KR100194035B1 - Backward compatible HDTV recording and playback system - Google Patents

Abstract

The first information signal is recorded as first type parallel slope tracks having a predetermined space between each inclined track, and the second information signal is better than the width of the first type inclined tracks on either side of the first inclined track. A magnetic tape recording format and a recording / reproducing apparatus corresponding thereto are disclosed. Moreover, two of the tracks of the second type are located between each of the tracks of the first type. In addition, the azimuth angles of the first type tracks alternate different predetermined values for successive tracks, and the azimuth angles of the second type tracks are both different from the azimuth angles of the first type tracks located therebetween. This format is particularly advantageous for use in the customer rental market because it allows a tape to provide both high resolution television signals and standard VHS signals.

Description

Backward compatible HDTV recording and playback system

1 is a conventional track format on a video tape formed by a two-head VHS VTR.

2 shows a track format according to the invention with standard VHS tracks spanning additional tracks for recording and playing back additional information signals according to the invention.

3 is one useful way to create the track format of FIG.

4 is a recording apparatus according to the present invention.

FIG. 5 is a playback apparatus for reproducing a magnetic tape having a track format of FIG.

The present invention relates to a magnetic tape recording and reproducing format and an apparatus according to the format, and more particularly to an HDTV recording and reproducing magnetic tape format and apparatus having backward compatibility with other formats such as a standard VHS television signal recording format.

U.S. Patent No. 4,963,991, filed October 16, 1990, describes a high resolution television signal (HDTV: High) with a narrow bandwidth format, such as a conventional National Television System Committe (NTSC) signal with a bandwidth of about 4 mHz and a bandwidth of 8-20 mHz. In both wide-band formats such as Definition Television, tape recording formats and recording devices are available that can record and reproduce television signals. This is done only by writing either the narrowband signal or the wideband signal on the tape at a time. When wideband signals are recorded, instead of increasing the speed of the recording tape, two small heads are used to digitally record the time-expended channels of the wideband signal and the recording heads are mounted. The speed of the rotating drum being increased is correspondingly increased. Thus, the tape speed will be the same for both formats. However, since only one format is recorded on the tape at a time, video tape players who are not installed to use the television signal selected for recording on the tape cannot use this tape.

U.S. Patent No. 4,941,055, filed on July 10, 1990, describes a method for magnetic recording of two signals on a video floppy disk: low frequency components in the frequency range below 4 mHz and high frequency components in the 4-6 mHz. Announcing the format. The low frequency component is recorded on a number of main slant tracks with spaces in between, and the high frequency component is used to minimize pick-up of adjacent tracks while the head is erroneously tracking. It is recorded in the guard band between the main tracks at the main track and other azimuth angles. Although two-track recording has been published, only one television signal format is recorded and reproduced. As such, there is no compatibility with other television signal formats at the same time, and compatibility will increase the user's demand for such things as tapes that have been previously recorded in multiple television signal formats, and would make the system desirable. Moreover, since the total frequency component of a single signal is divided between two channels and two recording and pickup heads, the inventors of the present invention will necessarily have time-base errors between the reproduced signals and the best time. I am sure that it will be impossible to correct even with bass correctors, thereby making it difficult to accept HDTV performance.

U.S. Patent No. 4,843,485 dated June 27, 1989, discloses a format of a recording and a recording and reproducing apparatus in accordance with the format, which is either a wideband or portable quality television signal on magnetic tape. The recording and reproduction of one of the two are simultaneously supplied. Here the tape is divided vertically into upper half and lower half. Each of the upper half and the lower half receive a digital record of one-half of the signal components of the wideband signal, so picking up only one vertical track allows reproduction of low quality signals, while picking up two tracks At the same time it causes a high quality signal.

US Pat. No. 4,928,186 by Masamoto et al. On May 22, 1990, discloses a tape recording format and a corresponding recording and playback device that records video signals on the main tracks of a video floppy disk. It also records additional information (audio) in guardband space between the main tracks. Another aspect of the present invention is that the guard bend signal is recorded at only 40-80% of the electromotive force used in the main tracks, which indicates the deterioration of the main tracks during recording of the guardband tracks. It is to minimize.

It is an object of the present invention to provide a magnetic medium recording format which enables the recording of two different signals in two different formats on a single medium, and to provide for selective reproduction of signals from either of the two recorded formats. .

Another object of the present invention is to provide a recording format in which recording and reproduction of signals are relatively simple.

The objects of the present invention described above will become apparent from the following detailed description of the embodiments of the present invention, the drawings, and the claims.

A magnetic recording medium having a recording format of the following type includes a plurality of first type parallel tilt tracks recorded on the magnetic medium and having a predetermined space, a predetermined track width, and a predetermined azimuth therebetween. Substantially one half of the predetermined space between successive tracks of the first type, recorded on a magnetic medium parallel to the first type, so that the two tracks are between each track of the first type. It is composed of a plurality of second types located in.

Moreover, an apparatus for recording signals on a recording medium according to the present invention is provided for recording a first information signal on a medium as a plurality of first type parallel tilt tracks having a predetermined space and a predetermined band and a predetermined azimuth therebetween. Two tracks between each track of the first type and having a width substantially equal to one-half of the space between each of the successive first type tracks parallel to the first type. A plurality of second type inclined tracks to be recorded are composed of second means for recording a second information signal on a medium.

According to one aspect of the invention, the azimuth angles of the second type tracks are opposite to the azimuth angles of the first type tracks and, moreover, have an azimuth angle of at least twice the azimuth angles of the first type tracks.

According to another aspect of the invention, the first information signal consists of a standard analog VHS signal, and the second information signal consists of a digitized, randomly extracted HDTV signal.

According to another aspect of the invention, the second type tracks are initially formed using a relatively wide head, and the first type tracks are relatively narrowly within the track generated by the relative optical head. formed by the centering of a narrower head, thus forming a first type track having a second type track on either side of the first type track.

1 shows a conventional track format of video tape 10 for a two-head VHS VTR when recording in a two-hour mode.

The two-head VTR has 34 micron wide heads that track parallel slant track 12, leaving an unused space, or guardband 14, between 24 microns wide.

As is well known to those skilled in the VTR art, the recording and reproducing heads pick up signals from adjacent tracks when the pickup head scans adjacent tracks during playback, i.e. erroneous tracking. It is aligned at a predetermined azimuth angle to prevent a. As shown in FIG. 1, two recording heads are used with opposite azimuth angles of +6 degrees and -6 degrees. Four-head devices typically have two optical recording heads, each 58 micrometers wide, which are used for double-speed recording. In this case, there will be no guardband between the parallel tilt tracks. As is well known, 58 micron wide tracks are fully compatible with playback by a VTR with 34 micron wide heads. The 4-head VTR also has 34 micron wide heads for use in 4x and 6x recording.

The present invention requires that only 34 micron wide tracks in the double speed VHS recording formats are required for compatibility with the VHS system, and therefore, no supplemental information is used on the tape while the main tracks of the tape record standard VHS signals. It has the advantage of being able to be recorded in band parts. Thus, a tape is provided which enables the recording and reproduction of auxiliary signals, and is also backward compatible with standard VHS systems. In one embodiment of the invention, the auxiliary information is provided by a digital HDTV signal, a wide screen TV signal, or a standard VHS, rather than a partial band component of the standard VHS signal to discuss or improve the resolution. It is an independent signal like other TV signals with better definition than that, and the standard VHS signal is recorded on the main tracks.

FIG. 2 shows a new track format recorded on video tape 20 with standard VHS tracks 22-28 each having a width of 34 microns and a continuous alternating azimuth angle of +6 degrees and -6 degrees between them. Thus, these tracks are compatible with the recording and playback of standard VHS signals by a VTR having either a 34 micron wide or 58 micron wide head. In addition, tape 20 has pairs 29-40 of auxiliary tracks that span each standard VHS track. Thus, two subtracks are combined with each standard VHS track, making it available for recording and playback of additional signals (preferably HDTV signals). These tracks span each standard track, and by using an azimuth for secondary tracks with an azimuth that is opposite to the angle used by the spanning VHS standard track, from the pickup while the head is erroneously tracking in the standard VHS scheme. It is hidden. A combination of these three tracks, i.e., a VHS track of a predetermined azimuth, which is spanned by two narrow tracks that are the same azimuth but different from the azimuth of the VHS track between them, is called a composite track.

In this form, three essential purposes are combined. First, the azimuth angles of successive VHS tracks remain compatible with standard VHS. Second, when the VTR is operating as a VHS player, the VTR does not find auxiliary tracks at other azimuths (preferably opposite azimuths). Third, alternating azimuths are made between all consecutive tracks (both VHS and subtracks). These second and third objectives ensure that they have the same azimuth rejection capability which is very important for narrow track recording during playback. Azimuth rejection is not effective at low recording frequencies, so the information signal of the subtracks is pre-adjusted to be independent of low frequencies. This is a standard practice in digital recording systems using azimuth heads. While reproducing the signal from the subtracks, the low frequency portion is not used. By increasing the azimuth angle above 6 degrees with respect to the subtracks, greater rejection can be achieved at low frequencies. This allows the lower end of the frequency band (boundary) to be utilized for auxiliary tracks, and further increases the bandwidth available to the auxiliary tracks. The same orientation rejection for VHS regeneration and auxiliary track regeneration is maintained. Another advantage of increasing the azimuth of the auxiliary tracks is to improve the backward compatibility aspect of the scheme. That is, during playback, a +6 degree head that reads a +6 degree VHS track, if severely mistracked, will assist the nearest +6 degree away from two tracks, causing a wave pattern in the signal. You can pick up signals from the track. This is also true for the VHS head at -6 degrees. For example, increasing the azimuth angle of the subtracks to +18 and -18 degrees respectively will actually solve this problem.

Although it is assumed that the track format of FIG. 2 requires at least a pair of heads to record the auxiliary tracks, according to another aspect of the present invention shown in FIG. 3, the relative light tracks in which the auxiliary tracks use the auxiliary information are That is, 58 micron tracks are recorded first, followed by a 34-micron standard VHS track of opposite azimuth to the center of the light-assisted track, thereby forming a composite three-track format. According to another aspect of the invention, the azimuth angle of the optical track is different from the azimuth angle of the narrow tracks by two or three magnifications to reduce cross-pickup during the wrong tracking of the head.

According to another aspect of the present invention, in order to further reduce the cross-talk disturbance between the standard VHS and the auxiliary signal due to erroneous tracking, there is no low frequency component where the auxiliary signal can be opposed to the analog VHS signal. Digital signalization is desirable.

According to another aspect of the invention, a better improvement of reducing signal degradation due to erroneous tracking may be achieved if the digital signal is randomized over time, and those skilled in digital signal processing techniques. It is a technique well known to When the information content of the auxiliary signal is randomly extracted, severely incorrect tracking, which usually causes some information loss in the auxiliary signal, will not repeatedly degrade the signal of the information content, otherwise it will cause visible bands of interference. will be.

4 shows a recording apparatus according to the present invention for recording tapes having the format shown in FIG. VTR circuits are widely known, and only simple block diagrams and brief descriptions are necessary.

Although not shown, a standard NTSC color video signal is provided to the standard VHS encoder 41, i.e., a 525 line interlaced TV signal with luminance and color components. As is well known, encoder 41 processes NTSC signals according to color-under technology, where the FM modulated luminance signal is combined with a low frequency subcarrier with color information. The signals are added together to the output of the encoder 41 and then through the recording amplifier 42 to the appropriate amplitude level. Rotary transformer 43 applies these signals to magnetic recording heads 44a and 44b mounted to a rotating drum, not shown, and the tape is positioned to move in contact with the heads. The color subcarriers are then recorded on the video tape using the FM modulated luminance signal as a bias. Pickup heads 44a and 44b are directed to a drum, not shown, to produce standard VHS tracks with well-known alternating azimuth angles, such as +6 degrees and -6 degrees, respectively, as shown in FIG. These heads have a width of 34 microns. However, with regard to the recording technique of Fig. 3, these tracks are recorded after the recording of the subtracks, and are centered with respect to the recording of the subtracks.

The subtrack information, preferably the digitized and randomized HDTV signal, is applied to the data compressor and tape formatter processing block 45. Video compression encoding is required due to bandwidth limitations in the subtracks. Joint Photograph Experts Group (JPEG) using discrete cosine transforms (DST) and Moving Pictures Experts Group (MPEG) using DST with intra- and inter-frame compression algorithms. Several different types of digital video compression techniques are well known. For more information on the compression of HDTV signals, see Video Compression Makes Big Gains, by Ang et al. On pages 16-19 of the IEEE Spectrum, October 1991.

The formatting of the digitized signal may use any of several well-known formats for dividing the data stream to be recorded, for example, in sub-units or blocks containing synchronization data, identification code, image information. Can be. One such available format here is the well-known D1 standard proposed by the Society of Motion Picture and Television Engineers (SMPTE).

In addition, for high-density recordings such as HDTV subtracks, the playback intensity is relatively low, and furthermore, playback may be further degraded by incorrect tracking of the head and spatial variations between the head-tape. As such, the NRZ recording format can also be used. The technology and benefits of the various types of NRZ recording format were described in the January 1980 IEEE Transactions VOL. This is discussed in a paper by Nakazawa et al., Named A Study on Detection Methods of NRZ Recoding, published on pages 104-110 of MAG-16, NO.1.

The digitized, data compressed, and formatted HDTV signal is then at an appropriate level to be recorded by the recording amplifier 46, and the rotary transformer 47 applies the signal to the recording heads 48a, 48b having opposite azimuth angles. According to the recording technique of FIG. 3, the heads 48a and 48b are 58 microns wide, respectively, and are mounted on a rotating drum (not shown) having the heads 44a and 44b, so that the signals of 48a and 48b are applied to the magnetic tape 20. Positioned to be recorded first, the signals from heads 44a and 44b are then recorded in the center of the first recorded track, respectively. This results in the formation of a magnetic tape having the format shown in FIG. 2 and FIG. Optionally, process block 50 may divide the signal into two components, recording each separately but simultaneously using an additional pair of auxiliary track heads, each pair of auxiliary tracks being shown in FIG. Create a micron wide track. However, this technique is currently not preferred by the inventors due to the complexity caused by the four write heads for the subtracks.

5 illustrates a reproducing apparatus for reproducing a magnetic tape having the format of FIG. 2, which is essentially inverse to the recording apparatus shown in FIG. Standard VHS track information is converted into electrical signals by magnetic pickup heads 51a and 51b and applied to regenerative amplifiers 53a and 53b which increase the amplitude of the recovered signals via rotary transformers 52a and 52b. Amplifiers 53a and 53b not only increase the amplitude of the recovered signals, but also correct for the amplitude roll-off and phase shift characteristics inherent in magnetic recording processes. A multiplexer combines the signals recovered from heads 51a and 51b into a single signal using a headswitch signal, as is well known. The standard VHS decoder 54 recovers and recombines the luminance and color signals into standard NTSC signals.

The pickup heads 55a and 55b convert the auxiliary track information recorded at their respective azimuth angles into electrical signals, respectively, and the rotary transformers 56a and 56b apply these signals to the regenerative amplifiers 57a and 57b. Amplifiers 57a and 57b not only increase the amplitude of the recovered signals, but also correct for the amplitude roll-off and phase shift characteristics inherent in the magnetic recording process. The clock recovery circuits 58a and 58b are used to recover the clock signal from the recovered signal. The clock signals from the circuits 58a and 58b and the data recovered from the amplifiers 58a and 58b are all synchronized recovery, deformatting, decompression and output format processing blocks. Is applied to 59. Block 59 analyzes the recovered digital auxiliary signal and reconstructs the HDTV signal from the recovered digital auxiliary signal in the inverse manner of the applied formatting and compression techniques while recording HDTV information and, as a result, recovered from its output. It will generate an HDTV signal. As noted above for the selective use of two pairs of recording heads for recording auxiliary tracks, the heads may also be arranged in two pairs of pickup heads, each of only 12 microns wide, but this arrangement is currently limited in complexity. Not preferred due to

It is noted that in the current consumer market playback devices are needed to recover one of the recorded signal types, which is only VHS or HDTV. If in the future, the recorded signals can be combined to form display images, the playback device will have the complete playback structure shown in FIG.

Thus, a new magnetic recording and reproducing media format and a device according to the format have been presented and described, thereby satisfying all the aims and advantages that have been sought. Many modifications, variations, variations, and other uses and applications of the present invention will become apparent to those of ordinary skill in the art after considering the specification and the accompanying drawings, which disclose preferred embodiments. For example, it would be desirable to record the standard VHS signals on the main tracks and the addition signal on the subtracks, which may be combined with the VHS signal to provide an HDTV or wide aspect ratio signal. Can be. In this case, the playback device will be compatible to recover both types of recorded signals. All such modifications, changes, variations, other uses and applications of the invention are intended to be included within the scope of the following claims.

Claims (12)

A magnetic recording medium having a recording format, comprising: a plurality of first type parallel slant tracks having a predetermined space between a predetermined track width, a predetermined azimuth angle, and a parallel slant track, and recorded on the magnetic medium; Each parallel inclined track of the first type having a width of 1/2 of a predetermined space parallel to the type parallel inclined tracks and recorded on the magnetic medium, and the parallel inclined tracks are actually located between the first type parallel inclined tracks; A magnetic recording medium having a recording format in the form of a plurality of second type oblique tracks with two tracks positioned therebetween. The azimuth angle of claim 1, wherein the azimuth angles of the pair of second type tracks with the first type tracks between the tracks are both the same azimuth and are different from the azimuth angles of the first type tracks located between the second type tracks. Magnetic recording medium characterized in that. 3. The azimuth of claim 2, wherein the azimuth of each successive track of the first type tracks alternates between two opposingly regulated azimuths, wherein the azimuth of the pair of second type tracks is at least two than the azimuth of the first type track. Magnetic recording medium, characterized in that large magnification. An apparatus for recording signals on a recording medium, comprising: a plurality of first type parallel slope tracks having a predetermined bandwidth and a predetermined azimuth angle and a predetermined space between parallel slope tracks, the first information recording medium recording a first information signal on a medium; A plurality of second types in which two tracks are recorded between each track of the first type with a width substantially equal to one-half of the space between the means and the first type tracks parallel to the first type. And second means for recording a second information signal on the medium as inclined tracks. 5. The relative narrow track of claim 4, wherein the second means records the second information signal on the medium using a relative optical track, and wherein the first means is located substantially at the center of each relative optical track. Recording the first information signal on the medium using the device so that the second type tracks are on the side of the first type tracks. 5. Apparatus according to claim 4, wherein said first means comprises a standard VHS recording system and said second means comprises a recording system for a high resolution television signal. 7. Apparatus as claimed in claim 6, wherein said second means comprises a digital data compressor and a tape formatter. 8. Apparatus as claimed in claim 7, wherein said second means comprises means for randomly extracting a recording of a high resolution television signal. 5. The apparatus of claim 4, wherein each of the first and second means comprises magnetic recording head means having an azimuth angle associated with the second type tracks having the first type tracks located between the tracks. Wherein each of the azimuth angles associated with the tracks is the same azimuth angle and a different azimuth angle from the azimuth angle of the first type track located between the second type tracks. 10. The method of claim 9, wherein the azimuth angles of each successive track of the first type tracks alternate between two opposingly defined azimuth angles, wherein the azimuth angles of the pairs of the second type tracks are at least two greater than the azimuth angles of the first type tracks. Apparatus for recording signals on a record carrier, characterized in that the magnification is large. An apparatus for recovering signals from a record carrier, comprising: means for recovering a first information signal recorded on a medium as a plurality of first type parallel warp tracks having a predetermined bandwidth and a predetermined azimuth angle and a predetermined space between parallel warp tracks. And have a width substantially equal to one-half of the space between each successive track of the first tracks, parallel to the first track, so that the two tracks are recorded between each track of the first track. And second means for recovering a second information signal recorded on the medium as a plurality of second type inclined tracks. 12. The apparatus of claim 11, wherein the first means recovers the second information signal on the medium using a relative optical pickup head, and wherein the first means actually detects the medium at the center of each relative optical pickup head. And recover the first information signal on the medium using a relative narrow pick-up head located.