Methods for using a surface acoustic wave resonator for automobile security
AssigneeAnalog Devices, Inc.
InventorsHarvey Weinberg, Tze Lei Poo, Tao Yu, Eugene Oh Hwang
Life of this patent
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Abstract
Remote keyless entry (RKE) systems and devices are described. The RKE devices include one or more passive radios that respond to an interrogation signal from an interrogating device such as a vehicle. The passive radio sends a responsive signal that can include a decaying portion representing a ringdown signal. The passive radio includes a SAW resonator in some situations.
Claims20
A remote keyless entry apparatus comprising:
- a housing;
- an active radio disposed within the housing and comprising powered circuitry configured to receive signals from and send signals to a vehicle;
- and
- a passive radio disposed within the housing and comprising passive circuitry, the passive radio configured to resonate and transmit a resonating ringdown signal to the vehicle in response to receiving an interrogation pulse of a specific frequency from the vehicle, the resonating ringdown signal having a predetermined decaying envelope with a characteristic expected by the vehicle.
A method of operating a remote keyless entry apparatus having a housing, an active radio disposed within the housing, and a passive radio disposed within the housing, the method comprising:
- receiving, with the passive radio, an interrogation pulse of a specific frequency from a vehicle;
- and
- in response to receiving the interrogation pulse, resonating and transmitting to the vehicle, using the passive radio, a resonating ringdown signal having a predetermined decaying envelope with a characteristic expected by the vehicle.
A method of operating a vehicle transceiver, comprising:
- transmitting, with transmitter circuitry of the vehicle transceiver, an interrogation signal of a specific frequency to a remote keyless entry device;
- receiving, after transmitting the interrogation signal and using receiver circuitry of the vehicle transceiver, a ringdown response signal from a passive radio of the remote keyless entry device in response to the remote keyless entry device receiving the interrogation signal, the ringdown response signal having a predetermined decaying envelope with a characteristic expected by the vehicle transceiver;
- and
- processing the ringdown response signal to confirm authenticity of the remote keyless entry device.
Dependencies are inferred from the claim text.