And how is it used with ultrahigh-frequency RFID systems?
—Name withheld
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To answer your question, I reached out to the experts at Magellan Technology, an Australian firm that has been developing innovative RFID products for 15 years. Here is the response from one of the company’s engineers:
“PIE is used in UHF RFID systems where the disadvantages of its relatively low data rate and poor spectral occupancy are balanced against the advantages of continuously supplying power to the tag and the simplicity of detection circuits required on the tag.
“PIE encoding is based on a given minimum pulse duration or interval called a Tari, which is named after the ISO 18000-6 Type A Reference Interval. The Tari length is the minimum pulse width for the data 0 symbol. The data 1 symbol, as well as special symbols like Start Of Frame (SOF) and End Of Frame (EOF), are composed of differing numbers of Tari periods.
“The jitter performance is set by the ability to distinguish between the respective symbol Tari lengths. In principle, this would be half the relative Tari length between symbols. For example, with a data 0 symbol length of 1 Tari and a data 1 symbol length of 1.5 Tari, the maximum allowable jitter would be +0.25 Tari for the data 0 symbol and -0.25 Tari for the data 1 symbol. These represent best-case values, and are expected to reduce depending upon the detection and decoding circuits used on the tag.”
—Mark Roberti, Founder and Editor, RFID Journal