JPS5930211A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To perform conversion into a signal sequence having alternate signal and nonsignal periods and to carry out recording and reproduction with remarkably short wavelength by setting the gap length direction of a magnetic head to its relative movement direction, and imposing time-axis compression at intervals of unit time during recording operation. CONSTITUTION:The direction of the effective gap length L of the magnetic head 21 is set to its running direction. When its relative speed is V and the signal and nonsignal periods are M and N, an input signal is compressed on time-axis basis to have a recorded section with M/V and an unrecorded section T with N/V. A playback signal includes a signal P, nonsignal part E, signal Q, and nonsignal part F. The signal P is a signal reproduced by the front end part 22 of the magnetic head 22 and the signal Q is a signal reproduced by the rear end part 23. When M/V<L<N/V holds for the signal recorded section M/V and unrecorded section N/V of a track 5, the signals P and Q are reproduced while separated from each other with time. Consequently, signal waveforms reproduced by the front and back gaps of the reproducing head are separated with time to perform the recording and reproduction with remarkable short wavelength.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a magnetic recording/reproducing apparatus such as a video tape recorder suitable for short wavelength recording.

Conventional Structure and Problems Conventionally, longitudinal magnetization has been common in magnetic recording and reproducing devices such as video tape recorders. It is known that recording demagnetization occurs in longitudinal magnetization during short wavelength recording. For this reason, in video tape recorders and the like, recording demagnetization increases from a recording wavelength of about 1 μm, making it difficult to put shorter wavelength recording into practical use.

On the other hand, perpendicular magnetization systems aimed at recording at shorter wavelengths have been studied, and many proposals for practical use have been made. However, most of the perpendicular magnetization methods currently proposed require a main magnetic pole and an auxiliary magnetic pole for recording and reproduction, and also require a two-layer film structure of a perpendicular magnetization film and a horizontal magnetization film for the recording medium. There are drawbacks such as a complicated configuration.

In addition, the so-called transverse (TR
ANSVKR8I! i) Recording has also been proposed ≠ζ Previously, it was thought that only wavelengths longer than the gap length corresponding to the longitudinal magnetization gap width (actually about 6 times or more) could be recorded and reproduced, and significantly short wavelength recording It took a long time to realize this.

OBJECTS OF THE INVENTION 1. It is an object of the present invention to provide a magnetic recording/reproducing device which eliminates the above-mentioned conventional drawbacks and enables recording at significantly shorter wavelengths.

Structure of the Invention In order to achieve the above object, the present invention includes a moving device that moves a magnetic recording medium, a magnetic head, and their relative positions at a relative speed V, and a moving device that moves a magnetic recording medium, a magnetic head, and their relative positions at a relative speed V, and This is a magnetic recording and reproducing device that uses transverse recording in which the direction of position movement is the same as the direction of movement, and during recording, the recorded signal is compressed on the time axis for each unit time to create a signal period M and a non-signal period N. This is a configuration in which the effective gap length of the reproducing head satisfies v < L < v during reproduction.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. , FIG. 1 shows a configuration diagram of the main parts of the tape head system of the present invention,
It is composed of a magnetic head (1), a magnetic tape (2), and a magnetic head support (4). (G1) is a gap portion of the magnetic head (1). The arrow (3) indicates the direction of movement of the magnetic head (1), which corresponds to the gap fN.
This is the same direction as the gap length direction of (G1).

It should be noted that there is no problem even if the magnetic tape (2) runs relatively in the opposite direction to the arrow El] (3). This shows transverse recording in which the gap width GA of the gap portion (G1) is the track width.

FIG. 2 shows a configuration diagram of the main parts of the recording system circuit section of the present invention, and FIG. 5 is a signal waveform diagram of each part of the recording system.

Assuming that the signal waveform shown in Fig. 6 (A1K) is supplied to the input terminal 00, the time axis compression circuit (Kawa) compresses the time axis of this human input signal as shown in Fig. 6 (B), and sends it to the recording amplifier. The recording amplifier (12J) amplifies the level necessary for recording by 4 and supplies it to the magnetic head (1).Here, the relative speed between the magnetic head (1) and the magnetic tape (2) is V. 3rd [1(B) Let M be the signal period in K, and let N be the no-signal period.On the magnetic tape (2),
As shown in FIG. 4, a track (5) is formed that includes an N section (E+) in which a signal of length V is recorded and a section IIJI (T) in which a signal of length ■ is not recorded. be done. Such a recording pattern is determined by the rear end gap in the traveling direction of the magnetic head (1) and is not dependent on the gap length of the magnetic head (1).

At the time of reproduction, a configuration substantially similar to the configuration diagram shown in FIG. 1 is used. The detailed shape of the reproducing magnetic head is shown in FIG. 5 as magnetic head j2+1. It is shown in FIG. The effective gap length of the magnetic head 21) is L, and the gap width is GB.
shall be. The gap width GB is the same as the gap width GA of the recording magnetic head (1), and is used for tracking and reproduction during playback.
Considering mistakes, it is better to be narrower than GA. When a recording track (5) as shown in FIG. 4 is scanned and reproduced using such a magnetic head (21), the magnetic head (21)
) A reproduced signal as shown in FIG. 6 is obtained from the coil ρ9). 6 In FIG. 1, the reproduced signal is a signal train consisting of a signal P, a no-signal portion E, a signal Q, and a no-signal portion F.

Signal P indicates the reproduced signal at the front end of the magnetic head (21) (4), and signal Q indicates the reproduced signal at the rear end of the head (231).The effective gap length of the reproducing head (211) If the length of the section (S) where the signal is completely recorded in track (5) and the length of the section (T) where no signal is recorded satisfy the following formula, then 6
As shown in the figure, signal P and event signal Q are reproduced temporally separated.

-<L<- ■v By extracting the signal P from the signal sequence reproduced by KL in this way and expanding the time axis, a reproduced signal is obtained.The signal P in Fig. 6 is the signal in Fig. 3. It is shown in the differential form of .

This is a phenomenon that occurs when a magnetic flux differential type head as shown in FIG. 5 is used as a reproducing head, and is a phenomenon that is usually observed even when magnetized in the longitudinal direction. This is done using longitudinal magnetization, but
A flat film can be used for modulating or equalizing the recording signal. Similarly, by extracting the signal Q from the reproduced signal sequence and expanding the time axis, a reproduced signal can be obtained. Similarly, a reproduced signal can also be obtained by extracting the signal P, adding the inverted signal Qf to the signal delayed by LmV, and then extending the time axis. Here, the level of the reproduced signal is doubled.

The reproducing circuit section using signal A will be explained with reference to FIG. The signal reproduced by the reproduction head 21) is supplied to the gate circuit (251) via the preamplifier t241. The P signal is extracted from the signal train and supplied to the time axis extension operation.The control signal applied to the control terminal M
) produced by a circuit that generates a pulse signal. Such a circuit can be easily realized by a combination of a differentiating circuit, a thread 7-jord circuit, a monostable multipipe rake circuit, and the like.

For the time axis expansion circuit t261, a semiconductor delay circuit such as a COD is used. The time axis expansion circuit (26) starts its time axis expansion operation in response to a control signal applied to the control terminal &. In this way, the output terminal (2 power is
A continuous playback signal is obtained.

When extracting the signal Q, another control signal may be applied to the control terminal Q81 in FIG. This control signal is generated by a circuit that detects the negative rising edge of Qf, for example, and generates a pulse signal for a predetermined time (that is, M).

This circuit can be realized with the same configuration as P signal extraction. In addition, in Fig. 6, if (time of no-signal section E) is a (time j of no-signal section F...), then measure the time of no-signal section and check whether the current no-signal section is E or not. By determining whether the signal is F, it is possible to detect whether the next signal is P or Q, and it is also possible to extract the signal P or Q using this method.

It is said that in transverse recording, recording demagnetization does not occur, similar to perpendicular magnetization. However, as mentioned above, conventionally it was thought that only wavelengths longer than the gap length corresponding to the gap width of longitudinal magnetization could be reproduced, but as mentioned here, it is possible to reproduce the recorded signal over time. By performing axial compression and selecting the gap length of the playback head to an appropriate value during playback, the signal waveform played back at the front gap and the signal waveform played back at the back gap are temporally separated. Since the reproduction wavelength is no longer restricted by the gap length, it becomes very effective when reproducing a significantly short wavelength recorded signal due to transverse recording. This recording wavelength is sufficiently shorter than the longitudinal magnetic field. Although this embodiment has been described with respect to recording and reproducing a signal waveform close to a sine wave, the same holds true for digital signals and the like.

Effects of the Invention According to the present invention, it is possible to temporally separate the signal waveform reproduced by the front gap of the reproduction head and the signal waveform reproduced by the back gap. The limitations of this technology can be removed, making it possible to record and reproduce significantly shorter wavelengths using transverse recording. Furthermore, the present invention has features such as not requiring a special head such as a perpendicular magnetization type and a special medium, and has extremely great industrial value.

[Brief explanation of the drawing]

FIG. 1 is a schematic perspective view showing an example of the configuration of a tape head system according to the present invention, FIG. 2 is a schematic block diagram showing an example of a recording system circuit diagram according to the present invention, and FIG. Signal waveform diagrams of various parts, FIG. 4 is a conceptual diagram showing an example of a recording pattern in the present invention, FIG. 5 is a schematic perspective view showing an example of the configuration of a reproducing head in the present invention, and FIG. 6 is an example of a reproduced waveform. FIG. 7 is a schematic block diagram showing an example of a reproduction system circuit section in the present invention. (1)...11n head, (2)...magnetic tape, (5)...recording track, (river...time axis compression circuit, j21)...magnetic head for reproduction, +22) ...
Head front end of magnetic head 121), dark)...Head rear end of magnetic head t21, (26)...Gate circuit, (26)...Time axis extension circuit representative Yoshi Morimoto Private 1 Figure 2 Figure 3 NM Figure 4 Figure 5

Claims (1)

[Claims] 1. A moving device for moving a magnetic recording medium, a magnetic head, and their relative positions at a relative speed V, and a gear lug length direction of the magnetic head and a direction for moving the relative positions. This is a magnetic recording and reproducing device using transverse recording in which the signals are in the same direction, and during recording, the recorded signal is compressed on the time axis for each unit time, so that a signal period M and a non-signal period N are continuous. It is converted into a signal string and recorded, and when played back,
1. A magnetic recording and reproducing device characterized in that the effective gap length of the reproducing head satisfies -<L<y. 2. The magnetic recorder S* according to claim 1, characterized in that during reproduction, the signal reproduced by the front end portion (i.e., front gap) of the reproduction head is time-axis expanded to produce a reproduction signal. ＋'i 'l Sノ、＃
. B. During playback, the rear end of the playback head (i.e. the pack
The magnetic recording and reproducing apparatus according to claim 1, characterized in that the reproduced signal is expanded in time axis with a gap) to produce a reproduced signal. A signal that can be reproduced at the rear end (i.e., back gap), is extended in time, and is inverted while being delayed by L) (V time). 2. The magnetic recording/reproducing apparatus according to claim 1, wherein a signal obtained by adding the above is used as a reproduction signal.