Noncontact Tag Clock Extraction for Low-Power ASK Demodulation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Noncontact tags face challenges in accurately demodulating data with different modulation indices (100% and 10%) due to power consumption and circuit size issues, particularly when trying to extend communication distance without increasing power consumption or circuit complexity.
Innovation Solution
A noncontact tag design that includes a clock extraction unit, demodulation unit, division unit, and decoding unit, which generates and controls a division clock based on the logic state of the demodulated signal, allowing accurate decoding of modulated data without the need for additional clock generation circuits like PLLs, and operates effectively with both ASK 100% and ASK 10% modulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a clock generation circuit such as PLL is mounted to avoid clock stoppage during ASK 100% modulation, then communication continuity is improved, but power consumption increases
Solution Approach 1:
The invention extracts and removes the clock generation circuit (such as PLL) from the tag device, relying instead on the reader/writer to provide a continuous carrier wave that serves as the clock source. This extraction eliminates the power consumption associated with onboard clock generation while maintaining communication continuity through the reader-provided carrier.
Solution Approach 2:
The carrier wave from the reader/writer acts as an intermediary that transfers both data and clock timing information to the tag. By using the carrier wave as a mediator, the system avoids the need for independent clock generation in the tag, reducing power consumption while ensuring reliable communication timing.
2Length of stationary object
If the communication distance is extended, then application range is improved, but power consumption increases
Solution Approach 1:
The invention extracts the clock generation function from the tag and relocates it to the reader/writer side. This removal of power-intensive components from the tag enables extended communication distance without increasing tag power consumption, as the tag operates passively using only the received carrier wave.
3Reliability
If a clock generation circuit is added to ensure continuous operation, then communication reliability is improved, but device complexity increases
Solution Approach 1:
The invention extracts and removes the clock generation circuit from the tag device entirely. By eliminating this complex circuitry and relying on the reader/writer to provide the carrier wave as the timing reference, the system achieves operation continuity without increasing device complexity.
Solution Approach 2:
The carrier wave from the reader/writer serves multiple functions simultaneously: it carries data information and provides the clock timing reference. This multi-functionality eliminates the need for separate clock generation circuits, reducing device complexity while maintaining reliable operation.
4Productivity
If ASK 100% modulation is used for data transmission, then data transmission capability is improved, but clock extraction becomes impossible during modulation
Solution Approach 1:
Instead of trying to extract the clock from the modulated carrier (which becomes impossible during ASK 100% modulation), the invention inverts the approach by using the reader/writer's continuous carrier generation as the clock source. The tag simply responds to this external clock reference without needing to extract or regenerate it locally.
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 solution reduces power consumption, maintains accurate communication, and prevents increased circuit size or reduced communication distance, enabling the noncontact tag to handle both modulation systems efficiently without the need for multiple decoding circuits or power-intensive components.
Implementation Method 1
an antenna (i.e., a loop type) for receiving a radio wave (called a 'carrier' hereinafter) from a reader/writer
Implementation Method 2
a power supply circuit for generating power from the received carrier
Data Source
AI summary
The present invention is to provide a noncontact tag, comprising: a clock extraction unit for extracting a clock from a received carrier wave; a demodulation unit for outputting a demodulated signal comprising a logic signal whose logic state changes responding to each of a non-modulation period and modulation period of the carrier wave; a division unit for generating a division clock from the clock input from the clock extraction unit and also restraining the division clock from being output according to a logic state of the demodulated signal; and a decoding unit for decoding information included in the carrier wave by using a value of counter driven by the division clock.