JPH03165357A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To enable insert editing so that a track pattern is continuous and uniform without adding any magnetic head by performing reproduction and recording in a cycle period by using a multichannel magnetic head. CONSTITUTION:For normal recording, a tracking actuator 60 fixes two channel magnetic heads 58 and 59 to perform the recording. For the insert editing of a recorded magnetic tape 61, the heads are rotated twice in a one-cycle period and in the 1st rotation, a track 1 is reproduced; and the playback signal of the magnetic head 59 is inputted to a tracking error signal detecting circuit 64 through a changeover switch 56 and a playback amplifier 63, a capstan servo circuit 65 controls a capstan motor 62, and a tracking servo circuit 66 drives the tracking actuator 60. In the 2nd rotation, the circuit 66 generates a driving voltage which is generated one rotation before and recording on a track 2 is carried out. Consequently, the insert editing is performed so that the track pattern becomes continuous and uniform without adding any magnetic head.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a magnetic recording/reproducing apparatus that performs an insert/collection process using a multi-channel magnetic head mounted on a rotating drum.

[Conventional technology]

Insert editing is editing in which a part of an already recorded track is rewritten with another signal, and is one of the effective functions in a VTR (video tape recorder) that records and plays back video and audio signals. The so-called 8 mm video servo system using 8 mm tape employs a four-frequency pilot system, and a conventional insert editing system is disclosed in Japanese Patent Application Laid-open No. 79550/1983.

The conventional device is a magnetic recording/reproducing device that employs a pilot signal method, and is capable of insert The trunk pattern is made continuous and uniform even during editing.

This will be explained below using figures.

The fourth @ is a layout diagram of the magnetic heads installed on the rotating drum. Two ordinary recording/reproducing magnetic heads 21 and 22 are installed at a position of 180", and the magnetic heads 2
Another pair of magnetic heads 23 and 24 are installed on the same plane as magnetic heads 1 and 22 at positions rotated by 90 degrees with respect to the magnetic heads 21 and 22, respectively.

FIG. 5 shows a circuit configuration of a rotary head type VTR to which a magnetic recording/reproducing apparatus according to the present invention is applied. Fifth
In the figure, reference numeral 19 denotes a first cyclic frequency generator, which generates signals of four frequencies for each field by circulating them in four fields in response to a head switching pulse inputted to the input terminal 1.

These four frequencies are, for example, NTSC (Nation
al Telelvision System Com
m1ttee) system video signal, f
,,C-378fh (rh: horizontal synchronization signal frequency)
As, f, = fosc 158. ft ””fo-
c150. fs =f0s-/36. and f4=fo
, c/40.

The output of this frequency generator 19 is superimposed on the modulated video signal input to the input terminal 3 by the adder circuit 2,
This superimposed signal is recorded in the amplifier 4. The signal is applied to the magnetic heads 21 and 22 through the switch 5 and the rotary transformer 20 to record on the magnetic tape. As shown in FIG. 6, the recording pattern is recorded by rotating from Fl to F4.

Next, normal playback will be explained.

Reference numeral 8 denotes a regenerative amplifier, the output of which is passed through a low-pass filter (hereinafter abbreviated as LPF) 9 to remove the video signal component and extract the pyro signal component. The frequency is set to f, , f, for each field according to the viroft signal component extracted by this LPF 9 and the head switching pulse.
, F3. f.

and the output of the cyclic frequency generator 19, which is generated sequentially, are input to the mixer 10. By passing the output of the mixer 10 through a first band pass filter (hereinafter abbreviated as BPF) 11 and a second BPF 12, the signal frequency of the output of the cyclic frequency generator 2 and the pilot signal component of the output of the LPF 9 are combined. A difference frequency signal component with the frequency of is obtained.

By the way, in the case of an NTSC video signal, f,,c=
Since it is 5.95MHz, f,,f,.

f, and F4 are fI 102KHz, fz 2l
19KHz, fsy165KHz, f4=149KHz
becomes. As a result, f,-f,,f,-f4=16.
5KHz, F4-f, 2f3-f, = 46.5KHz. Therefore, the passband of the first BPFII is set to 16.5.
Near KHz, the passband of the second BPF 12 is 46.5
Suppose that it is selected near KHz. When the magnetic head 21 is tracking the track Fl as shown in FIG. 6, a signal having an amplitude proportional to the magnitude of the biloft signal (frequency f2) component of the trunk F2 is transmitted to the first BPFil.
A signal having an amplitude proportional to the magnitude of the pilot signal (frequency f4) component of the F4 track is obtained from the second BPF 12.

The outputs of the first BPF II and the second BPF 12 are envelope-detected by a first detector 13 and a second detector 14, respectively, and these first and second detectors 13.14
By passing the respective outputs of the 6th
The voltage level in the subtracter 15 corresponds to the amount of positional deviation of the magnetic head 21 from the trunk center to the left or right in the figure.
is obtained as the output of

As is clear from the recording pattern in FIG. 6 and the frequencies of f=, fz, fz, and F4, in FIG. In some cases,
The polarity of the output of the subtracter 15 is reversed when the magnetic head 21 is displaced from the trunk center. Therefore, if the output of the subtracter 15 and the signal obtained by inverting the output of the subtracter 15 by the inverting amplifier 16 are selected by the switch 17 in synchronization with the head switching pulse, the amount of positional deviation of the magnetic head 21 from the track center An output voltage proportional to is obtained from the output terminal 18.

Good tracking can be obtained by feeding back the signal obtained from this output terminal 18 to a capstan motor (not shown).

Next, we will explain the configuration and operation of Inser).

A switch 25 supplies the reproduction output of the magnetic head 23 or 24 to the reproduction amplifier 8 during insert editing. 26 is a delay circuit that shifts the phase of the head switching pulse by 90'', and 27 is the aforementioned fl, 2+ based on the output of the delay circuit 26.
28 is a switch for supplying the output of the second cyclic frequency generator 27 to the mixer 10 during insert editing; 29;
31 is a switch that selects the output of the first detector 13 or the second detector 14 for each field based on the output of the delay circuit 26 and supplies it to the amplifier 30; This is a switch that supplies power to the output terminal 18.

During insert editing, the output of the first cyclic frequency generator 19 is superimposed on the video signal led from the input terminal 3, and this signal is sent to the recording amplifier 4. A signal is applied to the magnetic heads 21 and 22 through the switch 5 and the low retransformer 20 to record on the magnetic tape TP. On the other hand, the signal on the magnetic tape TP is reproduced by the magnetic head 23 and the magnetic head 24, and this signal is supplied to the reproduction amplifier 8 through the rotary transformer 20 and switch 25.

To start signal recording in insert editing, first perform the tape running control in normal playback described above, enter synchronization control, and then switch to insert editing mode at the desired recording start point. At this time, the positional relationship between the recording pattern on the magnetic tape TP and each magnetic head 21 to 24 is as follows.
For example, it is as shown in FIG. magnetic head 21
is located at the leading end of the F1 track, and the magnetic head 22 is located at the rear end of the F4) rack. Therefore, since the magnetic head 23 is in the positional relationship shown in FIG. 4, it is located in the center of the trunk and on the boundary line between the F4) rack and the Fll-rank. The delay circuit 26 shifts the phase of the head switching pulse by 90 degrees, so that the switching position of the magnetic head 23 or the magnetic head 24 is the same as that of the magnetic head 21 or the magnetic head 22.
The head is switched to the same position as the head switching position in the tape width direction. Furthermore, this delay circuit 26 outputs 'I+ffi' from the second cyclic frequency generator 27 in a predetermined order.
A signal having a frequency of +f3 or F4 is sequentially generated.

In the magnetic position shown in FIG. 6, it is assumed that a frequency f is generated by the second circulating frequency generator 27. At this time, the first cyclic frequency generator 19 switches and generates frequencies from the frequency F4 to f.

At the position of the magnetic head 23 shown in FIG. 6, the signal reproduced by the magnetic head 23 includes a pilot signal component with a frequency f corresponding to the head width, and a pilot signal component with a frequency f corresponding to the head width A. A frequency component of F4 with a corresponding thickness is included. The above two pilot components are extracted at the LPF 9 and added to the mixer 10. On the other hand, since the second circulating frequency generator 27 generates a frequency of f,
.

A signal whose difference frequency component has an amplitude corresponding to 2 of the head width is obtained from the second BPF 12. Further, when the magnetic head 24 is on the boundary line between the Fl) rank and the F2 track in FIG. When the position is below the tape width, the second circulating frequency generator 27 generates a signal with a frequency of f, so the difference frequency component between f and F8 is on rank F2). A signal with an amplitude proportional to the width of the head is the first BP.
Obtained from FII.

When the frequency generated by the second cyclic frequency generator 27 is controlled by a signal obtained by shifting the head switching pulse by 90 degrees from the delay circuit 26 in this way, the magnetic head 23 moves to the boundary between the F4) rack and the F1 track. When the position is on the line or on the boundary line between the F2) rack and the F3 track, a signal with an amplitude proportional to the positional deviation from the boundary line of the magnetic head 23 is obtained from the second BPF 12, and the magnetic head 24 is located on the F1 trunk. and F2) on the border of the rack,
Alternatively, when the magnetic head 24 is on the boundary line between the F3) rack and the F4) rack, a signal with an amplitude proportional to the amount of positional deviation of the magnetic head 24 from the boundary line is obtained from the first BPFII.

Therefore, if the output of the first detector 13 or the output of the second detector 14 is selected by the output of the delay circuit 26 using the switch 29, the output of the magnetic head 23 or 24 will be proportional to the amount of positional deviation from the boundary line. voltage can be obtained.

This equivalently represents a voltage value proportional to the amount of positional deviation of the magnetic node 21 or 22 from the track. This signal is applied to an amplifier 30 to give it an appropriate C offset and amplifier gain, and is applied to the output terminal 18 through a switch 31.

When the output of the second circulation frequency generator 27 is fixed at a frequency f, the output voltage of the output terminal 8 is shown in FIG. 7 with respect to the amount of positional deviation of the magnetic head 24 in the tape longitudinal direction.

In FIG. 7, when this output voltage is integrated in the longitudinal direction of the tape, it becomes . The output voltage at the desired tracking position is ■.

Therefore, it is obvious that the lock range when the control B loop is constructed is severely limited. Therefore, if synchronization is carried out in the normal playback mode before the start of the insert i collection, even if the mode shifts to the insert editing mode, the control ability for small signal components is sufficient and the control can be performed without any problem. Therefore, by doing the above, it is possible to obtain a uniform and continuous recording pattern even when inserts are assembled.

[Problem to be solved by the invention]

Since conventional magnetic recording and reproducing devices are configured as described above, it is necessary to add at least one magnetic head in addition to the normal recording and reproducing head, which increases costs and makes it difficult to downsize the drum. There were problems such as.

This invention was made in order to solve the above-mentioned problems, and its purpose is to provide a digital recording and reproducing device that can perform insert editing with a continuous and uniform trunk pattern without adding any magnetic heads. do.

[Means to solve the problem]

The magnetic recording and reproducing device according to the present invention is a device that records or reproduces N trunks of information in one cycle period, and uses a multi-channel magnetic head to reproduce at least one track worth of signals in one cycle period. This system records signals for N tracks, controls magnetic tape running during playback, and records N tracks during recording.

[Effect]

In this invention, by performing reproduction and recording within one cycle using a multi-channel magnetic head, it is possible to control the running speed of the magnetic tape from the reproduction signal of at least one track, and to control the running speed of the magnetic tape from the reproduction signal of at least one track, and to control the running speed of the magnetic tape from the reproduction signal of at least one track. This can be done so that the pattern is continuous and uniform.

〔Example〕

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

In FIG. 1, 51 is an input terminal for modulated video/audio signals, 52 is an input terminal for pulses synchronized with drum rotation, 53 is a servo pyro/node signal generation circuit, 54 is an addition circuit, and 55 is a recording An amplifier, 56 a recording/reproduction switching switch, 57 a rotating drum, 58 and 59 two medium tunnel magnetic heads with mutually different azimuth angles, and 60 for moving the magnetic heads 58° and 59 perpendicularly to the diagonal trunk. tracking actuator 61 is the rotating drum 5
7 is a 180@ wound magnetic tape, 62 is a capstan motor, 63 is a regenerative amplifier, 64 is a tracking error signal detection circuit, 65 is a capstan servo circuit, and 66 is a tracking servo circuit.

Next, the operation will be explained using both the trunk pattern diagram of FIG. 2 and the time chart of FIG. 3.

In this embodiment, one cycle period is one frame of image (NTS
In the C method, the recording time is approximately 1/30 second) and is recorded on two tracks. The video/audio signal input from the input terminal 51 is triggered by the drum rotation pulse (here, 60 Hz) of FIG. do.

However, the part written W in FIG. 3 (dl) is the recording period, and as will be described later, the magnetic heads 58 and 59 are 2-inch tunnel heads, so Fl is written for each W.

F2 and F3. F4 is generated alternately. This pilot signal is superimposed on the video/audio signal in an adder circuit 54, and then sent to a recording amplifier 55. Selector switch 56° rotary transformer (
(not shown) and are recorded on the magnetic tape 61 by magnetic heads 58 and 59.

The magnetic head shown in FIG. 1 is a two-channel head that is movable by a tracking actuator 60.

During normal recording, recording is performed with the position of the tracking actuator 60 fixed. The track recorded in this way is shown in the track pattern diagram of FIG. 2. I and If correspond to magnetic heads 58 and 59, respectively, and have different azimuth angles, and the head width is slightly wider than the track width.

Now, a case where insert editing is performed on a magnetic tape recorded in this manner will be described. First, it is rotated twice in one cycle period (here, one frame). That is, the third
The drum rotation pulse of C1 is set to 60 Hz, and at least one track is reproduced in the first rotation. Here, a reproduction signal from the magnetic head 59 is used to apply reproduction servo. The reproduction signal of the magnetic head 59 is transferred to the selector switch 56. The signal is inputted to a tracking error signal detection circuit 64 via a regenerative amplifier 63. The tracking error signal is obtained by the method described in the conventional example, and the capstan servo circuit 65 controls the capstan motor 62 to control the tape feeding speed. On the other hand, the tracking actuator is driven from the tracking servo circuit 66 as shown in FIG. 3 <6) to follow the track bend.

The second rotation is recorded on two tracks as follows. Since the tape is being fed during playback mode, it is running at a constant speed. If the tracking servo circuit 66 performs recording by generating a driving voltage generated one revolution before, as shown in FIG. 3(f), a continuous and uniform track pattern and track curvature similar to that of the playback trunk can be obtained. .

The state of the magnetic head and track pattern for recording and reproduction is shown in Figure 2 (C1).Since the machine runs in the playback mode until it enters insert editing, the pattern recorded with head 1 is played back with head 2.

In this case, although the azimuth angle is different, since the pilot signal is a low frequency signal, a sufficient signal level can be ensured. The insert part is shown in Figure 2 (as in C1, the second rotation of the previous cycle is shaded).

Recording is performed in step (3), and reproduction is performed in the first rotation of the next cycle. In this case, the width of the head I recording pattern in the area reproduced by head (2) becomes slightly smaller, but this has no effect because the pilot signal is of low frequency. Also, a part of the head I side of the signal played by HERADO ■ is played back by the inserted recorded pattern, but the pattern before insert editing is played back from the opposite side of the head ■. However, if you use a magnetic head with 3 or more channels, you can fully reproduce the pattern before insert editing.

In the above embodiment, a 2 channel x 1 N% head is used, but any number of channel heads may be used.

In addition, in the above embodiment, 2 N tracks are processed during one cycle.
Although we have described the case where the scanning is performed once, it is sufficient if the scanning is performed twice or more, and one of the scanning times may be allocated to recording.

Further, in the above embodiment, a movable head is used, but a fixed head may be used as long as it does not follow track bending.

〔Effect of the invention〕

As described above, according to the present invention, since signals for at least one track are reproduced and signals for N tracks are recorded during one cycle period, the track pattern can be This has the effect of producing an insert that is continuous and uniform.

[Brief explanation of the drawing]

Fig. 1 is a block diagram centered on servo signals of a magnetic recording/reproducing device according to an embodiment of the present invention, Fig. 2 is a track pattern thereof, Fig. 3 is a time chart of servo signals, and Fig. 4 is a conventional one. FIG. 5 is a block diagram centered on servo signals of a conventional magnetic recording and reproducing device; FIG. 6 is a trunk pattern diagram and a diagram showing the state of the magnetic head; FIG. The figure is a diagram of the output voltage with respect to a displacement of one position in the longitudinal direction of the magnetic tape when the signal frequency of the cyclic frequency generator is fixed at f. 57 is a rotating drum, 58 and 59 are magnetic heads, 60 is a tracking actuator, 64 is a tracking error signal detection circuit, 65 is a capstan servo circuit, and 66 is a tracking servo circuit. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Claims] (1) In a helical scan magnetic recording and reproducing device that records and reproduces N tracks (N: an integer) of information during one cycle of information using a multi-channel magnetic head that carries information such as video or audio signals on a rotating drum, A magnetic recording/reproducing apparatus characterized in that a magnetic tape is controlled by a tracking error signal obtained by reproducing at least one track within one cycle period, and then N tracks are recorded.