RF tag reading and writing devices are one of the two important components of RFID systems (tags and readers). RF tag reading and writing devices also have some other popular names according to the specific implementation features, such as: Reader, Interrogator, Communicator, Scanner, Reader. And Writer), programmer, reading device, portable readout device, AEI device (AutomaTIc Equipment IdenTIficaTIon Device), and the like.
Generally, RF tag reading and writing devices should be designed according to the read and write requirements of RF tags and application requirements. With the development of radio frequency identification technology, RF tag reading and writing devices have also formed some typical system implementation modes. The focus of this chapter is also to introduce the implementation principle of this reader.
From the most basic principle, RF tag reading and writing devices generally follow the basic mode as shown.
The reader/writer corresponds to the radio frequency tag reading and writing device, and the reader/writer device and the radio frequency tag must transmit the command to the radio frequency tag through the spatial channel, and the radio frequency tag receives the command of the reader/writer and makes the necessary response. This implements radio frequency identification. In addition, in the radio frequency identification application system, in general, the contactless collection of the radio frequency tag data by the reader/writer or the tag information written by the reader/writer to the radio frequency tag are all returned in the application system or from the application system. The application system, which forms the API (ApplicaTIon Program Interface) between the RF tag reading and writing device and the application system program. In general, the reader/writer is required to receive commands from the application system and respond accordingly according to the command of the application system or the agreed protocol (returning the collected tag data, etc.).
The reader itself can be divided into two parts from the perspective of circuit implementation, namely: RF module (RF channel) and baseband module.
The RF module implements two main tasks. The first one is to modulate (load) the command to be sent to the RF tag by the reader/writer to the RF signal (also known as the RF operating frequency of the reader/RF tag). Transmitted via the transmit antenna. The transmitted RF signal (which may contain command information to the tag) is spatially transmitted (illuminated) onto the RF tag, and the RF tag responds to the RF signal illuminated thereon to form a reflected echo returning to the reader antenna. signal. The second task of the RF module is to perform the necessary processing on the echo signal of the RF tag back to the reader, and demodulate (unload) the data sent back by the RF tag.
The task implemented by the baseband module also includes two items. The first item is to implement the command processing (encoding) from the reader smart unit (usually the computer unit CPU or MPU) to facilitate modulation (loading) of the code modulation on the RF signal. signal. The second task is to perform necessary processing (including decoding) on ​​the tag return data signal that has been demodulated by the radio frequency module, and send the processed result to the reader intelligent unit.
In general, the intelligent unit of the reader is also assigned to the baseband module. In principle, the intelligent unit is the control core of the reader. From the perspective of implementation, the embedded MPU is usually used, and the corresponding MPU control program is used to realize intelligent processing of the transmitted and received signals and between the final application. Interface API.
The interface between the RF module and the baseband module is modulation (loading)/demodulation (unloading). In the system implementation, usually the RF module includes a modulation/demodulation part, and also includes necessary processing for echo small signals after demodulation ( Such as zooming, shaping, etc. The transmission and reception separation of the RF module is a key issue that the RF module must handle when using a single antenna system.
As a result of advanced microprocessor and unique choDiscovery echo processing technology, guided wave radar level meter can be used in a variety of complex conditions.Because of the type of process connections and detection components, making 70X Series Guided Wave Radar Level Meter is suitable for a variety of complex conditions and applications. Such as: high temperature, high pressure and low dielectric constant media.Pulsed work, guided wave radar level instruments transmit power is very low, can be installed in a variety of metals, non-metallic container, no harm to humans and the environment.
Radar Level Meter,Guided Wave Radar Level Meter,60X SERIES Radar Level Meter
Taizhou Jiabo Instrument Technology Co., Ltd. , https://www.jbcbyq.com