Passive RFID Reader Signal Amplification for Weak Chip Responses
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Solution Overview
Problem
Current methods for processing signals from passive RFID chips, particularly at low frequencies, face challenges in amplifying weak signals effectively without incurring significant costs, and existing solutions are limited to specific signal modulation types, such as amplitude modulation, failing to improve reading quality for frequency and phase modulated signals.
Innovation Solution
A method utilizing an operational amplifier connected as a summing amplifier, in conjunction with an AD converter and DA converters, shifts and amplifies the RFID chip signal by setting optimal voltage ratios to process both positive and negative signal halves, enhancing signal strength without additional external components, and is applicable to all types of signal modulation (ASK, FSK, and PSK).
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If additional external components are used to amplify the signal, then the signal strength is improved, but the cost and device complexity increase considerably
Solution Approach 1:
The operational amplifier is integrated within the reader device itself, allowing the system to amplify its own received signal without requiring external amplification components. The amplifier uses the received RFID signal directly and processes it through the summing amplifier configuration, making the system self-sufficient for signal enhancement.
Solution Approach 2:
The operational amplifier is configured as a summing amplifier that can process multiple signal types (AM, FM, PM) through a single unified circuit architecture. By summing the received signal with a reference signal, the circuit universally handles different modulation types without requiring separate amplification paths for each modulation scheme.
2Adaptability or versatility
If traditional demodulation methods are used, then amplitude modulated signals can be processed, but frequency and phase modulated signals cannot be effectively handled
Solution Approach 1:
The summing amplifier configuration creates a universal demodulation architecture that effectively processes amplitude modulated (AM), frequency modulated (FM), and phase modulated (PM) signals through the same circuit. The operational amplifier sums the received signal with a reference signal, and this approach works for all three modulation types, enabling the reader to handle diverse RFID card types with a single unified processing path.
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
This approach increases the magnitude of the RFID chip signal, improving reader sensitivity and enabling the processing of weak signals from LF RFID cards, particularly for contactless authorization systems, without the need for costly external components, thus enhancing reading quality across various signal modulation types.
Implementation Method 1
the received RFID chip signal and the output of the first DA converter is fed to the inverting input of the operational amplifier, and the output of the second DA converter or the output of the source of constant voltage is fed to the non-inverting input of the operational amplifier
Data Source
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AI summary
The subject of the invention Is a method of processing a signal of a passive RFID chip (1) with a reader (2) in order to amplify the useful signal. A method of processing a signal of a passive RFID chip (1) with a reader (2) comprising an antenna (3), an operational amplifier (4), an AD converter (5) and a first DA converter (6) and a second DA converter (7) or a source of constant voltage consists of steps of transmitting the source signal of the antenna (3), receiving the source signal of the antenna (3) by the RFID chip (1), transmitting the RFID chip (1) signal and receiving the RFID chip (1) signal by the antenna (3), wherein the received RFID chip (1) signal and the output of the first DA converter (6) is fed to the inverting input of the operational amplifier (4) and the output of the second DA converter (7) or the output of the source of constant voltage is fed to the non-inverting input of the operational amplifier (4). After converting the signal by the AD converter (5) the amplitude of two consecutive peaks belonging to a single wave is subtracted, wherein the individual signals are temporarily stored in the buffer (12) before subtraction.