Clock circuit and data decoding circuit of non-contact type IC (Integrated Circuit) card

Abstract

The invention discloses a clock circuit and a data decoding circuit of a non-contact type IC (Integrated Circuit) card. The clock circuit comprises a receiver, a first frequency divider, a second frequency divider and a clock generator, wherein the receiver is used for receiving radio-frequency (RF) signals with a pause period; the first frequency divider is used for carrying out frequency division on the received RF signals; the second frequency divider is used for carrying out secondary frequency division on frequency division clock signals generated by the first frequency divider; and the clock generator is used for generating synchronous clock signals according to the clock signals generated by the second frequency divider and the RF signals. The data decoding circuit comprises a data decoder and a data frame indicator, wherein the data decoder is used for carrying out data decoding according to the outputs of the first frequency divider and the second frequency divider and the RF signals to obtain data decoding signals and widening pause signals; and the data frame indicator is used for generating data frame indicator signals of a received data frame according to the output of the first frequency divider and the widening pause signals. The invention can be used for generating the synchronous clock signals and decoding the received data signals so as to be compatible with an ISO (International Standardization Organization) / IEC (International Electrotechnical Commission)14443A type protocol interface, can realize various communication rates and has strong capacity of resisting disturbance.

Description

technical field [0001] The invention relates to the field of non-contact IC (integrated circuit) cards, in particular to a clock circuit of a non-contact IC card conforming to the ISO / IEC14443A protocol. The invention also relates to the data decoding circuit of the non-contact IC card. Background technique [0002] Since the birth of credit cards in the 1920s, various types of electronic information cards have been produced, such as cash cards, credit cards, identity cards, and department store cards. Recently, IC cards integrated with silicon chips have become popular due to their convenience, stability, security, and numerous applications. [0003] Compared with traditional electronic information cards including magnetic media types, IC cards have many advantages of high stability, write-protected data, and high security, and are widely accepted as the next generation of multimedia information media. The synchronous clock signal and data decoding circuit of the existing...

AI Technical Summary

Problems solved by technology

The disadvantage of this method is that the circuit is complex, the width of the pause period solved is limited, and there are multiple narrow pause periods in a complex environment (environment with severe interference) or a narrow pause period within one ETU (Essential Time Unit) cycle easy to lose the ability to decode

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