Actively Transmitting Tag Phase Synchronization Circuit
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Solution Overview
Problem
Existing actively transmitting tags face challenges in maintaining phase and frequency matching with interrogator signals during high-frequency communication, especially when transmitting long data frames according to protocols like ISO 14443 B and ISO 14443 A, particularly at higher bit rates, due to the lack of time windows for phase rematching.
Innovation Solution
The method involves synchronizing the phase and frequency of the transmitted signal with the interrogator signal within each half-period of the subcarrier, using phase inversions at transitions between half-periods, allowing the actively transmitting tag to transmit long data frames even without a time window for phase rematching, by controlling the phase shifts during data frame transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the actively transmitting tag matches phase and frequency before transmitting the data frame, then the initial phase matching is achieved, but no reliable communication can be guaranteed during transmission of long data frames
Solution Approach 1:
The patent implements continuous phase and frequency tracking during data frame transmission by detecting the phase of the interrogator signal at regular intervals and adjusting the tag's transmitted signal accordingly. This feedback mechanism ensures that phase matching is maintained throughout the entire transmission, resolving the contradiction between initial matching and sustained communication reliability.
Solution Approach 2:
The patent transitions from static pre-transmission phase matching to dynamic continuous adjustment during transmission. The system automatically adapts phase and frequency parameters in real-time based on detected signal conditions, enabling reliable communication over extended periods without requiring time windows for rematching.
2Productivity
If the tag transmits continuously without time windows for phase rematching, then productivity is improved, but phase and frequency matching deteriorates
Solution Approach 1:
The patent uses continuous feedback from the interrogator signal to maintain phase and frequency matching during uninterrupted transmission. By detecting signal parameters at regular intervals and adjusting the transmitted signal accordingly, the system achieves both continuous transmission (high productivity) and sustained phase matching (high reliability).
Solution Approach 2:
The patent dynamically changes the phase and frequency parameters of the transmitted signal based on real-time detection of the interrogator signal. This continuous parameter adjustment allows the tag to maintain optimal matching conditions throughout transmission, eliminating the need for transmission pauses while preserving phase accuracy.
3Volume of moving object
If the tag uses a tiny antenna to build up sufficient signal strength, then the antenna size is reduced, but the signal strength at the interrogator antenna becomes insufficient for reliable communication
Solution Approach 1:
The patent employs dynamic phase and frequency adjustment to optimize signal transmission from the tiny antenna. By continuously matching the transmitted signal to the interrogator signal characteristics, the system maximizes the effective radiated power and signal strength at the interrogator antenna, compensating for the limited size of the antenna.
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 enhances the communication efficiency by ensuring constructive interference at the interrogator antenna, increasing the communication range and enabling reliable transmission of long data frames across various protocols, including ISO 14443 B and higher bit rates.
Implementation Method 1
A signal of an actively transmitting tag constructively interferes with an interrogator's transmitted signal at an interrogator antenna
Implementation Method 2
the tag's circuit observes a phase of a tag's antenna signal before the tag starts transmitting a data frame
Data Source
AI summary
A circuit of an actively transmitting tag includes an antenna, a digitizer, a voltage-controlled oscillator (VCO), an output amplifier, a phase-displacement detector, and a regulator. The input of the digitizer connects to the antenna. The outputs of the digitizer and the output amplifier are connected to the input terminals of the phase-displacement detector. The output amplifier connects the output of the VCO to the antenna and the regulator connects the output of the phase-displacement detector to the VCO.