JP2960527B2 - DAT combined VTR device - Google Patents

Description

The present invention relates to a VTR (Video Tape Recorder) that can be used as a DAT (Digital Audio Tape Recorder), and more particularly to the reproduction of a DAT and a VTR such as an 8 mm video. The present invention relates to sharing and miniaturization of a reproducing mechanism and a circuit for enabling the same.

[Prior art] Conventionally, there is no DAT / VTR device, for example, 8 mm VTR and DA
And T were used independently.

[Problems to be Solved by the Invention] Therefore, when reproducing an 8 mm video tape and a digital audio tape, two devices, an independent VTR and a DAT, are required. there were.

SUMMARY OF THE INVENTION It is an object of the present invention to reduce the size and cost of a device by configuring a DAT / VTR device so that both tapes can be reproduced by a single device.

[Means for Solving the Problems] In order to achieve the above object, a DAT / VTR apparatus of the present invention comprises: a rotating drum in which four heads having azimuth angles opposite to each other are alternately arranged at 90 ° intervals; Winding angle switching means for switching the tape winding angle with respect to the rotating drum, rotating speed switching means for switching the rotating speed of the rotating drum, rotating shaft driving means for switching the inclination angle of the rotating shaft in the rotating drum, and types of VTR and DAT And a control means for controlling the winding angle switching means, the rotation speed switching means, and the rotation axis driving means based on the identification signal.

[Operation] By traversing the rotation surface of the head of the rotary drum by a predetermined angle between the VTR and the DAT, the tape track of the VTR and the DAT can be traced by the head.

The circuit from the head to the equalizer can be commonly used as a circuit for processing signals from the head.

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

FIG. 1 shows an 8 mm video tape pattern with an underline on the DAT tape format. As is clear from the figure, the major differences between the two are shown in the table below.

Practical rotary drums have a 8mm VTR of 40mmφ
26.67mmφ, DAT is mainly 30mmφ, and some are 15mmφ.

As described above, although there are differences in specifications between the 8 mm VTR and the DAT, a shared playback device is configured as an embodiment of the present invention under the following conditions.

First, a rotary drum head of a 4-head type of 26.67 mmφ of 8 mm VTR is used. Figures 2 (a) and (b) are 8m
Tape T for rotating drum heads A to D of mVTR and DAT
Shows the state of winding. As is clear from the figure, 8mm VTR
In the image part, the winding angle of the tape is 270 ゜, the whole is 331
On the other hand, while the DAT has a winding angle of 90 ° for the conventional type of 30 mmφ for DAT, it has a portion of 101.25 ° for 26.67 mmφ.

The drum rotation speed is 2700rpm (45rps) for 8mm VTR.
On the other hand, in the DAT mode, if the relative speed between the tape and the head is the same as the conventional one, then 2000 x 30 / 26.67 =
Although it is 2250 rpm, if the winding angle is 101.25 ° with respect to the head position at 90 ° intervals, it is inconvenient for the next reading.
Therefore, in DAT mode, the drum rotation speed of normal DAT is 2000rp.
m (33 rps). Therefore, the relative speed is 88.88% of the normal drum rotation speed, and the frequency of the signal from the head is also reduced to approximately 89% of the normal speed, but can be sufficiently processed by the normal reproduction system.

FIG. 3 shows the relationship between the positions of the heads A to D and the tracks # 1 to # 5 in the DAT mode. The circles indicate that the azimuth of the heads match the tracks, and the half circles indicate the half. The head area coincides with the track, and a black circle indicates that the azimuth of the head and the track are opposite.

In FIG. 3, the drum having a DAT track length of 26.67 mm has a tape wrap angle of 101.25 °. Therefore, in the heads shown in FIG. When the tape T is scanned and reaches the end A of the pattern, the head B at a position delayed by 90 ° scans the pattern at a position having a rotation angle of 21.25 °.

At this time, as shown by a circle in FIG. 3, if the azimuth of the head A coincides with the azimuth of the recording on the tape T and the center of the tape T is scanned, the head B has just two tracks at that time. , The azimuth of the head also matches the azimuth of the recording pattern ♯2, and the other 1/2 of the head scans the track of ♯1. The azimuth is out of phase, and there is almost no read output from the # 1 track.

Further, the head C scans the center of the # 2 track,
As can be seen from the arrangement of the heads in FIG. 2, when the same head as the 8 mm VTR is used, the azimuth of the head C is in the opposite phase to the azimuth of the tape recording pattern of the # 2 track, and almost no read output is produced therefrom. .

When the head D scans between the tracks # 2 and # 3, the head D starts scanning from the track # 2 similarly to the head B.
A read output of 1/2 is output, and no read output is output from the # 3 track.

FIG. 4 is a timing chart of the reading of each of the heads A to D. It can be seen from FIG. 4 that the reading of the heads A and B is overlapped by 21.125 minutes (0.9375 ms in time).

FIG. 5 is a chart of the read timing from the memory in which the read output of the head is stored in the DAT mode. The read output of each head is stored once and the time axis is extended (usually doubled. 15 / 8.9375 = 1.77 = 16 /
9 times). The frequency for this expansion is (1 / k) fc (4.562) with respect to the write clock frequency fc.
5 = (9/16) fc).

FIG. 6 shows an example of the configuration of a signal processing circuit according to the present invention for obtaining the read output of FIG. 5, wherein 1 to 3 are input terminals for output signals from heads A to D, and 4 to 6 are for memory selective writing. Switches, 7 to 11 are memories, 12 and 13 are read switches, 14 is an addition circuit, and 15 is a memory output switch. In this example, the output of the head C is not used. Further, for example, switch 4 writes the output A ₁ of FIG. 5 at a clock frequency fc to A ₁ 'memory 7, the switch 12 from the memory
As a result, the data is read out as A ₁ ′ in the figure at the clock frequency fc / k. The read timing of A ₁ ′ is from t ₀ ′ to t ₁ ′,
Double the period t ₇ ~t ₈ the write timing t ₁ ~t ₁₀ of A _2. Therefore the memory 8 is provided, the included only writing A ₂ the memory 8 is used. That is, the memory 7 is a dedicated memory for A ₁ , A ₃ ..., And the memory 8 is a dedicated memory for A ₂ , A ₄ . Read timing of these memories _{t 0 '~t 1', t} 2 ' becomes ~.

The output of the head B is also stored in the memory 9 by the switch 5 as B ₁ , B
₃ ..., B ₂ , B ₄ . That is, a signal B ₁ of t ₁ ~t ₄ writing clock fc, added reading, the adder circuit 14 as B ₁ 'to the timing of t _1' ~t ₂ 'by the switch 13. Where t ₀ ′ to t ₁ ′, t ₁ ′ to t
₂ 'is, for example, 15 msec.

On the other hand, the output D ₁ of the head D is written into the memory 11 by the switch 6 at a timing of t ₅ ~t _8, read as D ₁ 'at the timing of t _1' ~t ₂ '. This is the same timing as B ₁ ′, and is added as B ₁ ′ + D ₁ ′ by the adder circuit 14, and is switched to the output of the head A by the switch 15.
A ₁ ′, B ₁ ′ + D ₁ ′, A ₂ ... Are output as continuous signals.

FIG. 7 shows the writing of the head A into the memory (a),
(C) and reading (b), in the timing chart of (d), at t ₀ ~t ₂ = 8.375ms timing of the write to memory FIG output A ₁ 'of the head A (a), which is the At time t ₀ ′ to t ₁ ′ = 15 ms in FIG. 6B, the data is read out after being time-expanded, and the output A ₂ is output from t ₀ as shown in FIG.
30 ms (drum one rotation time) is the memory at the timing of t ₇ ~t ₁₀ late, has been shown to initiate a read from FIG. (D) 't ₂ which is delayed 15ms from' t ₁ as .

FIGS. 8 and 9 are conceptual diagrams of the addition processing of the head output. FIG. 8 shows an example in which a head having the same narrow head width as the DAT is used. In FIG. 8A, if the amplitudes of A ₁ and A ₂ are 1, B ₁ and D ₁ are 0.5, and C ₁ is Since it is 0 as described above, the addition is performed as shown in FIG. 6, and in FIG. 6B, the level is obtained when the addition is performed at the timing of FIG. A ₁ , B ₁ + D ₁ , A ₂
Is a continuous signal.

FIG. 9 shows a case where a head having a wide head width (20.5 μm) of 8 mm VTR is used, and the output of the head is as shown in FIG. 9A due to the relationship between azimuth and track width. Here, the output of the head C is not used as in FIG. FIG. 6B shows a case where these head outputs are added.

Now, as shown in FIG. 3, the head A scans the center of the track, and the azimuth coincides with the tape and the head. On the contrary, the head C is at the center of the track, but the azimuth is opposite to the tape. . The heads B and D are in a state where only 1/2 of the area thereof matches the azimuth of the tape.

In DAT, the head scans the trunk using an ATF (automatic tracking) method. Usually the signal shown in Fig. 3
_{A 1, C 1, A 2} , ( if the DAT in 40mmφ drum used) C ₂ to 7.5ms by intermittently reading, ATF signal contained in the portion of the beginning and end and a portion of the recording pattern of 7.5ms (First
(See the figure) to drive the servo system to track and trace.

In the embodiment of the present invention, as shown in FIGS. 3 to 5, since the head C has an azimuth reverse to the pattern, the head C hardly produces an output. The heads B and D have outputs of 1/2, and since the center of the head is in the middle of the track, the azimuths are also the same at 1/2 of the head. Therefore, as shown in FIG. 10, the servo system is operated by the ATF intermittently with the signals A ₁ and A ₂ . That is, the signal A ₁ is a head output of FIG. 10 (a)
Since T _1, T _2, A ₂ of T _3, using ATF signals T _4, to operate the AFT servo as shown in FIG. (B), between T ₂ through T ₃ is servo controlled in T ₂ Hold the value.

Next, the width of the 8 mm VTR and DAT tapes is different from 8 mm and 3.81 mm, and the inclination of the tape and the head drum is also different from 4 ゜ 54′13.22 ″ and 6 ゜ 22′59.5 ″.

FIG. 11 shows the relationship between each tape and the rotating surface of each head drum when the centers of the tapes are matched. In the figure, MO
M 'indicates the 8mm VTR, and NON' indicates the DAT rotation surface. Accordingly, it can be seen from FIG. 12 that, based on the 8 mm VTR, the rotating surface of the drum must be inclined by Δθ = 1 ゜ 28′45.3 ″ in the case of DAT. 'But
The 8mm VTR drum rotation shaft, 00 "is the DAT drum rotation shaft.

FIG. 13 shows an example of a mechanism for switching the inclination between the drum rotation axis 00 'of the 8 mm VTR and that of the DAT 00 "shown in FIG. 12. This switching mechanism is centered on the center 0 of the rotating surfaces MOM' and NON 'of the head. Is to switch the rotation angle of Δθ, 16 is a drum,
The motor mount, 17 is a reference duct, and 18 and 19 are solenoids. The reference dust 17 is a fan-shaped groove having an inner diameter with a radius r around the zero and an outer diameter with a radius r '. The drum and motor mount 16 are fitted in the groove 17 so as to be movable around the zero. ing. Center line 00 ', MO
An 8 mm VTR indicated by M ', a DAT drum head indicated by 00' and NON 'and a rotary motor are attached. The rotation of Δθ excites the solenoid 18 or 19 to pull and fix the mounting base 16 to the right end or the left end. That is, in the 8 mm VTR mode, the solenoid 18 is turned on, the solenoid 19 is turned off, and the DA
In the T mode, the solenoid 18 is turned off and the solenoid 19 is turned on.

FIG. 14 shows an example of a drive system using a capstan motor in the embodiment of the present invention. In the figure, reference numeral 43 denotes a pulley connected to a capstan motor (not shown), reference numerals 44 and 45 denote 8 mm VTR and DAT pulleys, and reference numerals 46 and 47 denote timing belts. 8mm VTR tape running speed is 49.447mm / se
c, DAT is 32.098mm / sec.
45 has a larger diameter than the pulley 44. 8mm VTR
When the diameter of the pulley 44 and D _8, the diameter D of the pulley 45 of the DAT
₈ is D ₈ = 1.54D ₈ .

FIG. 15 shows an example of a signal processing circuit according to an embodiment of the present invention. In the figure, 20 to 23 are input terminals of outputs of heads A to D, 24 to 27 are head amplifiers, 28 to 31 are equalizers, 29 is a head switching electronic switch, and 30 is a frequency f _F
/ 4 switch drive pulse generator (f _F is 30Hz at frame synchronization frequency), 31 is FM demodulator, 32 is color demodulator, 33 is
NTSC signal generator, 34 is an output terminal, 35 to 37 are RF demodulators, 38
Is a circuit shown in FIG. 6, 39 is a digital decoding circuit, 40 is a stereo signal generator, and 41 and 42 are output terminals of E _R and E _C , respectively.

In the circuit of FIG. 15, in the 8 mm VTR mode, the head A
~ D are applied to input terminals 20 ~ 23,
24-27, is added to the electronic switch 29 via the equalizer 28 to 31, wherein _{f F / 4 (30 / 4Hz} ) A every 1 / 30S in pulses, B,
It can be switched like C, D, A, B ... The switch output switched in this manner is output to the FM demodulator 31 and the color demodulator 32.
, A luminance signal E _Y and a color difference signal are obtained. Further, the NTSC signal generator 33 synthesizes the NTSC signal according to the two signals and outputs the synthesized signal to the output terminal.

On the other hand, in the DAT mode, since the outputs of the heads A, B, and D are used, the outputs of the equalizers 28, 29, and 31 are RF-demodulated by the RF demodulators 35 to 37 and added to the circuit 38. The output of the circuit 38 is decoded into a digital signal by a digital demodulation circuit 39, and in response to this signal, a stereo signal generator 40 outputs the stereo signals E _R and E _L to output terminals 4
A summary of the above-described embodiment of the present invention is provided below.

(I) The rotating drum has a diameter of 40 × 2/3 = 26.66 mmφ, and four heads are arranged at 90 ° intervals.

(Ii) The azimuth of the head arranged at the position of 0 °, 180 ° has an azimuth of − ゜, 90 °, and 270 ° at the head of −270 °. Is 10 ゜ for 8mm VTR mode priority and 20 ゜ for DAT playback priority. The balance between the two may be between 10 and 20 degrees.

(Iii) The tape wrap angle is 270 ° for the video part for 8mm VTR, 331.5 ° for the whole, and 10 for DAT.
1.25.

(Iv) The tape running speed is controlled by a servo system using a commonly used capstan motor, and the standard running speed is used for both the 8 mm VTR and the DAT mode.

(V) The rotation speed of the head drum is 2700rp in 8mm VTR mode
m (45 rps) and 2250 rpm (37.5 rps) in DAT mode.

(Vi) When aligning the lower end of the tape in both the 8 mm VTR and DAT modes during tape running, the rotation radius of the head drum from the head contact surface of the tape is 1145.9 mm, and Δθ = 1 ゜ 28'4
The rotation of 6.28 "is performed when the mode is switched. However, in the case where a mechanism is adopted in which the center of the tape coincides in both modes, the head drum is moved around the tape contact surface and Δθ = 1 ゜ 28 '.
46.28 ”turn.

(Vii) When the head tracks the track of the recording pattern, a standard method may be used for the 8 mm VTR mode. However, in the DAT mode, one of the following two methods is used.

(A) The automatic tracking servo system is operated for 7.5 ms when the head azimuth matches the tape pattern, and this servo system is turned off at the output of the next three heads.

(Viii) The signal reproduction processing in the 8 mm VTR mode may be the standard method.

However, the signal reproduction processing in the DAT mode is as follows.

(A) There is a period during which the outputs of the two heads A and E are simultaneously output as a reproduction output, and the time length is 8.4375 ms.

(B) The reproduction outputs written to the two memories are read out, added and processed in relation to the position of the head and the tape track.

(C) Writing and reading of the head reproduction output with a time length of 8.4375 ms to and from the memory are performed at a write frequency fc and a read frequency of 9/16 fc, and the reproduction output is extended to 15 ms.

(Ix) The head amplifier is shared in both the 8 mm VTR mode and the DAT mode, and the subsequent signal processing may use a standard signal processing circuit except for the memory reproduction in the DAT mode of (viii).

[Effects of the Invention] As described above, according to the present invention, the functions of the VTR and the DAT can be shared by one device, so that the overall volume is reduced,
Cost reduction can be achieved.

[Brief description of the drawings]

FIG. 1 is a diagram showing an 8 mm VTR format with an underline added to a DAT tape format, FIG. 2 is a diagram showing a relationship between a drum head and a tape winding angle, and FIG. 3 is a position of a head in a DAT mode. FIG. 4 is a timing chart of head reading, FIG. 5 is a timing chart of memory reading, FIG. 6 is a block diagram showing a memory processing circuit for head output, and FIG. 8 and 9 are timing charts for writing and reading the output of the memory, and FIGS.
Conceptual diagram of each signal processing in the case of mmVTR, FIG. 10 is a timing chart showing the relationship between head output and ATF signal,
FIG. 11 is a diagram showing the relationship between the tape of 8 mm VTR and DAT and the rotating surface of the drum head, FIG. 12 is an explanatory diagram of the rotation of the drum head, and FIG. 13 is a diagram of the mode switching mechanism in one embodiment of the present invention. FIG. 14 is a diagram showing a capstan driving mechanism in the above embodiment, and FIG. 15 is a block diagram showing a signal processing circuit in the above embodiment. A to D: Head, 16: Drum, motor transfer stand, 17
…… Reference duct, 19,20 …… Solenoid.

Claims (1)

(57) [Claims] 1. A rotating drum in which four heads having opposite azimuth angles are alternately arranged at intervals of 90 degrees, a winding angle switching means for switching a tape winding angle with respect to the rotating drum, and a rotation speed of the rotating drum. Rotation speed switching means for switching the rotation angle of the rotary drum in the rotary drum, identification signal output means for outputting an identification signal corresponding to the type of VTR and DAT, based on the identification signal A DAT / VTR device, comprising: a winding angle switching unit, a rotation speed switching unit, and a control unit that controls a rotating shaft driving unit.