NFC Transceiver Variable Attenuator for Signal Demodulation
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Solution Overview
Problem
Near field communication (NFC) systems face challenges in maintaining effective data communication due to high attenuation ratios of reception data compared to reception carrier signals, limiting communication distance and increasing transmission power consumption.
Innovation Solution
A data transceiver device with a matching and filtering circuit incorporating a variable attenuator, which adjusts attenuation ratios differently with frequency, ensuring the attenuation of reception data is smaller than that of the reception carrier signal, thereby enhancing communication distance and reducing transmission power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a matching and filtering circuit attenuates the reception carrier signal to a target input range, then the carrier signal level is improved, but the reception data is also attenuated with the same ratio, causing the data to become too weak for proper demodulation
Solution Approach 1:
The patent applies different attenuation ratios to different frequency components of the received signal. The variable attenuator is configured to attenuate the carrier signal (center frequency) with a first attenuation ratio while attenuating the data signal (sideband frequencies) with a second attenuation ratio that is smaller than the first. This local differentiation of attenuation characteristics allows the carrier to be brought to the appropriate input level for the demodulator while preserving sufficient data signal strength for reliable demodulation.
Solution Approach 2:
The patent employs a variable attenuator whose attenuation ratio can be dynamically adjusted based on the input signal characteristics. The attenuator changes its attenuation ratio differently with frequency, enabling adaptive control where the carrier signal experiences higher attenuation than the data signal. This dynamic adjustment ensures optimal signal levels for demodulation while maintaining data integrity.
2Length of stationary object
If the transmission power is increased to overcome attenuation and extend communication distance, then the communication distance is improved, but the power consumption increases
Solution Approach 1:
The patent changes the attenuation parameter of the matching and filtering circuit to differentiate between carrier and data signals. By setting the attenuation ratio for data signals to be smaller than that for carrier signals, the system optimizes the received signal levels without requiring increased transmission power. This parameter optimization enables extended communication distance while maintaining low power consumption.
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 allows for increased communication distance and reduced transmission power consumption by ensuring the reception data is demodulated with sufficient size without increasing transmission power, effectively addressing the attenuation challenges in NFC systems.
Implementation Method 1
The variable attenuator is configured to vary an attenuation ratio differently with a frequency such that an attenuation ratio of the reception data is smaller than that of the reception carrier signal
Implementation Method 2
The matching and filtering circuit is connected between the antenna and the transceiver and configured to perform filtering and impedance matching for the reception signal and the transmission signal
Implementation Method 3
The receiver is configured to demodulate a reception signal, received through the antenna, including reception data modulated by a reception carrier signal
Implementation Method 4
The transmitter is configured to transmit a transmission signal, obtained by modulating transmission data via a transmission carrier signal
Data Source
AI summary
A data transceiver device for near field communication is provided which includes a matching and filtering circuit connected between an antenna and a transceiver and configured to conduct filtering and impedance matching for a reception signal and a transmission signal. The matching and filtering circuit includes a variable attenuator of which the impedance varies with a frequency so that an attenuation ratio of the reception data is smaller than that of the reception carrier signal.