Modulation depth variable rfid signal generating device

Abstract

The invention discloses an RFID signal generation device with variable modulation depth, comprising: a buffer, a microcontroller, a first analog switch, an active crystal oscillator, a second analog switch, and an output bandpass filter; the microcontroller The output of the built-in digital-to-analog converter is connected to the input end of the buffer, the output of the buffer is connected to the normally closed end of the first analog switch, the normally open end of the first analog switch is connected to the 5V power supply, and a general-purpose IO port of the microcontroller is connected to To the input terminal of the first analog switch, the common output terminal of the first analog switch is connected to the normally open terminal of the second analog switch, the normally closed terminal of the second analog switch is grounded, and the input terminal of the second analog switch is connected to the active crystal oscillator , the common output terminal of the second analog switch is connected to the output bandpass filter. Its advantages are: the user can adjust the modulation depth of the transmitted signal without changing the circuit and RFID reader; it is suitable for electronic tags with different application distances and different performances.

Description

technical field [0001] The invention relates to an RFID signal generation device with variable modulation depth, which belongs to the field of electricity. Background technique [0002] Radio Frequency Identification (RFID) is a non-contact automatic identification technology that uses radio frequency The signal automatically identifies the target object and obtains relevant data. The identification work does not require manual intervention. As a wireless version of the barcode, RFID technology has the advantages of waterproof, antimagnetic, high temperature resistance, long service life, large reading distance, and data on the label. Encryption, larger storage data capacity, and free change of stored information, etc., its application will give retail, logistics and other industries to bring about revolutionary changes. [0003] The RFID system is composed of three parts: reader, electronic tag and application software. Its working principle is that the reader emits a wi...

AI Technical Summary

Problems solved by technology

For the ASK modulation method, if the modulation depth of the RF signal is small, the electronic tag will not be able to demodulate, and if the modulation depth is too large, it will cause insufficient energy. Therefore, the modulation depth should be adjusted according to different applications and different batches of labels

Many reader systems use OOK modulation or fixed-mode ASK modulation, which is difficult to adapt to the needs of different electronic tags for RF signals at different distances, and it is difficult to exert optimal performance. Other readers use complex circuit structures to achieve modulation depth Adjustable, but increases cost and reduces reliability

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