JPH0683478B2 - Recording method of television signal - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a helical scan type video tape recorder (hereinafter abbreviated as VTR), and particularly a good method for recording a wide band television signal by dividing it into a plurality of tracks. Is provided.

Conventional technology The rotary 2-head helical scan method is adopted as the basic method for home VTRs. In this system, the rotation frequency of the rotary head cylinder is used as a frame frequency, and a television signal of one field is recorded as one video track on the magnetic tape every 180 ° rotation.

In order to record a wider-band television signal using this VTR, for example, a high-definition signal having a frequency band about 6 times the normal frequency, the relative speed between the magnetic tape and the magnetic head is increased by 6 times, 6 signal bands to record
Need to double. That is, the number of rotations of the rotary head cylinder and the tape feed speed are multiplied by 6 to record 6 video tracks per field.

A method of dividing an image of one field into a plurality of parts (segments) and recording each part on another track is called a segment recording method.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention However, in the above segment recording, since the rotary head cylinder rotates at high speed, the load on the mechanical system becomes large and the life of the head becomes extremely short.

Further, the signal of 1 field is divided into 6 in terms of time to obtain 6
Since it is recorded on one video track, special playback such as slow and search causes great difficulty.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a method capable of recording and reproducing a wideband television signal such as a high-definition television signal with high performance and easily obtaining a special reproduction image.

Means for Solving the Problems According to the present invention, when recording a television signal composed of a luminance signal of a wide band and two color signals having a bandwidth of half or less of the luminance signal, the luminance signal is recorded in one horizontal scanning period. Is used as a unit to expand the time axis about twice and convert it into a luminance signal of 2 channels, a second step of converting two color signals into a color signal of 1 channel, and three heads each. Consisting of head blocks H _A and H _B
Rotating head cylinders mounted opposite to each other at an angle of 180 degrees are rotated at a frequency equal to the field frequency of the television signal so that adjacent video tracks on the magnetic tape have different azimuth angles. 3 of each of the head blocks H _A and H _B
Of the two heads, the first channel head pair consisting of H _Aa and H _Ba and the third channel head pair consisting of H _Ac and H _Bc are assigned the luminance signals of the above two channels, The second consisting of H _Ab and H _Bb sandwiched between the head pair of channel 1 and the head pair of channel 3.
The method of recording a television signal is characterized in that the color signal of one channel obtained in the second step is allocated and recorded to the head pair of the channel.

With the configuration of the present invention as described above, a wideband television signal can be recorded and reproduced with high performance, and the luminance signals of two channels of the same segment are recorded by the head pair having the same azimuth angle. The reproduction luminance signal of the segment to be reproduced at the time of special reproduction can be efficiently reproduced, and the special reproduction image can be easily obtained.

Embodiment FIG. 1 is a recording pattern on a tape in an embodiment of the present invention, in which v _H is a head rotation scanning direction, v _t is a tape running direction, 7 is a magnetic tape, and 1 to 6 are video tracks.
FIG. 2 is a head layout diagram showing head blocks H _A and H _B each consisting of three heads a, b and c attached to a rotary head cylinder and their azimuth angles. In FIG. 2, reference numeral 8 is a rotary head cylinder, which has H _Aa , H _Ac ,
And H _Bb have the same azimuth angle, and H _Ba , H _Bc and H
_Ab has the opposite azimuth angle. H _Aa and H _{Ba form} the first channel head pair, H _Ab and H _{Bb form} the second
The pair of heads of the channel is formed, and the pair of heads of the third channel is formed by H _Ac and H _Bc .

FIG. 3 shows a method of dividing a television signal channel. In this embodiment, two color signals C ₁ and C _{2 are used.}
Will be described by taking as an example the case of time-axis compression and time division multiplexing on one channel. In FIG. 3, 9 indicates the luminance signal Y, and H _Y1 , H _Y2, ... Respectively indicate one horizontal scanning period. The luminance signal 9 is time-doubled in each horizontal scanning period and converted into two-channel recording signals Y _a 10 and Y _c 11. Reference numerals 12 and 13 represent two color signals C ₁ and C ₂ , respectively, which are time-axis compressed to about 1/2 and color signal C _b 14 of one channel.
Is converted to. A verse signal indicating the starting position of C ₂ is inserted between C ₁ and C ₂ of C _b 14, but the sync signal and the burst signal are omitted in FIG.

The operation of the present embodiment configured as described above will be described below.

The rotary head cylinder 8 shown in FIG. 2 rotates at the field frequency of the television signal (60 Hz in this case).
Therefore, one field of the television signal is segment-recorded by the two head blocks H _A and H _B. Further, as described above, since each head block is composed of three heads, the video tracks 1, 2, and 3 shown in FIG. 1 are displayed in the upper half on the television screen via the head block H _A. The signal was recorded simultaneously within the time of 1/2 field. In the video tracks 4, 5, and 6, the lower half television signals are simultaneously recorded via the head block H _B , and three tracks are sequentially recorded. The luminance signal 9 of the television signal and the two color difference signals 12 and 13 are expanded and compressed on the time axis as described above to obtain the luminance signal Y _a 10 of two channels.
It is converted into Y _c 11 and color signal C _b 14 of one channel. Y _a
Signal in the first segment period of 10 through the head H _Aa, signal in the second segment period is recorded on a magnetic tape through a head H _Ba. The signal in the first segment period of Y _c 11 is recorded via the head H _Ac, and the signal in the second segment period is recorded via the head H _Bc . C _b 14 is
It is recorded via the heads H _Ab and H _Bb . That is, the luminance signal Y _a is included in the three video tracks of one segment.
− Color signal C _b − Luminance signal Y _e are recorded adjacent to each other in the order of Y _a
The video tracks of Y _c and Y _c are recorded by the video heads having the same azimuth angle, and the luminance signals of the first segment and the second segment are recorded by the video heads having the opposite azimuth angles.

In the reproduction, an operation reverse to the processing at the time of recording is performed, so that it will be briefly described.

The reproduced 2-channel luminance signals are time-axis error-corrected, then time-axis-compressed about twice, combined into 1-channel, and output. On the other hand, the reproduced color signal of one channel is subjected to time-axis error correction and then expanded in time axis about twice to be converted into two color signals and output. The burst signal inserted at the time of recording is used to detect the start position of Y ₂ .

FIG. 4 shows traces of the head axis which traces on the magnetic tape at the time of special reproduction of this embodiment, and a waveform of the output of each head is shown in b. In the same figure, a case where a double speed search is performed will be described as an example. In the figure a, v _H is the head rotation scanning direction, v _t
Is the tape running direction, and the television signal of the first segment is recorded on the video tracks 15, 16, 17, and 21, 22, 23, the luminance signal is recorded on 15 and 17, and the color signal is recorded on 16. There is. The video signals of the second segment are recorded on the video tracks 18, 19, 20 and 24, 25, 26.

In the figure b, 27 is H _Aa , 28 is H _Ac , 29 is H _Ba , 30 is H
It is each reproduction signal output from _Bc . The shaded areas show the luminance signals of the first segment and the second segment, respectively.

FIG. 5 shows a monitor screen at the time of double speed search. The shaded area is the noise bar due to track crossing. The 31st section of the first segment in the monitor screen 30 is an image reproduced from the video tracks 15-a and 17-c. The section of 32 is an image reproduced from the video track 17-a.

Similarly, in the screen of the second segment, the section 33 is the image reproduced from the video track 24-c, and the section 34 is the video track.
It is an image reproduced from 24-a and 26-c. Here, in the sections 32 and 33, only the luminance signal of one channel of the luminance signals of two channels is reproduced. That is, only the luminance signals of every other line are reproduced, but 19-c, 22-a (Fig. 4b) of the other channel which is not reproduced is replaced with the luminance signals 17-a, 24-c of the reproduced channel. For example, the vertical resolution is halved, but the content of the reproduced image can be fully confirmed. The images corresponding to the sections 32 and 33 cannot be assigned to the luminance signals of the heads of three channels by other than the present invention.

As described above, according to the present embodiment, the number of rotations of the rotary head cylinder is the field frequency of the television signal,
The luminance signal is divided into 2 channels by time-axis expansion and 2
The two color signals are time-axis compressed and combined into one channel,
A head block pair consisting of three heads of a rotating cylinder is arranged on a magnetic tape so that adjacent video tracks are recorded by heads having different azimuth angles, and a recording signal of three channels is recorded on the video track in a Y direction.
As it is recorded in the order of -C-Y, it is recorded by allocating to each of three head pairs, and since the rotating cylinder rotation speed is kept at twice the normal speed (60 Hz), noise does not matter either. , Mechanical reliability is also high. Furthermore, 3
Two channels of luminance signals are assigned to the heads of the same azimuth in one head pair, and the signals of the same segment are recorded at the same azimuth angle. Therefore, even if there is no auxiliary head, the signal of the same segment is used for most of the time. Since the image can be reproduced, the content of the reproduced image can be sufficiently confirmed.

The above embodiment has been described by exemplifying the case where two color signals are time-axis compressed and combined into one channel, but even if they are combined into one channel by line-sequential processing, the effect of the present embodiment is unclear. There is no such thing.

EFFECTS OF THE INVENTION As described above, according to the present invention, a wideband signal such as a high-definition television signal is divided into two channels by extending the luminance signal in the time axis and dividing the signals for each horizontal scanning. Is converted into 1 channel, and the recording signals of these 3 channels are allocated to the head pair of 3 channels on the magnetic tape so as to be arranged in the order of luminance-color-luminance, and recorded.
It is possible to record efficiently and reliably at a rotation speed of about 60 Hz, and it is possible to reproduce almost all luminance signals over the entire screen even during special reproduction without the auxiliary head, so it is possible to fully confirm the content of the reproduced image. You can
Its practical effect is very large.

[Brief description of drawings]

FIG. 1 is a magnetic tape recording pattern diagram in an embodiment of the present invention, FIG. 2 is a magnetic head layout diagram, FIG. 3 is a conceptual diagram showing a channel dividing method for producing a recording signal, and FIG.
Is a head locus diagram at the time of search, FIG. 5B is a waveform diagram showing the output signal of each head at that time, and FIG. 5 is a monitor screen diagram at the time of search.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kiyoshi Sasaki 1006 Kadoma, Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Yutaka Higashida 1006 Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd. 72) Inventor Hiroshi Taniguchi 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (56) Reference JP-A-62-196993 (JP, A)

Claims (4)

[Claims] 1. When recording a television signal composed of a wide band luminance signal and two color signals of a band less than half of the luminance signal, the luminance signal has a time axis of about 2 in units of one horizontal scanning period. A first step of doubling and converting into a two-channel luminance signal, a second step of converting two color signals into a one-channel color signal, a head block H _A consisting of three heads, and H _{B is} almost
Rotating head cylinders mounted opposite each other at an angle of 180 degrees are rotated at a frequency equal to the field frequency of the television signal so that adjacent video tracks on the magnetic tape have different azimuth angles. 3 of each of the head blocks H _A and H _B
Of the two heads, the luminance signals of the two channels are assigned to the head pair of the first channel composed of H _Aa and H _Ba and the head pair of the third channel composed of H _Ac and H _Bc .
The color of one channel obtained in the second step is applied to the head pair of the second channel consisting of H _Ab and H _Bb sandwiched between the head pair of the first channel and the head pair of the third channel. A method for recording a television signal, characterized by allocating a signal for recording. 2. A second step compresses the time axis of each of the two color signals in units of one horizontal scanning period at a predetermined compression ratio and time-division-multiplexes in one horizontal scanning period.
The television signal recording method according to claim 1, wherein a color signal of a channel is obtained. 3. A burst signal is inserted between two time-compressed color signals when two color signals are time-axis compressed and combined into one channel. Recording method of the described television signal. 4. The television signal according to claim 1, wherein the second step is to line-sequentially convert two color signals to obtain one-channel color signal. Recording method.