Stylus Sensing Circuit With Multi-Frequency Noise Selection
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Solution Overview
Problem
Conventional easy pens lack effective anti-noise capability due to their inability to change downlink signal frequencies in response to noise interference, leading to compromised signal processing accuracy.
Innovation Solution
A stylus sensing circuit and stylus design that outputs downlink signals with multiple frequency components, allowing the detection circuit to select a noise-free frequency for processing, thereby ensuring accurate signal transmission despite interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single frequency is used for downlink signal transmission, then device complexity is reduced and cost is lowered, but anti-noise capability deteriorates
Solution Approach 1:
The downlink signal is segmented into multiple frequency components instead of using a single frequency. The signal generator generates first and second frequency signals with different frequencies, and the modulator modulates these segmented frequency signals separately before combining them. This segmentation allows the system to avoid noise on any single frequency while maintaining overall signal integrity.
Solution Approach 2:
The system changes the frequency parameter of the downlink signal by using multiple frequency components instead of a fixed single frequency. The signal generator produces frequency signals with different frequencies, and the system can selectively use different frequency combinations based on noise conditions, thereby adapting to varying electromagnetic environments and improving anti-noise capability.
2Reliability
If multiple frequency signals are transmitted, then anti-noise capability is improved, but device complexity increases
Solution Approach 1:
The modulator merges the first and second frequency signals by combining them into a single modulated downlink signal. The combining circuit integrates these multiple frequency components into one unified signal that can be transmitted through the antenna, reducing the need for separate transmission channels while maintaining the benefits of multi-frequency transmission for noise resistance.
Solution Approach 2:
The signal generator and modulator are designed to handle multiple frequency signals universally. The signal generator can produce frequency signals with different frequencies, and the modulator can modulate any combination of these frequencies, making the system versatile and adaptable to different noise conditions without requiring separate dedicated circuits for each frequency.
3Reliability
If frequency hopping is implemented, then signal reliability under noise interference is improved, but ease of operation deteriorates
Solution Approach 1:
The system performs preliminary frequency selection by generating multiple frequency signals in advance through the signal generator. The modulator is pre-configured to modulate these predetermined frequency signals, so when noise interference occurs, the system can immediately switch to alternative frequencies without complex real-time frequency hopping or synchronization procedures.
Solution Approach 2:
The modulator acts as an intermediary that simplifies frequency management. Instead of requiring the receiving end to perform complex frequency hopping and synchronization, the modulator handles all frequency selection and combination logic, translating complex multi-frequency operations into a single streamlined modulated signal that is easy to transmit and receive.
Data Source
AI summary
A stylus sensing circuit includes a receiving circuit, a demodulation circuit and a detection circuit. The receiving circuit receives a downlink signal from a stylus, wherein the downlink signal includes a plurality of frequency signals. The demodulation circuit, coupled to the receiving circuit, demodulates the downlink signal to extract each of the plurality of frequency signals. The detection circuit, coupled to the demodulation circuit, chooses one of the plurality of frequency signals to perform a signal processing.