| 摘要 |
A transducer and interrogator device is disclosed in which the interrogator provides power and information to the transducer via a magnetic field. The transducer is a passive actuator device that includes an inductive pickup coil that, when subjected to the interrogator's magnetic field, powers the passive actuator and an external electrical device. The magnetic field produced by the interrogator can be modulated in such a manner as to provide identification, commands, or other information to the passive actuator without substantially reducing the power transferred to the passive actuator. Modulation can be by amplitude, phase, frequency, pulse width, or pulse position. An antiphase magnetic field can also be generated to cancel far field radiation. The passive actuator can include a logic circuit to demodulate any received data from the interrogator via the magnetic field, which data can be used to control the operation of the external device. The passive actuator can also include a circuit for transmitting information back to the interrogator using the power extracted from the interrogator's magnetic field. Transmission can be either by a modulated electromagnetic signal generated by an oscillator internal to the passive actuator or by coupled impedance signalling using the passive actuator's pickup coil.
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