Dynamic magnetic information storage or retrieval – General processing of a digital signal – Head amplifier circuit
Reexamination Certificate
1994-04-04
2001-08-21
Faber, Alan T. (Department: 2651)
Dynamic magnetic information storage or retrieval
General processing of a digital signal
Head amplifier circuit
C360S065000
Reexamination Certificate
active
06278565
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a circuit for reading out data from a disc in a disc drive, and more particularly to a disc read-out circuit capable of filtering data in different bands of frequencies;
BACKGROUND ART
Magnetic disks are generally used for reading and writing data in connection with various equipment such as personal computers and word processors. However, owing to limited disk size, data written on the disk is often compressed, to increase the volume of data stored within a given area on the disk.
To meet this requirement, an apparatus which can read and write data having different periods onto one disk has been developed to increase the volume of data that can be stored on the disk. The apparatus which is disclosed in U.S. Pat. No. 4,805,047 entitled “Read/Write Magnetic Disk Apparatus Operable in Plural Density Modes,” is a disk drive capable of reading and writing data while using plural density modes.
Referring to
FIG. 1
, the data read-out circuit in the disk drive of the above patent includes: a head
10
for reading out data stored on a disk
1
; a gain controlled amplifier
11
; a first filter
13
for filtering servo data in the data supplied from head
10
via gain-controlled amplifier
11
; a second filter
14
for filtering information data in the data supplied from head
10
via gain-controlled amplifier
11
; a signal controller
15
for recognizing the frequencies corresponding to the servo data and information data having different bandwidths from each other, and generating a signal for activating one filter corresponding to the recognized frequency; a differentiator
16
for differentiating the signal filtered in first and second filters
13
and
14
; a differential comparator
17
for eliminating a distorted signal; and a pulse generator
18
for producing one-shot pulse from the servo and information data. Here, gain controlled amplifier
11
amplifies the servo and information data supplied from head
10
, and then supplies the amplified data to first and second filters
13
and
14
. At this time, one filter is selected to filter the data by generating a servo signal, so that signal controller
15
activates either first filter
13
when the signal supplied from head
10
corresponds to the servo data or second filter
14
when the signal from head
10
corresponds to the information data.
Meanwhile, the frequency bands employed in the servo and information data may be identical to each other, but the frequency band of the information data is generally higher, so that much more data can be written in this section. Currently, a zone bit recording mode is utilized to maximize the recording density of the information data, wherein the servo data has the same frequency throughout every zone on a disk; but the data on the region where the information data is recorded, is recorded and reproduced as frequencies having different bands for the respective zones.
Therefore, in the conventional disk drive, the greater difference between the frequency band corresponding to the data written in the servo and information data sections induces greatly different signal qualities of the servo and information data. As a result, the function of the filter is lowered which affects the quality of the disk drive.
SUMMARY OF THE INVENTION
In order to solve the above-described problem, the object of the present invention is to provide a disk read-out circuit including means capable of filtering respective frequencies of different bands, thereby providing a signal of high quality.
To achieve the object of the present invention, there is provided a circuit for reading out servo and information data from a disk having a plurality of tracks forming concentric circles partitioned into a plurality of sectors, each sector consisting of a first region recorded with the servo data of the same frequency and a second region to be recorded with information data of different frequencies, the data read-out circuit comprising:
pickup means for picking up the data written on the disk as an electrical signal;
first filter means for filtering a signal corresponding to the servo data only in the picked-up electrical signal;
second filter means consisting of a plurality of filters for filtering a signal corresponding to each frequency band of the information data in the picked-up electrical signal; and
filter selection control means having signal control means for recognizing each frequency of the data of different bands to supply the recognized data to a corresponding filter, whereby a servo signal is generated to allow the first filter means to be active when the picked-up electrical signal corresponds to the servo data, and a corresponding filter in the second filter means to be active by recognizing each data frequency band corresponding to data having different bands when the electrical signal corresponds to the information data.
Also, there is provided a data read-out circuit for reading out servo and information data from a disk having a plurality of tracks forming concentric circles partitioned into a plurality of sectors, each sector consisting of a first region having servo data of the same frequency and a second region having information data of different frequencies, the data read-out circuit comprising:
pickup means for picking up the data written on the disk as an electrical signal;
first filter means for filtering a signal corresponding to the servo data in the picked-up electrical signal;
second filter means for filtering a signal corresponding to the information data in the picked-up electrical signal; and
filter selection control means for generating a servo signal to allow the first filter means to be active when the picked-up electrical signal corresponds to the servo data, and the second filter means to be active when the electrical signal corresponds to the information data.
REFERENCES:
patent: 4535371 (1985-08-01), Harr et al.
patent: 4805047 (1989-02-01), Nasu et al.
patent: 4894734 (1990-01-01), Fischler et al.
patent: 5196970 (1993-03-01), Seko et al.
patent: 5327302 (1994-07-01), Khoury et al.
patent: 5418661 (1995-05-01), Nakamura
patent: 5422760 (1995-06-01), Abbott et al.
Faber Alan T.
Samsung Electronics Co,. Ltd.
Sughrue Mion Zinn Macpeak & Seas, PLLC
LandOfFree
Disk read-out circuit employing separate servo data and... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Disk read-out circuit employing separate servo data and..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Disk read-out circuit employing separate servo data and... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2439446