EMR Sensor Controller Coil Switching for Pen-Signal S/N
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Solution Overview
Problem
Existing electromagnetic resonance systems face a challenge in improving the signal-noise ratio of pen signals without decreasing the frequency of position detection or increasing the circuit scale of the sensor controller.
Innovation Solution
A method where multiple coils are connected in different connection polarities during each pen signal detection period, allowing the sensor controller to separately acquire the level of the pen signal through a restoration operation on detected values, enabling simultaneous reception by a single circuit and subsequent signal separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the transmission period of the pen signal is increased to improve the S/N ratio, then the S/N ratio is improved, but the frequency of position detection decreases
Solution Approach 1:
Multiple Rx coils are combined into a single reception circuit through sequential switching. The sensor controller connects different combinations of Rx coils to the single reception circuit across multiple detection periods, allowing parallel reception capability without requiring multiple independent reception circuits. This merging approach enables the system to achieve the S/N ratio improvement of parallel reception while maintaining high detection frequency and avoiding increased circuit scale.
Solution Approach 2:
The sensor controller performs periodic switching between different coil connection modes across multiple detection periods. By systematically varying which coils are connected in each period and applying restoration operations, the system accumulates signal information over time to improve S/N ratio while maintaining continuous detection capability through the periodic nature of the switching sequence.
2Measurement precision
If parallel reception by multiple Rx coils is implemented to improve the S/N ratio, then the S/N ratio is improved, but the circuit scale of the sensor controller increases
Solution Approach 1:
Multiple Rx coils are merged into a single reception circuit through time-division multiplexing. The sensor controller sequentially connects different Rx coils or coil combinations to the single reception circuit across multiple detection periods. This merging strategy enables the system to achieve parallel reception capability equivalent to having multiple independent circuits, while actually using only one reception circuit, thus improving S/N ratio without increasing circuit scale.
Solution Approach 2:
The single reception circuit is designed to perform multiple functions by receiving signals from different Rx coils at different time periods. Through the switching mechanism, one reception circuit universally handles what would otherwise require multiple dedicated circuits, enabling parallel reception capability while maintaining a compact circuit design with reduced complexity and scale.
3Measurement precision
If the detection period of the pen signal is increased N times to improve the S/N ratio, then the signal level becomes N times, but the noise level becomes N1/2 times
Solution Approach 1:
The system uses periodic switching between different coil connection modes across multiple detection periods. By systematically varying connections and applying restoration operations, the effective signal accumulation achieves N-time signal level improvement while noise only increases by N1/2, all within a total time period that maintains the original detection frequency. The periodic nature allows time-efficient signal accumulation without extending the overall detection cycle.
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 signal-noise ratio of pen signals without reducing detection frequency or increasing circuit complexity, while maintaining efficient position detection.
Implementation Method 1
The EMR sensor includes a plurality of Tx coils arranged side by side in a y direction and a plurality of Rx coils arranged side by side in an x direction. The sensor controller detects the position of the electromagnetic induction pen by sequentially sending alternating magnetic fields from the plurality of Tx coils
Implementation Method 2
An electromagnetic resonance system (EMR system) is one of the known systems for detecting the position of an electromagnetic induction pen on a panel surface
Data Source
AI summary
To improve the S/N ratio of a pen signal received in a sensor controller, without decreasing the frequency of position detection or increasing the circuit scale of the sensor controller, a method according to the present invention is executed by a sensor controller of an electromagnetic resonance system, and in each of a plurality of pen signal detection periods T1 to T3, three loop coils LCxn−1 to LCxn+1 are connected in connection modes having different connection polarities for each pen signal detection period, a result value indicating a level of a pen signal is detected via the three loop coils LCxn−1 to LCxn+1, and the level of the pen signal corresponding to each of the three loop coils LCxn−1 to LCxn+1 is separately acquired by performing a restoration operation according to the connection polarities on a plurality of the result values detected in the respective pen signal detection periods.