< ? $key="0430"; ?>
The ability to ‘tune in’ to specific frequencies makes possible all wireless communications–from mobile telephony to wireless data transfer. It beams our television signals, brings music to our radios … and it makes contactless cards contactless.
With an understand of radio waves and frequencies, we move to a discussion of modulation–the process by which information can be ‘written’ onto radio waves. Specific changes, or modulations, made to a wave form the building blocks for the communication of data.
So just how does the modulating of radio waves enable data transmission? The answer is found in the concept of coding. Coding refers to a modulation pattern that is understood and shared by both a transponder and a receiver. It forms the ‘language’ that lets and RF transmitter and receiver speak.
Think of an RFID ‘collision’ as multiple cards crashing into each other within a reader’s field. Each card is sending information to the reader at the same time such that the reader cannot differentiate between cards. Anticollision schemes make it possible to process cards when collisions occurs.
If the purpose of the recent SmartTalk Teleconference hosted by the Smart Card Alliance was to generate enthusiasm and optimism for contactless technology, it certainly succeeded thanks to the latest positive results of contactless trials reported by two of the majors–MasterCard and American Express.