JPH0475710B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a color video signal recording device suitable for recording a color video signal in a narrow band.

[Prior art]

2. Description of the Related Art Conventionally, video tape recorders, video disks, and the like have been known as video signal recording and reproducing devices. In such video signal recording devices, one field of video signals is usually recorded on one track so that special playback such as slow and still playback can be easily performed. In a tape recorder, 1
By recording one field of video signals on a track, it is possible to slow down the tape speed and improve the recording density, and it is also possible to splice together the video signals that are sequentially played back from each track to create a series of signals. , there is an advantage that the effect of this seam does not appear on the playback screen.

Therefore, in the conventional video signal recording apparatus, the relative speed between the recording medium and the recording/reproducing head is determined, and the recordable band is also limited. In particular, in recent years, in order to enable long-term recording, video tape recorders have
Considering that there is a tendency to reduce the running speed of magnetic tape as much as possible, it is difficult to expect an expansion of the recordable band of video signal recording and reproducing devices.

Such a limit on the recordable band limits the frequency band of the recording signal, which limits the resolution of the reproduced image, making it no longer possible to obtain a reproduced image of a certain level of image quality.

By the way, in video tape recorders, which have become extremely popular in recent years, there is a growing demand for higher quality playback images, and some kind of countermeasure has become necessary. One method is to increase the relative speed between the recording medium and the head to expand the recordable band of the video signal recording and reproducing device. It is conceivable to increase the rotation speed and diameter of the cylinder. However, if the rotational speed of the head cylinder is increased, it is no longer possible to record one field of video signals on one track, and the tape speed must be increased to prevent tracks from overlapping, resulting in a decrease in recording density. However, increasing the diameter of the head cylinder increases the size of the video signal recording/reproducing apparatus, which is not desirable.

Another method is to narrow the band of the video signal by time expansion so that the frequency band of the video signal falls within the recordable band of the video signal recording and reproducing device without limiting the frequency band of the video signal. There is a way. However, this method, for example,
Extract the video signal every other field and divide it into two
As in the case where the time axis is expanded during the field period to narrow the band, part of the information content is discarded, and the resolution inevitably deteriorates.

[Purpose of the invention]

The purpose of the present invention is to eliminate the drawbacks of the above-mentioned prior art,
To provide a color video signal recording device capable of recording a color video signal without limiting its frequency band or amount of information.

[Summary of the invention]

In order to achieve this object, the present invention provides a first partial video signal consisting of at least every 1H (where H is a horizontal scanning period) of a video signal to be recorded, and a second portion consisting of at least every other 1H. The feature is that the video signals are each expanded on the time axis and recorded on separate tracks.

The first and second partial video signals together contain all the information signals of the original video signal, and are narrow-banded by time axis expansion.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to the drawings. First, an embodiment of a video signal recording and reproducing apparatus according to the present invention will be described with reference to FIGS. 1 to 6.

FIG. 1 is a pattern diagram showing a track pattern to be formed, in which 1 is a magnetic tape, 2, 3,
4, 5, 6, and 7 are tracks.

FIG. 2 is a layout diagram showing the arrangement of heads forming the track of FIG. 1 on a head cylinder,
8 is a head cylinder, 9, 10, 11, 12, 1
3 and 14 are heads, and 15 and 16 are tape regulating posts.

In FIGS. 1 and 2, the magnetic tape 1 is obliquely abutted over more than half the circumference of the head cylinder 8 by the tape regulating posts 15 and 16, and
Drive in the direction.

The head cylinder 8 is provided with heads 9 to 14 so as to come into contact with the magnetic tape 1. Head 9,
The heads 10 and 11 are close to each other and are arranged at a predetermined interval in the circumferential direction of the head cylinder 8, with a step approximately equal to the track width in the direction of the rotation axis. They are arranged close to each other with the above-mentioned intervals and steps. The head 9 and the head 12 are located at symmetrical positions with respect to the rotation axis of the head cylinder 8,
Similarly, heads 10 and 13, and heads 11 and 14 are located symmetrically to each other.

The head cylinder 8 rotates at a rate of one revolution in the direction of arrow B during two fields (one frame) of the video signal. Therefore, while the head cylinder 8 rotates once, the heads 9, 10, and 11 rotate for one field period. The magnetic tape 1 is scanned over a period of one field, and the heads 12, 13, and 14 also scan the magnetic tape over one field period.
Heads 9, 10, 11 and heads 12, 13, 14
This means that the magnetic tape 1 is alternately scanned field by field.

Therefore, while the head cylinder 8 makes one rotation,
The tracks formed on the magnetic tape 1 by the heads 9-14 are as shown in FIG.

That is, track 2 is formed by head 9,
Track 3 is formed by head 10, and tracks 4, 5, 6 and 7 are formed by heads 11, 12 and 1, respectively.
3 and 14, the heads 9, 10, and 11 simultaneously form tracks 2, 3, and 4 on the magnetic tape 1 during a half rotation of the head cylinder 8, and the next track of the head cylinder 8 During the half rotation, tracks 5, 6, 7 are formed on the magnetic tape 1.
are formed simultaneously. In this way, three tracks are simultaneously formed by three heads each time the head cylinder 8 makes a half revolution.

In this case, the magnetization directions are made to be different between adjacent tracks (for example, track 2 and track 3), so that an azimuth effect is generated during playback and crosstalk between adjacent tracks can be suppressed. , heads 9, 11, 1
3 have the first azimuth angle in common, and
The heads 10, 12, and 14 have a second azimuth angle in common that is different from the first azimuth angle.

FIG. 3 is a block diagram showing a specific example of a recording circuit for forming recording signals to be supplied to each head in FIG. 2 is a reference pulse addition circuit, 20 is an addition circuit, 21 is a subtraction circuit, 2
2, 23 are time axis expansion circuits, 24, 25 are digital-to-analog conversion circuits, 26, 27 are frequency modulation circuits, 28, 29, 30, 31 are recording amplifier circuits,
32 is a simultaneous-sequential conversion circuit, 33 is a reference pulse addition circuit, 34 is a frequency modulation circuit, 35 and 36 are recording amplifier circuits, and heads 9 to 14 correspond to each head in FIG.

Next, the operation of this specific example will be explained.

In the figure, the luminance signal Y is digitized by an analog-to-digital conversion circuit (hereinafter referred to as an A/D circuit), and the digital luminance signal Yn is converted to a 1H delay circuit 1.
8, is supplied to an addition circuit 20 and a subtraction circuit 21.
A reference pulse is added to the digital luminance signal delayed by the 1H delay circuit 18 in a reference pulse adding circuit 19. The digital luminance signal to which this reference pulse is added is represented by Yd.

The digital luminance signal Yd is supplied to the adder circuit 20 and added to the digital luminance signal Yn, and
The digital luminance signal Yn is supplied to the subtraction circuit 21.
is subtracted.

The sum signal (Yn+Yd) from the adder circuit 20 is supplied to a time axis expansion circuit 22. Time axis expansion circuit 2
2 extracts this sum signal (Yn+Yd) 1H every 1H and expands each extracted 1H signal into a 2H signal. In other words, the sum signal (Yn+Yd)
Each 1H signal every 1H is time-expanded to 2H to become a continuous signal (hereinafter referred to as time-axis expanded sum signal (Yn+Yd)'). Similarly, the difference signal (Yd-Yn) from the subtraction circuit 21 is also supplied to the time axis expansion circuit 23, and each 1H signal every 1H is time expanded to 2H, resulting in a continuous signal (hereinafter referred to as
This signal becomes a time axis expansion difference signal (Yd−Yn)′).

The time axis expansion circuits 22 and 23 each consist of a digital memory such as a random access memory (RAM), and are simultaneously written every 1H by a clock pulse synchronized with the sampling in the A/D circuit 17, and read out in the following manner.
This is done using a clock pulse with a repetition frequency that is 1/2 that of the clock pulse used during writing.

The time axis expanded sum signal (Yn + Yd)′ is digital −
Analog conversion circuit (hereinafter referred to as D/A circuit) 2
4, it is converted into an analog signal, and the frequency modulation circuit 2
6, amplified by recording amplifier circuits 28 and 29, and supplied to heads 9 and 12. Further, the time axis expanded difference signal (Yd-Yn)' is converted into an analog signal by the D/A circuit 25, modulated by the frequency modulation circuit 26, amplified by the recording amplifier circuits 30 and 31, and supplied to the heads 10 and 13. be done.

On the other hand, the two color difference signals (R-Y) and (B-Y) are supplied to a simultaneous-sequential conversion circuit, and a line-sequential color difference signal consisting of these color difference signals is generated. This line-sequential color difference signal is supplied to a reference pulse addition circuit 33 to which a reference pulse is added, modulated by a frequency modulation circuit 34, amplified by recording amplifier circuits 35 and 36, and supplied to the heads 11 and 14.

Therefore, in FIG. 1, the head cylinder 8
(Fig. 2), head 9 sends a time-domain expanded sum signal (Yn+Yd)' to track 2, and head 10 sends a time-domain expanded difference signal (Yd) to track 3.
-Yn)' is simultaneously recorded on the track 4 by the head 11, and in the next half rotation of the head cylinder 8, the time axis extended sum signal (Yn-Yd)' is recorded on the track 5 by the head 12. However, the time axis expanded difference signal (Yd-Yn)' is recorded on the track 6 by the head 13, and the line-sequential color difference signal is recorded on the track 7 by the head 14 simultaneously.
In this way, each signal is simultaneously recorded one field at a time on separate tracks, but in order to align the time axes of these signals during playback, the reference pulse adding circuit 19 generates a time axis expanded sum signal ( Yn + Yd)′, time axis expansion difference signal (Yd
-Yn)', and the reference pulse adding circuit 33 adds the reference pulse to the line-sequential color difference signal.

These reference pulses have constant pulse widths and levels, and are added to the respective signals at the same timing, for example, in the back porch portion of the horizontal blanking period. Then, the time axis reference for aligning the time axis of each signal is set as, for example,
This is the rising edge of the reference pulse.

Figure 4a shows the time-axis expanded sum signal (Yn+Yd)' to which a reference pulse has been added, Figure 4b shows the time-axis expanded difference signal (Yn-Yd)', and Figure 4c shows the same line. The color difference signals are shown sequentially, and 37 is the reference pulse added by the reference pulse addition circuit 19;
7' is a reference pulse added by the reference pulse adding circuit 33.

FIG. 5 is a block diagram showing a specific example of a reproduction circuit for processing reproduction signals from each head in FIG. Switcher, 44 and 45 are demodulation circuits, 46 and 47 are A/D circuits, 48 and 49 are time axis compression circuits, 50 is an addition circuit, 51 is a subtraction circuit, 52 is a 1H delay circuit, 53 is a synthesis circuit, 54
is a D/A circuit, 55 and 56 are preamplifier circuits, and 57
58 is a switch, 58 is a demodulation circuit, 59 is a variable delay circuit, 60 is a 1H delay circuit, 61 is a changeover switch, and heads 9 to 14 correspond to the heads in FIG.

Next, the operation of this specific example will be explained.

In FIG. 5, heads 9 and 12 reproduce a time-axis expanded sum signal (Yn+Yd)' which is frequency-modulated alternately for each field. Each time-domain expanded sum signal (Yn+Yd)' is amplified by a preamplifier circuit 42,
A switcher 42 combines the signals into a continuous signal, which is frequency demodulated by a demodulation circuit 44. The demodulated time-domain expanded sum signal (Yn+Yd)' is converted into a digital signal by the A/D circuit 46, and is supplied to the time-domain compression circuit 48, where the signal every 2H is time-domain compressed to 1H, resulting in an intermittent signal (hereinafter referred to as , is called an intermittent sum signal).

Heads 10 and 13 are time-axis expanded difference signals (Yd-Yn)' which are frequency-modulated alternately for each field.
Play. This time axis expansion difference signal (Yd−
Similarly to the time axis expanded sum signal (Yn+Yd)', the preamplifier circuits 40, 41 and the switcher 4
3. The signal is supplied to the time-base compression circuit 49 through the demodulation circuit 45 and the A/D circuit 47, and the signal every 2H is time-base compressed to 1H to become an intermittent signal (hereinafter referred to as an intermittent difference signal).

The time axis compression circuits 48 and 49 are also composed of digital memories such as RAMs, and their writing speed is made equal to the reading speed of the time axis expansion circuits 22 and 23 (FIG. 3), and their reading speed is also the same as that of the time axis expansion circuits 22 and 23 (FIG. 3). equal to the write speed of 23, 2H
A long signal is read out in a 1H period, and reading is stopped in the next 1H period, so that reading and stopping can be repeated alternately every 1H period. Furthermore, the readout timings of the time axis compression circuits 48 and 49 are made to coincide with each other by the reference pulse 37, so that the time difference between the intermittent sum signal (Yn+Yd) and the intermittent difference signal (Yd−Yn) is Make sure to remove any misalignment. Furthermore, the sampling pulses of the A/D circuits 46 and 47 and the write clock pulses of the time axis compression circuits 48 and 49 are changed to the reference pulse 37 (the fourth pulse).
(Fig.) can be multiplied.

Intermittent sum signal (Yn+Yd) and intermittent difference signal (Yd−
Yn) is the digital luminance signal added by the adder circuit 50 and output from the A/D circuit 17 in FIG.
An intermittent signal Yd every 1H of the digital luminance signal Yd obtained by delaying Yn by the 1H delay circuit 18 is obtained. Further, the subtraction circuit 51 receives an intermittent sum signal (Yn+
Yd) is subtracted by the intermittent difference signal (Yd-Yn) to obtain an intermittent signal Yn every 1H of the digital luminance signal Yn from the A/D circuit 17 in FIG.

These intermittent signals Yn and Yd each contain different information contents every 1H of the original luminance signal, but
The intermittent signal Yd is delayed by the 1H delay circuit 18 (FIG. 3) and is in phase with the intermittent signal Yn.

Therefore, the intermittent signal Yn is delayed by the 1H delay circuit 52 and set in the correct time relationship with the intermittent signal Yd,
It is supplied to the synthesis circuit 53 and becomes a continuous signal, and the D/
The A circuit 54 converts it into an analog signal to obtain the original luminance signal Y.

On the other hand, the heads 11 and 14 alternately reproduce line-sequential color difference signals for each field. These line sequential color difference signals are amplified by preamplifier circuits 55 and 56, respectively.
The signals are combined by a switcher to form a continuous line-sequential color difference signal. This line-sequential color difference signal is frequency-demodulated in a demodulation circuit 58, and a reference pulse 3 is output in a variable delay circuit 59.
7 and 37' (FIG. 4), the time lag with the luminance signal Y is removed. The line sequential color difference signal from the variable delay circuit 59 is supplied to a sequential-to-simultaneous conversion circuit consisting of a 1H delay circuit 60 and a changeover switch 61.
Color difference signals RY and BY are obtained.

In the manner described above, the recording and reproduction of luminance signals and color difference signals is performed. As is clear from the above explanation, the recording signal by the heads 9 and 12 is one 1H of the luminance signal Y to be recorded.
It is the sum signal of the every 1H signal and the other signal every 1H, and the recording signal by the heads 10 and 13 is
Similarly, the luminance signal Y is a difference signal, and in the process of forming these sum and difference signals, the information content of the luminance signal Y is not subject to any restrictions, and during reproduction, the original luminance signal can be derived from these sum and difference signals. It will be restored. Furthermore, D/A circuits 24 and 25 (third
The time axis expanded sum signal (Yn + Yd) and the time axis expanded difference signal (Yd - Yn) from Figure 1) are each a 1H signal.
Since it has been expanded to a length of 2H, the frequency band of the original luminance signal Y has been compressed and narrowed to 1/2, and therefore, the frequency band of the head cylinder 8
(The diameter in Figure 2 is the same as the diameter of the head cylinder of a conventional video tape recorder, and even if the recordable band is the same as that of a conventional video tape recorder, there is no restriction on the frequency band of the recording signal, It is possible to record and reproduce the luminance signal Y in a sufficiently wider frequency band than the video tape recorder.

That is, a wide band luminance signal can be recorded in a narrow band without losing the amount of information, and a high-resolution, high-quality reproduced image can be obtained even in a limited recordable band.

In the specific examples shown in FIGS. 3 to 5, the sum signal and the difference signal of one H signal of the luminance signal Y and the other H signal are used as the recording signals. The recorded signal by one of the luminance signals Y
It is also possible to use a signal every 1H, and the recording signal by the heads 10 and 13 to be a difference signal between a signal every 1H on one side of the luminance signal and a signal every 1H on the other side.
In this case, in FIG. 3, the adder circuit 20 is removed and the digital luminance signal Y is directly supplied to the time axis expansion circuit 22. The configuration and operation other than this are the same as described above.

In addition, in the reproducing circuit of FIG. 5, the output signal of the time axis compression circuit 48 is delayed by a 1H delay circuit and supplied to the synthesis circuit 53.
The output signals of 8 and 49 may be added and supplied to the combining circuit 53. Therefore, a subtraction circuit is not required.

As described above, the luminance signal Y is divided into two tracks and recorded in two channels.Generally, when a signal is divided into multiple channels and recorded and reproduced, there is a gap between each channel during reproduction. Although a time lag occurs, it is extremely difficult to eliminate this time lag. However, when recording and reproducing the luminance signal Y by dividing it into two channels as described above, the time difference occurs in the difference signal, and this difference signal has a low level due to the correlation between the horizontal scanning lines of the image. Therefore, the effect of this time lag on the screen is reduced.

However, as mentioned above, even the reference pulse can accurately remove the time difference between each channel, so the recording signal of one channel is set as a signal every 1H of the luminance signal Y, and the recording signal of the other channel is The other 1H of the luminance signal Y
It can be used as a warning signal.

FIGS. 6a and 6b are block diagrams showing a specific example of a recording circuit and a reproducing circuit for forming such a recording signal, and parts corresponding to FIGS. 3 and 5 are given the same reference numerals. Furthermore, since the processing of color difference signals is the same as the specific examples shown in FIGS. 3 and 5, the description thereof is omitted.

In FIG. 6a, the luminance signal Y is from the A/D circuit 1.
7, it becomes a digital luminance signal, a reference pulse is added by a reference pulse addition circuit 19, and the signal is supplied to time axis expansion circuits 22 and 23, respectively.

The time axis expansion circuits 22 and 23, like the time axis expansion circuits 22 and 23 in FIG.
The time axis is expanded to 2H length for each period signal, but extraction of 1H period of digital luminance signal is as follows:
This is performed alternately in the time axis expansion circuits 22 and 23. Therefore, from the time axis expansion circuit 22, a signal Y _O ′ consisting of signals every 1H of one side of the digital luminance signal, each of which has been expanded twice in time axis (hereinafter referred to as time axis expanded signal Y _O ′) is generated. is obtained, and the other digital luminance signal is obtained from the time axis expansion circuit 23.
A time axis expanded signal Y _E ' consisting of signals every 1H is obtained.

These time axis expansion signals Y _O ′ and Y _E ′ are respectively D/A
The signals are converted into analog signals by circuits 24 and 25, and are recorded by heads 9 and 12 and heads 10 and 13, similar to the recording circuit shown in FIG.

Next, in FIG. 6b, the time axis expanded signal Y _O ' reproduced by the heads 9 and 12 is processed in the same way as the reproduction circuit shown in FIG. The time-base expanded signal Y _E ' reproduced by the heads 10 and 13 is similarly supplied to the time-base compression circuit 49 as a digital signal.

Similarly to the time axis compression circuits 48 and 49 in FIG.
Although the time axis is compressed to 1H length, each readout timing is shifted by 1H from each other.
For this reason, intermittent signals every 1H are obtained from the time axis compression circuits 48 and 49, and the timing relationship of these intermittent signals is that of one of the original luminance signals Y.
It matches the timing relationship between the every 1H signal and the other every 1H signal.

Therefore, the original luminance signal can be obtained by combining the respective intermittent signals mentioned above in a combining circuit 53 and converting the resulting signal into an analog signal in a D/A circuit 54.

In this specific example, the read timing of the time axis compression circuits 48 and 49 is determined by the reference pulse addition circuit 19.
As a result, the time lag that occurs during the recording and reproduction process of the time axis expansion signals Y _O ′, Y _E ′ is removed, and the intermittent signals from the time axis compression circuits 48 and 49 are The timing relationship between them is set accurately. Furthermore, compared to the specific examples shown in FIGS. 3 and 5, two 1H delay circuits, an adder circuit, and a subtracter circuit are not required, and the circuit configuration is greatly simplified.

In the embodiments described above, the luminance signal and the color difference signal were recorded on separate tracks, but other embodiments of the video signal recording and reproducing apparatus according to the present invention record these signals on the same track. An example will be explained with reference to FIGS. 7 to 10.

FIG. 7 is a pattern diagram showing a track pattern to be formed, and 62, 63, 64, and 65 are tracks, respectively.

FIG. 8 is a layout diagram showing the arrangement of the heads forming the track of FIG. 7 on the head cylinder,
66, 67, 68, and 69 are heads.

In addition, in Fig. 7 and Fig. 8, Fig. 1 and Fig. 2
Portions corresponding to the figures are given the same reference numerals, and some explanations are omitted.

In FIGS. 7 and 8, the heads 66 and 67 are installed close to each other at a predetermined interval in the circumferential direction of the head cylinder 8, and with a step equal to the track width in the direction of its rotation axis. head 6
Heads 8 and 69 are arranged in the same manner, and heads 66 and 68, heads 67 and 6
9 are in a mutually symmetrical positional relationship with respect to the rotation axis of the head cylinder 8.

The head cylinder 8 rotates once every two fields (one frame) of the video signal, and in the half rotation, the head 66 forms the track 62 and the head 67 simultaneously forms the track 63, and in the next half rotation, the head 68 forms the track 62 and the head 67 simultaneously. Track 64 and head 69 simultaneously form track 65. In this way, every half rotation of the head cylinder 8, the heads 66, 67 and the head 6
8 and 69 alternately form a track. In this case, so that the magnetization direction differs between adjacent tracks,
The heads 66 and 68 have a first azimuth angle in common, and the heads 67 and 69 have a second azimuth angle different from the first azimuth angle.

FIG. 9 is a block diagram showing a specific example of a recording circuit for forming recording signals supplied to each head in FIG. Synthesis circuit, 72 and 73 are A/D
circuits, 74 and 75 are reference pulse addition circuits, 76;
77 is a time axis compression circuit, and parts corresponding to those in FIG. 3 are given the same reference numerals.

FIGS. 10A to 10A are timing charts showing the timing relationship of signals of each part in FIG. 9.

Next, the operation of this specific example will be explained.

In FIG. 9, a digital luminance signal Yn (FIG. 10a) is supplied from the A/D circuit 17 to an addition circuit 20 and a subtraction circuit 21, and this digital luminance signal is delayed by 1H (FIG. 10b). , reference pulses are added and supplied to an addition circuit 20 and a subtraction circuit 21. Sum signal from adder circuit 20 (Yn+Yd)
(Fig. 10c) also applies to the time axis expansion circuit 22'.
Difference signal (Yd-Yn) from the subtraction circuit (Figure 10d)
is supplied to the time axis expansion circuit 23'. Up to this point, the recording circuit is the same as the recording circuit shown in FIG.

The time axis expansion circuits 22' and 23' extract the sum signal and the difference signal every 1H at the same timing, and expand the time axis by 1.5 times. Therefore, from the time axis expansion circuit 22', a time axis expansion sum signal (10th
Figure e) is obtained and fed to the synthesis circuit 70. Similarly, a time axis expansion difference signal (FIG. 10f) in which a series of 1.5H long signals are arranged at 0.5H intervals is obtained from the time axis expansion circuit 23' and is supplied to the synthesis circuit 71.

On the other hand, the color difference signal (R-Y) is converted into a digital color difference signal (R-Y) (Fig. 10g) by the A/D circuit 72, and a reference pulse is added by the reference pulse addition circuit 74 and sent to the time axis compression circuit 76. Supplied. Also,
The color difference signal B-Y is also turned into a digital color difference signal (B-Y) (FIG. 10i) by the A/D circuit 73, and a reference pulse is added by the reference pulse addition circuit 75, and the signal is supplied to the time axis compression circuit 77.

The time axis compression circuits 76 and 77 convert the supplied signals into
Time axis is compressed every 2H, and the signal of 2H period is compressed to 0.5H length. As the time axis compression circuits 76 and 77
A digital memory such as RAM can be used, and the writing and reading timings of both are made to match, so that the written signal of 2H period is read out in 0.5H period. Therefore, from the time axis compression circuit 76, a digital color difference signal (R-Y) every 2H is output as an intermittent digital color difference signal (hereinafter referred to as a time axis compressed color difference signal) that is 0.5H long and arranged between 1.5H. )(RY)' (FIG. 10h) is obtained, and similarly, a time-domain compressed color difference signal (B-Y)' (FIG. 10j) is obtained from the time-domain compression circuit 77.

The read timing relationship between the time axis expansion circuits 22', 23' and the time axis compression circuits 76, 77 is 0.5H of the time axis compressed color difference signals (RY)', (B-Y)'.
The respective long signals are set to temporally coincide with the 0.5H gap between the time axis expanded sum signal (FIG. 10e) and the time axis expanded difference signal (FIG. 10f). This read timing relationship is determined by the time axis expansion circuit 2.
Assuming that the recording capacity of 2' and 23' is 1H, and the recording capacity of the time axis compression circuits 76 and 77 is 2H, it is clear from Figure 10 c, d, e, f, and g, h, i, j of Figure 10. As shown, the time axis expansion circuits 22' and 23' start reading after writing the 1H signal,
This can be achieved by making the time axis compression circuits 76 and 77 start reading when the signal is written for a period of 1.5H.

The time axis compressed color difference signal (R-Y)' is synthesized by the synthesis circuit 7.
0 and the time axis extended sum signal (Figure 10e)
A composite signal (Fig. 10k) in which both are time-division multiplexed is obtained. Similarly, the time-domain compressed color difference signal (B-Y)' is combined with the time-domain expanded difference signal (FIG. 10f) in the combining circuit 71, and a composite signal (FIG. 10) in which both are time-division multiplexed is obtained. can get.

These composite signals are converted into analog signals by D/A circuits 24 and 25, respectively, and are converted into analog signals by frequency modulation circuits 26 and 25, respectively.
27 and supplied to heads 66, 68 and heads 67, 69.

Therefore, in FIG.
64, one of the luminance signal Y, which is a time-axis expanded signal every 1H, and a time-axis compressed color difference signal (R
-Y) are recorded by time division multiplexing, and track 6
3 and 65, the other time-axis expanded signal of the luminance signal Y every 1H and the time-axis compressed color difference signal (B-Y) are recorded by time division multiplexing.

In the reproducing circuit, although not shown, in FIG. 5, the time axis expanded sum signal and the time axis compressed color difference signal (R-
Y)' and the A/D circuit 47.
A separation circuit for separating the time-domain expanded difference signal and the time-domain compressed color-difference signal (B-Y)' is provided before or after the time-domain compressed color-difference signal (B-Y).
By extending the time axis of Y)' and (B-Y)',
Original luminance signal Y and color difference signal (RY), (B-Y)
is obtained.

In this embodiment, similarly to the embodiments shown in FIGS. 1 to 6, in the limited recordable band,
In addition to being able to record luminance signals in a narrow band without losing their information content, the head can be shared for recording and reproducing luminance signals and color difference signals, which simplifies the configuration. The number of tracks formed is also reduced, making it possible to reduce the running speed of the magnetic tape, reducing the amount of magnetic tape used, increasing the recording capacity per unit length of the magnetic tape, and extending the recording time. Ru.

In this embodiment as well, as mentioned earlier, the adding circuit 20 in FIG. 9 is removed, and the heads 66 and 68 record one of the luminance signals Y whose time axis is expanded every 1H. It is also possible to configure a luminance signal processing circuit. Furthermore, in this embodiment, as in FIG. one of the
The circuit configuration can be further simplified by recording a signal whose time axis has been expanded every 1H, and by recording the other signal whose time axis has been expanded every 1H at the heads 67 and 69. However, in this case, it is clear that the read timings of the time axis compression circuits 76 and 77 do not match and must be set according to the read timings of the time axis expansion circuits 22' and 23.

Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments.
Various modifications are possible.

For example, when performing time axis expansion or time axis compression of a luminance signal or color difference signal, it is not necessarily necessary to convert it to a digital signal, but by using a variable delay element such as a CCD (charge coupled device), it is possible to convert it into an analog signal. You can do it as you like. Further, in order to correct the time difference between each channel, a reference pulse is inserted into the recording signal, but a horizontal synchronizing signal may be used instead. In this case, the horizontal synchronization signal is not included in the time axis expanded difference signal, but as mentioned earlier, the time shift of the time axis expanded difference signal has no effect, so the color difference Although an additional circuit for adding a horizontal synchronization signal to the signal is required, the luminance signal processing circuit does not require a reference pulse addition circuit. Furthermore, other color signals such as I and Q signals may be used instead of the color difference signals (R-Y) and (B-Y).
Furthermore, in FIGS. 1 and 7, the track on which the time-axis expanded difference signal is recorded and the track on which the line-sequential color difference signal is recorded can be made narrower, making it possible to record for a longer time.

Although the embodiments of the present invention have been described above, the present invention is capable of compatible playback with a system in which the number of horizontal scanning lines is 1/2, that is, 1/2 the number of horizontal scanning lines of a recorded video signal.
It is possible to obtain a video signal that allows image reproduction in a television reception system consisting of two horizontal scanning lines. This point will be briefly explained.

In FIGS. 3 and 6a, the signals recorded by the heads 9 and 12 are signals for one field period per track and have half the number of scanning lines as the original luminance signal. In the case of FIG. 3, the signals recorded by the heads 9 and 12 are continuous sum signals in which signals every 1H on one side and signals every 1H on the other side of the original luminance signal are added. Also, Figure 6a
In the case of , it consists of a continuous signal every 1H of the original luminance signal. Therefore, the signals reproduced by the heads 9 and 12 can be directly used as a luminance signal for a system with half the number of scanning lines of the original luminance signal, and the reproduced image can be The resulting image is obtained by removing every other horizontal scanning line from the reproduced image.

In this case, the color difference signals (R-Y) and (B-Y) are
Since it is played back as a signal with the time axis compressed to 1/2, it is necessary to expand the time axis by twice.
To this end, in FIG.
-Y) and expand each of them twice using a time axis expansion circuit.

The same applies to the embodiment shown in FIG. 9, but the sum signal reproduced by heads 66, 68 is expanded to 4/3 times as a luminance signal, and the sum signal reproduced by heads 66, 68 and heads 67, 69 is Each color difference signal is expanded four times.

This shows that the present invention allows a high definition television system with 1050 lines per frame to be converted to a current television system with 525 lines per frame. Furthermore, the present invention makes it possible to record and reproduce video signals in the above-mentioned high-definition television system in a frequency band comparable to that of the video signals of current television systems, without loss of information content.

Although the above embodiment describes a video tape recorder which is basically the same as a 2-head helical scan system, the present invention is not limited to this; for example, a 1.5-head helical scan system It is also possible to use a video tape recorder similar to the system. In this case, it is only necessary to provide one auxiliary head for recording and reproducing the vertical blanking period, and the main head has 2 to 3 and the auxiliary head has 1.
Only three to four heads in total need to be provided, which greatly reduces the number of heads.

It is also possible to increase the overlap recording portion of the head and record the time-base compressed audio signal in that portion. In this case, for example, by recording the main audio signal with the head that records the sum signal and recording the sub audio signal with the head that records the difference signal, the high-precision method can be changed from the current standard method as described above. , the main audio signal can be played back.

Furthermore, the present invention is applicable not only to video tape recorders but also to other video signal recording and reproducing devices, such as
It can also be applied to video discs, etc.
In this case, two or three spiral or annular tracks may be formed in parallel on the disk, and the sum signal, difference signal or color difference signal may be recorded as described above.

[Function and effect of the invention]

As explained above, according to the present invention, a wideband video signal is recorded and reproduced by narrowing the band within a limited recordable band without increasing the relative speed between the recording medium and the head and without losing the amount of information. It is possible to obtain a reproduced image with high resolution and good image quality, and it is not particularly heavy or large, and the number of scanning lines is in a 1:2 relationship between two televisions. It is possible to reproduce video signals that are compatible with any system, and in particular, the recording and reproduction of video signals for high-definition television systems, which have twice the number of scanning lines as the current television system, is highly efficient. In addition to achieving high resolution, compatibility with the current standard television system can be realized, and a video signal recording and reproducing device with superior functions not found in the above-mentioned prior art can be provided.

[Brief explanation of the drawing]

FIG. 1 is a pattern diagram showing a track for an embodiment of the video signal recording/reproducing apparatus according to the present invention, and FIG. 2 is a configuration diagram showing an embodiment of the video signal recording/reproducing apparatus according to the present invention forming the track of FIG. 1. figure,
FIG. 3 is a block diagram showing a specific example of a recording circuit for forming recording signals supplied to each head in FIG. 2, and FIGS. 4a, b, and c explain recording signals according to FIG. 3. FIG. 5 is a block diagram showing a specific example of a reproducing circuit that processes the reproduced signals from each head in FIG. 2, and FIG. 6a shows a recording signal supplied to each head in FIG. 2. FIG. 6b is a block diagram showing another specific example of a recording circuit for forming a recording circuit, and FIG. 8 is a pattern diagram showing a track for another embodiment of the video signal recording and reproducing apparatus according to the present invention, and FIG.
FIG. 9 is a block diagram showing another embodiment of the video signal recording/reproducing apparatus according to the present invention which forms the track shown in FIG. Block diagram showing an example,
FIGS. 10A to 10A are timing charts showing the timing relationship of signals of each part in FIG. 9. 1...magnetic tape, 2-7...track, 8...
...Head cylinder, 11-14...Head, 18
...1H delay circuit, 20...addition circuit, 21...
Subtraction circuit, 22, 22', 23, 23'... Time axis expansion circuit, 48, 49... Time axis compression circuit, 50
... Addition circuit, 51 ... Subtraction circuit, 52 ... 1H
Delay circuit, 53...Synthesis circuit, 67-69...Head.

Claims (1)

[Scope of Claims] 1. Luminance component generation means for generating first and second luminance components separated at predetermined intervals from a luminance signal in a color video signal to be recorded; first and second time axis expansion means for time axis expansion of the first and second luminance components into signals having a period shorter than twice the predetermined period; and chromaticity in the color video signal. chromaticity component generating means for generating first and second chromaticity components separated from the signal at predetermined intervals; and first and second chromaticity component generating means for time-base compressing the first and second chromaticity components, respectively. a time axis compression means; a time axis reference generation means for generating a time axis reference signal; an output signal of the first time axis expansion means; an output signal of the first time axis compression means; and a time axis reference generation means. a first time multiplexing means for time multiplexing the time axis reference signal from the second time axis expanding means, an output signal from the second time axis compressing means, and the time axis reference generating means. a second time multiplexing means for time multiplexing the time axis reference signal of the first and second time multiplexing means; and first and second time multiplexing means for recording the output signals of the first and second time multiplexing means as mutually adjacent diagonal tracks on the magnetic tape, respectively. A color video signal recording device comprising: a rotating head;