Data demodulation
AssigneeSankyo Seiki Mfg. Co., Ltd.
InventorsHiroshi Nakamura, Mitsuo Yokozawa
Life of this patent
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Abstract
The accuracy of demodulation of data from a magnetic stripe is enhanced by comparing time intervals between successive peaks of each character of the signal read from the stripe against a set of predetermined reference successive peak time intervals for the data characters.
Claims11
A data demodulating method in which binary data are defined by two-frequency encoded signal composed of a combination of high and low frequency signals, binary data for one character are defined by a predetermined number of said binary data and a parity bit, peak points are detected in a reproduced signal waveform obtained by reproducing a recorded data signal to demodulate said binary data, comprising the steps of:
- preparing in advance a reference line pattern for each character, composed of peak interval values of bits that constitute one character;
- measuring time intervals between successive peaks of said reproduced signal;
- and
- comparing each of said peak interval values that constitute one character with said reference line patterns by a pattern matching to determine the character corresponding to said reference line pattern having the highest degree of similarity as the character.
A data demodulating method in which binary data are defined by a two-frequency encoded signal composed of a combination of high and low frequencies, data for one character are produced with a predetermined number of said binary data and a parity bit, and peak points of a reproduced signal waveform obtained by reproducing a recorded data are detected to read said binary data, comprising steps of:
- measuring peak time intervals between successive peaks of said reproduced signal waveform;
- comparing each of said peak interval values that constitute one character with a reference value to convert said signal waveform to a bit line composed of said binary data;
- for demodulating data of one character,
- selecting a plurality of segment length candidates for demodulation, on the basis of a reference segment length equal to a data interval for one character and peak positions;
- and
- performing pattern matching on a plurality of said segment length candidates with reference waveform data to determine the character according to the similarity.
A data demodulating apparatus in which binary data are defined by a two-frequency encoded signal composed of a combination of high and low frequencies, data for one character are produced with a predetermined number of said binary data, and peak points of a reproduced signal waveform obtained by reproducing a recorded data are detected to read said binary data, comprising:
- a means of measuring peak time intervals between successive peaks of said reproduced signal waveform;
- a means of demodulating data for one character by comparing each of said peak interval values that constitute one character with a reference value to convert said signal waveform to a bit line composed of said binary data;
- and
- for demodulating data of one character,
- a means of determining the character, wherein a plurality of segment length candidates for demodulation are selected on the basis of a reference segment length equal to a data interval for one character and peak positions;
- pattern matching is performed on a plurality of said segment length candidates with reference waveform data to determine the character according to the similarity.
Dependencies are inferred from the claim text.