A Carrier Cancellation System

Abstract

The invention provides a carrier cancellation system, comprising a transmitter module, a first directional coupler, a circulator, a coarse tuning module, a first power detection module, a fine tuningmodule, a first combiner, a second directional coupler, a second power detection module, a control module and a receiving module, wherein each output ends of the first power detection module and the second power detection module are connected with the input end of the control module for transmitting the detected reference power and the cancelled signal power to the control module, a third port ofthe circulator and the output end of the fine tuning module are respectively connected with a first input end and a second input end of the first combiner, and the first combiner cancels the signals output by the fine tuning module and the signals output by the third port of the circulator. The invention is simple in structure and short in consuming time, and improves the sensitivity of an ultrahigh radio frequency identification reader without influencing the inventory work efficiency.

Description

technical field [0001] The invention relates to a cancellation system, in particular to a carrier cancellation system for an ultra-high frequency radio frequency identification reader. Background technique [0002] In the same-frequency / simultaneous communication mechanism of sending and receiving, the radio frequency signal emitted by the transmitting module will have an adverse effect on the reception. On the one hand, due to the limited isolation of the device itself, the RF signal will leak into the receiving path in the circuit board, which is called a leakage signal; on the other hand, the transmitted RF signal will be reflected back to the receiving path, which is called a reflected interference signal. Both the leaked signal and the reflected signal will interfere with the reception, restricting the improvement of the reception sensitivity. Therefore, related technologies need to be used to cancel the interference signal. [0003] The specific process of carrier ca...

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Problems solved by technology

[0004] In order to overcome the disadvantages of unstable cancellation process, low efficiency and low precision in the above-mentioned prior art, the present invention provides a carrier cancellation system, by setting a transmitting module, a first directional coupler, a circulator, and a coarse , The first power detection module, the fine adjustment module, the first combiner, the second directional coupler, the second power detection module, the control module and the receiving module realize carrier cancellation with good cancellation effect and high efficiency

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