ASK (Amplitude Shift Keying) demodulation circuit with wide demodulation range used for passive RFID (Radio Frequency Identification) label chips

A RFID tag and ASK demodulation technology, which is applied to record carriers used in machines, instruments, computer components, etc., can solve the problems of high circuit demodulation accuracy and demodulation errors, and achieve the goal of improving accuracy and strong anti-noise ability Effect

Inactive Publication Date: 2012-12-05
GUANGZHOU SYSUR MICROELECTRONICS
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  • Abstract
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Problems solved by technology

The circuit can demodulate the ASK signal whose modulation depth is between 7% and 100%, which solves the demodul...

Method used

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  • ASK (Amplitude Shift Keying) demodulation circuit with wide demodulation range used for passive RFID (Radio Frequency Identification) label chips
  • ASK (Amplitude Shift Keying) demodulation circuit with wide demodulation range used for passive RFID (Radio Frequency Identification) label chips
  • ASK (Amplitude Shift Keying) demodulation circuit with wide demodulation range used for passive RFID (Radio Frequency Identification) label chips

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Embodiment Construction

[0021] The specific embodiment of the present invention will be further described below in conjunction with accompanying drawing:

[0022] Such as figure 1 As shown, the present invention includes an envelope signal extracting circuit for extracting the envelope signal of the ASK demodulated signal received by the RFID tag chip, a comparison circuit for comparing two-way envelope signals, and a comparison circuit output for judging, and draws And output the decision circuit of the demodulated data. The antenna signals anten1 and anten2 are input to the envelope signal extraction circuit to obtain the fast-varying envelope signal vfast and the slow-varying envelope signal vslow; these two envelope signals are input to the comparison circuit to obtain two comparison output results vs and vr; the output of the comparison circuit is connected to the input of the judgment circuit for judgment, and finally the data signal data is obtained; the control signal enable from the digital...

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Abstract

The invention discloses an ASK (Amplitude Shift Keying) demodulation circuit with a wide demodulation range used for passive RFID (Radio Frequency Identification) label chips. The ASK demodulation circuit comprises an envelope signal extraction circuit, a comparison circuit and a decision circuit, wherein the envelope signal extraction circuit is used for extracting two antenna voltage signals received by the RFID label chip to obtain two antenna envelope signals including a fast varying envelope signal and a slowly varying envelope signal; the comparison circuit is used for comparing the sampling voltages of the two antenna envelope signals outputted by the envelope signal extraction circuit to obtain envelope changing edges of the antenna envelope signals; the decision circuit is used for deciding the output voltage of the comparison circuit to obtain and output demodulation data. According to the ASK demodulation disclosed by the invention, the influence of overshoot of the antenna envelope signals on the demodulation circuit is completely eradicated, the precision of the demodulation circuit is improved, an ASK demodulation signal of which the depth is 7%-100% can be demodulated, and the demodulation circuit has stronger anti-noise performance, and can be widely applied in the passive RFID label chips.

Description

technical field [0001] The invention relates to a demodulation circuit of a non-contact RFID tag chip, in particular to an ASK demodulation circuit for a wide demodulation range of a passive RFID tag chip. Background technique [0002] The non-contact RFID tag protocol stipulates that the reader sends the data through electromagnetic waves after ASK modulation, and the RFID tag chip needs to demodulate the modulated data after entering the reader's launch field to complete the receiving of the data sent by the reader and Order. According to the agreement, the ASK signal sent by the reader has two modulation depths: 10% and 100%, but in fact the modulation depth of the ASK signal sent by the reader can reach 7%-100%. Therefore, in order to accurately demodulate the data sent by the reader, an ASK demodulation circuit with a wide demodulation range is very important. [0003] Generally speaking, there are mainly two methods for demodulating the ASK signal, which are the enve...

Claims

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Application Information

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IPC IPC(8): G06K19/077
Inventor 王桥波张俊胡建国段志奎丁颜玉王德明路崇丁一尹秀文
Owner GUANGZHOU SYSUR MICROELECTRONICS
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