JPS62236105A - Recording system for digital information signal - Google Patents

Abstract

PURPOSE:To execute the recording with a high recording density by recording a digital information signal with a recording azimuth of approximately zero degree with a magnetic head so as to form an adjoining track without a guard band onto magnetic media. CONSTITUTION:Onto a magnetic tape, a digital video signal is recorded with the recording azimuth of approximately zero degree by a rotating magnetic head so as to form an inclining track without a guard band. When the digital video signal is recorded to the magnetic tape, the frequency band (recording wavelength area) of the recording signal has a wide band over a low frequency, (direct current), (long wavelength), a high frequency (70-80MHz) and (short wavelength), the correlation hardly exists between a reproducing signal from a certain inclining track and a crosstalk component from an adjoining inclining track, and therefore, the cross modulating distortion will hardly occur. The recording can be executed to this with a high recording density.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a recording method for recording digital information signals on a magnetic medium.

[Summary of the invention]

The present invention relates to a recording method for digital information signals, and is capable of achieving high recording density by recording digital information signals with a recording azimuth of approximately 0 degrees using a magnetic head so as to form adjacent tracks on a magnetic medium without a guard band. The S/N ratio of the reproduced signal is good, there is little cross-modulation distortion due to crosstalk of the reproduced signal, and the magnetic head can be easily attached.

[Conventional technology]

As shown in FIG. 3, the conventional video signal recording method is to form a plurality of inclined tracks T on a magnetic tape via a guard band g.
As shown in Fig. 4, a method of recording video signals with an azimuth of about 100 degrees, and a method of recording video signals with alternately opposite recording azimuths using a rotating magnetic head, forming a plurality of inclined tracks T on a magnetic tape without a guard band, as shown in Figure 4. There is a method for recording video signals. In addition, in Figures 3 and 4, TV
, 'rp are the track width and track pitch of the inclined track T, respectively.

[Problem that the invention seeks to solve]

Now, in FIGS. 3 and 4, if the recording density is the same, that is, the track pitch Tp is the same, then in the case of the recording method shown in FIG. When scanning and reproducing data using a video signal (equal to
On the other hand, since the track width Tw is narrow, there is a drawback that the level of the reproduced signal is lowered.

Incidentally, when the track width Tw of the inclined track T is increased, the recording density of the magnetic tape is reduced.

On the other hand, in the case of the recording method shown in FIG. 4, when the inclined track is scanned and reproduced by the rotary magnetic head H, the track width Tw is wide, so the S/N of the reproduced signal is good, and This has the advantage that there is less possibility of cross-modulation distortion due to crosstalk based on the tracks of the rotating magnetic head H (in the case of analog video signals), but on the other hand, the rotating magnetic head must be attached to the rotating drum with high positional accuracy. First, the actual recording wavelength becomes shorter than when the recording azimuth is 0 degrees, and the S/N of the reproduced signal decreases (
In the case of digital video signals, there is a drawback that the error rate decreases. Furthermore, during variable speed playback using the multi-track recording and playback system, particularly in the case of digital video signals, there is a drawback that the playback information is reduced to approximately 1/2 of that when the recording azimuth is 0 degrees.

In view of these points, the present invention provides a digital information signal that can be recorded at high recording density, has a good S/N ratio of the reproduced signal, has little cross-modulation distortion due to crosstalk of the reproduced signal, and can easily attach a magnetic head. This is an attempt to propose a recording method.

[Means for solving problems]

The digital information signal recording method according to the present invention is characterized in that the digital information signal is recorded with a recording azimuth of approximately 0 degrees by a magnetic head so as to form adjacent tracks on a magnetic medium without a guard band. It is.

[Effect]

According to the present invention, a digital information signal is recorded with a recording azimuth of approximately 0 degrees by a magnetic head so as to form adjacent tracks on a magnetic medium without a guard band.

〔Example〕

An embodiment of the present invention will be described in detail below with reference to FIG. As shown in FIG. 1, a digital video signal is recorded on a magnetic tape with a recording azimuth of approximately 0 degrees by a rotating magnetic head so as to form an inclined track without a guard band.

Next, it will be explained that even if a digital video signal is recorded on a magnetic tape in this way, no trouble will occur. First, when recording analog video signals on magnetic tape, the frequency band (recording wavelength range) of the recording signal is
is a narrow band (narrow area), as shown as an in FIG. Cross-modulation distortion occurs.

However, when recording digital video signals on magnetic tape, the frequency band (recording wavelength range) of the recording signal is
Low frequency (DC) (long wavelength) to high frequency (several 70 to 80M
Hz) (short wavelength), there is almost no correlation between the reproduced signal from a track with a certain slope and the crosstalk component from an adjacent slope track, resulting in cross-modulation. Almost no distortion occurs. Then, the crosstalk component simply leads to an increase in the noise component by the root mean square of the crosstalk component.

In FIG. 1, when a rotary magnetic head with a gap width equal to the width Tw of the tilted track scans the tilted track T and reproduces a digital video signal, suppose that the rotary magnetic head shifts by d in the width direction of the tilted track T. , assuming that the reproduced signal is proportional to the reproduced track width and that the level of crosstalk components due to track deviation is sufficiently larger than amplifier noise, tape noise, etc., then the S/N of the reproduced signal is S/N=
20Jog ((Tw-d)/d)(dB). There is no problem as long as this S/N deterioration is not inferior to the error rate required for a digital video signal recording/reproducing system.

In addition, the frequency characteristic of azimuth loss in the case of azimuth recording is as shown by the curve az in Fig. 5, but in the case of digital recording, the frequency band of the recording signal is wide band as described above, so the azimuth loss is in the high frequency range. Since it is effective only in the short wavelength region, and almost no azimuth loss can be expected in the low frequency region (long wavelength region), there is almost no benefit from azimuth recording in digital video signals.

As shown in FIG. 2, when the gap width of the rotating magnetic head for reproduction is set smaller than the trunk width 'l'w (the gap width of the rotating magnetic head for recording), the level of the reproduced signal decreases. However, the possibility of noise generation due to crosstalk is reduced.

Note that the digital information signal is not limited to a digital video signal, but may also be a digital audio signal, a digital data signal, or the like. Further, the magnetic medium is not limited to a magnetic tape, but may also be a magnetic disk (having a concentric trunk or a nearly circular spiral track).

〔Effect of the invention〕

According to the present invention described above, it is possible to record with high recording density,
It is possible to obtain a digital information signal recording system in which the S/N of the reproduced signal is good, cross-modulation distortion due to crosstalk in the reproduced signal is small, and a magnetic head can be easily attached. Further, in the case of a digital VTR using a multi-track recording/reproducing method, the amount of reproduced information increases during variable speed reproduction, which is preferable.

[Brief explanation of drawings]

Fig. 1 is a recording pattern diagram for explaining an embodiment of the present invention, Fig. 2 is an explanatory diagram of the embodiment, Figs. 3 and 4 are conventional recording pattern diagrams, and Fig. 5 is a characteristic curve diagram. It is.

Claims (1)

[Claims] A recording method for digital information signals, characterized in that the digital information signals are recorded with a recording azimuth of approximately 0 degrees by a magnetic head so as to form adjacent tracks without guard bands on a magnetic medium.