JPH02312385A - Magnetic recording and reproducing device for high definition color video signal - Google Patents

Abstract

PURPOSE:To record and reproduce a high definition video signal only by means of four magnetic heads at plural recording and reproducing modes by setting the forms of the travel tracks of the magnetic heads to be similar even at a standard mode or a long time mode. CONSTITUTION:Four magnetic heads A(+), B(-), C(+) and D(-) are provided for a rotary cylinder 8 by setting them symmetrical with respect to a rotational center by 90 degrees. Then, recording signals 1 of two channels are respectively supplied to two pairs of the magnetic heads which are symmetrical with respect to the rotational center of the rotary cylinder 8 among four magnetic heads by one channel, and the recording signals of two channels are recorded and reproduced on a magnetic tape 10. Since all recording track patterns of respective magnetic heads are symmetrical, the track patterns do not change even if a tape feed speed changes, and the same magnetic head as for the standard mode can be used even at the long time mode. Thus, a high vision base band signal can be recorded and reproduced at plural recording and reproducing modes only by four magnetic heads.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a high-definition color video signal recording and reproducing apparatus such as a home high-definition VTR that records and reproduces high-definition color video signals on a magnetic tape.

2. Description of the Related Art Conventionally, attempts to record and reproduce high-definition video signals for the purpose of applying them to home VTRs have included consideration of recording and reproduction in the form of a MUSE signal, which is a band-compressed signal for high-definition signals, as proposed by NHK. It is being done. For example, Proceedings of the Television Society of Japan 1987 Annual Conference No. 7-1.
6 and Television Society Recording Study Group, VR88-4, p.
age19-24. This is the recording method shown on January 27, 1986.

Problems to be Solved by the Invention In VTRs that record and reproduce these MUSE signals, complex algorithms and relatively large-scale signals are required to convert the MUSE signals, which are analog sample values, into high-definition baseband signals. This method requires a processing circuit, making it difficult to apply to camera-integrated VTRs, etc., and since analog sample value transmission is used, there is a problem in that it has large negative effects such as aliasing noise caused by fluctuations in the VTR's time axis. Also, VT that records and plays back MUSB signals.
In R, solid recording without a guard band has the disadvantage that image quality deteriorates significantly, such as motion detection errors due to interfering with wall talk from adjacent tracks.

In view of the above-mentioned problems, the present invention records and reproduces a high-definition baseband signal, which is a high-quality video signal, by dividing it into two-channel signals, and uses four magnetic heads, which is extremely simple in terms of mechanism and circuit. With a camera-integrated VT
It can be easily extended to R, etc., and azimuth recording has no guard bands, resulting in high recording density and long recording/returning time.Furthermore, the recording track pattern of the four magnetic heads is symmetrical even when feeding different tapes at different speeds. Therefore, it is easy to deploy for home use with many wonderful features such as being able to use the four given magnetic heads both in the standard mode as well as in the long-term mode, and eliminating the need to add four new magnetic heads. This provides a high-definition VTR.

Means for Solving the Problems In order to solve the above problems, the present invention provides a signal processing circuit that divides a high-definition baseband signal into two-channel recording signals. 2 memory to store
It is equipped with two pairs of four magnetic heads that are arranged 90 degrees symmetrically on a rotating cylinder that rotates once per field and are supplied with two channels of recording signals. It is composed of a capstan motor drive circuit that changes the time between standard mode and long-term mode.

The present invention has the above-described configuration, and although it is a VTR that records and plays high-definition baseband, it achieves high-density recording without a guard band, and is capable of long-time recording suitable for home use. Despite recording and reproducing signals, the relative speed of the tape head is relatively small, and there are four magnetic heads used, so the rotating cylinder, which requires precision, is extremely simple both mechanically and in terms of circuitry. To achieve this, it is possible to realize a VTR having a similar configuration, and also to realize a VTR having two or more types of recording/playback time for the same tape, such as a standard mode and a long time mode.

EXAMPLE An example of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of main parts in one embodiment of the present invention. In FIG. 1, for example, the input terminals 1, 2, and 3 are each shown in FIG. 2(a).

A high-definition baseband luminance signal Y and two color difference signals Cw and Cn as shown in [1) and (C) are input. Here, Y, Cw and Cn are each 20M
It is assumed that the bandwidth is Hz, 7M7 and 5.5M7, and a frame has 2 fields and 1125 lines. These three Y, Cw and Cn signals reach the recording side video signal processing circuit 4. The recording side video signal processing circuit has a configuration as shown in FIG. 3, for example, and the Y signal is separated into a horizontal synchronization signal H5ync and a vertical synchronization signal Vsync in a synchronization signal separation circuit 19, each of which is configured by a microcomputer. The signal is input to the control circuit 20. In the control circuit 20, there are three A/A converters A/A 21.
Generates A/A conversion clocks for A/A 22 and A/A 23. 8b with A/A converters 21, 22 and 23
Y, Cw and Cn, which have been A/A converted into it, are recorded in the memory 24 and the memory 25 in the order of line numbers, with their addresses and write timings controlled by the control circuit, respectively. Here, Y to memory 24 and memory 25,
The format in which Cw and Cn are written is as follows:
It is assumed that odd lines are written into the memory 24 and even lines are written into the memory 25. The Y, Cw and Cn signals written in the memory are converted to the time axis of two channels A and B as shown in FIG. Output from 25 and 2
The signals are converted into analog signals by two D/A converters 26 and 27, and input to FM modulators 6 and 7 shown in FIG. 1, where they are FM modulated and then recorded and amplified to become recording signals A and B.

However, Y after time axis conversion in A and B.

The Cw and Cn'll regions are made the same. Two channels of recording signals A and B are recorded by four magnetic helads A(+) arranged 90 degrees symmetrically on a rotating cylinder 8.

Leading to B(-), C(+) and D(-). However, these four heads are a pair of heads that are located symmetrically with respect to the center of the rotating cylinder and have the same azimuth angle, and the adjacent heads on the cylinder circumference have an opposite azimuth relationship. .

The rotary cylinder rotates in the direction of arrow 9, and a magnetic tape 10 is wound around its circumference over a distance of about 180''. This magnetic tape 10 is moved in the direction of arrow 12 by a capstan motor 11.

Here the rotating cylinder 8 and the capstan motor 11
The respective rotational phases are controlled by commands from a rotation control circuit 5 which changes the rotation mode in response to a mode switching signal inputted to the outer shell. The rotation cylinder 8 is rotationally controlled so that it rotates once during one field period of the input high-definition baseband signal. The rotation of the capstan motor is controlled so that the recording track width on the tape is approximately equal to the head width, or approximately half the head width.

Figures 4(a), (b) and (C) show the frequency spectra of the input Y, Cw and Cn signals, and Figure 4(d) shows the frequency spectra of the input Y, Cw and Cn signals.
Recording baseband signal A divided into channels (B)
shows the frequency spectrum of In the FM modulators 6 and 7, for example, as shown in FIG. 4(e), the sync chip frequency is 17 MHz and 100% white is FM-modulated to 20 MHz. For example, if the rotating cylinder of a VH3 type VTR rotates at 600 revolutions per second, the relative speed will be approximately 11.6 m/sec, but sufficient recording and reproduction is possible using a high-performance metal head and metal tape. FIG. 5 shows a recording track pattern recorded by four magnetic heads. In Figure 5, the neighbor of Y is Y, and the neighbor of Cw is Cw.
Since the neighbor of Cn is Cn, good image quality can be ensured since even in solid writing recording, the wall talk interference after FM demodulation is reduced due to the correlation value of the video signal. In the present invention, since the four magnetic heads on the rotating cylinder are arranged 90 degrees symmetrically, for example, Japanese Patent Application No. 61-937
As explained in Japanese Patent No. 36, even if the tape feed speed changes, the recording trunk patterns of the four magnetic heads are all symmetrical. Therefore, even if the tape feed speed changes, the track pattern does not change, so the same magnetic head used in the standard mode can be used in the long time mode.

Now, in the standard mode and the long time mode, the signals recorded as shown in FIGS. 5 and 6, respectively, are reproduced by the same magnetic head as when they were recorded. In Fig. 1, the magnetic head, A (+), A
(-), B (+), and B(-), the two-channel signals A'□ and B'□ reproduced by the two magnetic heads that are always in contact with the magnetic tape IO are sent to the FM decoder 13, respectively. and 14, is reproduced and amplified, then FM demodulated, and then inputted to the reproduction side signal processing circuit 15. The re-main side signal processing circuit 15 performs the reverse processing to that performed in the recording side signal processing circuit 4 (see FIG. 2), and reproduces three channels of high-definition baseband signals Y' and Cw'. and Cn' are obtained. Y'
, Cw' and Cn' are output from output terminals 16, 17 and 18, respectively.

By the way, the four magnetic heads are Mn-formant and β-formant.
- If two channels are mounted close to each other on a rotating cylinder like a conventional 2-channel VTR such as CAM, the same track pattern cannot be obtained in long-time mode and standard mode, so recording and playback cannot be performed. It's impossible.

Further, the present invention is applied to various video signal recording apparatuses in which an electromagnetic conversion system is capable of two-channel recording. In other words, the human input signals to the circuit system are the R signal and the G signal.

Whether it is a 3-channel signal such as a B signal, a 1-channel signal, a 2-channel signal, or a 3.4-channel signal, it is sufficient to convert it into a 2-channel signal and record it. Also, the recording track pattern on the magnetic tape is the fifth
Without being limited to the diagrams shown in the figure, for example, nH
The same effect can be obtained by switching the luminance signal and color signal every (n is a natural number) and performing signal processing so that the luminance signal is recorded adjacent to the luminance signal and the chrominance signal is recorded adjacent to the chrominance signal. It will be done.

Furthermore, although the present embodiment has been described for the case of 4 heads, the same effect can be obtained when N is 6 heads, or when N is an integer greater than 3 and 2N heads.

Effects of the Invention In conventional VTRs that record and play back MUSE signals, aliasing noise occurs due to time axis errors, and in solid recording, crosstalk between adjacent tracks causes large deterioration of image quality, such as mismatch between video mode and still image mode. There is a point. Also, considering the circuit scale, a camera-integrated VT
It is difficult to expand to R as well.

However, as shown in the present invention, the shape of the running track of the magnetic head can be made into the following shape in both the standard mode and the long-time mode. Recording and playback of high-definition baseband signals is possible.Furthermore, since baseband signals are handled, it is easy to develop into a camera-integrated VTR.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a main part in an embodiment of the present invention, and FIG. 2 is an explanatory diagram chronologically explaining changes in signal form in field period units of a Pi-Vision signal in the present invention.
FIG. 3 is a block diagram of main parts explaining the operation of the recording side signal processing circuit, FIG. The figure is an example of a recording track pattern in the present invention. 1.2.3... Input terminal, 4... Recording side signal processing circuit, 5... Rotation control circuit, 6, 7
...FM modulator, 8...Rotating cylinder, 9...Rotation direction of rotating cylinder, 10...
...Magnetic tape, 11...Capstan motor, 12...Magnetic tape moving direction, 13°14...FM demodulator, 15...・Playback side video signal processing circuit, 16.17.18... Output terminal, 19... Synchronization signal separation circuit, 20...
...Control circuit, 21.22.23...A/A
Converter, 24.25... Memory, 26.27.
...D/A converter. Name of agent: Patent attorney Shigetaka Awano 1 person + -≧
, l)-e O ward and u* Fig. 2 qCc. Ward > k
'1C) Accumulation No. 4 Figure Shoulder C1? fz]

Claims (15)

[Claims] (1) A device for recording and reproducing an input high-definition color video signal on a magnetic recording medium, and the recording and reproducing device includes a means for converting the high-definition color video signal into a two-channel recording signal and a device for converting the high-definition color video signal into a two-channel recording signal; The rotary cylinder drive circuit is provided with a rotary cylinder drive circuit that rotates a rotary cylinder once for each field of a high-quality color video signal, and the rotary cylinder is equipped with four magnetic heads 90 degrees symmetrical with respect to the center of rotation, and furthermore, the two The recording signals of the two channels are supplied one channel at a time to two pairs of magnetic heads that are 180 degrees symmetrical with respect to the rotation center of the rotating cylinder among the four magnetic beds, and the recording signals of the two channels are transferred to the magnetic recording medium. A high-definition color video signal magnetic recording and reproducing device that records and reproduces a high-quality color video signal. (2) It is characterized by comprising means for converting an input high-quality color video signal into two-channel video signals of a luminance signal and a color signal, and means for frequency-modulating the two-channel video signal into the recording signal. A high-quality color video signal magnetic recording and reproducing apparatus according to claim (1). (3) means for converting an input high-definition color video signal into two-channel video signals of a luminance signal and a chrominance signal; a means for time-axis expansion of the luminance signal and time-axis compression of the color signal; The high-definition color video signal according to claim 1, further comprising means for channel-switching the axis-expanded luminance signal and the time-axis compressed color signal every M lines, where M is an integer greater than 1. Magnetic recording and reproducing device. (4) The azimuth angles of the four magnetic head gaps are such that pairs that are 180 degrees symmetrical with respect to the center of rotation of the rotating cylinder have the same azimuth angle, and pairs that are adjacent on the circumference of the rotating cylinder have different azimuth angles. A high-quality color video signal magnetic recording and reproducing apparatus according to claim 1, characterized in that: (5) The device according to claim (4), further comprising a drive circuit that changes the feeding speed of the magnetic recording medium for each of a plurality of modes, and changes the width of a recording track by the four magnetic heads for each of a plurality of modes. High-quality color video signal magnetic recording and reproducing device. (6) A device for recording and reproducing an input high-definition color video signal on a magnetic recording medium, and the recording and reproducing device is a means for converting the input high-definition color video signal into a three-channel recording signal. and a rotary cylinder drive circuit that rotates the rotary cylinder once for each field of the color video signal, and the rotary cylinder is equipped with six magnetic heads symmetrically at 60 degrees with respect to the center of rotation, and Three channels of recording signals are supplied one channel at a time to three magnetic head pairs that are 180 degrees symmetrical with respect to the rotation center of the rotating cylinder among the six magnetic heads, and the three channels of recording signals are magnetically transmitted. A high-quality color video signal magnetic recording and reproducing device characterized by recording and reproducing on a recording medium. (7) Means for converting an input high-quality color video signal into a three-channel video signal in which a luminance signal and a color signal are mixed in a time-axis converted form, and converting the three-channel video signal into the recording signal. 7. The high-quality color video signal magnetic recording and reproducing apparatus according to claim 6, further comprising modulating means. (8) A means for converting an input high-quality color video signal into a 3-channel video signal in which a luminance signal and a chrominance signal are mixed in a time-axis converted form; Claim (6) characterized in that it is provided with means for switching four channels every M lines.
) High-quality color video signal magnetic recording and reproducing device. (9) The azimuth angles of the six magnetic head gaps are such that pairs that are 180 degrees symmetrical with respect to the center of rotation of the rotating cylinder have opposite azimuth angles, and adjacent pairs on the circumference of the rotating cylinder have different azimuth angles. A high-quality color video signal magnetic recording and reproducing apparatus according to claim 6, characterized in that: (10) Claim (9), further comprising a drive circuit that changes the feeding speed of the magnetic recording medium for each of a plurality of modes, and changes the recording track width by the six magnetic heads for each of the plurality of modes. The high-definition color video signal magnetic recording and reproducing device described above. (11) A device for recording and reproducing an input high-definition color video signal on a magnetic recording medium, and the device for recording and reproducing the input high-definition color video signal into N channels, where N is an integer larger than 3. and a rotary cylinder drive circuit that rotates a rotary cylinder once for each field of the color video signal, and the rotary cylinder is rotated at (180 degrees/N) degrees with respect to its center of rotation. N sets of magnetic heads are provided with N symmetrical magnetic heads, and are 180 degrees symmetrical with respect to the rotation center of the rotary cylinder among the 2N magnetic heads, each of which records the N channels of recording signals one channel at a time.・
A high-definition color video signal magnetic recording/reproducing apparatus characterized in that the recording signals of the N channels are supplied to each pair and recorded and reproduced on a magnetic recording medium. (12) A means for converting an input high-quality color video signal into an N-channel video signal in which a luminance signal and a color signal are mixed in a time-axis converted form, and converting the N-channel video signal into the recording signal. 12. The high-quality color video signal magnetic recording and reproducing apparatus according to claim 11, further comprising modulating means. (13) A means for converting an input high-quality color video signal into an N-channel video signal in which a luminance signal and a color signal are mixed in a time-axis converted form; Claim (1) characterized in that the method comprises means for switching channels every M lines.
1) The high-quality color video signal magnetic recording and reproducing device as described above. (14) The azimuth angle of 2N magnetic head gaps is
12. The high-quality color video signal magnetic recording and reproducing apparatus according to claim 11, wherein adjacent pairs on the circumference of the rotating cylinder have different azimuth angles. (15) Claim (14) characterized by comprising a drive circuit that changes the feeding speed of the magnetic recording medium for each of a plurality of modes, and changes the width of a recording track by 2N magnetic heads for each of a plurality of modes. The high-definition color video signal magnetic recording and reproducing device described above.