Variable-Frequency Key Signal Sampling Against False Triggers
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing key detection methods suffer from high false triggering and missed detection rates due to environmental interference, such as noise from mobile phones and other electric appliances, as they rely on fixed sampling frequencies that are easily interfered with by varying external signals.
Innovation Solution
The method involves sampling key signals at varying frequencies, increasing from a first frequency to a second frequency and then decreasing back, with specific time spans at each frequency point, and initiating the detection process after receiving external signals within a predetermined frequency range, thereby reducing interference and improving detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If fixed sampling frequency is used, then the key detection process is simple, but the false triggering rate and missed detection rate increase due to environmental interference
Solution Approach 1:
The patent applies dynamics by changing the sampling frequency from a fixed value to a variable value that changes over time. Specifically, the sampling frequency varies periodically according to a predetermined pattern, making it dynamic rather than static. This dynamic sampling approach prevents external interference signals at fixed frequencies from consistently aligning with sampling moments, thereby reducing false triggering and missed detection while maintaining relatively simple system complexity.
2Reliability
If sampling frequency varies, then the successful key detection rate increases, but the detection system becomes more complex
Solution Approach 1:
The patent implements periodic action by making the sampling frequency vary periodically according to a predetermined pattern. The sampling frequency follows a periodic variation law where it changes over time but returns to its initial value after a complete cycle. This periodic variation is simple to implement and effectively prevents external interference signals from consistently coinciding with sampling moments, thereby improving successful detection rate while keeping the control mechanism relatively simple.
3Object-affected harmful factors
If external signal reception is added, then interference detection capability improves, but the overall system complexity increases
Solution Approach 1:
The patent uses the varying sampling frequency as an intermediary mechanism to indirectly handle interference signals. Rather than directly detecting and filtering external interference signals, the system uses the frequency variation to prevent interference signals from consistently aligning with sampling moments. This intermediary approach effectively reduces the impact of interference without requiring complex direct interference detection and filtering systems.
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A method and an apparatus for detecting a key are provided. The method comprises: detecting the key to obtain a key signal (S11); sampling the key signal with a variable frequency; and outputting a control signal when the number of times of sampling the key effective signal in a pre-set time range reaches or exceeds a pre-set number (S12), wherein sampling with the variable frequency means that the sampling frequency is gradually increases from a first frequency to a second frequency, then gradually reduced from the second frequency to the first frequency, and the gradual increasing and reducing processes are repeated, moreover, the sampling frequency stays for a pre-set time in each frequency. The method and the apparatus for detecting the key reduce the probability of key detection being interfered by external signals.