect to a recording current when a plurality of data exceeding a threshold value exist.

FIG. 9 is a schematic diagram showing the arrangement of heads on the rotating drum and the running direction of the tape.

FIG. 10 is a schematic diagram showing an arrangement of a rotating drum, a head and a track.

FIG. 11 is a characteristic curve diagram showing a reproduction output with respect to a recording current of a tape having a high coercive force, and a characteristic curve diagram showing a reproduction output with respect to a recording current when a plurality of data exceeding a threshold value exist.

FIG. 12 is a schematic diagram showing an arrangement of heads on a rotating drum and a tape running direction according to another embodiment.

FIG. 13 is a schematic diagram showing an arrangement of tracks according to another embodiment.

FIG. 14 is a timing chart showing a recording level and a reproduction level and a timing in a conventional tape running state.

FIG. 15 is a timing diagram showing a recording level and a reproduction level and timing in a conventional recording paused state.

FIG. 16 is a schematic diagram showing the arrangement of audio heads and image heads.

FIG. 17 is a schematic diagram showing a recording state by an audio head and an image head.

FIG. 18 is a characteristic curve diagram showing the reproduction output characteristics of the image head and the audio head with respect to the recording current of the image head.

FIG. 19 is a schematic diagram showing mutual interference due to residual signals having the same azimuth angle.

FIG. 20 is a characteristic curve diagram showing reproduction output when recording currents of a pair of heads are simultaneously changed.

FIG. 21 is a characteristic curve diagram showing a reproduction output when a flat portion exists near the maximum value.

FIG. 22 is a schematic diagram showing a step between an audio head and an image head.

[Explanation of reference numerals] 1, 2, 12, 13, 44 to 47 ... Head, 3, 3
8, 43 ... Rotating drum, 4-9, 34-37 ... Characteristic curve, 10 ... Video tape recorder, 11 ... Magnetic tape, 14 ... Control block, 15 ... Recording signal processing block, 16 ... FM modulator, 17, 18 ... Gain control amplifier, 22 ... Mechanical block, 23 ... Reproduction signal processing block, 24 ... Reproduction output level detection section, 27 ... Work data storage section, 28 ... Optimal recording current Measurement setting program section, 29 ... Control section including a micro computer,
31 ... Mechanism drive system, 39 ... Rotating shaft, 40 to 42, 4
8 to 51, 53 ... Track, S1 ... Input signal, S2
...... Recording signal of the first channel, S3 ...... Recording signal of the second channel, S4, S5 ...... Reproduction signal of the first and second channels, S6 ...... Reproduction output level detection signal, S7 ......
Work data control storage signal, S8 ... Recording signal processing block control signal, S9 ... Mechanism drive system control signal, S10 ...
Optimal recording current measurement setting program control storage signal, S11
...... Playback signal block control signal, S12 ...... Playback output signal, S13 ...... Control block internal control signal, S14 ......
Control bus signal.

Claims (17)

[Claims] 1. A first measurement result obtained by controlling a value of a recording signal current to record the recording signal on a magnetic recording medium at a first azimuth angle and measuring a reproduction output level of the recording signal. Based on the above, in the recording signal current setting method for setting the value of the recording signal current that maximizes the reproduction output level, the value of the recording signal current is controlled to a constant value, and the recording signal is set to Second different from first azimuth angle
The first process for performing almost saturated recording on the magnetic recording medium at the azimuth angle, and controlling the value of the recording signal current to a value equal to or less than the predetermined value, and performing the substantially saturated recording by the first process. A recording signal current setting method, further comprising: a second process of recording the recording signal at the first azimuth angle at each measurement step so as to be superimposed on the signal. 2. A third process for measuring a reproduction output level of the recording signal which is recorded by the first and second processes in an overlapping manner and remains at the second azimuth angle at each of the measuring steps, A fourth process of measuring the reproduction output level of the recording signal recorded by superimposing at the first azimuth angle by the process of 2 at each measurement step, and the first measurement result obtained by the fourth process. And the third above
5. The fifth process of setting the value of the recording signal current that maximizes the reproduction output level, based on the second measurement result obtained in the process of. Recording signal current setting method. 3. In normal recording / reproducing, a first recording / reproducing head for recording / reproducing at the first azimuth angle and a second recording / reproducing head for recording / reproducing at the second azimuth angle. A third recording / reproducing head for recording and reproducing at the first azimuth angle;
The fourth recording / reproducing head for recording / reproducing at the azimuth angle of 1) sequentially records / reproduces on / from the magnetic recording medium. When the above setting is made, the fourth or second recording / reproducing is performed in the first processing. It is recorded by a head and recorded in the first process in the second process.
The recording signal current setting method according to claim 1, wherein the recording is performed by a third recording / reproducing head. 4. The recording signal current setting method according to claim 1, wherein the recording signal is reproduced by a recording / reproducing head on which the recording signal is recorded. 5. A recording / reproducing head arranged immediately before a recording / reproducing head for recording at the first azimuth angle for substantially saturated recording at the second azimuth angle. The recording signal current setting method described. 6. The recording signal current setting method according to claim 1, wherein the recording signal in the first and second processes is a carrier signal modulated with an arbitrary signal. 7. A first recording / reproducing head for recording and reproducing at a first azimuth angle, and a first recording signal current value adjusting for adjusting a value of a recording signal current corresponding to the first recording / reproducing head. Means for recording the recording signal on the magnetic recording medium by the first recording / reproducing head;
The recording signal recorded on the magnetic recording medium is converted into the first signal.
A first reproducing means for reproducing by the recording / reproducing head of
Reproduction output level measuring means for outputting a first measurement result of measuring a reproduction output level of the recording signal recorded on the magnetic recording medium at the first azimuth angle, and a measurement for storing the first measurement result. Result storage means, control means for controlling the first recording signal current value adjusting means, the first recording means, the first reproducing means, and the reproduction output level measuring means,
The control content storing means for storing the control content of the control means and supplying the control procedure signal to the control means, and the recording for maximizing the reproduction output level based on the first measurement result. In a signal recording device for setting a value of a signal current, a second recording / reproducing head for recording and reproducing at a second azimuth angle different from the first azimuth angle and a value of the recording signal current for the second recording. And a second recording means for adjusting the recording signal current value adjusting means corresponding to a reproducing head and a second recording means for recording the recording signal on the magnetic recording medium by the second recording / reproducing head. At the time of setting, the value of the recording signal current is controlled to be a constant value, and the recording signal is almost saturated-recorded on the magnetic recording medium at the second azimuth angle at each measurement step. Constant value Controlled to a value below to overlap the substantially saturated recorded recording signal, a signal recording apparatus and recording the recording signal for each of the measuring step in the first azimuth angle. 8. A second reproducing means for reproducing the recording signal recorded on the magnetic recording medium by the second recording / reproducing head, wherein the second recording means is superposed and recorded at the second azimuth angle. The second measurement result obtained by measuring the remaining reproduction output level of the recording signal at each measurement step and the reproduction output level of the recording signal recorded by being superposed at the first azimuth angle at each measurement step. 8. The signal recording apparatus according to claim 7, wherein the value of the recording signal current that maximizes the reproduction output level is set based on the first measurement result obtained by performing the measurement. 9. The first recording / reproducing head, the second recording / reproducing head, and the first azimuth angle for recording / reproducing on the magnetic recording medium in order during normal recording / reproducing. A third recording / reproducing head for reproduction and a fourth recording / reproducing head for recording / reproducing at the second azimuth angle are sequentially arranged, and the value of the recording signal current corresponds to the third recording / reproducing head. The third recording signal current value adjusting means, the fourth recording signal current value adjusting means for adjusting the value of the recording signal current corresponding to the fourth recording / reproducing head, and the recording signal. Third recording means for recording on the magnetic recording medium by the third recording / reproducing head, and fourth recording means for recording the recording signal on the magnetic recording medium by the fourth recording / reproducing head. With the above settings Recording the recording signal substantially saturated by the fourth or second recording / reproducing head, superimposing it on the recording signal almost saturated recording, and recording by the first or third recording / reproducing head. The signal recording device according to claim 7. 10. A second recording / reproducing head for reproducing the recording signal recorded on the magnetic recording medium by the second recording / reproducing head.
And a third reproducing means for reproducing the recording signal recorded on the magnetic recording medium by the third recording / reproducing head.
And a reproducing means for reproducing the recording signal recorded on the magnetic recording medium by the fourth recording / reproducing head.
8. The signal recording apparatus according to claim 7, further comprising: a reproducing unit for reproducing the recording signal by the recording / reproducing head on which the recording signal is recorded when the setting is performed. 11. In the above setting, the recording / reproducing head disposed immediately before the recording / reproducing head for recording at the first azimuth angle performs substantially saturated recording at the second azimuth angle. Claim 7
The signal recording device according to. 12. The signal recording device according to claim 7, further comprising a measurement control unit for arranging the measurement result storage unit, the control unit and the control content storage unit for controlling the measurement and control procedure. . 13. The same circuit is switched by the control means during recording to be used as the first and second recording means or the first and fourth recording means, and the same circuit is reproduced during reproduction. 8. The switching means is used by the control means to be used as the first and second reproducing means or the first and fourth reproducing means.
The signal recording device according to. 14. The first and second recording signal current value adjusting means has a gain setting storage means for storing a gain set by a gain setting control signal given by the control means, When alternately recording on the magnetic recording medium with the first and second recording / reproducing heads, a control signal given from the control means is synchronized with the start of recording of the first and second recording / reproducing heads. 8. The signal recording apparatus according to claim 7, wherein the gains respectively set corresponding to the first and second recording / reproducing heads are switched. 15. A value of the recording signal current that maximizes the reproduction output level is set based on a measurement result of the reproduction output level of the recording signal recorded by controlling the value of the recording signal current. When recording at the first azimuth angle on a magnetic recording medium on which the recording signal is recorded by a signal recording device that records at an azimuth angle and a second azimuth angle different from the first azimuth angle. When setting the value of the recording signal current, the value of the recording signal current is controlled to a constant value, and the recording signal is almost saturated-recorded on the magnetic recording medium at the second azimuth angle at each measurement step. Controlling the value of the recording signal current to a value equal to or less than a certain value, and superimposing the recording signal on which the saturation recording has been performed, and recording the recording signal at the first azimuth angle at each measurement step. Characteristic The magnetic recording medium. 16. The magnetic recording medium according to claim 15, wherein the magnetic recording medium is a magnetic recording tape. 17. The magnetic recording medium according to claim 15, wherein the magnetic recording medium is a magnetic recording disk.