Signal Supply Device Frequency Adjustment for Antenna Resonance
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Solution Overview
Problem
In wireless communication systems, particularly in vehicle smart key systems, frequency deviations between the signal supply device and the antenna can lead to decreased communication performance and detection accuracy due to variations in antenna circuit constants, causing the resonance frequency to deviate from the drive frequency.
Innovation Solution
A signal supply device that includes a frequency adjuster, modulator, amplifier, current measurer, and controller to execute a test signal supply process, measuring antenna currents at varying frequencies and setting the usage frequency to the value corresponding to the largest antenna current, thereby minimizing frequency deviations between the resonance and drive frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the drive frequency is set according to design specifications, then the device complexity is reduced, but the frequency deviation from resonance frequency increases due to circuit constant variations
Solution Approach 1:
The patent performs preliminary frequency measurement and adjustment during the manufacturing process. The resonance frequency is measured before the antenna is installed in the vehicle, and the drive frequency is adjusted in advance to match the measured resonance frequency. This preliminary action ensures frequency matching without requiring complex adjustment mechanisms in the final product.
Solution Approach 2:
The patent uses the antenna itself to measure its own resonance frequency by detecting the current flowing through it when a test signal is applied. The system automatically identifies the resonance frequency and adjusts the drive frequency accordingly, eliminating the need for external measurement equipment or complex manual adjustment procedures.
2Adaptability or versatility
If the resonance frequency varies due to circuit constant variations, then the adaptability to different manufacturing tolerances is improved, but the communication performance deteriorates due to frequency deviation
Solution Approach 1:
The patent implements a feedback mechanism where the resonance frequency is measured by detecting the current through the antenna, and the drive frequency is adjusted based on this measurement. The system continuously monitors and adjusts the frequency to maintain alignment with the resonance frequency, ensuring stable communication performance despite variations in circuit constants.
3Reliability
If frequency measurement and adjustment is performed, then the communication performance is improved, but the measurement precision requirement increases
Solution Approach 1:
The patent uses electrical vibration (resonance) of the antenna circuit to identify the resonance frequency. By applying a test signal and measuring the current response, the system detects the frequency at which the antenna resonates, indicated by maximum current flow. This vibration-based measurement approach provides sufficient precision for frequency matching without requiring extremely high measurement accuracy.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach effectively suppresses frequency deviations, ensuring stable communication performance by setting the usage frequency to the value with the smallest deviation from the resonance frequency, thus maintaining accurate detection and communication strength.
Implementation Method 1
measuring an antenna current corresponding to the frequency each time the frequency of the carrier wave is changed... the frequency corresponding to the antenna current on a larger side among the antenna currents measured
Data Source
AI summary
The signal supply device includes a frequency adjuster, a modulator, an amplifier, a current measurer, a frequency setter, and a controller. While the controller executes 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, the controller measures an antenna current corresponding to the frequency each time the frequency of the carrier wave is changed. The frequency setter sets, as a usage frequency used as the frequency of the carrier wave, the frequency corresponding to the antenna current on a larger side among the antenna currents measured during execution of the test signal supply process.