Methods and apparatus for increased magnetic coding density by precise placement of magnetic transitions

A reading device for reading data from a magnetic medium, comprising:

• read head for reading magnetic transitions on a magnetic track to produce a read signal;
• an amplifier for amplifying the read signal to produce an amplified read signal;
• an analog to digital converter for producing a digital data stream representing the amplified read signal;
• and
• a processor operative to interpret the digital data stream to identify conventional bits encoded as sequences of magnetic transitions and also to identify additional bits encoded as deviations from nominal positions of transitions between conventional bits, the data stream representing a series of conventional bits and additional bits, the conventional bits and the additional bits being encoded as a string of data on a magnetic medium, the string of data comprising the additional bits merged with the conventional bits, the string of data occupying the same space on the magnetic medium that is occupied by the conventional bits alone, the string of data providing increased data density beyond the data density that would be provided by the conventional bits alone.

A reading and writing device for reading data from and writing data to a magnetic medium, comprising:

• a read head for detecting magnetic transitions appearing on a magnetic medium to produce a read signal representing the magnetic transitions;
• a write head for writing magnetic transitions to the magnetic medium based on an amplified write signal representing data to be written to the magnetic medium;
• a read amplifier for amplifying the read signal to produce an amplified read signal;
• a write amplifier for amplifying the write signal to produce the amplified write signal;
• an analog to digital converter for creating a digital data stream based on the amplified read signal;
• a digital to analog converter for creating a write signal to be furnished to the write amplifier for amplification to produce the amplified write signal, the write signal being based on an out put digital data stream representing data to be written on the magnetic medium;
• and
• a processor for receiving the digital data stream to identify bits represented by the digital data stream, the processor being operative to identify conventional bits encoded as sequences of magnetic transitions on the magnetic medium and also to identify additional bits encoded as deviations from a nominal position of transitions between conventional bits, the processor also being operative to produce the output digital data stream, the output digital data stream directing placement of sequences of magnetic transitions to encode conventional bits on the magnetic medium, the output digital data stream also directing placement of deviations from a nominal position of transitions between conventional bits in order to encode additional bits to be placed on the magnetic medium as a string of data, the string of data representing a series of conventional bits and additional bits, the conventional bits and the additional bits being encoded as a string of data on a magnetic medium, the string of data comprising the additional bits merged with the conventional bits, the string of data occupying the same space on the magnetic medium that is occupied by the conventional bits alone, the string of data providing increased data density beyond the data density that would be provided by the conventional bits alone.

A method of magnetic card generation, comprising the steps of:

• assembling identifying information to be written on the card;
• reading magnetic information from the card to identify a magnetic fingerprint;
• creating a numerical fingerprint comprising a numerical representation of the magnetic fingerprint;
• merging the identifying data and the numerical fingerprint to form a data stream;
• and
• writing the data stream to the card, the identifying data being represented as conventional bits and the numerical fingerprint being represented as additional bits, each additional bit being represented as a deviation from a nominal placement of a magnetic transition included in a conventional bit, the data stream representing a series of conventional bits and additional bits, the conventional bits and the additional bits being encoded as a string of data on the magnetic card, the string of data comprising the additional bits merged with the conventional bits, the string of data occupying the same space on the magnetic card that is occupied by the conventional bits alone, the string of data providing increased data density beyond the data density that would be provided by the conventional bits alone.

A method of authenticating a magnetic card, comprising the steps of.

• reading magnetic information from the card;
• interpreting and storing identifying information encoded as conventional bits;
• reading magnetic information from the card to create a magnetic fingerprint;
• creating a numerical fingerprint comprising a numerical representation of the magnetic fingerprint;
• storing the numerical fingerprint;
• examining magnetic transitions in the magnetic information to determine if the magnetic transitions deviate from a nominal position by more than a predetermined amount;
• if the magnetic deviations deviate from the nominal position by more than a predetermined amount, interpreting the magnetic transitions to identify additional information stored on tie card as additional bits encoded as deviations from a nominal position of magnetic transitions, each additional bit being represented as a deviation from a nominal position of a magnetic transition included in a conventional bit, the additional bits being merged with the conventional bits in a string of data, the string of data occupying the same space on the magnetic card that is occupied by the conventional bits alone, the string of data providing increased data density beyond the data density that would be provided by the conventional bits alone;
• decoding the additional information to create a decoded numerical fingerprint;
• comparing the decoded numerical fingerprint to the stored numerical fingerprint;
• if the comparison fails, rejecting the card;
• and
• if the comparison passes, retrieving and processing the identifying information.