Ultrahigh-frequency RFID reader transmission circuit

A transmitting circuit and ultra-high frequency technology, applied in the field of ultra-high frequency passive radio frequency identification, can solve the problems of signal attenuation, high implementation cost, large circuit size, etc., and achieve the effect of suppressing noise and fast response.

Active Publication Date: 2018-01-12
SHENZHEN MARKTRACE
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, its mixing gain is only -8dB, and the signal attenuation caused needs to be compensated by increasing power amplification.
[0013] The circuit uses two dedicated low-pass filters and an operational amplifier, which is expensive to implement and has a large circuit size

Method used

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  • Ultrahigh-frequency RFID reader transmission circuit
  • Ultrahigh-frequency RFID reader transmission circuit
  • Ultrahigh-frequency RFID reader transmission circuit

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Embodiment Construction

[0039] In order to make the technical means realized by the present invention clear, the present invention will be further described below in conjunction with the accompanying drawings.

[0040] Such as figure 1 The circuit block diagram shown is an embodiment of the present invention, including a microcontroller MCU, a phase-locked loop frequency generator PLL, a power amplifier, an active low-pass filter, an analog switch, resistors and capacitors. The phase-locked loop frequency generator generates the local oscillator frequency signal under the control of the microcontroller. The output signal of the phase-locked loop frequency generator is directly connected to the power amplifier RF3225. The microcontroller outputs a square wave modulation signal through the DAC interface. The high level of the modulation signal is 1.0V to 1.8V, and the low level is 0V. The specific value of the high level also determines the size of the output power. The modulated signal is fed into...

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PUM

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Abstract

The invention provides an ultrahigh-frequency RFID reader transmission circuit. The ultrahigh-frequency RFID reader transmission circuit comprises a micro control unit (MCU), a phase-locked loop frequency generator (PLL), a power amplifier, an active low-pass filter, a resistor, an analogue switch and a capacitor; and the analogue switch is connected to a modulation signal line output by the active low-pass filter through the resistor, the capacitor is connected to the other end of the analogue switch, and the capacitor has a high reaction speed and a good filter performance. According to theultrahigh-frequency RFID reader transmission circuit, an analogue modulation signal is filtered by connecting the capacitor to the analogue switch when carrier waves are transmitted and a label signalis received, noise of the modulation signal can be effectively inhibited, and therefore the modulation signal cannot influence receiving of the label signal; and when the modulation signal is transmitted, passing of the transmitted signal is not influenced by switching off the capacitor through the switch.

Description

[technical field] [0001] The invention belongs to the technical field of ultra-high frequency passive radio frequency identification, in particular to a transmitting circuit of an ultra-high frequency passive radio frequency reader. [Background technique] [0002] UHF RFID has the advantages of long recognition distance, fast speed, strong multi-tag reading ability, and low tag cost. Now it has been widely used in logistics, transportation and other fields, and the demand for UHF readers is also increasing. bigger. The transmitting circuit is an important part of the UHF RFID reader. The transmitting circuit of the UHF reader must meet the following conditions: [0003] 1. The output power and frequency meet the requirements, can wake up the tag and support tag backscatter communication; [0004] 2. The signal timing meets the standard air interface requirements; [0005] 3. The emission spectrum meets the radio management requirements of various countries or regions; ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04B1/04
CPCY02D30/70
Inventor 高军刁尚华钟干李青
Owner SHENZHEN MARKTRACE
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