JPS63121175A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To previously reproduce a time base compressed and recorded audio signal with a small height difference without displacing a magnetic head by reproducing a video signal by a second magnetic head at the time of a reproduction and previously reproducing the audio signal by a first magnetic head. CONSTITUTION:At the time of recording, the time base compressed audio signal is initially recorded at a position preceding by a prescribed quantity (timing difference of the first magnetic heads 10, 11 and the second magnetic heads 12, 13) to the longitudinal direction of a magnetic tape. During a reproduction, both signals are reproduced respectively by the opposite heads at the time of the recording, thereby, the audio signal can be reproduced in a further preceding timing. Thereby, the effective audio signal can be previously reproduced with the small head mounting height difference and without displacing both heads.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a magnetic recording and reproducing apparatus having a rotating magnetic head such as a helical scan video tape recorder (hereinafter referred to as VTR), and in particular to a magnetic recording and reproducing apparatus having a rotating magnetic head. The present invention relates to a magnetic recording and reproducing device configured to record and reproduce audio signals.

BACKGROUND OF THE INVENTION Conventional magnetic recording and reproducing devices include, for example, Japanese Patent Application Laid-open No. 1983-
It is shown in Japanese Patent No. 127203. FIG. 6 shows a plan view of the rotating drum device of this conventional magnetic recording/reproducing device. Here, in the above publication, a method is described in which the luminance signal and chrominance signal in the video signal are mixed and recorded and reproduced using one magnetic head, but here, the luminance signal and chrominance signal are separately recorded and reproduced. The explanation will be based on the Y and C separate recording method in which recording is performed using a head.

In FIG. 6, the magnetic tape 1 is wound around a rotating drum 2 and runs at a constant speed in the direction of arrow a in the figure. The rotating drum 2 rotates at high speed in the direction indicated by the arrow in the figure, and is equipped with a brightness signal magnetic head 3 and a color signal magnetic head 4, which have opposite azimuth angles and have a height difference equivalent to one track pitch. are doing.

Further, heads 3' and 4' of the same specifications are provided at angular positions of 1800 degrees with this head, and each record and reproduce signals for one field. Further, the magnetic head 3
Similar magnetic heads 5, 6.5', 6' are provided on bimorph plates 7, 7' composed of piezoelectric elements at positions preceding fields 4, 3', 4', and the magnetic heads 5, 6. direction. Further, the flying erase heads 27, 27' simultaneously erase the luminance signal and two color signal tracks. With the above configuration, first, during recording, the magnetic heads 3, 4, 3', 4' are used to move luminance signal video tracks (VYl, VY2°...) and chrominance signal tracks (VCl, VO2°...) as shown in FIG. ,...), followed by a two-channel audio signal (A, CHl-1°A, CHl-2, A, CH
l-3...) (A, CH2-1゜A, CH2-
2, A, CH2-3, . . . ) are recorded at the timing shown in FIG. During reproduction, only the audio signal is reproduced one field ahead of the video signal by the magnetic heads 5, 6.5', 6' in order to match the output timings of the video signal and the audio signal, as shown in FIG. Also, during recording, bimorph plates 7, 7' are used to check for clogging of the recording head and monitor the recording state.
The magnetic heads 5, 6, 5', and 6' simultaneously reproduce the tracks recorded by the magnetic heads 3, 4, 3', and 4'.

Problems to be Solved by the Invention However, in the above configuration, the magnetic heads 5, 6
, 5', and 6' must be displaced from the audio advance playback position (C in FIG. 7) to the simultaneous playback position (FIG. 7d), and a displacement amount of 4 track pitches in FIG. 7 is required. This is the YC separation recording method V that is currently in practical use.
This is the same amount as the unidirectional displacement of about ±4 track pitches (approximately 2x speed from methyl) during special playback of TR, and the maximum voltage must always be applied to the piezoelectric element during simultaneous playback. Shorten the life of the piezoelectric element. (It is generally said that the life of an element is inversely proportional to the product of applied voltage and time.) Furthermore, the YC separation recording method is a method used in high-end VTRs for broadcasting, and high quality sound is also required. Therefore, if a longer time is required for the compression processing and reproduction processing shown in FIG. 8, it is necessary to start the previous track again from position C in FIG. 7, further shortening the lifespan. Furthermore, when applied to a high-quality VTR or the like in which one field signal is recorded by dividing it into a plurality of tracks, the amount of displacement required increases significantly. In addition, since the Palmorph 7.7' has a mechanism that fixes one side and uses the deflection of the other side to displace the head position, as the displacement increases, the head step tilts and the contact with the magnetic tape deteriorates, causing the output during simultaneous playback to deteriorate. becomes insufficient for monitoring. Furthermore, as a method for pre-reproducing audio signals, the present inventor proposed the
A configuration shown in Publication No. 5804 was proposed. During recording, the time-axis compressed audio signal is recorded using a separate head that scans behind the video recording head, and during playback, the same head plays both the video and audio, allowing the audio signal to be played in advance relative to the video recording head. The simultaneous playback is to play back the video signal during the audio non-recording period of the audio signal recording head. Although this method does not require the head to be displaced in the track width direction, it is necessary to provide a timing difference between both heads necessary for advance audio playback, and an interval of several track pitches is required in the head height direction. When a magnetic tape is wound helically around a drum with such a head arrangement, physical conditions such as tape tension and air fill amount differ greatly between the head positions, so it is difficult to maintain good contact between the magnetic tape and both sides. The problem was that it was difficult to secure the

In view of the above, an object of the present invention is to provide a novel magnetic recording and reproducing apparatus that can pre-reproduce audio signals recorded by compressing the time axis with a small height difference without displacing the magnetic head.

Means for Solving the Problems The present invention provides a drum with a first magnetic head for recording a video signal and a second magnetic head for recording a time-axis compressed audio signal at a position subsequent to the first magnetic head, The present invention is a magnetic recording/reproducing apparatus configured such that the second magnetic head reproduces a video signal and the first magnetic head reproduces an audio signal in advance during reproduction.

Function: During recording, the present invention first records a time-base compressed audio signal at a position that is ahead by a predetermined amount (timing difference between the first and second magnetic heads) in the longitudinal direction of the magnetic tape.
During playback, by playing back both signals using the heads opposite to those used during recording, the audio signal can be played back at an earlier timing. Audio signal advance playback can be performed.

Embodiment FIGS. 1(a) and 1(b) show a plan view of a rotating drum of a magnetic recording and reproducing apparatus in an embodiment of the present invention and a configuration diagram showing the height relationship of a magnetic head provided on this drum. . In FIG. 1(a), 8 is a magnetic tape that runs in the direction of arrow e. Further, this magnetic tape 8 is helically wound and guided around the outer periphery of a drum 9 rotating in the direction of arrow f.

A video head 10 for the luminance signal of the video signal and a video head 11 for the color signal are fixed to the drum 9, and another set of similar heads 10.1 is located at a position facing them.
1' is fixed. Also, a similar magnetic head 1 is located at a position 6o0 behind this head in the direction of drum rotation.
2.13 is provided on a bimors plate 14 consisting of two piezoelectric elements, and is movable in the height direction. A set of similar units 12', 1 is also located opposite to this.
3', 14.

The magnetic heads 12.13 are mounted lower than the magnetic heads 10.11 by two track widths, as shown in FIG.
' is also similar. Next, the erasing head 15.about.15' is provided at a position 60 degrees ahead of the magnetic heads 10 and 11 in the citram rotational direction, and is configured to erase both tracks (luminance signal and chrominance signal) at the same time. The bimorphs 14 and 14' are connected to a tracking control circuit and a bimorph drive circuit, respectively, and each video head is connected to each circuit as shown in FIG. First, during recording, magnetic heads 10, 11, 1 as shown in FIG.
0'11' is connected to the video signal recording circuit via the changeover switch 16, and the magnetic heads 12, 13, 12
'.

13' is connected to a video signal simultaneous reproduction circuit or an audio signal recording circuit via changeover switches 17 and 18. Further, during playback, as shown in FIG. 2(b), the magnetic heads 10, 11, 10', 11' are connected to the audio playback circuit, and the magnetic heads 12, 13, 12' are connected to the audio playback circuit.

13' is connected to a video signal reproducing circuit.

The operation of the magnetic recording/reproducing apparatus of this embodiment configured as described above will be explained below.

First, to explain the recording process, each circuit and the magnetic head are connected as shown in Figure 2 (a), and the changeover switch 16, 17
The two sets of magnetic heads are alternately switched for each field to record signals on the magnetic tape.

The recording tracks by the magnetic heads 10, 11 and 12, 13 at this time are shown in FIG.
forms video signal tracks 19 and 20 and magnetic head 1
2.13 is audio signal track 21 (CHl)
, 22 (CH2) is formed.

The timing of the video signal and audio signal recorded on the tape at this time will be explained with reference to FIG. 4. The magnetic head 10.
11 records video signal A on track 19°2o, and magnetic head 12.13 follows magnetic head 10.11.
records the compressed audio signal in the shaded period in FIG. 4 at the recording signal position.

At this time, the magnetic head IQ recorded the video signal as in the past.
, 11, the audio compressed signal is recorded at the position described as the compressed signal in FIG. On the contrary, the signal is recorded at the preceding position. In this embodiment, the timing difference is 4/
Since it is set to 3 fields, the audio signal is recorded in advance by 4/3 fields at the time of recording. Next, the time of reproduction will be explained. During playback, Figure 2 (
As shown in (b), each circuit is connected to a magnetic head.9 Basically, the head that recorded the video signal reproduces the audio signal, and the head that recorded the audio signal reproduces the video signal.

Therefore, since the magnetic head 12.13 reproduces the video track 23.24 in FIG. 3, and the magnetic head 10.11 reproduces the audio track 25.26, the audio signal at the time of reproduction is changed from the time of recording as shown in FIG. Furthermore, since 4/3 fields are reproduced in advance, it is possible to output in the same phase as the video signal even though the signal is reproduced in advance by one field in total. Next, simultaneous reproduction during recording will be explained. Simultaneous playback is performed using the audio signal recording magnetic heads 12, 13,
12'.

13', the operation is carried out only during the period when no audio signal is recorded, and the changeover switch 18 in FIG. 2(A) is used to switch between the two operations. FIG. 5 shows this operation, in which video tracks 23 and 24 of FIG. 3 are played back and monitored during the playback mode. The reason why the recording mode period is started earlier than the audio recording period by S is to sufficiently stabilize the recording system circuit. Further, in the present invention, the audio signal recording heads 12, 13, 12', 1
3' is attached to the bimorph plates 14 and 14', so it is common to control the tracking position during recording. Next, its operation will be explained. First, during the simultaneous reproduction period, a signal from the piezoelectric element control signal A shown in FIG. 5 is supplied to the bimorphs 14 and 14', and the magnetic head 12°13.
2' and 13' by a predetermined amount in both directions along the track width, and at the same time, the level L of the head reproduction output during the T period.
Tracking alignment during recording is performed by checking the maximum level position and supplying a control signal at the maximum level position during the recording mode period. The reason why the level check period is set to the T period of the playback output is that poor contact occurs at the contact start and end positions of the head, making accurate checking impossible. Therefore, the piezoelectric element control signal may also be displaced only during the T period as shown in B. In addition, if the above control is performed during the entire recording operation period of the device, good simultaneous playback output cannot be obtained, so it is performed only for 1 field at the start of recording (actually 2 fields because it is necessary to perform up to the head at the opposing position). After that, the configuration is such that the control signal is held. When recording continuously for a long time, the above-mentioned check may be repeated at regular intervals and corrections may be made if any changes occur.

Therefore, an audio track can be faithfully formed as an extension of a video track recorded with a fixed head.

Furthermore, if we add a further explanation to the audio advance playback operation mentioned above, the total required advance playback timing can be calculated from the time required to perform various signal processing of the audio signal (compression processing and playback processing in Figure 4). Basically, the mounting phase difference between the video signal recording magnetic head and the audio signal recording magnetic head (8/3 field in this embodiment) is set to the above total advance amount in kG (4/3 field in this embodiment). This can be set by the relative mounting angle and relative mounting height difference between both heads as shown in FIG. Although the value can theoretically be set arbitrarily, in practice it is greatly restricted in terms of head arrangement and the range in which it can be set is limited. Also, during special reproduction, the conventional Sibimorph plates 14 and 14' are used to connect the magnetic heads 12 and 1.
3. This can be done by displacing 12' and 13'.

DETAILED DESCRIPTION OF THE INVENTION According to the present invention, as described above, a first magnetic head for recording a video signal and a second magnetic head for recording a time-axis compressed audio signal at a subsequent position thereof are rotated. The second magnetic head is provided on the drum, and the second magnetic head is configured to play back the video signal while the first magnetic head is used to play the audio signal, thereby eliminating the need to displace the head and reducing the amount of damage compared to conventional methods. (approximately %) It is possible to perform advance playback of audio and simultaneous playback of video signals during recording using the head installation phase difference. Magnetic head during playback (excluding special playback),
This has the effect of easily ensuring good contact between the magnetic tapes and stabilizing it for a long period of time. Furthermore, by controlling the tracking of the movable magnetic head during audio signal recording using the optimal tracking signal during simultaneous playback, it is possible to improve the pattern accuracy of the recording track and obtain a good playback audio signal. . In addition, by configuring the above-mentioned tracking optimization during simultaneous playback to be repeated at the start of recording and at regular intervals thereafter, high-precision tracking can be maintained for a long time without interfering with the playback output during simultaneous playback. can be ensured, and its practical effect is 0.

[Brief explanation of the drawing]

(7) A plan view of a rotating drum and a configuration diagram of a head of a magnetic recording/reproducing device according to an embodiment in the first embodiment, a block diagram showing connections with each circuit during recording and reproduction of a second embodiment, Fig. 3 is a plan view showing signal tracks recorded on the magnetic tape of the same embodiment, Fig. 4 is a timing chart showing the elapse of time during recording and reproduction of video and audio signals of the same embodiment, and Fig. 5 is a plan view showing signal tracks recorded on the magnetic tape of the same embodiment. Detailed diagrams of various signals related to tracking control; FIG. 6 is a plan view of a rotating drum of a conventional magnetic recording/reproducing device; FIG. 7 is a plan view showing a tape pattern recorded by the conventional device; FIG. 8 is a plan view of a conventional video recording device. and a timing chart showing the passage of time of the audio signal. 9... Rotating drum, 10, 11. 10', 11
'...First magnetic head, 12, 13, 1
2', 13'... Second magnetic head, 14
, 14'...bimorph plate. Name of agent: Patent attorney Toshio Nakao and 1 other person9-
~-Review of the series, Otsu, /414---) (Imotsu reflex board C) (B) Figure 2G) Figure 5 (F3) Figure 6

Claims (4)

[Claims] (1) A first magnetic head that records a video signal on a magnetic tape, and a second magnetic head that records a time-axis compressed audio signal at a position subsequent to the first magnetic head, and when recording, the second magnetic head is provided. The video signal is simultaneously played back during the period when the magnetic head is not recording the audio signal, and during playback, the second
1. A magnetic recording and reproducing apparatus characterized in that the first magnetic head is used to reproduce a video signal, and the first magnetic head is used to reproduce an audio signal in advance. (2) Claim 1, characterized in that the mounting phase difference between the first magnetic head and the second magnetic head is set to approximately 1/2 of the amount of advance reproduction necessary for timing alignment of the audio signal. The magnetic recording and reproducing device described above. (3) A configuration in which the second magnetic head is provided on a member movable in the track width direction, and a tracking control means for the second magnetic head is provided, so that the tracking control of the audio signal recording period is performed using the tracking signal of the simultaneous reproduction period. A magnetic recording and reproducing device according to claim 1, characterized in that: (4) Tracking optimization control is repeatedly executed at the start of recording and at fixed time intervals thereafter, and the immediately preceding control signal is held between each control operation. The magnetic recording and reproducing device described above.