UHF band RFID reader application of intelligent research (1)

As the Chinese standard UHF band gradually became clear and the logistics, intelligent communications, and applications such as digital scenic spot, the UHF band RFID products in the RFID industry market share is growing.

Develop a data error correction, go to redundancy, store and forward, and time management features intelligent reader product line will be product development direction.

1 hardware system design

Reader hardware design including: RF control module (hardware and firmware firmware processor), Intel R1000 internal integration of the RF transceiver modules, power amplifier PA module, as well as external communication control and storage modules.

Where radio frequency control module with Atmel AT91SAM9263 chip company, primarily to complete firmware control and intelligent air interface protocol, RFID control logic and host command decode control, and host communication is done through the USB interface; RF transceiver module including RF multiplexing circuit, high frequency switch, Circulator and coupler circuit; external communication control and storage module mainly complete PC and control chip communications, debugging, and the control of the firmware.

Reader's transceiver with 2 independent channels, respectively by the transmitting antenna and receiving antenna and associated filtering circuit.

Each group of antenna system through high-frequency switching external antenna 4 groups, 4 sets of sending and receiving antenna can AT91SAM9263 to choose. Send and receive separate ways can effectively improve the overall performance of the RFID system, receiving and sending of interference between systems, in the actual design can also be changed through the external circuit design using a single antenna.

This design with 4 groups, antenna, in a special occasions can effectively expand the electronic label TAG reception space and scope.

Hardware structure diagram shown in Figure 1.

UHF band RFID system can be divided into radio frequency circuit and the baseband circuit in two parts. RF Circuit part is the tag and reader between high-frequency interface for complete high-frequency signal modulation/demodulation, transmit/receive. Baseband circuit parts mainly for RF system control, high-frequency signal decoding capabilities, while complete UHF RFID reader and an external device or Host communication interface between hosts. Baseband circuit part is the core of the whole reader platform control part, support the entire RFID reader system work to complete RF module for control and communication.

In the design of the reader, in order to be able to the entire system for better detection, real-time information on the operation of the system, specifically designed to increase a system testing section.

R1000 chip integrates A/D module, but its accuracy is conversion rate does not meet the requirements of the design, so in design incorporates external A/D converters to complete the conversion of the heartbeat, and then converts the signal to ARM microcontroller complete system status monitoring.

In order to enable the equipment to networking and remote reading and transmitting data, design using Ethernet design, so that the reader can be at a greater distance in space, on labels, reading, writing, and complete the massive network.

Host the host as the core of the entire system of master is responsible for the transmission control, ARM microcontroller networking data transfer operations are managed from Host to host.

USB interface is not only used for data transmission, but also to complete PC and dialogue among readers. By design in the PC-control software, you can send to the reader in real-time control signals (such as system reset, work to, labels, reading, writing, data transmission, power control, etc.); at the same time, the reader will Host host feedback appropriate status signal (such as antenna switch status and power signals, etc.), thereby combining top software to control the work process of the system. Finally, through JTAG interface to complete the work of the State of the reader's real-time monitoring and debugging, to accurately verify the work throughout the reader, label reading, writing and data processing of the correctness and reliability of the design requirements are met.

In the design, R1000 RF chip not only integrates a large number of radio frequency components, but also in internal integrated temperature measurement and detection capabilities, in power within various key core RF Circuit there is an external detection output pin, so that the Board of health and power detection enables real-time detection and control, to ensure the good running of the system.

2 external PA circuit design

2.1 overall design

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