Touch Panel Signal Filtering With Anti-Aliasing and Comb Stages
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Solution Overview
Problem
Conventional input interfaces like keyboards and mice can be inconvenient for users, leading to the need for signal processing circuits that effectively process sensing signals from touch panels to enable more intuitive user interactions with electronic devices.
Innovation Solution
A signal processing circuit comprising an analog-front-end circuit, a filter circuit with an anti-aliasing filter and a comb filter, and an analog-to-digital converter, which captures, filters, and converts sensing signals from touch panels into digital format, optimizing signal processing and reducing circuit complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional input interfaces (keyboard and mouse) are used, then device compatibility is good, but user convenience deteriorates
Solution Approach 1:
The patent replaces mechanical input devices (keyboard and mouse) with a touch panel that uses sensing signals detected through capacitive or resistive touch. This substitution eliminates the need for physical mechanical components, thereby improving user convenience while reducing interface complexity.
2Measurement precision
If signal processing circuit processes sensing signal through multiple filtering stages, then signal quality is improved, but circuit complexity increases
Solution Approach 1:
The signal processing circuit is divided into distinct functional modules: an anti-aliasing filter for initial signal conditioning, a comb filter for noise removal at specific frequencies, and an analog-to-digital converter for signal digitization. This segmentation allows each module to perform a specific function efficiently, improving signal quality while keeping the overall circuit design manageable and not overly complex.
Solution Approach 2:
The anti-aliasing filter performs preliminary filtering of the sensing signal before it enters the comb filter and analog-to-digital converter. By pre-conditioning the signal and removing high-frequency components that could cause aliasing, the preliminary action simplifies subsequent processing stages and reduces the complexity of the overall circuit.
3Measurement precision
If anti-aliasing filter provides preset bandwidth, then signal processing accuracy is improved, but circuit area increases
Solution Approach 1:
The anti-aliasing filter is designed with a preset bandwidth parameter that is optimized for the specific application. By fixing the bandwidth parameter during design, the filter achieves high signal processing accuracy without requiring large variable components or complex adjustment mechanisms, thereby minimizing the circuit area occupied by the filter.
Data Source
AI summary
A signal processing circuit is provided. The signal processing circuit includes an analog-front-end circuit and a filter circuit. The analog-front-end circuit is configured to receive a sensing signal from a touch panel and perform a signal capture operation on the sensing signal to output a current signal. The filter circuit is coupled to the analog-front-end circuit. The filter circuit is configured to receive the current signal from the analog-front-end circuit and perform a signal filter operation on the current signal to output a first voltage signal. The filter circuit includes an anti-aliasing filter and a comb filter coupled in series.