NFC Receiver Companding for Wide Dynamic Range Signals
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Solution Overview
Problem
NFC communication devices face challenges in handling signals with varying strengths and dynamic ranges across different operating modes, such as standard NFC, wireless charging, low-power card detection, and robust tag identification, requiring complex gain regulation to maintain reliable signal processing and avoid clipping or saturation.
Innovation Solution
The implementation of a communication device with a front-end that includes a compressor and expander, along with a shifter, to apply compression and expansion functions to analog input signals, allowing for seamless signal scaling and extending the dynamic range, thereby enabling the device to operate effectively in multiple modes without the need for complex gain regulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If complex gain regulation is used to handle signals with varying strengths, then signal processing reliability is improved, but device complexity increases
Solution Approach 1:
The patent applies companding (compression-expansion) to transform the signal dynamic range parameters. The compressor reduces the dynamic range of incoming signals with varying strengths, allowing a fixed-gain amplifier to process them reliably. The expander restores the original dynamic range after amplification. This parameter transformation eliminates the need for complex gain regulation while maintaining signal processing reliability across different operating modes.
2Adaptability or versatility
If the dynamic range is extended to handle multiple operating modes, then adaptability is improved, but device complexity increases
Solution Approach 1:
The companding mechanism provides universal adaptability across multiple operating modes (standard NFC, wireless charging, low-power card detection, robust tag identification). The compressor and expander enable a single fixed-gain amplifier to handle signals from all modes effectively, replacing the need for mode-specific gain regulation circuits. This multi-functional approach extends dynamic range while simplifying the overall device architecture.
3Device complexity
If fixed gain amplification is used, then device complexity is reduced, but signal clipping occurs
Solution Approach 1:
The compressor performs preliminary action by reducing the dynamic range of incoming signals before they reach the fixed-gain amplifier. This pre-compression ensures that signals with varying strengths are all within the acceptable input range of the amplifier, preventing clipping and saturation. The expander then restores the signal amplitude after amplification, maintaining signal processing reliability without requiring complex post-amplification gain control.
Data Source
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AI summary
In accordance with a first aspect of the present disclosure, a communication device is provided, comprising: a front-end configured to receive an analog input signal, wherein the front-end comprises an analog-to-digital converter configured to convert the analog input signal into a digital signal; a digital signal processor configured to receive and process said digital signal; wherein the front-end further comprises a compressor operatively coupled to an input of the analog-to-digital converter, wherein said compressor is configured to apply a compressor function to the analog input signal before said analog input signal is provided to the analog-to-digital converter. In accordance with a second aspect of the present disclosure, a corresponding method of operating a communication device is conceived.