JPH05174301A - Magnetic recording/reproducing device - Google Patents

Abstract

PURPOSE:To adjust interchangeability over a length more than that of a helical track specified by a format. CONSTITUTION:Recordings are made on helical tracks (4 to 7) over the length more than that of the helical track specified by the format and using a magnetic tape 1 whose helical tracks (4 to 7) are superimposed and recorded with at least one linear track (2, 3 or 8), the envelope outputs of a recorded track length are continuously taken out by a head switching whose duty lengths are unequal. Thus, interchangeability is adjusted over the length more than the specified one of the helical track.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording / reproducing apparatus for adjusting compatibility by using a magnetic tape.

[0002]

2. Description of the Related Art In recent years, a recording / reproducing apparatus utilizing magnetic recording has been widely used in VTRs and the like, and as a trend, due to an increase in signal amount due to digitization and the like, a head drum apparatus is rotated three times or more as compared with a conventional one. High-speed rotation, short-wavelength recording, narrower tracks, and thinner magnetic tapes are progressing. Under such circumstances, as a mechanical problem, a good head touch is required for the magnetic head to correctly trace a recorded track and to efficiently extract a recording signal having a short wavelength.

Conventionally, the format of a digital device of this type has a structure in which two channels are divided and recorded as shown in the schematic pattern diagram of FIG. In FIG. 4, 1 is a magnetic tape, 2 is a control track, 3 is a time code track, 15 and 16 are first pair tracks A and B different from each other in the azimuth direction, and 17 and 18 are second pair tracks different from each other in the azimuth direction. The pair tracks A, B and 8 are cue tracks.

Conventionally, the analog recording has been performed by overlapping recording in consideration of the fluctuation range of the head switching timing. However, in the case of digital recording, it is sufficient to obtain a signal, so recording is performed except for the necessary signal. It is usually unnecessary and overlap recording is not performed. Moreover,
In order to increase the recording density, the helical track is recorded up to a position close to the time code track 2 or the cue track 8. In the case of recording with the magnetic heads facing each other by 180 degrees, the recording track length is determined to be about 178 degrees in accordance with head switching with a duty of 50:50 by setting the timing to the same length. This track has only the track length required to record the entire signal. Further, the pair heads for recording the tracks in FIG. 4 are normally set to be displaced in the rotational direction (not shown). for that reason,
Tracks 15 and 17 and track 1 with different azimuth directions
Although 6 and 18 have the same timing on the track pattern, there is a time lag in head output. FIG. 5 is a schematic diagram showing the relationship between this switching and the envelope.
In FIG. 5, 9 is the head switching high of the track 15, 10 is the head switching low of the track 17,
9'is head switching high of track 16 and 10 '
Is a head switching row of the track 18, 19 is an envelope of the track 15, 20 is an envelope of the track 17, 21 is a gap between the envelopes 20 and 19, 22 is a gap between the envelopes 19 and 20, 19 ′. Is a track 16 envelope, 20 'is a track 18 envelope, 2
1'is a gap between the envelope 20 'and the envelope 19', and 22 'is a gap between the envelope 19' and the envelope 20 '.

In FIG. 5, each envelope has only the required length and has an open space,
I don't know the track path of the approach section of the track.

Furthermore, in the case of measuring using the azimuth time difference in which the outputs of the envelopes of the tracks 15 and 17 are used simultaneously, as shown in FIG. 5, the synchronizing signals of the video signals obtained from the envelopes are compared. However, no signal is obtained in the open mouth, and further,
It is not possible to compare only the magnetic head times of the pair of magnetic heads that are offset in the rotational direction.

[0007]

However, in the above-mentioned conventional configuration, when the track linearity is matched by using the envelope, it becomes unclear at the rising and falling positions, and further, before entering the main track. In the track linearity measuring method using the azimuth time difference in which the track locus is not known at all or the signals of 2ch are used at the same time, the part where the signals do not overlap on the time axis between the pair heads in both the open space and the recording track length However, there is a problem that a necessary signal cannot be obtained. SUMMARY OF THE INVENTION It is an object of the present invention to provide a magnetic recording / reproducing apparatus capable of obtaining a signal necessary for adjustment with a track length recorded on a format or more.

[0008]

In order to achieve this object, a magnetic recording / reproducing apparatus of the present invention has a length longer than a track length specified by a format, and is recorded on at least one linear track so as to be overlapped. A magnetic tape is used, and the head switching signal of 180 degrees is made unequal in length in the range where the envelope is continuous.

[0009]

According to the present invention, each head traces a recorded track length longer than the required length due to the format, and a signal of a track longer than the track length is caused by the longer unequal head switching. Can be played and is getting a continuous signal.

[0010]

Embodiments of the present invention will be described with reference to the drawings. Figure 1
FIG. 3 is a schematic view showing a recording pattern of the present invention. Reference numeral 1 is a magnetic tape, 2 is a control track, 3 is a time code track, 4 and 5 are reverse azimuth helical recording tracks of the same pair, and 6 and 7 are reverse pairs of the same pair that are 180 degrees out of phase with the recording tracks 4 and 5. Azimuth helical recording track, and 8 is a cue track.

In FIG. 1, the helical recording tracks 4,
Nos. 5, 6 and 7 are performed by solid writing without switching at the time of recording, and all the mechanical overlap of the magnetic tape with respect to the drum is recorded. For this reason, the recording tracks 4, 5, 6, 7 are also recorded on the control track 2 and the cue track 8 in an overlapping manner. The control track is necessary for the recorded magnetic tape 1 to run properly, and the helical recording tracks 4, 5, 6 and 7 for recording track video signals are high frequency signals, and the magnetic layer on the magnetic recording tape 1 is a magnetic layer. Since the control signal is recorded on the surface of the magnetic recording medium as a pulsed low-frequency signal and is recorded deep in the magnetic layer, superposition recording is possible.

On the other hand, FIG. 2 is a diagram showing the relationship between the head switching signal and the envelope of the present invention. Reference numeral 23 is a head switching signal corresponding to the helical recording tracks 4 and 6, 24 is a head switching signal whose duty is changed based on the head switching signal 23, 13 is an envelope of the helical recording track 4, and 14 is an envelope of the helical recording track 6. , 25 is a head switching signal corresponding to the helical recording tracks 5 and 7, 26 is a head switching signal whose duty is changed based on the head switching signal 24, 13 'is an envelope of the helical recording track 5, and 14' is a helical recording track. 7 envelope.

Either the pair of helical recording tracks 4, 5 or 6, 7 is used as a long head switching signal or a short head switching signal so that signals can be continuously taken out. In FIG. 2, the helical recording tracks 4 and 5 are long head switching signals, and the helical recording tracks 6 and 7 are short head switching signals.

FIG. 3 is a block diagram for obtaining the head switching signal of FIG. Standard duty 5
This is to obtain a signal having a non-uniform duty ratio from a reference signal of 0:50. The monostable multivibrator 1 is kept high for a predetermined time from the rising edge of the reference signal. The monostable multivibrator 2 is set high after a predetermined time has elapsed from the fall of the reference signal, and a signal having a predetermined duty ratio can be obtained by adding these signals.

In this example, the high time ratio is increased, but the same effect can be obtained even if the low time is increased by the inverting circuit.

[0016]

As described above, according to the present invention, the helical recording track and the linear recording track are partially overlapped and recorded, and the timing of the head switching signal is made unequal in the continuous envelope range.
The track linearity of the entire recording track length required in the digital signal format can be adjusted, and its practical effect is very large.

[Brief description of drawings]

FIG. 1 is a schematic pattern diagram of a magnetic tape used for adjusting a magnetic recording / reproducing apparatus according to an embodiment of the present invention.

FIG. 2 is a waveform chart showing the relationship between head switching and envelope output in the embodiment.

FIG. 3 is a block diagram showing a circuit example of a head switching circuit in the embodiment.

FIG. 4 is a schematic recording track pattern diagram of a conventional magnetic recording / reproducing apparatus.

FIG. 5 is a waveform diagram showing the relationship between conventional head switching and envelope.

[Explanation of symbols]

 1 magnetic tape 2 control track 3 time code track 4, 5, 6, 7 helical recording track 8 cue track

Claims (2)

[Claims] 1. A magnetic tape having at least one linear recording track recorded in the longitudinal direction of the magnetic tape, and a helical recording track which is superposed with the at least one linear recording track, for compatibility adjustment. A magnetic recording / reproducing apparatus characterized by being used as a tape. 2. A magnetic recording / reproducing apparatus, wherein the timing of head switching for switching a plurality of magnetic heads facing each other by 180 degrees is set to be unequal length within a range in which outputs of the facing magnetic heads are continuous.