JP2575098B2 - Video signal recording system - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a video signal recording method suitable for being applied to a digital VTR.

[Conventional technology]

Referring to the drawings below, a conventional digital VTR (Japanese Patent Application
7-69426). First, the rotary magnetic head device will be described with reference to FIG. DR
Is a tape guide drum. H _PA to H _PD is rotary magnetic head for reproduction, in H _RA or H _RD recording rotary magnetic heads, or consist of a fixed drum as a rotary drum and the lower drum as the tape guide drum DR (upper drum, as a vertical drum (A fixed drum and a rotating drum as a middle drum). The rotating magnetic heads for reproduction _HPA , _HPB and _HPC , _HPD are two sets of rotating magnetic heads for reproduction arranged at an angle of 180 °. or,
The recording rotary magnetic heads H _RA and H _RB and H _RC and H _RD are two sets of rotary magnetic heads for recording arranged at an angle of 180 °. Lines connecting the two sets of rotating magnetic heads for reproduction and the two sets of rotating magnetic heads for recording are orthogonal to each other.

The reproducing magnetic heads _HPA , _HPC and the recording rotary magnetic heads _HRA , _HRC have the same azimuth magnetic gap g as shown in FIG. 6, and the other reproducing rotary magnetic heads _HPB , HPB. _PD
And the rotating magnetic heads H _RB , H _RD for recording are different from the seventh embodiment.
It has a magnetic gap g of azimuth as shown in the figure. Recording rotary magnetic head H _RA, H _RB magnetic tape TP on the example 8 magnetic track having different such azimuth shown in FIG. T [alpha, forming a T [beta, which reproducing rotary magnetic head H _PA, is H _PB Reproduce. Similarly, the recording rotary magnetic head H _RC, H _RD magnetic track Tα as shown in Figure 8, and as recorded to form a T [beta,
The rotating magnetic heads _HPC and _HPD for reproduction reproduce the data.

Then, the winding angle θ of the magnetic tape TP with respect to the tape guiding drum DR is selected to be, for example, 260 °, which is larger than the nominal winding angle (here, 180 °) required for real-time processing.
TG ₁ and TG ₂ are guide poles for determining the winding angle of the magnetic tape TP with respect to the tape guide drum DR.

Next, a recording method of the digital video signal on the magnetic tape TP will be described. In FIG. 9, T _A through T _D is the scanning of the recording rotary magnetic head H _RA to H _RD described above, showing the oblique tracks formed on a magnetic tape TP. For example NT
In the case of the video signal of the SC system (525 system), the signal of one field is divided into five (six in the case of the 625 system) segment signals (1) to (5) as shown in FIG. 10A. After each of the segment signals (1) to (5) is shuffled separately, each of the segment signals is digitally divided into two channels, and then the time axis is extended according to the winding angle of the magnetic tape TP around the tape guiding drum DR. And the obtained two divided segment signals (1 ₁ ), (1 ₂ ); (2 ₁ ), (2 ₂ );
(5 _1), (5 ₂₎ of recording rotary magnetic head H _RA as shown in FIG. 10 B~E, H _RB; H _RC, are sequentially supplied to the H _RD, each divided into two as shown in FIG. 9 The segment signals obtained are recorded on the magnetic tape TR so as to form one inclined track. Therefore, one segment signal is divided into two channels, which are respectively recorded on adjacent inclined tracks T _A , T _B or T _C , T _D by the recording rotary magnetic heads H _RA , H _RB or H _RC , H _RD . Will be recorded. The rotation for reproducing magnetic head H _PA to H _PD
Each segment signal reproduced by the above is compressed on the time axis, and each segment signal (1 ′ ₁ ), (2 ′ ₂ ),... ‥‥ obtained as shown in FIGS. ,
(5 ′ ₁ ) and (1 ′ ₂ ), (2 ′ ₂ ), ‥‥, (5 ′
₂ ) are returned to the segment signals, respectively, and then deshuffled separately to obtain the original segment signals (1) to (5).
Is obtained.

Next, the configuration of the digital VTR will be described with reference to FIGS. 11 and 12. First, the recording system shown in FIG. 11 will be described. Luminance signal Y and chrominance signals U and V from input terminals (10Y), (10U) and (10V) are A / D converters (11Y), (11U),
(11V) and converted to a digital signal, and then to a multiplexer (12). Multiplexer (1
The digital video signal from 2) is applied to the vertical parity addition circuit (1
The signal is supplied to the shuffling memory (14) via 3), and shuffling in each segment signal is performed. The digital video signal from the shuffling memory (14) is supplied to a time base expansion memory (17) via a horizontal parity addition circuit (15) -synchronous word / address addition circuit (16), and is supplied to each of the divided segment signals. Each of the two divided segment signals which are time-axis-expanded and output from the output terminals (18A) to (18D) are respectively divided into two by an amplifier (not shown). _RA
Are respectively supplied to to H _RD, it is recorded as described above on the magnetic tape TP.

Next, the reproducing system shown in FIG. 12 will be described. Each divided segment signals reproduced by the reproducing circuit magnetic head H _PA to H _PD described above is supplied to an input terminal (19A) ~ time warp memory from the (19D) (20), are each divided into two compressed time axis for each segment signal, reproducing rotary magnetic head _{H PA, H PC; H PB} , signals of respective two channels corresponding to H _PD synchronization word address detection circuit (21 _1), (21 ₂₎ , And each output is supplied to a horizontal error correction circuit (22 ₁ ), (22 ₂ )
Supplied to Each output of the horizontal error correction circuits (22 ₁ ) and (22 ₂ ) is supplied to a deshuffling memory (23) to perform deshuffling in the segment signal. The digital video signal from the deshuffling memory (23) is supplied to a demultiplexer (26) through a vertical error correction circuit (24) and an error correction circuit (25), and is inverted to the original luminance signal Y and color signals U and V. After the conversion, the D / A converter (27Y),
(27U) and (27V) and are converted into an analog luminance signal Y and a chrominance signal UV, and output terminals (28Y), (28U),
(28V).

Incidentally, such a conventional digital VTR has the following disadvantages. Since the segment signals are recorded on the magnetic tape TP so as to form two inclined tracks on each of the recording rotary magnetic heads H _{RA to} H _RD , some of the recording rotary magnetic heads may be defective or impossible to record. If this happens, flicker and banding will occur on the playback screen.

Therefore, in order to solve such problems, digital VT
The following recording methods are considered for R. This will be described with reference to FIGS. 13 and 14, which correspond to FIGS. 9 and 10, respectively. That is, as shown in FIG.
Each oblique tracks T _A through T _D the respective first and second track portion
Divide into t ₁ and t ₂ . Then, the segment signals to be recorded on the magnetic tape TP are sequentially recorded over the first or second track portions t ₁ and t ₂ of the adjacent inclined tracks T _{A to} T _D. That is, for example, the segment signal (1) of each two channels is divided into the first half and the second half signal sections (1 ₁₁ ), (1 ₁₂ ); (1 ₂₁ ), (1 ₂₂ ), and each is divided into a certain set of inclined tracks T. sequentially recorded in the second track portion t ₂ of _a through t _D. Next, the segment signal (2)
Signal portion of the first half and the second half (2 _11), (2 _12); (2 _21), divided into (2 _22), respectively of the next set oblique tracks T _A through T first track portion t of _D Record in ₁ . Then, the signal of the first half and the second half segment signals (3) (3 _11), (3 _12); (3 _21), divided into (3 _22), oblique tracks of the same set respectively T _A through T _D second recorded in the track portion t ₂ of the. The same is repeated hereafter.

In this way, even if one recording rotary magnetic head becomes defective or incapable of recording, it is only one segment signal of the four divisions that causes defective reproduction or inability. This can be compensated for, and flicker and bounding of the playback screen can be avoided or reduced.

[Problems to be solved by the invention]

However, in such a recording method, as can be seen from FIG. 14, during recording, for example, a segment signal (1 ₁₁ )
During reading of (1 ₂₂ ) and (2 ₁₁ ) to (2 ₂₂ ) from two sets of memories (memory 1 and 2) for extending the time axis, the segment signals (3 ₁₁ ) to (3 ₂₂ ) Must be written to another set of memories (memory 3) for time-base expansion, which requires a total of three sets of memories.

Further, when the reproduction signal is compressed on the time axis at the time of reproduction, the continuity of the segment signal of each channel is broken as shown in FIGS. 14F and 14G, so that a rearrangement circuit is required in the reproduction apparatus.

When electronic editing is performed in units of fields, the starting point of the field signal is the beginning or middle of each inclined track, or a section. Therefore, a complicated circuit is required to perform electronic editing in consideration of this. .

In view of such a point, the present invention can reduce the deterioration of the image quality of the reproduction screen due to the recording failure or the failure even when a part of the plurality of rotary magnetic heads becomes defective or impossible, and also simplifies the configuration of the recording apparatus. It is intended to propose a video signal recording method capable of performing the following.

[Means for solving the problem]

According to the present invention, the guide drum has an angular interval of 180 °,
In a video signal recording method, a video signal is recorded by a first and a second pair of rotating magnetic heads arranged as one set so as to form a tilted track on a magnetic tape sequentially and repeatedly. When recording a video signal on the first and second track portions formed by dividing the inclined track formed above at predetermined intervals at the center of the track, the signal of one field is converted into a plurality of segment signals. Divides the divided segment signals, sequentially writes the divided segment signals into a plurality of memory units, and wraps the divided segment signals obtained by dividing the shuffled segment signals for each memory unit into four parts around a guide drum of a magnetic tape. The time axis is converted according to the angle and read out from the memory unit, and two of the four divided segment signals are divided. The first pair of rotating magnetic heads records data on the second track portion of the pair of recording tracks ahead of the pair of recording tracks adjacent to each other, and the remaining two divided segment signals are recorded on the first pair of recording tracks of the next pair of recording tracks. Is recorded on the track portion by a second pair of rotating magnetic heads.

[Action]

According to the present invention, a signal of one field is divided into a plurality of segment signals, and each of the divided segment signals is sequentially written into a plurality of memory units. The divided segment signals are time-axis converted in accordance with the winding angle of the magnetic tape around the guide drum and read out from the memory unit. Then, of the four divided segment signals, two divided segment signals are recorded on a second track portion of a pair of recording tracks ahead of a pair of adjacent recording tracks by a first pair of rotating magnetic heads. The remaining two divided segment signals are recorded on the first track portion of the next pair of recording tracks by the second pair of rotating magnetic heads.

〔Example〕

Hereinafter, an embodiment of the method of the present invention will be described with reference to FIG. 1 and FIG. Note that this embodiment is a digital
Although applied to a VTR, the configuration and operation of the rotary magnetic head device are the same as those described with reference to FIGS. 5 to 8 described above.

In Figure 1, the T _A through T _D by the scanning of the recording rotary magnetic head H _RA to H _RD described above, shows the oblique tracks formed on a magnetic tape TP, the first and respectively first and second halves of It is divided into _second track portions t ₁ and t ₂ . For example, in the case of a video signal of the NTSC system (525 system), as shown in FIG. 2A, a signal of one field is composed of five segment signals (1).
To (5), and each segment signal (1)
(5) are alternately shuffled by two memories (memory 1 and 2) and then digitally divided into four channels, respectively, and a tape guide drum of a magnetic tape TP.
The time axis is extended according to the winding angle with respect to the DR, and the segment signal is divided into the first half and second half signal portions (1 ₁₁ ), (1 ₁₂ ); (1 ₂₁ ),
(1 ₂₂ ); (2 ₁₁ ), (2 ₁₂ ): (2 ₂₁ ), (2 ₂₂ ): ‥‥: (5 ₁₁ ),
(5 ₁₂ ); (5 ₂₁ ), (5 ₂₂ ).

Then, the segment signal is divided into the first half (second half) of one set of recording tracks ahead of the two adjacent recording tracks and the next one.
Recording is performed separately in the latter half (first half) of a set of recording tracks.
That is, for example, as shown in FIGS. 1 and 2 B to E, the second track of the first half of the signal unit (1 _11), (1 ₁₂₎ is an inclined track T _A, T _B of the segment signal (1) part t ₂ recorded in the second half of the signal unit (1 _21), is recorded in the first track portions t ₁ of the oblique tracks T _C, T _D a (1 _22). Then, the signal of the first half of the segment signal (2) (2 _11), (2 ₁₂₎ to the oblique tracks T _C, recorded on the track section t ₂ a second of T _D, the second half of the signal section (2 ₂₁₎ records the next oblique tracks T _a, the first track portion t ₁ of T _B (2 _22).
Hereinafter, this is repeated.

The signal reproduced by the rotary magnetic head for reproduction H _PA to H _PD is time-base-compressed, FIG. 2 F, each divided into two segments signal obtained as shown in G ₍₁ '1)
{(1 ′ ₁₁ ), (1 ′ ₂₁ )}; (2 ′ ₁ )
{(2 ′ ₁₁ ), (2 ′ ₂₁ )}; ‥‥; (5 ′ ₁ )
｛(5 ′ ₁₁ ), (5 ′ ₂₁ ) and (1 ′ ₂ )
{(1 ′ ₁₂ ), (1 ′ ₂₂ )}; (2 ′ ₂ )
{(2 ′ ₁₂ ), (2 ′ ₂₂ )}; ‥‥; (5 ′ ₂ )
{(5 ′ ₁₂ ), (2 ′ ₂₂ )} are returned to the original segment signals (1) to (5), respectively, and then deshuffled separately to obtain the original segment signals (1) to (5). Is obtained.

Next, the configuration of the digital VTR will be described with reference to FIGS. First, the recording system shown in FIG. 3 will be described. The analog luminance signal Y and chrominance signals U and V from the input terminals (10Y), (10U) and (10V) are input to the A / D converter (11Y), (1
1U) and (11V) and converted into a digital signal, and then supplied to a multiplexer (12). The digital video signal from the multiplexer (12) is passed through a vertical parity addition circuit (13) to shuffle and time-base expanded memory (1).
The signals are switched to 4 ₁ ) and (14 ₂ ) to perform shuffling in each segment signal and to extend the time axis for each segment signal of each channel. This memory (14 ₁ ),
(14 ₂ ) is used by being alternately switched so that one is for writing and the other is for reading. shuffling·
Time-base decompression memory (14 _1), (14 ₂₎ than in the digital video signals of four channels corresponding to the respective recording rotary magnetic head H _RA to H _RD is obtained, a horizontal parity adding circuit (15) and a synchronous word Output terminal (18) via address addition circuit (16)
A) to (18D) are supplied in common, and the output terminals (18A) to (1
8D), the first half and second half signal portions of the time-axis-expanded segment signal are supplied to the above-described recording magnetic heads H _{RA to} H _RD via amplifiers (not shown), respectively. It is recorded on the magnetic tape TP as described above.

Next, the reproducing system shown in FIG. 4 will be described. Signal reproduced by the reproducing rotary magnetic head H _PA to H _PD described above, it is supplied to the input terminal (19A) ~ time warp memory from the (19D) (20) compression time axis, a rotary magnetic head for reproducing _{H PA, H PC; H PB} , signals of respective two channels corresponding to H _PD synchronization word address detection circuit (21 ₁₎ is supplied to the (21 _2), each output is respectively horizontal error correction circuit (22 ₁ ) and (22 ₂ ). Each output of the horizontal error correction circuits (22 ₁ ) and (22 ₂ ) is supplied to a deshuffling memory (23) to perform deshuffling in the segment signal. A digital video signal from the deshuffling memory (23) is supplied to a demultiplexer (26) through a vertical error correction circuit (24) and an error correction circuit (23), and is converted into an original digital luminance signal Y and color signals U and V. After inverse conversion, each D / A converter (27
Y), (27U), and (27V), and are converted into an analog luminance signal Y and color signals U and V, and output terminals (28Y) and (28
U), (28V).

〔The invention's effect〕

According to the present invention described above, even if a part of the plurality of rotary magnetic heads becomes defective or impossible to record, it is possible to reduce the image quality deterioration (flicker, banding, etc.) of the reproduction screen due to this and to reduce the recording device. A video signal recording method capable of simplifying the configuration can be obtained.

Also, in the case of a recording / reproducing method in which the video signal is extended on the time axis and recorded on the magnetic tape, and the reproduced signal is compressed on the time axis, only two sets of memory shuffling and time axis extension memory of the digital VTR are used. In addition, since the signal rearranging circuit is not required in the recording system, the configuration can be simplified.

Further, since the segment signals are equally distributed and recorded on four tracks by the first and second pair of rotary magnetic heads (four rotary magnetic heads), for example, one of the four tracks is recorded. Even if the track becomes unusable due to head damage or the error rate deteriorates extremely, only 1/4 of one segment is affected,
It is possible to suppress the minimum image quality deterioration.

Further, the four divided segment signals are time-axis converted in accordance with the winding angle of the magnetic tape around the guide drum and read out from the memory unit, and two of the four divided segment signals are read out. Is recorded on a second track portion of a pair of recording tracks ahead of a pair of recording tracks adjacent to each other by a first pair of rotating magnetic heads, and the remaining two divided segment signals are recorded on a second pair of recording tracks of a next pair of recording tracks. Since recording is performed on one track portion by the second pair of rotating magnetic heads, the capacity of the memory portion can be reduced, and furthermore, the memory portion performs segment signal four division processing, shuffling processing, and time axis conversion. Therefore, the entire circuit configuration is simplified.

Further, since there is a predetermined interval between the first track portion and the second track portion, electronic editing can be easily performed.

When digital editing is performed with a digital VTR, 525 format, 6
In any of the 25 systems, the starting point of each segment signal can be unified to the middle point of the inclined track, so that the circuit configuration for electronic editing is simplified.

[Brief description of the drawings]

FIGS. 1 and 2 are a pattern diagram and a timing chart, respectively, showing a recording pattern according to an embodiment of the method of the present invention.
4 and 5 are block diagrams showing a recording system and a reproducing system of a digital VTR suitable for applying the method of the present invention, respectively. FIG. 5 is a plan view showing a tape guiding drum of a conventional digital VTR, and FIG. 7 is a diagram showing the tape contact surface of the rotary magnetic head, FIG. 8 is a pattern diagram showing the recording track, and FIGS. 9 and 10 are recording patterns of the conventional video signal recording system, respectively. FIGS. 11 and 12 are block diagrams showing a recording system and a reproducing system of a digital VTR to which the conventional video signal recording system is applied, respectively, and FIGS. 13 and 14 are for reference only. 3A and 3B are a pattern diagram and a timing chart showing a recording pattern of a video signal recording method.

 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Takao Abe 6-7-35 Kita-Shinagawa, Shinagawa-ku, Tokyo Inside Sony Corporation (56) References JP-A-58-188314 (JP, A)

Claims (1)

(57) [Claims] A guide drum having an angular interval of 180 °;
A video signal recording method in which a video signal is recorded by a first and a second pair of rotating magnetic heads arranged one by one so as to sequentially form inclined tracks on a magnetic tape. When recording a video signal on first and second tracks formed by dividing an inclined track formed on a tape at a predetermined interval at the center of the track, a signal of one field is converted into a plurality of segment signals. , And sequentially writes the divided segment signals into a plurality of memory units. The divided segment signals obtained by shuffling each memory unit for each memory unit are divided into four divided segment signals. The time axis is converted in accordance with the winding angle with respect to the drum and read out from the memory unit, and two of the four divided segment signals are divided. A segment signal is recorded on a second track portion of a pair of recording tracks ahead of a pair of adjacent recording tracks by a first pair of rotating magnetic heads, and the remaining two divided segment signals are recorded on a next pair of recording tracks. A second pair of rotating magnetic heads for recording on the first track section.