MadSci Network: Engineering |
Passive RF can come in a number of forms. One of the early methods was to excite a module with RF energy and measure the frequencies at which the module resonated. Most recently modules derive their energy from RF energy aimed at them and they return a digital signal that is either active or based on switching the load the module presents to the transmitter. I do not know what method is used with "Easy Pass" tolls. Gus Calabrese wft@frii.com