Patent ID: 6543279
Filing Date: 2003-04-08
Classification: B60C

Abstract:
In combination with a pneumatic tire, a passive transponder disposed within the pneumatic tire, the transponder including:an antenna; a rectifier circuit connected to the antenna to provide electrical power from an RF signal received by the antenna to other components of the transponder; a modulator circuit, operatively connected to the antenna to form an RF signal output for the transponder by modulation of the RF signal received by the antenna; a temperature sensor for sensing temperature within the tire; a pressure sensor for sensing pressure within the tire; a timing generator for generating a first timing window during which temperature is measured and a second timing window during which pressure is measured; a temperature register for capturing first data indicative of the temperature within the tire; a pressure register for capturing second data indicative of the pressure within the tire; and the modulator circuit impressing the first data as a first portion of a data stream on a signal output by the transponder, and impressing the second data as a second portion of the data stream on the signal output by the transponder; characterized by: an oscillator outputting a signal having a first frequency which is indicative of the temperature within the tire during the first timing window, and having a second frequency which is indicative of the pressure within the tire during the second timing window; and a register/counter circuit which counts the oscillations of the oscillator signal during the first timing window to capture the first data in the first register, and which counts the oscillations of the oscillator signal during the second timing window to capture the second data in the second register.