Patent ID: 11971439
Assignee: DENSO CORPORATION
Field: Telecommunications (Electrical engineering)
Classification: CPC G  H | IPC G  H

Claim 7:
8. A fault detection device comprising a processor and a memory, the memory storing instructions configured to, when executed by the processor, cause the processor to perform:
execution of a test signal supply process for changing a frequency of a carrier wave within a frequency range predetermined as a range of a resonance frequency of an antenna, modulating the carrier wave with a test signal as an input signal, amplifying the carrier wave that is modulated, and supplying the carrier wave that is amplified as an output target signal to the antenna;
measurement of an antenna current corresponding to the frequency each time the frequency of the carrier wave is changed while executing the test signal supply process, the antenna current being an electric current that flows through the antenna; and
detection of a fault caused by a difference or a change in a characteristic of the antenna, wherein
the instructions are further configured to, when executed by the processor, cause the processor to:
repeatedly perform the execution of the test signal supply process and the measurement of the antenna current corresponding to the frequency for each frequency of the carrier wave in a predetermined cycle, wherein the test signal supply process is executed for a plurality of cycles; and
detect the fault that the characteristic of the antenna changes when a frequency difference, which is a difference between the frequency corresponding to a maximum value of the antenna current measured for each frequency of the carrier wave during execution of the test signal supply process in a current cycle of the plurality of cycles and the frequency corresponding to a maximum value of the antenna current measured for each frequency of the carrier wave during execution of the test signal supply process in a previous cycle of the plurality of cycles, is equal to or greater than a predetermined threshold value.