JPH04163713A - Magnetic recording apparatus - Google Patents

Abstract

PURPOSE:To decrease the noises induced by the inversion of a current in writing of data by approaching the resonance point formed with the coil and the capacitor of a magnetic head for regenerating the servo signal of the deep layer part of a medium to the vicinity of the servo signal, and decreasing the high-frequency noises. CONSTITUTION:A magnetic head 12 is constituted of a data recording and regenerating coil 4 and a servo-signal regenerating coil 5. A capacitor 6 is added across both ends of the servo-signal regenerating coil. The output is inputted into an amplifier 7. A resonance circuit is formed of the L of the servo-signal regenerating coil 5 and the C of the capacitor 6 in the magnetic head 12. When the resonance point is brought close to the servo signal, the frequency characteristic of the output is high in the servo signal region and is rapidly attenuated in the noise region. Thus, the noises induced by the inversion of the current in the writing of the data can be decreased.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic recording device, and particularly to servo technology for a floppy disk device.

[Conventional technology]

Conventionally, the mainstream servo for floppy disk drives is sector servo, which uses a medium on which servo information is recorded for each sector. Recently, a layer for writing and reading data is provided on the surface of the medium, and a layer for writing servo data is provided in the deep layer, and servo data is obtained from the deep layer to servo the operation of the magnetic head of the device. Deep servos have also been used.

[Problem to be solved by the invention]

In the conventional sector servo mentioned above, servo information exists discontinuously in each sector, so in order to achieve high-precision servo, it is necessary to increase the number of sectors and increase the servo information, but this reduces format efficiency. This will result in a decrease.

On the other hand, deep servo has the disadvantage that it is difficult to obtain a good servo signal due to large noise, especially when writing data.

[Means to solve the problem]

The present invention provides a magnetic recording head with a first coil for recording and reproducing and a second coil for reading servo signals, and a capacitor is added to both ends of the second coil to create a resonance point near the frequency of the servo signal. It has a servo signal detection circuit.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

Fig. 1 is a diagram showing a part of a magnetic head, medium, and servo signal detection circuit according to an embodiment of the present invention, Fig. 2 is a frequency characteristic diagram, and Fig. 3 is a diagram showing recording current, noise, and servo signal with and without a capacitor. FIG.

In FIG. 1, a medium 11 is composed of a surface layer 1, an erasing section 2 for separating data and servo signals on the medium, and a deep layer 3. Data 1a for recording and reproduction is written in the surface layer 1. Furthermore, a servo signal 3a is written in the deep portion 3.

Next, the magnetic head 12 is composed of a recording/reproducing data coil 4 and a servo signal reproducing coil 5.

A capacitor 6 is added to both ends of the servo signal reproducing coil 5, and its output is input to an amplifier 7. This results in
A resonance circuit is formed by L of the servo signal reproducing coil 5 of the magnetic head 12 and C of the capacitor 6, and when this resonance point is brought close to the servo signal, the frequency characteristics of the output will be as shown by the dotted line in FIG. The output is high in the servo signal region and rapidly attenuates in the noise region.

As a result, as shown in FIG. 3, the low density servo signal 61
Since the frequency region is around (A) in Figure 2,
The output increases to look like servo signal 62. On the other hand, the noise 51 induced in the servo signal coil 5 by the reversal of the recording current 41 during data writing has a frequency higher than the resonance point, and its frequency region is near FIG. 3(B). It is rapidly attenuated and reduced like noise 52. Furthermore, this also allows S/W when writing data.
Detect N good servo signals.

〔Effect of the invention〕

As explained above, according to the present invention, the resonance point of the coil and capacitor of the magnetic head that reproduces the servo signal in the deep part of the medium is brought closer to the vicinity of the servo signal, and high frequency noise is reduced. Noise induced by inversion can be sufficiently reduced. Furthermore, by increasing the servo signal component with resonance characteristics,
This has the advantage that a servo signal with a good S/N ratio can be detected not only when reading data but also when writing data.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing a part of a magnetic head, medium, and servo signal detection circuit according to an embodiment of the present invention, Fig. 2 is a frequency characteristic diagram, and Fig. 3 is a diagram showing recording current, noise, and servo signal with and without a capacitor. FIG.

Claims (1)

[Claims] In a magnetic recording device that uses the surface layer of a magnetic recording medium for recording and reproducing data, and pre-records servo information at a lower density than the data portion in the deep layer and uses it as a servo signal. , the magnetic head is equipped with a first coil for recording and reproducing and a second coil for reading servo signals, and a capacitor is added to both ends of the second coil to have a resonance point near the frequency of the servo signal. A magnetic recording device characterized by having a servo signal detection circuit.