Dynamic magnetic information storage or retrieval – General processing of a digital signal – Head amplifier circuit
Reexamination Certificate
2001-02-21
2003-12-23
Hudspeth, David (Department: 2651)
Dynamic magnetic information storage or retrieval
General processing of a digital signal
Head amplifier circuit
C360S065000, C714S701000, C714S795000, C375S341000
Reexamination Certificate
active
06667841
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention generally relates to apparatuses for recording and regenerating data, and more particularly to an apparatus for recording and regenerating data, which apparatus can reduce data regeneration errors caused by a defect of a recording medium or waveform interference between data indicated by a regenerative signal and improve a data generation rate.
Also, the present invention relates to the apparatus for recording and regenerating data which apparatus can eliminate low-frequency noise and high-frequency noise included in a regenerative signal of recorded data and then regenerate the recorded data.
2. Description of the Related Art
Recently, there are many kinds of apparatuses for recording data such as a magnetic disk, a magnetic tape, an optical disk, a magneto-optical disk or the like. A magnetic recording mark is mainly used to record data to these apparatuses. These apparatuses can permanently maintains data more than a semiconductor memory. Thus, since a large amount of data is currently required to process, these apparatus for computers are essential to record graphics and image data for computers.
In a conventional data recording apparatus, data are recorded in accordance with a predetermined format.
FIG. 1
is a diagram showing a conventional data format. In the conventional data format, data or data blocks are recorded simultaneously while a VFO area for an AGC (Automatic Gain Control) adjustment and a PLL (Phase-Locked Loop), a Sync-pattern indicating a start of data, or a Resync-pattern for re-synchronizing is inserted. In
FIG. 1
, these patterns are omitted. In the conventional data recording apparatus, data or data blocks are recorded once on a track or a sector.
FIG. 2
is a diagram showing a conventional circuit configuration for regenerating data recorded in accordance with the data format shown in FIG.
1
. In
FIG. 2
, the conventional circuit configuration is for a most likelihood decode. In the conventional circuit configuration, a BM (Branch Metric) for a sample value
10
obtained by sampling a regenerative signal is calculated at a BM (Branch Metric) calculator
11
and pass metric values are compared at an ACS (Add-Compare-Select)
13
. Then, selected pass data is sent to a pass memory
14
and also accumulated in a pass metric memory
12
for a next pass metric calculation. In the pass memory
14
, a pass merge occurs and then a most likelihood data is output to a DataOUT
15
as a decoded data. It is called a most likelihood detection known as a decoding method that is strong against noise.
However, since a data recording technology has been developed quickly to record data at higher density, a signal to noise ratio (SNR) is deteriorated by data recorded at higher density. Thus, the data recorded at higher density can not be properly decoded by the conventional most likelihood detection.
Thus, it is desired to improve a regeneration performance for the data recorded at higher density.
SUMMARY OF THE INVENTION
It is a general object of the present invention to provide apparatuses for recording and regenerating data in which the above-mentioned problems are eliminated.
A more specific object of the present invention is to provide an apparatus for recording and regenerating data, which apparatus can reduce data regeneration errors caused by a defect of a recording medium or waveform interference between data indicated by a regenerative signal and improve a data generation rate.
The above objects of the present invention are achieved by a n apparatus for recording and regenerating data, the apparatus including: a recording part iteratively recording the data on a recording medium predetermined times; a sample value storing part storing a sample value obtained by sampling a regenerative signal from the data iteratively recorded on the recording medium; a pass metric calculating part calculating a branch metric and a pass metric based on the sample value stored in the sample value storing part; and a likelihood converting part converting a calculation result obtained by the pass metric calculating part into likelihood of the calculation result, wherein the pass metric calculating part calculates the pass metric based on the likelihood converted by the likelihood converting part and decodes the data recorded on the recording medium.
According to the present invention, it is possible to provide an apparatus in which data is iteratively recorded predetermined times on the recording medium and the likelihood is update every time the same data iteratively recorded on the recording medium is iteratively decoded. Therefore, it is possible to successfully correct a distortion of a regenerative signal caused by a defect of the recording medium.
The above objects of the present invention are achieved by an apparatus for recording and regenerating data, the apparatus including: recording part iteratively recording the data at a data unit dividing the data by a predetermined data length by sequentially changing a predetermined numbers of recording areas on a recording medium; plurality of storage sample value storing parts corresponding to the predetermined numbers of recording areas, respectively, each storage sample value storing part storing a sample value obtained by sampling a regenerative signal from the data recorded on each recording area at the data unit; plurality of pass metric calculating parts corresponding to the plurality of storage sample value storing parts, respectively, each pass metric calculating part calculating a branch metric and a pass metric based on each sample value; plurality of likelihood converting parts corresponding to the plurality of pass metric calculating parts, respectively, each likelihood converting part converting a calculation result obtained by the each pass metric calculating part into likelihood of the calculation result, wherein the each pass metric calculating part calculates the pass metric based on the likelihood converted by the each likelihood converting part and decodes the data recorded on the recording medium.
According to the present invention, it is possible to provide an apparatus in which data is iteratively recorded on the predetermined numbers of recording areas and the data iteratively recorded on the predetermined numbers of recording areas are decoded by the plurality of decoding systems. Therefore, it is possible to decode the same data recorded on the predetermined numbers of recording areas in serial. In addition, the likelihood for the sample value from a previous recording area can effect a next result of the pass metric calculation in accordance with a sampling order of sampling the data recorded on the predetermined numbers of recording area. Therefore, it is possible to reduce the date decoding error caused by the defect of the recording medium.
The above objects of the present invention are achieved by an apparatus for recording and regenerating data, the apparatus including: a recording part recording original data and interleaved data in that a data order of the original data is changed, on the recording medium; a sample storing part storing sample values obtained by sampling regenerative signals from the original data and from the interleaved data recorded in the recording part; a pass metric calculating part calculating a branch metric and a pass metric based on each of the sample values stored in the sample value storing part; and a likelihood converting part converting each calculation result obtained by the pass metric calculating part into likelihood of the each calculation result; and an order changing-back part changing back an data order of the likelihood based on the change of the data order by the recording part, wherein the pass metric calculating part calculates the pass metric based on the likelihood which data order is changed back by the order changing-back part and decodes the data recorded on the recording medium.
According to the present invention, it is possible to provide an apparatus in which the inte
Itakura Akihiro
Taguchi Masakazu
Uchida Akiyoshi
Davidson Dan I.
Fujitsu Limited
Greer Burns & Crain Ltd.
Hudspeth David
LandOfFree
Apparatus for recording and regenerating data does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Apparatus for recording and regenerating data, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Apparatus for recording and regenerating data will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3129520