JPH0429128B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic recording/reproducing apparatus for recording or reproducing signals using a magnetic recording medium and a magnetic head.

Conventionally, magnetic recording and reproducing devices such as video tape recorders use magnetic tape as a magnetic recording medium, and the magnetic head or the magnetic tape is run almost perpendicularly or at an azimuth angle of several degrees with respect to the gap direction of the magnetic head. Recording or playback is performed by For this reason, it is possible to record at a short recording wavelength of about 1 μm, but the recording track width needs to be about 20 μm, so the areal recording density is an order of magnitude higher than that of video discs using magnetic recording lasers or capacitance detection methods. There was a problem with low recording density.

In addition, attempts have been proposed to make the gap direction of the magnetic head almost the same as the running direction of the magnetic tape, but this method would greatly improve the areal recording density because the gap length determines the limit of the recording/reproducing wavelength. I couldn't stop.

In the present invention, the direction of relative movement between the magnetic recording medium and the magnetic head is the gap direction of the magnetic head,
By improving the recording and reproducing method, it is possible to obtain an areal recording density equivalent to that of a laser reproducing disk or capacitance detection in magnetic recording.

Hereinafter, the present invention will be explained based on illustrated embodiments. FIG. 1 is a block diagram showing the concept of the present invention, which is composed of a magnetic head 1, a magnetic tape 2, and a magnetic head support 4. As shown in FIG. G1 indicates the gap portion of the magnetic head 1, and arrow 3 indicates the traveling direction of the magnetic head 1, which is the same direction as the gap portion G1. Note that there is no problem even if the magnetic tape 2 runs in a direction relatively opposite to the arrow 3.

FIG. 2 shows a magnetic track C which is recorded on the magnetic tape 2 by the magnetic head 1 and includes a signal group A for generating timing signals during reproduction and a digital signal group B as information. In the magnetic track C, the black areas indicate magnetization to the south pole, and the shaded areas indicate magnetization to the north pole. Note that the scale D is added for convenience of explanation in order to clarify the magnetization reversal portion, and one scale corresponds to one bit length of the recording signal. Furthermore, corresponding to the scale D, a gap G of the reproducing magnetic head 10 (this may be the same as the magnetic head 1).
The gap length L of 2 is shown. In FIG. 2, the gap length L corresponds to 2.5 bits of the recording signal on the magnetic tape 2. In FIG. Note that the gap length L may be any value that satisfies L=2n+1/2×T (where n is any positive integer), where T is the length of 1 bit.

FIG. 3 shows a block diagram of a reproduction system circuit in an embodiment of the present invention, and FIG. 4 shows a signal wavelength diagram of each part thereof. In FIG. 3, the signal reproduced by the magnetic head 10 is transmitted to a preamplifier 11 having an equalization function.
The signal is amplified to a signal wavelength as shown in FIG. 4e. This signal is supplied to a timing circuit 12 composed of a PLL or the like. As shown in FIG. 2, since the recording track C has the signal group A for timing signal generation recorded, the normal PLL
By using the above, the two-phase timing signals shown in FIG. 4e and f can be easily obtained.

The timing signal Φ1 is phase synchronized with the signal reproduced at the front end of the magnetic head 10 in the running direction, and the timing signal Φ2 is phase synchronized with the signal reproduced at the rear end of the magnetic head 10 in the running direction. The timing signal Φ1 is supplied to the identification reproducing circuit 13,
The timing signal Φ2 is supplied to the identification reproducing circuit 14. The identification and reproducing circuits 13 and 14 are usually composed of gate circuits and the like. A signal obtained by identifying the reproduced signal shown in FIG. 4e by the identification and reproducing circuit 13 is shown in FIG. 4g. Note that the scale shown in Figure 4a is the scale D in Figure 2.
It has the same properties as 1 of the recording signal of 1 scale.
Corresponds to bit length. The signals shown in FIGS. 4b and 4c are virtual signals, and show the signals reproduced at the front end and the rear end of the magnetic head 10, respectively. These signals are added by the magnetic head 10 to obtain the reproduced signal shown in FIG. 4d. The signal shown in FIG. 4g is the same signal as the signal shown in FIG. 4b. In other words, the identification and reproduction circuit 13 outputs the same signal as the signal reproduced at the front end of the magnetic head 10 to the output terminal 15. The magnetic head 10 is a wire-wound head, and its reproduction characteristics exhibit differential characteristics, so that the signal output to the output terminal 15 represents the differential form of the signal recorded on the magnetic tape 2. In this way, the recorded signal is demodulated. Similarly, a signal obtained by identifying and reproducing the reproduced signal shown in FIG.
Shown below. The polarity of this signal is inverted by the inverting circuit 16 and output to the output terminal 17. This output signal also shows the differential form of the signal recorded on the magnetic tape 2. Furthermore, in order to improve the signal-to-noise ratio of the output signal by about 3 dB, the signal obtained at the output terminal 15 is delayed by an amount equivalent to the gap length L (in the case of this embodiment, equivalent to 2.5 bit length), and the signal obtained at the output terminal It is sufficient to add it to the signal obtained in step 17. The differential signal obtained in this way is processed by an integrating circuit (not shown).
Then, the signal is demodulated into the same signal as the recorded signal.

For example, if the gap width of gap G1 or G2 is 0.6 μm and the gap length L is 2.5 μm, then
The area required to record 1 bit is 1.5×10 ^-12 m ²
Therefore, an areal recording density almost equivalent to that of a laser reproduction disk or a capacitance detection disk can be obtained.

In the above description, the direction of the gap G2 of the reproducing magnetic head 10 is the same as the direction of the magnetic track C recorded on the magnetic tape 2.
Almost the same effect can be obtained even if the angle is constant.

Although FIG. 2 shows a signal group A for timing signal generation, this signal group A may be recorded in burst form. For example, in the case of a video signal obtained by digitizing digital signal group B as information, it may be recorded for each horizontal synchronization signal or for each vertical synchronization signal. Further, when encoding is performed that allows self-timing, recording of signal group A may be omitted.

As described above, according to the present invention, the recording density can be significantly increased, and the effects thereof are very large.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an example of the main part of the present invention, and FIG. 2 is an explanatory diagram of a recording track recorded by a magnetic head.
FIG. 3 is a block diagram showing an example of the configuration of a reproducing system according to the present invention, and FIG. 4 a, b, c, d, e, f, g, and h are signal wavelength diagrams of each part of FIG. 3. 1...Magnetic head, 2...Magnetic tape, G1...
...Gap portion of magnetic head 1, 10...Magnetic head, G2...Gap portion of magnetic head 10, 12
...Timing circuit, 13, 14...Identification reproducing circuit.

Claims (1)

[Scope of Claims] 1. A magnetic recording medium, a magnetic head, and a moving device for moving their relative positions, the gap direction of the magnetic head being the same as the direction in which the relative positions are moved, and a digital A magnetic recording and reproducing device characterized by being configured to record and reproduce signals. 2. The magnetic recording according to claim 1, characterized in that the effective head width of the magnetic head during reproduction is an odd multiple of 1/2 of the 1-bit length of the digital signal recorded on the magnetic recording medium. playback device. 3. At the time of recording, a signal for generating a clock during reproduction is recorded in addition to the digital signal as information, and at the time of reproduction, a two-phase clock is reproduced from the signal for generating the clock, and the first phase of the clock is at the front end in the running direction. The second phase has the same phase as the digital signal reproduced by the gap at the rear end in the running direction, and the signal obtained by demodulating the reproduced digital signal with the first phase clock is the demodulated signal. A magnetic recording and reproducing apparatus according to claim 1 or 2, characterized in that: 4. At the time of recording, a signal for clock generation during reproduction is recorded in addition to the digital signal as information, and at the time of reproduction, a two-phase clock is reproduced from the clock generation signal, and the first phase of the clock is at the front end in the running direction. The second phase is the same phase as the digital signal reproduced by the gap at the rear end in the running direction, and the second phase clock is used to demodulate the reproduced digital signal, and the signal is inverted. 3. A magnetic recording and reproducing apparatus according to claim 1 or 2, characterized in that the demodulated signal is a demodulated signal. 5. At the time of recording, in addition to the digital signal as information, a signal for clock generation during reproduction is recorded, and at the time of reproduction, a two-phase clock is reproduced from the clock generation signal, and the first phase of the clock is at the front end in the running direction. The second phase has the same phase as the digital signal reproduced by the gap at the rear end in the running direction, and the signal demodulated from the reproduced digital signal by the first phase clock and the second phase
3. The magnetic recording and reproducing apparatus according to claim 1, wherein the demodulated signal is a signal obtained by adding a signal obtained by demodulating the reproduced digital signal using a phase clock and an inverted signal.