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

Claim 6:
7. A fault detection device for detecting a fault of an antenna, comprising:
a central processing unit (CPU) configured to detect the fault; and
an integrated circuit (IC) configured to:
adjust a frequency of a carrier wave;
modulate the carrier wave with an input signal;
amplify the input signal that is modulated to generate an output target signal and supply the output target signal to the antenna; and
measure an antenna current that flows through the antenna, wherein

while the IC executes a test signal supply process for changing the frequency of the carrier wave within a frequency range predetermined as a range of a resonance frequency of the antenna, modulating the carrier wave with a test signal as the input signal, amplifying the carrier wave that is modulated, and supplying the carrier wave that is amplified as the output target signal to the antenna, the IC measures the antenna current corresponding to the frequency each time the frequency of the carrier wave is changed,
the IC 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 CPU 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.