Electronic label read-write

　　An electronic label is attached to on the antenna by the micro chip constitution. In the different application situation, has the different type the label, the initiative RFID label has a battery, this battery uses for the micro chip electric circuit revolution to provide the electric quantity, and (is same to the electronic label read-write transmission signal with honeycomb telephone message signal to base depot principle). The passive label does not have the battery, on the contrary, it from read-write obtains the electrical energy. The read-write transmission electromagnetic wave, has formed the electric current in the label antenna. The semi-active label provides the electrical energy with a battery for the micro chip revolution, when the transmission signal and accepts the signal is actually from read-write place obtains the energy. Driving and the semi-active label when traces the high value commodity extremely useful, because they need the long-distance range the scanning, for instance on track train, but this kind of label must consume 1 US dollar or are more, this causes him not to suit applies in on the low cost commodity.

　　Electronic label read-write use many ways and the label interactive information, the short distance reading in the passive label the information most commonly used method is the inductance type coupling. So long as draws close to, read-write coils around the antenna and the label coil around between the antenna has formed a magnetic field. The label is uses the electromagnetic wave which this magnetic field the energy transmission returns to give read-write. These return the electromagnetic wave is transformed into the data message, is the label electronic products code. An electronic label read-write cost probably is 1,000 US dollars are even more.

　　A question read-write meets which using the electronic label is, read-write sends out the signal from to be possible the signal which overlaps read-write with another cover scope sends out to disturb mutually. This kind of phenomenon is called the read-write conflict, usually uses one kind is called the time-sharing multichannel visit (TDMA) the mechanism to avoid conflicting. In brief, is read-write was instructed reading the information in the different time interval, but is not all attempts in the identical time reading the information, this had guaranteed they cannot disturb mutually. But this meant will read-write be in two read-write to think highly of folds the region any RFID label all reading two times of information.

　　Another electronic label read-write meets the question is needs reading many chips in the identical scope the information, when read-write surpasses a chip in the identical time to return to the signal, such label conflict has occurred, it read-write enables clearly to judge the information.

　　The electronic label read-write reading the information the distance to be decided the frequency which and read-write and the label uses for in the read-write energy to exchange. Usually says, the high-frequency label has in a big way reading the distance, but they need the read-write output the electromagnetic wave energy to be bigger. A typical low frequency label must reading in a foot, but a UHF label may in reading 10 to 20 feet distances in. In certain application situations, reading the distance is the key question which needs to consider, for example when under train compartment track distinguishes them to need long reading the distance. But long reading is away from not necessarily is the merit, if you have two read-write in a soccer field that big warehouse, perhaps you knew which has to store goods, but read-write cannot help you to determine some product the concrete position. Regarding supplies the chain to say, best some network many read-write in warehouse, they can accurately verify a label the accurate location.