NFC Resonant Circuit Gain Control via Test Signal Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
NFC communication performance deteriorates due to variations in parts, particularly in the resonance frequency of the resonant circuit, leading to reduced communicable distance, and existing solutions require adding a variable capacitor, which increases size and cost.
Innovation Solution
A communication apparatus and method that generates a test signal to detect influence parameters affecting the active load modulation signal, allowing for control of its intensity without the need for a variable capacitor, by adjusting the phase shift and output impedance of the synchronizing signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a variable capacitor is added to correct resonance frequency, then communication performance is improved, but device size and cost increase
Solution Approach 1:
The patent changes the control parameter from capacitance (variable capacitor) to resistance (fixed resistor values). By selecting different fixed resistor values for the gain control section, the system adjusts the gain to compensate for resonance frequency deviations without requiring a variable capacitor, thus improving communication performance while avoiding increased device size and cost
Solution Approach 2:
The patent uses a detection signal transmission mechanism that copies the approach of PTL 1 but implements it differently. Instead of using a variable capacitor for correction, the system transmits a detection signal and uses the received signal level to determine appropriate fixed resistor values, achieving the same correction goal with a simpler, more cost-effective solution
2Reliability
If resonance frequency is adjusted manually, then communication performance is improved, but operation complexity increases
Solution Approach 1:
The patent implements an automatic feedback mechanism where the transponder transmits a detection signal, the R/W receives and measures it, then determines the appropriate gain setting based on the received signal level. This automated feedback loop eliminates manual resonance frequency adjustment, improving communication performance while maintaining ease of operation
Solution Approach 2:
The system performs self-adjustment through the automatic gain control process. The R/W autonomously detects the resonance frequency deviation via the detection signal and automatically selects the appropriate fixed resistor value to correct the gain, eliminating the need for manual user intervention in the resonance frequency adjustment process
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
Improves communication performance by minimizing the impact of variations in parts while avoiding the size and cost increases associated with variable capacitors, maintaining effective communication distances without manual adjustments or external resonance frequency adjustments.
Implementation Method 1
The R/W and the transponder communicate with each other through electromagnetic induction between their coils acting as antennas
Implementation Method 2
the coils acting as the antennas in the R/W and the transponder constitute a resonant circuit each. The resonance frequency of the resonant circuit varies typically with variations in the parts making up the resonant circuit
Data Source
AI summary
This technology relates to a communication apparatus and a communication method adapted to improve the deterioration of communication performance due to variations in parts, for example.A test signal generating section generates a predetermined test signal. A detecting section detects, given a received test signal obtained by a transmitting and receiving section upon receipt of the test signal, an influence parameter affecting the intensity of an active load modulation signal that combines a transmission carrier with a synchronizing signal synchronized with a received signal obtained upon receipt of the transmission carrier. A controlling section controls the intensity of the active load modulation signal in accordance with the influence parameter. This technology applies to cases where short-range wireless communication is performed using magnetic fields.