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

Claim 0:
1. A fault detection device for detecting a fault of an antenna, comprising:
a frequency adjuster configured to adjust a frequency of a carrier wave;
a modulator configured to modulate the carrier wave with an input signal;
an amplifier configured to amplify the input signal that is modulated to generate an output target signal and supply the output target signal to the antenna;
a current measurer configured to measure an antenna current that flows through the antenna;
a fault detector configured to detect the fault; and
a controller, wherein
while the controller executes a test signal supply process in which the controller controls the frequency adjuster to change the frequency of the carrier wave within a frequency range predetermined as a range of a resonance frequency of the antenna, controls the modulator to modulate the carrier wave with a test signal as the input signal, and controls the amplifier to amplify the carrier wave that is modulated and supply the carrier wave that is amplified as the output target signal to the antenna, the controller controls the current measurer to measure the antenna current corresponding to the frequency each time the frequency of the carrier wave is changed, and
the controller repeatedly executes the test signal supply process and 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
the fault detector detects 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.