JPH03216087A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To obtain a VTR whose head number is decreased by using a moving head so as to record and reproduce a video signal. CONSTITUTION:A reproducing FM signal extraction means 12 extracts an FM signal reproduced from an end of a deep layer recording track by a moving head 4 and a moving head scanning means 17 moves the moving head 4 by a prescribed quantity toward the track width direction sequentially every time the head 4 scans the end and outputs a scanning signal scanning by a prescribed width within a prescribed time to an actuator 8. A center position detection means 14 of a deep recording track detects the center position of the deep layer recording track from a level change in the reproduced FM signal within the scanning period and a moving head positioning means 15 sends a positioning signal suitable for the center position to the actuator 8 at surface layer recording to position the moving head 4. Thus, the surface layer recording and the reproduction at the standard speed by the moving head are implemented and special reproduction is implemented, then a stationary video head is not required.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to a VHS system HiFi video table recorder (
VT that performs multilayer recording such as rVTRJ (hereinafter referred to as rVTRJ)
Regarding R.

[Conventional technology]

Fig. 7 shows a VV that records a HiFi audio signal in the deep layer of a magnetic tape, records a video signal in the surface layer, and reproduces the video signal using a movable head at a speed different from the standard speed.
FIG. 2 is a plan view showing the arrangement of each magnetic head of the rotating drum of the TR and the running path of the magnetic tape. In the figure, (1)
is a rotating drum, (2a) . (2b) is an audio head with different azimuth angles for deep recording/playback, (3a),
(3b) is a video head with different azimuth angles for surface recording and playback, (4a) and (4b) are movable heads, and each head is attached to the rotating drum (1) at an index angle of 60°.

(5) is a magnetic tape, which is wound 190 degrees around the rotating drum (1) and travels in the direction of arrow A during recording.

Figure 8 is a cross-sectional view for explaining the deep/surface recording operation by the audio head (2) and video head (3). Approximately 4 μm when a large recording current is applied.
The audio signal is recorded to the deep part of the m-thick magnetic layer (5b), and then a small gap width g+ (for example, 0.3μ
A recording current is passed through the video head (3) formed in (m) to record the video signal on the surface layer of the recorded audio signal. The width of this video head (3) is the same as that of the audio head (2).
Wider width (e.g. 48 μm) than (e.g. 26 μm)
and is fixed to the rotating drum (1) with a predetermined step (for example, 16 μm), and the audio head (2
) is scanned so as to completely cover the track recorded by the video head (3) so that the audio signal does not remain on the surface layer, thereby preventing a drop in C/N during playback.

FIG. 9 is a diagram showing the track pattern recorded in this way, and FIG. 10 is a diagram showing a part of it.
I, A2... are tracks recorded by the audio head (2a) and video head (3a), B,, B2...
is the track recorded by the audio head (2b) and video head (3b), C is the control track, ■ is the part where the magnetic tape (5) is wrapped around the rotating drum (1) at 180 degrees, and corresponds to one field period. X O *
X l..., Yo. 'j+...' is the switching point where the playback signal is switched during playback, X is the part of the tape that is wrapped around the rotating drum (1) at an angle of 180° or more on the winding side, and Y is the part that is wrapped around the rotating drum (1) at an angle of 180° or more on the tape supply side. In this example, the wrapped portions overlap each other by 5 degrees, so that the reproduced signal becomes a continuous signal.

(L4-) in Figure 9. (L4b) is a movable head (
This shows the scanning pattern when 5x speed playback is performed with 4a) and (4b) fixed; in this case, only tracks recorded at the same azimuth angle (shaded in the figure) are played back. Therefore, noise bars appear on the playback screen.

FIG. 11 is a sectional view showing the configuration of the movable head (4).
(6) is a fixed drum, (7) is a bimorph type piezoelectric element, one end of which is fixed to the rotating drum (1), a video head (4) for playback is fixed to the free end, and the piezoelectric element (7) is fixed to the rotary drum (1).
) is configured to be displaced in the direction of the rotation axis as shown by the broken line in accordance with the voltage value of the saw-tooth drive signal applied to the The movable head (4a) is displaced as shown by AI,
A6...track, movable head (4b) is B3,B
a... Tracks are sequentially scanned.

Figure 12 is a timing diagram of the playback video signals of the movable heads (4a) and (4b) and the continuous playback video signal created from these playback signals, and shows the timing diagram of the playback video signals of the movable heads (4a) and (4b) and the continuous playback video signal created from these playback signals.
. , X+ (yo), X2 (y+), etc., it is possible to obtain a continuous playback video signal without noise bars.

[Problem to be solved by the invention]

Conventional dual-layer recording VTRs require a total of six heads, two audio heads and two video heads for recording and playback, and two movable heads for special playback, to be installed on a rotating drum, so the structure is complicated. It became complicated and became an obstacle to lower prices.

Furthermore, since the six heads are arranged at equal intervals on the rotating drum, there is a problem in that jitter increases due to minute vibrations caused by hitting the magnetic tape with the heads.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to obtain a VTR in which the number of heads is reduced by recording and reproducing video signals using movable heads.

(Means for Solving the Problems) A VTR according to the present invention uses a fixed head for deep recording and playback mounted on a rotating drum to deep record an FM signal on a track with a length exceeding a switching point and to play back the FM signal. In addition, different signals are recorded on the surface from above the deep recording track using a movable head for surface recording/playback mounted on a rotating drum, and playback at standard speed and special playback such as speed search or slow search are performed. The VTR has means for recording different signals on the surface layer by the movable head except for a portion of at least one end of the deep recording track that does not reach the switching point, and a means for recording different signals on the surface layer by the movable head, means for later extracting the FM signal reproduced from the end portion by the movable head; and means for scanning the movable head by a predetermined distance in the track width direction within a predetermined time every time the reproduced FM signal is extracted. A movable head scanning means for displacing and reproduction FM extracted within this scanning period.
The present invention includes means for detecting the center position of the deep recording track based on a change in the level of the signal, and means for positioning the movable head during surface recording to match the detected center position of the deep recording track. It is characterized by

[Function] The fixed head records the FM signal deeply by forming a track with a length exceeding the switching point, and the movable head records the FM signal deeply.
A different signal is superficially recorded on the surface layer of the deep recording track except for a range not exceeding the switching point at at least one end of the deep recording track. Play FM
The signal extracting means is configured to receive the F signal reproduced from the end by the movable head.
The movable head scanning means for extracting the M signal sequentially displaces the movable head by a predetermined amount in the track width direction each time the movable head scans the end portion, and sends a scanning signal that causes the movable head to scan by a predetermined width within a predetermined time to the position of the movable head. is output to the actuator that displaces it. The center position detection means of the deep recording track is
The center position of the deep recording track is detected from the level change of the reproduced FM signal within the scanning period. The movable head positioning means positions the movable head by sending a positioning signal matching the detected center position of the deep recording track to the actuator during surface recording.

As a result, the movable head can perform surface recording and playback at standard speeds similar to a fixed video head, and
Special playback is possible, eliminating the need for a fixed video head.

[Embodiments of the invention]

FIG. 1 is a block circuit diagram of one embodiment of the present invention, showing only the video signal recording system of one of the movable heads (4). In the figure, (8) is a voice coil type actuator (hereinafter referred to as "actuator"),
(9) is a recording signal processing circuit which converts the video signal into a video signal b formed by passing it through magnetic recording. (10) is a video signal on/off circuit, which will be described later.
The video signal input to the movable head (4) is turned on and off by the off signal g. (11) is a rotary transformer,
(12) is a reproduced audio signal extraction circuit, (13) is a peak detection/integration circuit, and (14) is audio track center position detection means, which detects the center position of the audio track from the level change of the integral signal. (15) is a movable head positioning signal generating means which generates a positioning signal for aligning the position of the movable head (4) with the center line of the detected audio track and outputs it to the actuator (8).

Reference numeral (16) denotes a timing signal generation circuit, which sends out timing signals g and h, which will be described later, at predetermined timings, respectively, based on the head switching signal.

(17) is a scanning signal generation circuit which generates a scanning signal that sequentially displaces the movable head (4) by a predetermined amount in the track width direction every period of the timing signal h to complete one scan per second. It is created and sent to the actuator (8).

FIG. 2 is a plan view showing the arrangement of the magnetic head of the rotating drum and the running path of the magnetic tape in this embodiment, and FIG.
Figure In-III line sectional view shows the sound head (2a
), (2b) and movable head (4a), (4
b) are arranged at 90° intervals. Magnetic tape(
5) is wound around the rotating drum (1) at 190 degrees, the audio signal is recorded deep in the same track pattern as in Fig. 9 by the audio heads (2a), (2b), and the video signal is recorded by the movable heads (4a), (2b). By (4b),
The audio signal is recorded on the surface layer of the track where the audio signal is recorded deep.

Figure 4 is a longitudinal cross-sectional view of the actuator (8), and (81)
, (82) is a gimbal spring, and cymbal spring (81
) A movable head (4) is fixed to one end of an arm provided in the head (4). (83) is a coil bobbin around which a coil (84) is wound, gimbal springs (81), (82)
It is held coaxially by. (85) is a permanent magnet,
(86) is a pole bead, (87) and (88) are yokes, which are assembled into a magnetic device that forms a circular magnetic gap, and a coil bobbin (8
3) are inserted coaxially and cymbal springs (81), (
The outer peripheral edge of the coil bobbin (82) is fixed to a stepped portion formed on the yoke (87) to support the coil bobbin (83) so that it can be displaced in the axial direction, and is movable according to the amount of current applied to the coil (84). The head (4) is configured to be axially displaced. (89) is a cap, and (90) is a connection terminal.

Next, the recording operation of this embodiment will be explained.

The deep recording operation by the audio heads (2a) and (2b) is the same as in the conventional example, so a description thereof will be omitted.

FIG. 5 is a timing diagram of the embodiment shown in FIG.
Based on the video signal on/off signal g (see C))
'i5 (g)) and reproduced signal extraction signal h (5th
(see figure (h)).

Surface recording of the video signal is performed by a movable head (4).

FIG. 6 is a diagram showing one track pattern according to this embodiment, in which (21) is an audio track recorded deep with the audio head (2), and (41) is a video track recorded superficially with the movable head (4). For example, the audio track (21)
The width of the video track (41) is 26μm, and the width of the video track (41) is 31μm.
m, and the track length of the audio track (21) is:
The track length of t1 to t4 corresponds to a length of 190° wrapped around the rotating drum (1), whereas the track length of the video track (41) corresponds to a wrapping length of 184°, for example. It is formed to have a track length of t2 to t3, and portions ZO+Zl in which only the audio track (21) is formed are formed at both ends of the track. This 2. , 2, for example, the diameter of the rotating drum is 6
For a 2mm VHS VTR, 62x rcX 3/360/0.370 (IH
interval) is 44.48.

Such video signal recording control is performed by controlling the video signal on/off circuit (10) using a video signal on/off signal g from the timing signal generation circuit (16).

The position control of the movable head (4) is performed by a positioning signal sent from the movable head positioning signal generating means (15).
A positioning signal is sent to the actuator (8) to perform the recording operation in the section t2 to t3, and a positioning signal is sent to the actuator (8) to set the position at 6 μm).
,-1. .
i)) by the interval Z. The audio signal is reproduced in Zl and inputted to the reproduced audio signal extraction circuit (l2) via the rotary transformer (11). The reproduced audio signal extraction circuit (12) extracts this reproduced audio signal under the control of the reproduced signal extraction signal h, and the peak detection/integration circuit (13)
This extracted reproduced audio signal is subjected to peak detection, and an integral signal of the detected signal is sent out. The level of this integrated signal is
The audio signal recorded on the audio track (21) is FM
wave, so the movable head (4) moves the audio track (21
) while the movable head (
4) becomes a signal whose level decreases as the amount of deviation from the audio track (21) increases. The audio track center position detection means (14) detects the scanning width of the movable head (4) (for example, 5
The center position of the audio track (21) is calculated from the position where the level of the integral signal decreases on both sides of 8 μm), and this position signal is output to the movable head positioning signal generating means (15). ) sends a positioning signal corresponding to this manually inputted position signal to the actuator (8) for the next 1 second to move the movable head (4).
) is set at the center position of the detected audio track (21).

By repeating the above operations of detecting the center position of the audio track (21) and controlling the position of the movable head (4),
Audio signals and video signals are sequentially overwritten and recorded using the track pattern shown in FIG.

Note that in the above explanation, the operation of one audio head (2) and one movable head (4) was explained, but the operation of the pair of audio heads (2a), (2b) and the pair of movable heads (4) was explained.
a). (4b) It goes without saying that the data are recorded alternately.

At the same time, when playing at standard speed, the audio head (2a)
, (2b) to reproduce the audio signal from the audio track (2l) and obtain a continuous reproduced audio signal in synchronization with the head switching signal C is the same as in the conventional example, and the reproduction of the video signal is the same as when recording. Similarly, movable head (4a).
(4b) to position the movable heads (4a) and (4b) by reproducing the audio signal of section 20, Zl,
As in the conventional example, the configuration may be such that the reproduced video signal reproduced from the video track (41) is switched in synchronization with the head switching signal C to obtain a continuous reproduced video signal.

Furthermore, during special reproduction such as speed search and slow search, by moving the movable heads (4a) and (4b) as in the conventional example, a reproduced video signal without noise bars can be obtained.

In the above embodiment, the voice coil type actuator (8) is used to displace the movable heads (4a), (4b), so that the surface of the magnetic tape (5) and the movable heads (4a), (4b) Since it is only possible to displace the disk with good responsiveness over several hundred μm while keeping the plane parallel to the plane of the disk, high-speed reproduction of 5 times or more can be performed.

Furthermore, in the above embodiment, the position control of the movable head during playback of the video signal at standard speed was performed by the same control means as the position control during recording, but as shown in Japanese Patent Application Laid-Open No. 1-282769, Furthermore, the envelope detection signal of the video signal reproduced by the movable head may be controlled so as to always be at the maximum level.

In addition, in the above embodiment, section 2. , 2, the reproduced audio signal was extracted from the audio track by the movable head, but it is also possible to extract the reproduced audio signal from only one of the sections.

Furthermore, in the above embodiment, the FM audio signal is deeply recorded,
Although a video signal was recorded on the surface, the signal to be recorded is not limited to this example, and may be a digital signal such as a PCM signal or a character signal, or an FM signal with a constant amplitude.
Any signal is fine.

〔Effect of the invention〕

As described above, according to the present invention, the FM signal is recorded deep to a portion beyond the head switching point using the fixed head mounted on the rotating drum, and other signals are recorded deep into the deep region using the movable head mounted on the rotating drum. Surface recording is performed using the same track pattern on a shorter track length than the recording track, and during this surface recording, the FM reproduction signal reproduced by the movable head is extracted from the portion of the deep recording track where the surface recording is not performed, and the movable head is When extracting the FM signal, the movable head is displaced by a predetermined amount and scanned in the track width direction by a predetermined amount within a predetermined time, and the center position of the deep recording track is detected from the level change of the reproduced FM signal extracted by this movable head. A VT characterized in that the movable head is positioned on the center line of the detected deep recording track to perform surface recording.
R, it is possible to record video signals, play back at standard speed, and perform special playback at different speeds using only a movable head, eliminating the need for a fixed video head for recording and playback, which was required in the past, and instead of using a rotating drum. V with fewer heads installed
This has the effect of obtaining TR.

[Brief explanation of drawings]

FIG. 1 is a block circuit diagram of the recording signal system and movable head position control system by one movable head during recording in an embodiment of the present invention, and FIG. 2 shows the head arrangement of the rotary head and the magnetic tape position in this embodiment. 3 is a sectional view taken along the line III-III in FIG. 2, FIG. 4 is a vertical sectional view of the voice coil actuator in this embodiment, and FIG. 5 is an implementation of the method shown in FIG. 1. 6 is a diagram showing one track pattern according to this embodiment, and FIG. 7 is a conventional rotating drum of a VTR equipped with a fixed head for dual-layer recording/playback and a movable head for special playback. FIG. 8 is a plan view showing the head arrangement and the running path of the magnetic tape; FIG. 8 is a cross-sectional view for explaining two-layer recording;
Figure 9 is a track pattern diagram recorded on a magnetic tape.
FIG. 10 is a diagram for explaining the recording pattern of a track, FIG. 11 is a sectional view showing the structure of a bimorph type movable head, and FIG. 12 is a timing diagram of a reproduction signal. (1)--Rotating drum, (2), (2a),
(2b) - Recording/playback audio head, (4),
(4a), (4b)...Movable head, (8)...
・Voice coil type actuator, (9)...recording signal processing circuit, (10)...video signal manual on/off circuit, (12)...playback audio signal extraction circuit, (13)...
)...peak detection/integration circuit, (l4)...audio track center position detection means, (15)...movable head positioning signal generation means, (lδ)...timing signal generation circuit, (17)... ...Scanning signal generation circuit, (21)
...Deep recorded audio track, (41)...Surface recorded video track. In each figure, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] (1) A fixed head for deep recording and playback mounted on the rotating drum performs deep recording of FM signals on a track with a length exceeding the switching point and playback, and a movable head mounted on the rotating drum performs deep recording and playback. A magnetic recording and reproducing apparatus configured to record different signals on the deep recording track at a surface layer, and to perform standard speed reproduction and speed search or slow search reproduction using the movable head, Means for recording different signals on the surface by the movable head except for a portion of at least one end of the track that does not reach the switching point, and reproducing from the end by the movable head before or after the surface recording by the movable head. means for extracting the reproduced FM signal; means for sequentially displacing the movable head by a predetermined amount in the track width direction so as to scan a predetermined width within a predetermined time every time the reproduced FM signal is extracted; means for detecting the center position of the deep recording track from the level change of the reproduced FM signal extracted from the above, and means for positioning the movable head during surface recording so as to match the detected center position of the deep recording track. A magnetic recording/reproducing device comprising: