US 6,674,592 B2 · Demodulation method and demodulator

Abstract

This invention provides a demodulation method and a demodulator for demodulating by converting analog signal obtained by reading information stored in a recording medium to digital signal so as to generate data representing that information. Consequently, correct data is obtained from signal having low S/N ratio. Over-sampling is carried out by an A/D converter 103A and a digital signal synchronous with a proper clock is reproduced by interpolation computation, maximum likelihood is detected and RLL decoded. Then, error is corrected by an error correction code.

Claims10

Dependent claims

A demodulation method for demodulation by converting analog signal carrying a first clock of a predetermined first frequency obtained by reading information recorded in a recording medium to digital signal so as to generate data representing said information, wherein

the analog signal is converted to a first digital signal by over-sampling synchronous with a second clock of a second frequency higher than the frequency of the first clock, the first digital signal is stored in a buffer, and a phase error of the first clock with respect to the second clock is obtained based on the first digital signal stored in the buffer.

A demodulator for demodulation by converting analog signal carrying a first clock of a predetermined first frequency obtained by reading information recorded in a recording medium to digital signal so as to generate data representing said information, said demodulator comprising:

an A/D converter for converting the analog signal to a first digital signal by over-sampling synchronous with a second clock of a second frequency higher than the frequency of the first clock;
a buffer for storing the first digital signal;
and
an operating portion for obtaining a phase error of the first clock with respect to the second clock based on the first digital signal stored in the buffer.

1 more element

Dependencies are inferred from the claim text.

Facts

Application

09/747,073Filed 21 Dec 2000

Priority

JP 2000-21233413 Jul 2000

Published

US 2002/0017950 A114 Feb 2002

Granted

6 Jan 2004

Term ends

Not estimatedThe source records don’t support an estimate.

Classification4 codes

G11B 20/10009
Digital recording or reproducing: improvement or modification of read or write signals
G11B 5/012
Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor: recording on, or…
G11B 5/09
Recording, reproducing, or erasing methods; Read, write or erase circuits therefor: digital recording
G11B
Information storage based on relative movement between record carrier and transducer

Abstract

Claims10

Dependent claims

the analog signal is converted to a first digital signal by over-sampling synchronous with a second clock of a second frequency higher than the frequency of the first clock, the first digital signal is stored in a buffer, and a phase error of the first clock with respect to the second clock is obtained based on the first digital signal stored in the buffer.

an A/D converter for converting the analog signal to a first digital signal by over-sampling synchronous with a second clock of a second frequency higher than the frequency of the first clock;
a buffer for storing the first digital signal;
and
an operating portion for obtaining a phase error of the first clock with respect to the second clock based on the first digital signal stored in the buffer.

1 more element

Dependencies are inferred from the claim text.

Demodulation method and demodulator

Life of this patent

Abstract

Claims10

Demodulation method and demodulator

Life of this patent

Abstract

Claims10