JPS6361407A - Rotary magnetic head device - Google Patents

Abstract

PURPOSE:To control an absolute height position between a pair of movable heads, by performing the driving control of respective displacement control element in a driving control system. CONSTITUTION:A pair of movable heads 3A and 3B are arranged on a rotary drum 2 through the displacement control elements 5A and 5B respectively, and fixed heads 4A and 4B are arranged on the drum 2 so as to trace lagging behind a recording track traced by respective head 3. At the time of recording a signal by respective head 3, a pilot signal is recorded on one side, and the signal is reproduced on the other side, and also, the pilot signal is recorded on one side, and the signal is reproduced on the other side. The element 5A is driven and controlled by comparing 30 each reproduced output level, and the driving control of element 5B is performed so as to maximize the signal level of a reproduced pilot signal of the head 4B. In this way, the control of the absolute height between a pair of heads 3 can be performed.

Description

[Detailed description of the invention] The present invention will be explained in the following order.

A. Industrial field of application B3 Summary of the invention C8 Prior art 0 Problems to be solved by the invention E0 Means for solving the problems F9 Effects G. Example (G-1) Rotating magnetic head device Mechanical configuration (Fig. 2,
(Figure 3) CG-2) Configuration of the drive control system of the rotary magnetic head device (Figure 1) (c-3) Operation of the embodiment (Figures 4 to 8) H9 Effects of the invention A, Industrial Field of Application The present invention relates to a rotary magnetic head device used in a helical scan type video tape recorder, etc., and in particular, the present invention relates to a rotary magnetic head device used in a helical scan type video tape recorder, etc., and in particular, a device for recording signals while performing tracking control using a pair of movable heads disposed on a rotary drum via a displacement control element. The so-called DTF (Dynamic
6B0 Summary of the Invention The present invention relates to a rotary magnetic head device having a DTP function, in which a pair of movable heads mutually record and reproduce biloft signals. By reproducing a pilot signal recorded by a movable head by a fixed head, the reproduced output can be used to control the absolute height position as well as the step of each movable head.

C8 Prior Art Conventionally, as a rotating magnetic head device used in a helical scan type video tape recorder, etc., a pair of rotary magnetic heads are installed on a rotating drum through displacement control elements each using an electrostrictive element such as a bimorph plate. A rotary magnetic head device having a DTP function is known in which a movable head mutually records and reproduces a pilot signal when recording a signal, and uses the reproduced output to adjust the height difference of each movable head. For example, the applicant of the present invention recorded a pilot signal used for level difference adjustment between a pair of movable heads alternately with a predetermined recording trunk separated by a pair of movable heads, thereby recording a signal in the same section as the biloft signal recording section. We have previously proposed a recording device that can be used as a reproduction section and that can reliably perform the DTP operation even when there is little deviation between the track start ends of adjacent tracks (
(See Japanese Patent Application No. 60-35899).

D9 Problems to be Solved by the Invention Incidentally, in a rotary magnetic head device having a DTP function, the height of each movable head may vary due to hysteresis characteristics or changes over time of the bimorph plate itself, which is used as a displacement control element for a pair of movable heads. Since the position changes, the absolute height position cannot be controlled even if relative step adjustment is performed, and conventionally it has not been possible to guarantee an absolute recording pattern on the magnetic tape.

Therefore, the present invention provides absolute recording on the magnetic tape by adjusting the relative height difference and controlling the absolute height position of each movable head. It is an object of the present invention to provide a rotating magnetic head device with a new configuration that can guarantee the A pattern.

Means for Solving Problem E1 In order to achieve the above-mentioned object, the rotating magnetic head mounting according to the present invention includes a pair of movable heads each disposed on a rotating drum via a displacement control element, and When a fixed head provided on the rotary drum and the pair of movable heads record a signal so as to trace a recording track traced by the movable head with a delay, one of the pair of movable heads records a biloft signal. , This pilot signal is reproduced by the other movable head, the pilot signal is recorded by the other movable head, this pilot signal is reproduced by one movable head, and the signal level of each reproduction output is compared. Then, the displacement control element of one of the movable heads is controlled using the comparison output so that the signal levels match, and the displacement control element of one of the movable heads is controlled so that the signal level of the pilot signal reproduced by the fixed head is maximized. and a drive control unit that controls the drive of the displacement control element of the other movable head, and by controlling the drive of each displacement control element with the drive control unit, the absolute height position between the pair of movable heads can be adjusted. It is characterized by being able to control the

F3 action In the rotary magnetic head device according to the present invention, the displacement control element of one of the movable heads is configured to match the signal level of the reproduced output obtained by mutually recording and reproducing viroft signals with the pair of movable heads. By controlling the drive of the other movable head, the relative level difference is adjusted, and by controlling the drive of the displacement control element of the other movable head so that the signal level of the pilot signal reproduced by the fixed head is maximized, the absolute height difference is adjusted. The height adjustment will be made accordingly.

G. Example Hereinafter, an example of a rotary magnetic head device according to the present invention will be described in detail with reference to the drawings.

Figures 1 to 8U! In the embodiment shown in J, the present invention is applied to an 8mm VTR that performs recording and playback according to the 3mm video format.

(G-1) Mechanical configuration of the rotating magnetic head device The mechanical configuration of the rotating magnetic head device in this embodiment is as shown in the schematic plan view of FIG.
Rotating drum 2 wound spirally over an angular range of °
Two pairs of magnetic heads 3A and 3B and 4A and 4B are arranged in the magnetic head. One pair of magnetic heads 3A and 3B have different azimuth angles and serve as both recording and reproducing heads, and each has a displacement control element 5A such as a bimorph plate.

It is attached to the rotary drum 2 via the rotary drum 2 via the rotary drum 2, and serves as a movable head whose displacement can be controlled at each height position by the displacement control elements 5A and 5B. Further, the other pair of magnetic heads 4A and 4B are arranged and fixed at positions shifted by 90@ with respect to the above-mentioned movable magnetic heads 3A and 3B for both recording and reproduction. As shown in FIG. 3, these fixed magnetic heads 4A and 4B have movable magnetic nodules 3A and 3 for both recording and reproduction.
With respect to B, the height position is shifted vertically by 1/2 of the width (Ho) of the movable magnetic hemlock (TP), that is, the width (Ho) of the movable magnetic hemlock 3A and 3B, and the valley width (H+), (
Hz) is formed to be twice as large as the above-mentioned Toranokubifuchi (Tr)).

(G-2) Drive control system for a rotating magnetic head device In the rotating magnetic head device of this embodiment, the height position of the pair of movable magnetic heads 3A and 3B for both recording and reproduction is at the first height position.
It is controlled by a drive control system configured as shown in the block diagram in the figure.

FIG. 1 shows that in the VTR of this embodiment, while the magnetic tape 1 is running in the forward direction, the video signal is transmitted over one field/field by the pair of movable magnetic heads 3A and 3B used for both recording and reproduction.
The above movable magnetic head 3A/3 when recording one track
FIG. 3 is a block diagram showing a drive control system at the height position B. FIG.

That is, in the block diagram of FIG. 1, one of the movable magnetic heads 3A for both recording and reproduction is connected to a recording amplifier 11 and a reproduction amplifier 12 via a changeover switch 10. A pilot signal (SFS) for head height position control is supplied to the recording amplifier 11 from a pilot signal generator 13 via a first gate circuit 14. Further, the regenerative amplifier 12 increases the reproducing output from the one movable magnetic head 3A by J1, and
The signal is supplied to a first sample and hold (S/H+) circuit 16 via a band pass filter (BPF) 15. The other movable magnetic head 3B for both recording and reproduction is connected to a recording amplifier 21 and a reproduction amplifier 22 via a changeover switch 20. The recording amplifier 21 is connected to the pilot signal generator 13 via a second gate circuit 24, and a pyro for height position control.

signal (SFs) is supplied.

Further, the regenerative amplifier 22 amplifies the reproducing output from the other movable magnetic head 3B and passes it through a band pass filter (BPFZ) 25 to a second sample and hold (
S/H2) circuit 26.

The pilot signal generator 13 generates four so-called ATF pilot signals for tracking control in an eight-channel VTR.
Frequency different from the type frequency (e.g. 230KHz)
A pilot signal (SF, ) for head height position control is supplied to each of the gate circuits 14 and 24. Each of the hand bus filters 15 and 25 is connected to each movable magnetic head 3.
The above 230K included in the playback output obtained at A and 3B
The Hz pilot signal (SFS) is extracted. Furthermore, each of the sample and hold circuits 16.
26 samples and holds the signal level of each reproduced pilot signal (SF5) supplied via each of the bandpass filters 15 and 25, and supplies the hold output to a comparator 30.

The comparator output from the comparator 30 is supplied via a hold circuit 31 to a first bimorph drive circuit 32 that drives a displacement control element 5A of one of the movable magnetic heads 3A for both recording and reproduction.

Further, one of the fixed magnetic heads 4A arranged and fixed on the rotating drum 2 is connected to an erase signal generator 40 via a drive circuit 41, and is designed as a flying erase head.

Furthermore, the other fixed magnetic head 4B functions as a flying erase head in the reverse recording mode, but in this embodiment it functions as a reproducing head and supplies its reproduction output to the reproducing amplifier 51. The regenerative amplifier 51 amplifies the reproducing output from the fixed magnetic head 4B, and the band pass filter (BPF3) 52
The signal is supplied to the envelope detection circuit 53 via. The bandpass filter 52 has the same bandpass characteristics as the other bandpass filters 15 and 25 described above,
The 230KH2 pilot (No. 8 (SF)) included in the reproduced output obtained from the throat 4B is extracted from the fixed magnetic field and supplied to the envelope detection circuit 53. Detection circuit 5
The detected output from I!3 is transmitted via the peak hold circuit 54 to the displacement control I! of the other movable magnetic head 3B for both recording and reproduction. It is supplied to a second bimorph drive circuit 55 that drives element 5B.

(G-3) Operation of the Embodiment In the embodiment configured as described above, the magnetic tape 1 is run in the forward direction by a capstan/pinch roller (not shown), and the rotating drum 1 is moved around the frame by a drum motor (not shown). It is rotated at a constant speed with a frequency of I&(30H2). A pair of movable magnetic heads 3A and 3B for both recording and reproduction, which are disposed on the rotary drum 2, are connected to the 221
The winding of 6 is about 3 on the starting end side, with the angle being 1 track.
In the 8IIVTR recording format as shown in Fig. 4, the period of 00 is the PCM recording area, and the period of m <180' is the recording area where video signals, FM audio signals, and pilot signals for ATF control are frequency-multiplexed. The corresponding recording tracks are alternately formed by azimuth recording.

In this embodiment, 3w as shown in FIG.
Margin area for after-recording of PCM signals in VTR recording format [approximately 3H minutes (
A pilot signal (SFS) for controlling the head height position is recorded as follows during the horizontal scanning period) to control the height position of the pair of movable magnetic heads 3A and 3B used for both recording and reproduction. .

That is, first, one of the fixed magnetic heads 48 fixed to the rotary drum 2 is activated by the erase signal supplied from the erase signal generator 40 to the pair of movable magnetic heads 3A and 3B for recording and reproducing. Prior to this, two tracks of each track are erased.

Then, a pair of movable magnetic nozzles 3A for both recording and reproduction are provided.
・3B is a recording track (T
By opening the first gate circuit 14 during the period (To) corresponding to the margin area (M A + ) of Ra+), the signal is supplied from the pilot signal generator 13 via the changeover switch circuit 10. A pilot signal (SFs) for controlling the head height position is recorded by one movable magnetic head 3A in the margin area <MA,) of each of the recording tracks (TRAI), and 3 frames from the recording period (To) are recorded. Each track (T Rax) for each 3 frame period after the first frame period and after the 5th field period
, each margin area (Maz)1(M
By opening the second gate circuit 24 during the periods (T3) and (TS) corresponding to I+3), the head height position supplied from the pilot signal generator 13 via the changeover switch circuit 20 A control pilot signal (SF) is sent to each track (TRiz) by the other movable magnetic head 3B.

Each margin area (Mgz) of (TRss), (A13
). Then, the one movable magnetic head 3A
is the recording period (T) of the other movable magnetic head 3B.
, ), when tracing the recording track (TRA3) next to the recording track (TRsz) in which the pilot signal (SFs) is recorded, in the reproduction operation period (T4) after one field period from the recording track ( The viroft signal (SFs) is reproduced as a crosstalk component from the margin area (Mo) of the first sample (TRsz).
It is supplied to the hold circuit 16. Further, the other movable magnetic head 3B receives the pilot signal (SFs) during the reproducing operation period ('r,) one field period after the recording period (To) of the one movable 6n magnetic head 3A. When tracing the next recording track (TRA+) of the recording trunk (TRAI) in which the
The comparator 30 compares the signal level of each hold output from the pilot signal (SF26) as a crosstalk component from the margin area (M At ) of the TRAI), and the first displacement control element 5A is driven by the comparison output. By doing so, the level difference adjustment, that is, the relative height position of the pair of movable magnetic heads 3A and 3B used for both recording and reproduction is controlled.

Further, in this embodiment, the other fixed magnetic head 4B, which is used as a flying erase head in the reverse direction reproduction mode, is operated during the field period (F,) immediately after the recording period (To) of the one movable magnetic head 3A. Two recording tracks (TRe3) adjacent to (TRAI
) during the playback period (T,.) in which each margin area (TR■), (TRAI) of
The biloft signals (SFs) recorded in TR, Y) and (TRA□) are reproduced, and the reproduced output is supplied to the envelope detection circuit 53. Then, the peak level of the detection output from the envelope detection circuit 53 is held by the peak hold circuit 54, and the second displacement control element 5B is driven by the hold output, so that the biloft by the fixed magnetic head 4B is controlled. The absolute height position of the pair of movable magnetic healds 3A and 3B used for both recording and reproduction is controlled so that the reproduced signal level of the signal (SFs) is maximized.

Here, in FIGS. 5 and 6, each movable magnetic head 3 in the so-called SP mode recording operation of an 81 mVTR is shown.
Although the height position control operations of A and 3B are shown, when performing a long-time (so-called LP) mode recording operation, the track width becomes 1/2 of the SP mode, and the fixed magnetic head 4
Since B will trace 4 tracks at the same time,
As shown in the timing chart of FIG. 7 and the track pattern of FIG. 8, head height position control is performed at a cycle of 6 frames (i.e., 12 fields F+-F+z) during the first 3 frame period. , four adjacent recording tracks (TRAt), (TR.

z), (TRAt), (TR++z) margin areas (MA2), (Msz), (Mas), (MI+3
) to the pilot signal (sp, ) for controlling the head height position.
Record each margin area (MAX), (Mat
), (MA3), (M.

, ), the absolute height of the movable magnetic head 3B is controlled by driving the second displacement control element 5B so that the signal level of the viroft signal (SPs) reproduced by the fixed magnetic head 4B is maximized. Control the position. Then, during the next 3 steamy sessions, the other movable magnetic head 3
B is the margin area (MB2) of the recording track (TRsa)
) is reproduced as a crosstalk component by one movable magnetic head 3A in the next field period, and the one movable magnetic head 38 further reproduces the pilot signal (SPs) recorded in the margin area (of the recording track (TRA6)). M.A.)
In the next field period, the viroft signal (sPs) recorded in By driving the element 5A, the pair of movable magnets.

Controls the level difference between rads 3A and 3B. As a result, the above 1
The pair of movable magnetic heads 3A and 3B can ensure relative and absolute height positions with reference to the height position of the fixed magnetic head 4B.

In addition, when performing reverse direction recording, the other fixed magnetic head 4B is used as a flying erase head, and the above-mentioned one fixed magnetic head 4A is used as a reproducing head for the head height position control Byron signal (SPs). The absolute height position of the pair of movable magnetic heads 3A and 3B for both recording and reproduction can be controlled by the reproduction output from the fixed magnetic head 4A.

H. Effects of the Invention As is clear from the description of the embodiments described above, in the rotary magnetic head device according to the present invention, the signal level of the reproduced output obtained by mutually recording and reproducing pilot signals with a pair of movable heads is Relative step alignment is performed by controlling the drive of the displacement control element of one movable head so as to completely defeat the other movable head, and the signal level of the pilot signal reproduced by the fixed head is maximized. Absolute height adjustment is performed by controlling the drive of the displacement control element of each movable head, so the absolute height position is controlled along with the relative height difference adjustment of each movable head. A recording pattern can be guaranteed.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment in which the present invention is applied to an 8+n VTR, and FIG. 2 is a schematic plan view showing how each magnetic head is arranged on a rotating drum in the above embodiment. Similarly, FIG. 3 is a schematic front view showing the height positional relationship of the mounting of each head, and FIG.
** This is a schematic diagram showing the recording formant of a VTR, and FIG. 5 is a timing chart for explaining the height position control operation of each movable head when performing an sp mode recording operation in the above embodiment. Similarly, FIG. 6 is a schematic diagram showing a trunk pattern for explaining the height position control operation in the SP mode, and FIG. 7 is a diagram showing each movable head when performing a recording operation in the LP mode in the above embodiment. FIG. 8 is a timing chart for explaining the height position control operation in the LP mode, and FIG. 8 is a schematic diagram showing a trunk pattern for explaining the height position control operation in the LP mode. 1...Magnetic tape 2...Rotating drum 3A, 3B...Movable magnetic head 4A, 4B...To fixed magnetic field 5A, 5B...Displacement control element 13...Pilot signal generator 14 .24...Gate circuit 15.25.52...Band pass filter i6, 26
...Sample/hold circuit 32.55...Bimorph drive circuit Figure 1

Claims (2)

[Claims] (1) a pair of movable heads each disposed on a rotating drum via a displacement control element; a fixed head disposed on the rotary drum so as to trace the recording track traced by the movable head with a delay; When a pair of movable heads records a signal, one of the pair of movable heads records a pilot signal, the other movable head reproduces this pilot signal, and the other movable head records the pilot signal. death,
This pilot signal is reproduced by one movable head, the signal levels of each reproduction output are compared, and the drive control of the displacement control element of the one movable head is performed using the comparison output so that the signal levels match. and a drive control unit that controls the drive of the displacement control element of the other movable head so that the signal level of the pilot signal reproduced by the fixed head is maximized, and the drive control unit controls each displacement. A rotary magnetic head device characterized in that the absolute height position between the pair of movable heads is controlled by controlling the drive of a control element. (2) The rotating magnetic head device according to claim 1, wherein a flying erase head is used as the fixed head.