A receiving link structure and working method of a surface acoustic wave reader based on amplitude coding

Abstract

The invention discloses a surface acoustic wave reader receiving link structure based on amplitude codes and a working method thereof and belongs to the field of radio-frequency identification. Superheterodyne or heterodyne structures of reader receiving links which adopts the traditional radio-frequency identification technique are abandoned. A radio-frequency power detector is directly used for converting echo power intensity signals of surface acoustic wave tags into voltage signals for post-processing. Since the surface acoustic wave tags based on amplitude codes are adopted, as long as the voltage signals are amplified to TTL (Transistor-Transistor Logic) or CMOS (Complementary Metal Oxide Semiconductor) level, if the pin rate and the processing speed of a post-processor are enough high, a complex and expensive high-speed ADC (Analog-to-Digital Converter) circuit can be omitted, the receiving link structure is simplified while the cost can be reduced. The structure disclosed by the invention comprises a transmitter-receiver isolation module, a low-noise radio-frequency amplifier module, a band-pass filter module, a logarithmic detector module and a comparator module. The receiving link structure disclosed by the invention has the advantages that the distance of the tag can be adaptively adjusted and the ISM (Industrial, Scientific and Medical) frequency bands of 433MHz, 915MHz and the like can be covered only by changing the pass-band range of the band-pass filter only.

Description

technical field [0001] The invention relates to a receiving link structure and working method of a surface acoustic wave reader based on amplitude coding, and belongs to the field of radio frequency identification. Background technique [0002] The surface acoustic wave radio frequency identification system mainly includes two parts: the surface acoustic wave tag and the reader. The working principle of the surface acoustic wave radio frequency identification system is as follows: figure 1 shown. figure 1 The working principle of the surface acoustic wave radio frequency identification system shown is as follows: the radio frequency query pulse 2 transmitted by the reader 1 is received by the tag antenna 3 and enters the interdigital transducer 4, and the electrical signal is converted into a surface acoustic wave signal through the inverse piezoelectric effect. When the surface acoustic wave travels along the substrate 5, it encounters the reflective grid 6 to generate re...

AI Technical Summary

Problems solved by technology

Whether it is a superheterodyne or a heterodyne structure, a high-speed ADC circuit is required to collect data and then process the data to realize tag decoding, which makes the receiving link not only complex in structure, but also high in cost

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