Differential Receiver Circuit With Adaptive Common-Mode Noise Filtering
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Solution Overview
Problem
Existing contactless communication devices face challenges in operating with different types of modulation and tolerating noise and interference in 1-bit amplitude-modulated signals, necessitating improved signal reception solutions.
Innovation Solution
A differential amplifier circuit with a variable common-mode signal and a comparator circuit to dynamically adjust the common-mode value based on the output signal, using high and low threshold values to filter noise and interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed common-mode signal is used in the differential amplifier circuit, then the circuit structure is simple, but the tolerance to noise and interference is reduced
Solution Approach 1:
The patent applies the dynamics principle by transforming the fixed common-mode signal into a variable one that dynamically adapts to the received signal characteristics. The common-mode signal is adjusted based on the output signal from the differential amplifier circuit, allowing the receiver to optimize its performance for different modulation types and noise conditions while maintaining circuit simplicity through automated adaptation.
2Reliability
If a variable common-mode signal is used to improve noise tolerance, then the tolerance to noise and interference is enhanced, but the device complexity increases
Solution Approach 1:
The patent implements feedback by using the output signal from the differential amplifier circuit to control the variable common-mode signal generator. This feedback mechanism allows the system to automatically adjust the common-mode signal level based on the actual received signal conditions, optimizing noise tolerance without requiring complex external control systems.
3Reliability
If higher power supply voltage is used to improve signal reception quality, then the signal integrity is improved, but the power consumption increases
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the common-mode signal voltage level based on the received signal characteristics and noise conditions. This allows the differential amplifier to maintain optimal signal integrity across varying input conditions while operating at lower power supply voltages, as the adaptive common-mode signaling maximizes the utilization of available voltage headroom.
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
Enhances the tolerance to noise and interference, improves interoperability, and reduces power consumption by allowing devices to operate with lower power supply voltages while maintaining signal integrity.
Implementation Method 1
a differential amplifier circuit comprising first and second differential inputs, the first input being configured to receive the input signal and the second input being configured to receive a common-mode signal
Implementation Method 2
the reader generates an electromagnetic field via its antenna... Inductive coupling between the reader and the contactless card is used to electrically power and transmit data
Data Source
AI summary
A device receives a 1-bit amplitude-modulated input signal. The device includes a differential amplifier circuit with first and second differential inputs, wherein the first input is configured to receive the input signal and the second input is configured to receive a common-mode signal having a variable value. The device also includes a circuit for modifying the value of the common-mode signal as a function of the value of an output signal of the receiver device obtained from an output signal of the differential amplifier circuit.