JPH02294174A - Rotary head type magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To realize noiseless 1/3-slow reproduction whose motion is performed linearly and picture is sharp by complementing a field block where the reproducing output signals of a pair of main rotary heads are lowered with the reproducing output signals of a pair of auxiliary heads setting one field as a unit in 1/3-slow reproduction. CONSTITUTION:The device is provided with the pair of main rotary heads M1 and M2 and the pair of auxiliary rotary heads S2 and S1, and is equipped with gate circuits 52, 55, 62, and 64, adders 53 and 56, a switching circuit 57, a 1/3-slow frequency division circuit 59, a switching circuit 66, and an inverter circuit 65. And one field at every three fields in which the reproducing output signals of the pair of main rotary heads M1 and M2 are lowered is replaced with the reproducing output signals of the pair of auxiliary rotary heads S2 and S1. Thereby, it is possible to realize noiseless 1/3-slow reproduction without generating a noise or a beat next to an adjacent beat and whose motion is smooth and picture is sharp.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention uses a pair of rotary heads having mutually different azimuth angles to record one field as a recording trajectory inclined with respect to the longitudinal direction of a magnetic tape. video signal of 1
This relates to a rotary head type magnetic recording and reproducing device that performs page-by-page recording and reproducing.In particular, it is a stable slow-motion image when a magnetic tape is run at a speed equal to the tape running speed during recording to obtain a slow-motion image during playback. It is constructed so that an image can be obtained.

BACKGROUND OF THE INVENTION In recent years, there has been an increasing demand for a special (variable speed) playback function in rotary head type magnetic recording and playback apparatuses, which allows playback at a tape speed different from that during recording. However, no device has been proposed in analog technology that achieves noise-free linear 1/3 slow playback while running the tape at a constant speed of 1/3 that of recording. .

Problems to be Solved by the Invention When the screen is output on a monitor when the tape is running at a constant speed of one-third of the time of recording, the speed is 1.
Since the playback output signal is obtained from two recording tracks with the same azimuth angle within the field, noise due to adjacent beats may be output across the screen, making the screen extremely difficult to view, or the playback output may drop and may not be sufficient. Since there are fields for which no reproduced output signal can be obtained, no-signal noise is output on the screen.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a magnetic recording and reproducing apparatus capable of performing noiseless, slow reproduction with linear and clear motion.

Means for Solving the Problems In order to solve the above-mentioned problems, the rotating helenoid type magnetic recording and reproducing apparatus of the present invention has first and second magnetic recording and reproducing apparatuses having different azimuth angles.
a main head consisting of a rotating head; and a pair of auxiliary heads consisting of third and third auxiliary rotating heads having the same azimuth angle as the first and second rotating heads, respectively, for reproducing magnetic tapes. sometimes one-third of the running speed at the time of recording
While running at a constant speed of 1 foot μ
The apparatus is constructed to include means for supplementing each code with a pair of auxiliary one and two reproduced output signals.

According to the above-described configuration, the present invention switches the use of a rotary head with the same azimuth angle every three fields, and within the three fields, switches the use of the main rotary head and the auxiliary rotary head every field. A clear, noiseless, slow-motion playback function is realized by ensuring that a good playback output signal is always obtained in the field.

Embodiments Hereinafter, a rotary head type magnetic recording/reproducing apparatus of the present invention will be explained based on the illustrated embodiments. Fig. 1 is a diagram showing the main part of an embodiment of the present invention, and Fig. 2 shows the recording pattern of a magnetic tape recorded azimuthally and the reproduction when the reproduction is run at a constant speed of one third of the recording speed. This shows the relationship with the head trajectory.

FIG. 3 is a time chart in an embodiment of the present invention.

In FIG. 1, M1 is the first rotating head with an azimuth angle of +6° and S2 is the third rotating head with an azimuth angle of −6°. M2 is the second rotating head with an azimuth angle of -6° and S1 is the /3rd rotating head with an azimuth angle of +6°. The first and second rotary heads M1 and M2 are arranged at a distance of K180° from each other with respect to the rotation center of the rotary drum 3, and constitute a main head pair.

The third and third rotary heads S2 and 81 are also 18
The two heads are arranged 000 apart and form a pair of auxiliary heads. These main head pair and auxiliary head pair are separated by a distance corresponding to two horizontal synchronization signal periods of the video signal, for example.
As shown in FIG. 1, it is attached to the rotating drum 3 on the same rotation plane. , the rotating drum 3 is rotated 1800 in the direction of the arrow 9 by the motor 6 via the rotating shaft 4.
r,p. It can be rotated at a rotation speed of H. The magnetic tape 6 is guided by guide posts 9 and 8, and is wound around the rotating drum 3 over an angle of 18 degrees or more, as shown by the arrow 1.
0 direction, pinch roller 11 and capstan 12
You can drive with it. A schematic track pattern of the magnetic tape 6 is shown in FIG. In FIG. 2, diamonds represent recording tracks, R represents the track recorded by the first head M1 having an azimuth angle of +60, and L represents the track recorded by the first head M1 having an azimuth angle of +60.
The tracks recorded by the second head M2 having an azimuth angle of 6° are represented, and the numbers represent the passage of time (recording order). That is, L1→R1→L2→R2→L3
→R3→L4..., and so on, and the same recording tracks are displayed overlapping in the horizontal direction. The first and second rotary heads M1 and M2 are configured to partially overlap the previously recorded recording trajectory of the other rotary head during recording, and sequentially record while erasing the overlapping portion. 21, 23.25 represent the locus of the lower end of the head during μ slow playback, and 22, 24.26 represent the locus of the upper end of the head during slow playback. Therefore, 21-22. 23
~24.26~26 corresponds to the head width during reproduction, and a reproduced output signal is obtained only in the portion where the azimuth angles of recording and reproduction match. That is, the vertical line portion shown in FIG. 2 becomes the reproduced output signal, and its magnitude is indicated by the vertical length of the vertical line portion. Fig. 2a shows the head trajectory of the main head pair during almost slow playback, Fig. 2b shows the head trajectory of the auxiliary head pair during slow playback, and Fig. 2C shows the main head during slow playback of the present invention. Figure 2 shows the head trajectories of the paired and auxiliary head pairs. Since the third rotary head S2 is mounted close to the first head M1 (in this embodiment, separated by a distance corresponding to two horizontal synchronization signal periods of the video signal), the third rotating head S2 is attached close to the first head M1. This results in almost the same playback head trajectory. Further, since the third head S1 is mounted close to the second rotary head M2, the reproducing head trajectory is almost the same as that of the second rotary head M2.

During such false slow playback, the main rotating head pair M1
, M2 each have an azimuth angle of +6° -6°, so that a hesode output signal as shown in FIG. 3d is obtained.

In addition, the auxiliary rotating head pair S1 and S2 are each -6°
, +6°, a head output signal as shown in FIG. 3e is obtained. Typically, these head output signals are FM with a carrier frequency of approximately 3.9 Ml-IZ.
The modulated luminance signal and color subcarrier frequency is approximately e29K
14 and a carrier color signal that has been low frequency converted. The time scale is shown in Figure 3j. Here, to indicates the field start time, and t1 indicates the field end time. That is, tO "" I + tl~t
Approximately 16.7 msec of 2 corresponds to one field K. Figure 3g shows the head switching signal and each field number 100, 10.
1 , 102 , 103 , 104 , 105 , 1
06 was shown. In Figure 3d, number 101, 10/
In field 3, there are two tracks at different times (in field 101, track R1 and track R
2} rack, L2} rack and L3} rack) are played at the same time in field 104K.
The black parts of the beat are played over the entire screen as adjacent beats. Since the adjacent beats are reproduced every three fields, the screen becomes very difficult to view. This point is a drawback of the conventional example. The present invention eliminates fields in which the reproduction head outputs of the main rotary head pair Ml, M2 have no signal or adjacent repeats, by using the auxiliary rotary head pair 82 . With a playback head output of 51, the third
By performing K substitution as shown in FIG. f, a clear noiseless A slow playback screen without noise or adjacent beats can be obtained.

According to the present invention, it is possible to obtain a clear, noiseless, slow-motion playback screen with no beats by supplementing the output of the pair of auxiliary rotary heads with the output of the pair of auxiliary rotary heads when the output of the pair of main rotary heads described above decreases or the fields become adjacent beats. An embodiment is shown in block diagram form in FIG. In FIG. 4, the same components as those explained in FIG. 1 are given the same reference numerals. The head output signal of the first head M1 is amplified by a preamplifier 61 and supplied to a gate circuit 62. The output signal of gate circuit 52 is supplied to adder 63.

The head output signal of the third head S2 is transmitted to the preamplifier 61
The signal is amplified and supplied to the gate circuit 62. The output signal of the gate circuit 62 is supplied to the adder 63. The output signal of adder 63 is supplied to switch circuit 6. The head output signal of the second head M2 is amplified by a preamplifier 54 and supplied to a gate circuit 56. The output signal of gate circuit 56 is supplied to adder 66. The head output signal of the third head S1 is amplified by the preamplifier 63 and supplied to the gate circuit 64. The output signal of the gate circuit 6/3 is supplied to the adder 66.

The output signal of the adder 66 is supplied to the switch circuit 57. The output signal of the switch circuit 57 is sent to the video signal demodulator 6
0, and the output signal of the video signal demodulator 6o is supplied to the output terminal 68. The head switching signal 68 is a signal having a duty of 50% and a frequency of 30 h that is synchronized with the rotational phase of the rotary head, and is supplied to the switch circuit 67, the almost frequency dividing circuit 59, and the switch circuit 66. A slow command signal 67 is supplied to the switch circuit 66 as a control signal for the switch circuit 66 . The output signal of the switch circuit 66 is transmitted to the gate control terminal of the gate circuit 52, the gate control terminal of the gate circuit 6/3, and the inverter circuit 65.
is supplied to The output signal of the inverter V866 is connected to the gate control terminal of the gate circuit 62 and the gate circuit 6.
6 gate control terminal.

Next, the operation of this embodiment will be explained with reference to the waveform diagrams of FIGS. 2 and 3. A During slow playback, main rotating head vs. M
1, M2 draw a reproducing head trajectory as shown in Figure 2a, the main rotating head pair M as shown in Figure 3d
1, M2's head reproduction output is sent to the preamplifier 61.
54 and gate circuits 52 . 55. Further, the auxiliary rotary head pair draws a reproducing head trajectory as shown in FIG. 2b, and the head output signals of the auxiliary rotary head pair 81 and is2 as shown in FIG. , gate circuit 62, respectively.
64. When the output signal of FIG. 3d is output as it is from the gate circuit 52.55, the field
, 104, the black portions are adjacent beats as described above, and a clear noiseless slow playback screen cannot be obtained. 3g is the head switching signal 58 of FIG. 4, which controls the switch circuit 6. That is, head switching signal 6
When head switching signal 8 is at a high level, the output signal of the switch circuit 57 becomes the output signal of the adder 53, and when the head switching signal 58 is at a low level, the output signal of the switch circuit 67 becomes the output signal of the adder 5e. 3h shows the output signal of the suinochi circuit 66 of FIG. 4 during almost slow playback, which controls the gate circuits 52 and 64 of FIG. 4. That is, when FIG. 3b is no level μ, the gate circuit 52 . 64
is opened, and the head output signal of the first head M1 is sent via the preamplifier 61 to the adder 53, and the head output signal of the third rotary head S1
The head output signal is sent to the adder 5θ via the preamplifier θ3.
is supplied to FIG. 31 shows the output signal of the inverter circuit 66 of FIG. 4 during low-speed reproduction, which controls the gate circuit 55, 82 of FIG. 4.

That is, when FIG. 3 1 is a high rep~, the gate circuit 55
．． 64 is opened, the output signal of the second rotary head M2 is supplied to the adder 56 via the preamplifier 64, and the head output signal of the third rotary head S2 is supplied to the adder 63 via the preamplifier 61. be done.

With such a configuration, the output signal of the first rotary head M1 in the field 101 of FIG. 3d is supplemented by the output signal of the third rotary head S2 of FIG. ″-Second rotary head M2 in the field 104
The output signal of the switch circuit 67 is supplemented by the output signal of the /3 rotary head S1 in FIG. 30, and the output signal of the switch circuit 67 becomes as shown in FIG. 3f. This field 100 to 1o
If the reproduced output signal in which one cycle is made up of six fields in s-1 is obtained continuously, then the number is K. The output signal of the switch circuit 67 is supplied to the video signal demodulator 60 and converted into a video signal. As is well known, this video signal demodulator SO consists of a luminance signal demodulator and a carrier color signal demodulator. The luminance signal demodulation system demodulates the FM-modulated luminance signal, and the carrier color signal demodulation system removes jitter from the reproduced low-frequency modulated carrier color signal and converts it into a carrier color signal. The output signal of this video signal demodulator 60 is transmitted to an output terminal 68.
A clear, slow-motion playback video signal without noise or adjacent beats can be continuously obtained.

In this way, during slow playback, the field in which the playback output signal of the main rotary head pair becomes noise or adjacent beats can be compensated for by the playback output signal of the auxiliary rotary head pair without noise or adjacent beats. can. As a result, a clear almost slow playback screen without noise or adjacent beats is obtained.

In the above explanation, it has been assumed that the rotary heads M1, M2, 52, and S1 are mounted on the same plane, but the pair of auxiliary rotary heads 52 . The same effect can be obtained even if the rotation planes 81 are set to rotation planes spaced apart by an even multiple of the track pitch.

Moreover, the above explanation is based on M1, M2 and 82. Although it is assumed that the head widths of 51 and 8 are almost the same, the auxiliary rotating head pair 8
Even if the head width of 2.81 mm is wider than the head width of the main rotary head pair M1 and M2, almost the same effect can be obtained. When a guard band is provided between the special K recording tracks, a wide head is advantageous in terms of reproduction output level.

Effects of the Invention As described above, the present invention has the main rotary head pair M1.
M2 and a pair of auxiliary rotary heads S2 and S1. During 14 slow playback, one field every three fields in which the reproduction output signal of the main rotary head pair M1 and M2 decreases is transferred to the auxiliary rotary head pair S2 and S1. Replace it with the reproduced output signal of
This makes it possible to perform noiseless A slow playback of a screen with smooth and clear movements without noise or adjacent bits, which is extremely useful in practice.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of the main parts of a rotary head type magnetic recording and reproducing apparatus according to an embodiment of the present invention, and FIG. 2 is a relationship between the recording track pattern of an azimuthally recorded magnetic tape and the head trajectory pattern during pseudo-slow playback. FIG. 3 is an operational waveform diagram in an embodiment of the present invention, and FIG. 4 is a main circuit block diagram in an embodiment of the present invention. M1, M2... Main rotating head, S1, S2
...Auxiliary rotating head, 3...Rotating drum,
e...Magnetic tape, a, b, c...Head trajectory during slow playback, 51, 54, 61.
83... Preamplifier, 52, 55, 62
．． 64-=--・-gate circuit, 63.66...
Adder, 57.66...Swiss circuit, 68.
...Head switching signal, 69...Visual frequency divider circuit, 66...Inverter circuit, co...Video signal demodulation lLf...Display slow in the present invention Reproduction output signal during reproduction, d, e...Reproduction output signal during A slow reproduction according to conventional technology, g...Head switching signal, L1, R1, L2, R2, L3
, R3, L4... Recording track pattern. Name of Daiji University Patent attorney Shigetaka Awano and 1 other person3,
．． One day hjira 4 Figure 3

Claims (1)

[Claims] (1) A pair of rotating heads having mutually different first azimuth angles and second azimuth angles constituting the main head pair are used alternately to transmit one field of video signals in the longitudinal direction of the magnetic tape. A rotary head type magnetic recording and reproducing apparatus that sequentially records data as an inclined recording trajectory, wherein a pair of rotary heads having the first and second azimuth angles constituting an auxiliary head pair are rotated at each rotation constituting the main head pair. A rotating head having an azimuth angle different from the azimuth angle of the rotating head is located near the magnetic head, and is arranged to scan on a recording trajectory by the rotating head of the main head pair,
When playing back a magnetic tape by running it at 1/3 of the tape speed during recording, one field out of every two fields of the playback output of the main head pair and the auxiliary head pair is used as the playback output of the other head pair. A rotary head type magnetic recording and reproducing device characterized in that it can be replaced.