Magcard decoding method

Abstract

The invention discloses a magcard decoding method comprising the following steps: S1. converting a sampled analog waveform to an initial digital waveform by adopting an extremum method and correcting the pulse width of the initial digital waveform by adopting a curve fitting method; S2. taking the pulse width of purported leading zero bits of a magcard as an initial reference pulse width, distinguishing a first pulse width of the corrected digital waveform by utilizing the initial reference pulse width, obtaining a second reference pulse width on the basis of the initial reference pulse width according to an EWMA (exponentially weighted moving average) formula, distinguishing a second pulse width of the corrected digital waveform by taking the second reference pulse width as a reference, and repeatedly executing the process of adjusting the reference pulse width and distinguishing the pulse width of the corrected digital waveform according to the corresponding reference pulse width until all of the pulse widths of the corrected digital waveform are distinguished; S3. converting the corrected digital waveform to a corresponding 0 / 1 bit sequence according to the distinguished result of the step S2; and S4. decoding the bit sequence according to magcard standards.

Description

technical field [0001] The invention relates to the decoding field, in particular to a magnetic card decoding method. Background technique [0002] The traditional magnetic card soft decoding scheme is: on the hardware, the magnetic head is connected to the amplification and shaping circuit to obtain the digital signal, and then input to the processor; on the software, by recording the duration of each level of the input digital signal (ie Pulse width), realize soft decoding according to the relationship of pulse width. [0003] Another solution is: use a special magnetic card decoding chip to directly identify and store the analog signal generated by swiping the card into a 0 / 1 sequence that the CPU can process, and then start the software to read the magnetic card decoding chip according to the successful signal fed back by the magnetic card decoding chip Internally stored 0 / 1 sequence data. [0004] However, the above technology has the following disadvantages: [0005...

AI Technical Summary

Problems solved by technology

[0005] Disadvantage 1: The hardware cost of the amplification and shaping circuit or the dedicated magnetic card decoding chip is relatively high

[0006] Disadvantage 2: The flexibility is low. The quality of the digital waveform output by the hardware depends on the design of the amplification and shaping circuit. When the hardware design is not good enough, the output waveform of some cards is not normal. Much smaller using the original waveform

[0007] Disadvantage 3: The magnetic card reading device using a dedicated magnetic card decoding chip has certain restrictions on the standard compatibility of the magnetic card. If a non-standard magnetic card cannot be recognized by the decoding chip, it cannot be solved by simply upgrading the software.

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