They are also used to measure distance by calculating the elapsed time between the sending of the interrogator signal and the receipt of the transponder's signal. For example, sonar devices are used to mark underwater positions, calculate depth, and trace positions.
It may sound as if this is a technology that the average consumer never uses, but even if that was once the case, it no longer is. The modern commuter probably has at least one transmitter in his car, probably mounted on the windshield or dashboard. These are for roads that use electronic tolling systems that compute the amount of tolls to be paid and complete the transaction without requiring the driver to so much as lower his window. Some newer cars are also equipped with ones that operators can use to locate the vehicle in the event of an emergency. Cellular phones use a similar, albeit smaller, chip to send the phone's location if it used to call an emergency number.
Even casual television viewing often involves the use of these devices. A network can uplink its ground-based satellites to communications satellites orbiting the Earth, send multiple channels of digitally compressed video and audio to a single transponder aboard it, and local stations can then pick up the program and re-broadcast it locally by aiming the appropriate ground-based dish.
They are also used to measure distance by calculating the elapsed time between the sending of the interrogator signal and the receipt of the transponder's signal. For example, sonardevices are used to mark underwater positions, calculate depth, and trace positions.
It may sound as if this is a technology that the average consumer never uses, but even if that was once the case, it no longer is. The modern commuter probably has at least one transmitter in his car, probably mounted on the windshield or dashboard. These are for roads that use electronic tolling systems that compute the amount of tolls to be paid and complete the transaction without requiring the driver to so much as lower his window. Some newer cars are also equipped with ones that operators can use to locate the vehicle in the event of an emergency. Cellular phones use a similar, albeit smaller, chip to send the phone's location if it used to call an emergency number.
Even casual television viewing often involves the use of these devices. A network can uplink its ground-based satellites to communications satellites orbiting the Earth, send multiple channels of digitally compressed video and audio to a single transponder aboard it, and local stations can then pick up the program and re-broadcast it locally by aiming the appropriate ground-based dish.
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