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System and method for suppressing carrier leakage

A technology for suppressing carrier waves and radio frequency carriers, applied in transmission systems, electrical components, etc., can solve the problems of increasing reverse signal insertion loss, unsatisfactory isolation effect, and low offsetting efficiency, achieving increased insertion loss, simple structure, and offsetting. Efficient effect

Active Publication Date: 2014-03-12
ZTE INTELLIGENT IOT TECH
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] In the reader, because the antenna impedance is affected by the environment and production process, it is impossible to completely match, the cable length between the antenna and the reader changes, and the device parameters inside the reader will change due to environmental temperature changes and different production batches. , the directional coupler can only provide about 20 to 30dB of isolation under the combined influence, and the isolation effect is not ideal
[0005] Further, some readers use the method of directional coupler and signal combination to generate a signal that cancels the original leakage signal, but the signal combination is performed through the combiner, the structure is complicated, the cancellation efficiency is low, and the combiner will Increase reverse signal insertion loss

Method used

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  • System and method for suppressing carrier leakage
  • System and method for suppressing carrier leakage

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Embodiment Construction

[0035] The technical solutions of the present invention will be further elaborated below in conjunction with the accompanying drawings and specific embodiments.

[0036] figure 1 It is a schematic structural diagram of a system for suppressing carrier leakage of the present invention, such as figure 1 As shown, the system includes: a directional coupler 11, a quadrature demodulator 12 and a reflected signal module 13, wherein,

[0037] The directional coupler 11 is used to output the leaked RF carrier signal from the isolation port to the quadrature demodulator 12;

[0038] Specifically, the power amplifier module 14 in the UHF passive RFID system outputs the forward RF carrier signal through the input port of the directional coupler 11 , and then outputs it to the antenna 15 from the output port. Under the joint action of the standing wave of the antenna 15 and the isolation of the directional coupler 11 , a part of the radio frequency carrier signal leaks to the isolation ...

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PUM

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Abstract

A system for suppressing carrier leakage is disclosed, said system includes: a directional coupler (11), a quadrature demodulator (12) and a reflection signal module (13), wherein said directional coupler is used for outputting a leaking radio frequency carrier signal from an insulation port (18) to the quadrature demodulator; said quadrature demodulator is used for demodulating the leaking radio frequency carrier signal to obtain an inphase signal and a quadrature signal, sending them to the reflection signal module, suppressing said leaking radio frequency carrier signal via a reflection signal reflected by said reflection signal module; said reflection signal module is used for obtaining a control signal for the reflection signal after filtering, phase rotation and gain control, inphase and outphase integrations of the inphase signal and the quadrature signal, controlling the reflection signal via the control signal, sending the reflection signal to the quadrature demodulator. A method for suppressing carrier leakage is also disclosed. The forward radio frequency carrier signal leakage can be suppressed simply and effectively by means of said system and method.

Description

technical field [0001] The invention relates to the field of carrier control in an ultra-high frequency passive radio frequency identification system, in particular to a system and method for suppressing carrier leakage. Background technique [0002] In the UHF passive RFID system, when the tag communicates with the reader, the reader needs to always send carrier waves to provide power for the tag, and the tag sends information to the reader by modulating backscatter. Therefore, when the reader receives the signal of the tag, the RF carrier sent forward by the reader will leak to the reverse receiving part of the reader. The strength of the backscattered signal from the tag is very small compared with the strength of the carrier signal sent forward. In the actual system, the strength difference between the reverse signal and the forward signal will reach more than 90dB. Therefore, UHF readers usually use directional couplers to isolate forward and reverse signals. [0003]...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H04B1/52
CPCH04B1/525
Inventor 曾祥希赵波曹诚
Owner ZTE INTELLIGENT IOT TECH
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