Contactless Communication Device Active Load Modulation Phase Compensation
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Solution Overview
Problem
Existing solutions for contactless communication using active load modulation face challenges due to phase shifts and amplitude variations caused by PVT variations and electromagnetic field coupling, which affect the detection sensitivity and communication efficiency.
Innovation Solution
A device for contactless communication by active load modulation, comprising a receive circuit, a transmit circuit with a modulation signal in phase with the reception signal, and a compensation circuit to determine and apply a phase-shift value to compensate for delays due to the transmit circuit and reception signal amplitude, ensuring stable phase transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If active load modulation is used with a CE device, then the device can transmit data actively with its own electromagnetic field, but phase shifts and amplitude variations occur due to PVT variations and electromagnetic coupling, degrading detection sensitivity
Solution Approach 1:
The patent implements a feedback mechanism where the received signal is fed back through the transmit circuit to measure the actual phase shift and amplitude variation. This feedback loop enables the system to detect deviations from the ideal in-phase condition and compensate for them, thereby maintaining detection sensitivity while preserving active data transmission capability.
Solution Approach 2:
The patent dynamically adjusts the phase and amplitude parameters of the transmitted signal based on measured PVT variations and electromagnetic coupling effects. By changing these parameters in real-time, the system compensates for the phase shifts and amplitude variations that would otherwise degrade detection sensitivity, while maintaining the active transmission mode.
2Adaptability or versatility
If the CE device generates its own electromagnetic field, then it can compensate for coupling effects, but PVT variations cause phase shifts that reduce communication efficiency
Solution Approach 1:
The system uses feedback from the received signal to measure the actual phase shift caused by PVT variations. This feedback information is then used to adjust the transmit circuit's phase, ensuring the transmitted signal remains in-phase with the received signal, thereby maintaining communication efficiency while preserving the ability to compensate for coupling effects.
Solution Approach 2:
The patent employs dynamic adjustment of the transmit circuit's phase and amplitude parameters based on real-time measurements of PVT variations and coupling effects. This dynamic approach allows the system to adapt to changing conditions, maintaining communication efficiency while preserving adaptability to compensate for electromagnetic coupling.
3Reliability
If a phase-locked loop is used to synchronize signals, then phase stability is improved, but the complexity of the transmit circuit increases
Solution Approach 1:
The patent implements a feedback mechanism where the received signal is fed back through the transmit circuit to measure the actual phase shift. This feedback information is then used to adjust the phase of the transmitted signal, providing phase stability without requiring a complex phase-locked loop, thereby maintaining reliability while minimizing circuit complexity.
Solution Approach 2:
The patent extracts the phase synchronization function from a complex phase-locked loop and implements it through a simpler feedback mechanism that measures phase shift through the transmit circuit and adjusts the transmitted signal accordingly. This extraction approach achieves phase stability with reduced circuit complexity.
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
The solution effectively compensates for delays and phase shifts, maintaining stable signal phase and improving communication efficiency, even with varying electromagnetic field amplitudes, thus enhancing detection sensitivity and communication reliability.
Implementation Method 1
a receive circuit (110) configured to receive as an input a reception signal (RFI) originating from an electromagnetic field intended to be received by an antenna (102)
Implementation Method 2
the reader generates an electromagnetic field via its antenna
Implementation Method 3
a transmit circuit (116) comprising an output coupled to the antenna (102) and having a modulation signal (RFO) in phase with the reception signal (RFI) intended to be delivered thereon
Data Source
AI summary
A device of contactless communication by active load modulation includes a receive circuit configured to receive as an input a reception signal originating from a magnetic field intended to be received by an antenna. A transmit circuit has an output coupled to the antenna with a modulation signal in phase with the reception signal intended to be delivered thereon. A circuit compensates for a delay of the modulation signal due to the transmit circuit and to the amplitude of the reception signal. The compensation circuit determines a phase-shift value to be applied to an input signal of the transmit circuit to compensate for the delay.