Electromagnetic Induction Distance Measurement via Signal Amplitude Normalization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing coordinate input devices cannot measure the distance between a coordinate indicator and the input device, despite being able to determine position coordinates in a two-dimensional plane.
Innovation Solution
The method involves using an electromagnetic induction plate with a measurement circuit to measure the actual amplitude of the output signal from a receiving coil, determining the distance based on this amplitude, a nominal amplitude, and a preset reference amplitude, utilizing a master and slave controller, signal generator, damping circuit, and gain control circuit to normalize the signal amplitude.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the coordinate input device uses electromagnetic induction to determine position coordinates, then the position information in two-dimensional plane can be obtained, but the distance between the coordinate indicator and the coordinate input device cannot be measured
Solution Approach 1:
The patent extends the measurement capability from two-dimensional plane coordinates to three-dimensional space by measuring the distance (height) between the coordinate indicator and the coordinate input device. This is achieved by measuring the signal amplitude received by the receiving coil, which varies with the vertical distance, thereby adding the third dimension (distance/height) to the previously two-dimensional coordinate system.
2Measurement precision
If the signal amplitude is used to determine distance, then the distance information can be obtained, but the signal amplitude may exceed the measurable range of the measurement circuit
Solution Approach 1:
The patent employs a dynamic gain control circuit that automatically adjusts its gain based on the measured signal amplitude. When the signal amplitude is large, the gain is reduced; when the signal amplitude is small, the gain is increased. This dynamic adjustment ensures that the signal always remains within the measurable range of the measurement circuit, preventing signal saturation or loss and ensuring reliable distance measurement across varying distances.
Solution Approach 2:
The measurement circuit measures the signal amplitude received by the receiving coil and feeds this information back to the gain control circuit. The gain control circuit uses this feedback to adjust the gain dynamically, creating a closed-loop control system that maintains the signal within the optimal measurement range regardless of the coordinate indicator's distance from the coordinate input device.
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
Enables accurate measurement of the distance between the coordinate indicator and the input device, overcoming the limitation of prior art by ensuring the signal remains within a measurable range and maintaining a linear relationship for precise distance calculation.
Implementation Method 1
The receiving coils receive the electromagnetic signals transmitted by the transmit coils and sensed by the resonating circuit
Data Source
AI summary
A method for measuring a distance between a coordinate indicator and a coordinate input device, which belongs to the technical field of computer peripheral equipments. The method comprises the steps of measuring an actual amplitude of an output signal of a receiving coil in the electromagnetic induction plate by a measurement circuit in the electromagnetic induction plate; determining a distance between the coordinate indicator and the coordinate input device in accordance with the actual amplitude of the output signal, a nominal amplitude of the output signal, and a preset reference amplitude of signal. In the present invention, the distance between the coordinate indicator and the coordinate input device is determined by converting an actual amplitude of the output signal of the receiving coil at one time to a nominal amplitude of the output signal normalized by a reference amplitude of signal, which overcomes the defect of the prior art which can not indicate a distance between the coordinate indicator and the coordinate input device.