| 摘要 |
A power-on reset for a transponder ( 102, 200, 400 ) capable of measuring one or more parameters (e.g., temperature, pressure) in an object (e.g., a tire, 104 ) and transmitting a data stream (FIGS. 3 C, 4 B) to an external reader/interrogator ( 106 ). The transponder typically operates in a passive mode, deriving its power (Vxx, Vcc, Vdd) from an RF interrogation signal received by an antenna system ( 210, 410 ), but can also operate in a battery-powered active mode. The transponder includes memory ( 238, 438 ) for storing measurements, calibration data, programmable trim settings ( 436 b), transponder ID and the like. A power-on reset circuit ( 600 ) prevents operation of the transponder until it is stable, and starts transmission of the data stream at a first bit of the data stream, in order to ensure a first-pass transmission of a complete data stream. It also prevents modulation of the antenna system for data stream transmission if the power levels are too low for stable transponder operation during modulation.
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