Active Pen Signal Detection via Downconversion
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Solution Overview
Problem
Existing capacitive sensing input devices struggle to detect active pen signals that are outside their operating range, requiring costly redesigns or separate detection circuits, and consume excessive power due to high sampling rates.
Innovation Solution
The method involves downconverting and aliasing active pen signals to bring them within the operating range of existing processing systems, allowing for detection without the need for redesign or separate circuits, and reducing power consumption by operating at lower sampling rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high sampling rates are used to detect active pen signals outside operating range, then signal detection capability is improved, but power consumption increases
Solution Approach 1:
The patent changes the frequency parameter of the active pen signal through downconversion, transforming high-frequency signals outside the operating range into lower-frequency signals within the detectable range. This allows the existing processing system to detect signals without increasing sampling rate, thereby maintaining low power consumption while improving signal detection capability
Solution Approach 2:
The patent introduces an intermediary frequency transformation process (downconversion and aliasing) between the active pen signal and the processing system. This intermediary mechanism enables signals at various frequencies to be converted into the operating range of existing circuits, avoiding the need for high sampling rates and associated power consumption
2Measurement precision
If separate detection circuits are used to detect active pen signals outside operating range, then signal detection capability is improved, but device complexity increases
Solution Approach 1:
The patent makes the existing processing system universal by enabling it to handle active pen signals at various frequencies through downconversion and aliasing. The same existing circuits can detect both signals within and outside the original operating range, eliminating the need for separate detection circuits and reducing overall device complexity
Solution Approach 2:
The patent introduces an intermediary frequency transformation process that acts as a bridge between signals outside the operating range and the existing processing system. This intermediary mechanism allows existing circuits to detect a broader range of signals without requiring additional dedicated detection circuits, thereby reducing device complexity
Data Source
AI summary
In a method of active pen signal detection, a signal is received from an active pen, wherein the active pen is configured for use with a capacitive sensing input device. At least one of downconverting and aliasing is performed on the signal to achieve a resulting signal. Presence of one of a plurality of possible resulting signal frequencies present in the resulting signal is detected. The detected resulting signal frequency is associated with a particular one of a plurality of possible transmission frequencies of the signal, and each of the plurality of transmission frequencies of the signal represents information about operation of the active pen.