JPH02296473A - Rotary head type magnetic video recording and reproducing device - Google Patents

Abstract

PURPOSE:To attain noiseless 1/2 slow reproduction by replacing 2-field for each frame when a reproduced output signal of a main rotary head pair is lowered with a reproduced output signal of an auxiliary rotary head pair at 1/2 slow reproduction. CONSTITUTION:A switch circuit 65 is connected to an operating command signal (i) of auxiliary rotary head pairs S2, S1 at 1/2 slow reproduction and a switch circuit 66 is connected to an operating command signal (h) of main rotary head pairs M1, M2. Thus, a field in which the reproduced head output of the main rotary head pairs M1, M2 has no signal and adjacent beat adjacent thereto is replaced by a reproduction head output of the auxiliary rotary head pairs S2, S1 to obtain a sharp noiseless 1/2 slow reproduction pattern without noise and adjacent beat adjacent thereto.

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. It relates to a rotating head type magnetic recording and reproducing device that sequentially records and reproduces video (image signals), and is especially stable when playing back by running the magnetic tape at a speed of % of the tape running speed during recording to obtain slow motion images. It is designed to provide slow motion images.

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 1/2 slow playback while running the tape at a constant speed of 1/2 that of recording. .

Problem to be Solved by the Invention If the screen is output on a monitor when the tape is running at a constant speed that is half that of recording, the speed of the tape during playback is 1/2.
Since the playback output signal is obtained from two recording tracks with the same azimuthal angle within the field, noise caused by adjacent beats may be output to the entire screen, making it extremely difficult to see, 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, and an object of the present invention is to provide a magnetic recording and reproducing device capable of noiseless, slow-slow reproduction with linear and clear motion.

Means for Solving the Problems In order to solve the above problems, a rotating head type magnetic recording/reproducing apparatus of the present invention includes a main head pair consisting of first and second rotating heads having mutually different azimuth angles; It has an auxiliary head pair consisting of first and second rotary heads and third and fourth auxiliary rotary heads having the same azimuth angle, respectively, and the magnetic tape is rotated at a constant speed of % of the running speed during recording during playback. While running, the reproduction outputs of the pair of main helenoids 1 and the pair of auxiliary heads are selectively switched sequentially every h2 fields to obtain a continuous signal.

Effect of the present invention The auxiliary head pair is arranged near the main head pair so that the scanning locus of the main head pair is scanned by a head having an azimuth angle opposite to that of the main head pair, and the auxiliary head pair is arranged so that the scanning locus of the main head pair is scanned by a head having an azimuth angle opposite to that of the main head pair. Focusing on the fact that when playing a magnetic tape by running it at a high speed, the playback outputs of the main head pair and the auxiliary head pair alternately obtain a good playback envelope every two fields, and the main head pair and the auxiliary head pair The reproduction output is alternately switched every two fields to obtain a good reproduction output.

Embodiment Hereinafter, a rotary head type magnetic recording/reproducing apparatus of the present invention will be explained based on the illustrated embodiment. 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 half 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, Ml is the first rotating head with an azimuth angle t- of +6° and S2 is the third rotating head with an azimuth angle t-6°.

M2 is the second rotating head with an azimuth angle of -6° and Sl is the fourth rotating head with an azimuth angle of +6°. The first and second rotary rads M1 and M2 are arranged 180° #1 from each other with respect to the center of rotation of the rotary drum 3, and constitute a main head pair. The third and fourth rotary heads S2 and 81 are also arranged 180° apart from each other and form an auxiliary head pair. The main head pair and the auxiliary head pair are mounted on the same rotating plane on the rotating drum 3, as shown in FIG. There is.

The rotating drum 3 is driven by a motor 5 via a rotating shaft 4.
It is rotated in the direction of arrow 9 at rotation speeds 1c1800r, p, and m. The magnetic tape 6 is guided by guide posts 7 and 8, is spirally wound around the rotating drum 3 for more than 1800 degrees, and is run in the direction of an arrow 10 by a pinch roller 11 and a capstan 12. . FIG. 2 shows a schematic track pattern of the magnetic tape 6. As shown in FIG. In FIG. 2, each diamond represents a recording track, R represents a track recorded by the first rotary head M1 having an azimuth angle of +6°, and L represents a track recorded by the first rotary head M1 having an azimuth angle of -6°. It represents the track recorded in M2, and the numbers represent the passage of time (recording order).

That is, LO→RO→L1→R1→L2→R2−+L3・
..., and the same recording tracks are expressed horizontally overlapping each other. Note that the first and second rotary heads M1. During recording, M2 partially overlaps the recording locus recorded in [111] by the other heno 1-, and is recorded sequentially while erasing the overlapping portion.

21.23.25 (d% represents the locus of the lower end of the head during slow playback; 22, 24.26 represents the locus of the upper end of the head during slow playback. Therefore, 21~22° 23~24.25
.about.26 corresponds to the head width during reproduction, and a reproduction 8-power signal is obtained only in the portion where the azimuth angles of recording and reproduction coincide. That is, the vertical line portion shown in the middle of FIG. 2 becomes the reproduced output signal, and its magnitude is indicated by the vertical length of the vertical line portion. Figure 2a shows the head trajectory of the main head pair during slow playback, the second
The figure shows the head trajectories of the auxiliary head pair during slow reproduction, and FIG. 2C shows the head trajectories of the main head pair and the auxiliary head pair during slow reproduction according to the present invention. Since the third rotary head S2 is mounted close to the first rotary head M1 (in this embodiment, separated by a distance corresponding to two horizontal opening signal periods of the video signal), The trajectory of the reproducing head is almost the same as that of the rotary head M1. Furthermore, since the fourth rotary 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 speed playback, the main head pair M1. M
2 have azimuth angles of +6° and -6°, respectively, so that head output signals as shown in FIG. 3d are obtained. Further, the auxiliary head pair S1. S2 is -6° and +6°, respectively.
Since the head has an azimuth angle of , a head output signal as shown in FIG. 3e is obtained.

Typically, these head output signals have a carrier frequency of approximately 3
．． It consists of an FM-modulated luminance signal having a frequency of 9 MHz and a carrier color signal whose color subcarrier frequency has been down-converted by approximately 629 KHz17. The time scale is shown in Figure 3j. Here, to indicates the field start time,
tl indicates the field end time. That is, 70~t
1. Approximately 16.7 m5eC from t1 to t2 becomes one field. The head switching signal and each field number 100 are shown in FIG. 39.

101, 102, 103, 104 were shown. In FIG. 3q, in the field numbered 1oO11o3.1o4, there are two tracks with different times (in FIG. 2, field 100 tel/'!, R1) 7 .

RO) rough, feel Ll in 103)
Rack and 12 tracks, R in field 104
1) Rack and R21-Rack) are played back at the same time, so the black portions in FIG. 3d are adjacent beats that are played back over the entire screen. Since the adjacent beats are reproduced every two fields, the screen becomes very difficult to view. This point is a drawback of the conventional example. The present invention provides such a main head pair M1. A field in which the playback head output of M2 has no signal or adjacent beats is detected by the auxiliary head pair S2,!, as shown in FIG. 3e. By replacing the playback head with a playback head output of 31 as shown in FIG. 3 f4C, a clear noiseless slow playback screen without noise or adjacent beats can be obtained.

- To obtain a clear noiseless slow playback screen with no beats by capturing the field in which the output of the main head pair decreases or adjacent beats occur as described above with the output of the auxiliary head pair. An embodiment of the present invention that can be used is shown in a block diagram 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 rotary head M1 is amplified by a preamplifier 51 and supplied to a gate circuit 52. Gate circuit 5
The output signal of 2 is supplied to an adder 53. The head output signal of the third rotary head S2 is amplified by the preamplifier 61 and supplied to the gate circuit e2. The output signal of the gate circuit e2 is supplied to the adder 53. The output signal of adder 63 is supplied to switch circuit 67. The head output signal of the second rotary head M2 is amplified by the preamplifier 54 and supplied to the gate circuit S6. Gate circuit 65
The output signal of is supplied to an adder 66. The head output signal of the fourth rotary head S1 is amplified by a preamplifier 63, supplied to a gate circuit 64, and amplified.
supplied to The output signal of the gate circuit 64 is supplied to the adder 66. The output signal of the adder 56 is supplied to the switch circuit 67. The output signal of the switch circuit 57 is supplied to the video signal demodulator 67.
The output signal of is supplied to output terminal 68.

The head switching signal 58 is a signal with a duty of 60% and a frequency of 30 Hz that is synchronized with the rotational phase of the rotating head.
The signal is supplied to the switch circuit 6 and the % frequency divider circuit 69. The output signal of the frequency dividing circuit 69 is supplied to the inverter circuit 60, and at the same time, it is supplied to the switch circuit 66 as a command to use the main rotary head pair M1, M2. The output signal of the inverter circuit e6 is transmitted from the auxiliary rotary head pair S1. This becomes the use command 1 of S2 and is supplied to the switch circuit 66. The output signal of the % slow command circuit 69 is sent to the switch circuit 65.68.
is supplied as a control signal to The output signal of the switch circuit 66 is supplied to the gate control terminal of the gate circuit 52,55. Switch times! The output signal of 65 is supplied to the gate control terminals of the gate circuits 62 and 64.

Next, the operation of this embodiment will be explained with reference to the waveform diagrams of FIGS. 2 and 3. When playing 3A slot, the main rotating head pair M1. If M2 draws a reproducing head trajectory as shown in FIG. 2a, the main rotary head pair M1.M2 as shown in FIG. 3d. The reproduced output signals of M2 are output from preamplifiers 51.54 and fed to gate circuits 52.56, respectively. Further, the auxiliary rotary head pair S2. S1 draws a reproducing head trajectory as shown in FIG. 2, and the reproducing output signal of the auxiliary rotary head pair S2, 31 as shown in FIG. 3e is transmitted to the preamplifier 61.
63 and supplied to gate circuits 62 and 84, respectively. The gate circuit 6 uses the output signal of Fig. 3 d as it is.
When outputting from 2.55, fields 100 and 103
, 104, the black portions are adjacent beats as described above, and a clear noiseless slow playback screen cannot be obtained. 3q shows the head switching signal 58 shown in FIG. 4, which controls the switch circuit 57. In FIG. That is, when the head switching signal 58 is at a high level, the output signal of the switch circuit 57 is the output signal of the adder 53, and when the head switching signal 68 is at a low level, the output signal of the switch circuit 57 is the output signal of the adder 56. becomes the output signal.

The third diagram shows the main rotating head pair M1 during % slow playback.
, M2 use command signal, gate circuit 52.55
is under control. In other words, when the third figure is at a high level,
The gate circuit 52,55 is opened, the head output signal of the first rotating head M1 is fed to the adder 53 via the preamplifier 61, and the head output signal of the second rotating head M2 is fed to the preamplifier 64. The signal is supplied to an adder 56 via the signal. Figure 3 i shows the auxiliary rotating head pair S2°S during % slow playback.
This is a command signal for use of 1, and controls the gate circuits 62 and 64. That is, when FIG. The head output signal of head S1 is supplied to adder 56 via preamplifier 63. The % slow command signal 69 controls switch circuits 65 and 66.

That is, during % slow playback, the switch circuit 66 is connected to the use command signal 1 for the pair of auxiliary rotary heads S2, Sl, and the switch circuit 66 is connected to the use command signal 1 for the pair of auxiliary rotary heads M1.
During normal playback, the switch circuit 86 is connected to the GND (earth) side, and the switch circuit 66 is connected to the VCC (constant voltage) side. With such a configuration, the output signal of the first rotary head M1 in the field 100 of FIG. 3d is supplemented by the output signal of the third rotary head S2 of FIG. 3e, and the output signal of the third rotary head S2 of FIG. The output signal of the second rotary head M2 in the field 103 is supplemented by the output signal of the fourth rotary head S1 in FIG.
The output signal of is as shown in FIG. 3f. This field 10
1. Switch circuit 67, which continuously obtains a reproduction output with one cycle of 4 fields from 0 to 1o3
The output signal is supplied to a video signal demodulator 67 and converted into a video signal. As is well known, the video signal demodulator 67 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 67 is supplied to an output terminal 68 and is a clear % signal free from noise and adjacent beats.
A slow playback video signal can be obtained continuously.

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 that does not have noise or adjacent beats. can. As a result, a clear % slow playback screen without noise or adjacent beats is obtained.

Although the above explanation assumes that the rotating head pairs Ml, M2 and S2°Sl are mounted on the same surface,
Main rotating head pair M1. The same effect can be obtained even if the rotation plane of the auxiliary rotation head pair 82 and 81 is set to a rotation plane that is separated from the rotation plane of M2 by an even multiple of the track pitch.

The above description also includes the main rotation head pair M1°M2 and the auxiliary rotation head pair S2. It is assumed that the head widths of the auxiliary rotating head pair S2°Sl are almost the same, but the head widths of the auxiliary rotating head pair S2°Sl are different from that of the main rotating head pair M1. Even if the head width is wider than that of M2, almost the same effect can be obtained. Particularly when a guard band is provided between recording tracks, a wide head is advantageous in terms of reproduction output level.

Effects of the Invention As described above, the present invention provides the main rotary head pair M1.
M2, and an auxiliary rotating head pair S2. SL, and during % slow playback, the main rotating head pair M1.

By replacing the two fields in each frame in which the reproduced output signal of M2 decreases with the reproduced output signals of the auxiliary rotary head pair S2 and Sl, a smooth noiseless rotation with no noise or adjacent beats can be achieved. Since it can be reproduced, it is extremely useful in practical terms.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of the main parts of a rotating head type magnetic recording/reproducing device 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 % slow playback. FIG. 3 is an operational waveform diagram in an embodiment of the present invention, and FIG. 4 is a block circuit diagram of a main part of the embodiment of the present invention. Ml, M2... Main rotating head, 32. Sl...
...Auxiliary rotating head, 3...Rotating drum,
6...Magnetic tape, alblc...%
Head trajectory during slow playback, 51.54, 61.63・
...Preamplifier, 52, δ5.62.64...
...Gate circuit, 53゜56...Adder, 5
7,65.66...Switch circuit, 68...
...Head switching signal, 59...% frequency division circuit,
60... Inverter circuit, 67... Video signal demodulator, 68... Output terminal, f river... Playback output signal during % slow playback in the present invention, d...・・・
...Reproduction output signal during % slow playback of the main rotary head in the conventional technology, e...Reproduction output signal during % slow playback of the auxiliary rotary head in the conventional technology, q...
...Head switching signal, RO, Li, R1, L2°R
2, L3, R3, L4, R4... Output recording track change. Name of agent: Patent attorney Shigetaka Awano and 1 other person 1st
Figure 2-v! - Open diagram diagram

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. Rotary heads with azimuth angles different from the azimuth angle of the rotary head are located near the head, and are arranged so as to scan along the scanning locus of the rotary head of the pair of main heads, and the magnetic tape is A rotary head type magnet, characterized in that, when reproducing by running at a speed of s, the reproduction outputs of the main head pair and the auxiliary head pair are continuous signals that are sequentially and selectively switched every two fields. Recording and playback device.