A reference frequency automatic calibration method of an electromagnetic pen

Abstract

A reference frequency automatic calibration method for an electromagnetic pen comprises the following steps that after the electromagnetic screen enters a calibration mode, when the electromagnetic screen detects a signal of the electromagnetic pen, the electromagnetic screen reads the signal for multiple times and stores multiple frequency signal values of the electromagnetic pen respectively; Determining a maximum value and a minimum value in the plurality of frequency signal values; The difference between the maximum value and the minimum value in the frequency signal values is compared, ifthe difference between the maximum value and the minimum value is smaller than a preset threshold value, the multiple frequency signal values are filtered to remove jitter, the processed frequency signal values are obtained, and the processed frequency signal values are determined as the calibrated reference frequency. According to the reference frequency automatic calibration method of the electromagnetic pen, a calibration mode is entered through manual operation; When a calibration mode is entered, the electromagnetic screen automatically scans and judges, the reference frequency of the electromagnetic pen is automatically calculated for calibration, the calibration is very convenient and fast, errors are very low, batch calibration and test requirements can be met, no technical requirements for operators exist, and the electromagnetic screen is easy to implement and suitable for vigorous popularization.

Description

【Technical field】 [0001] The invention relates to the field of electromagnetic screens, in particular to a method for automatically calibrating a reference frequency of an electromagnetic pen. 【Background technique】 [0002] In the electromagnetic screen system, the principle of pressure sensitivity is realized by the different frequencies generated by the different forces on the electromagnetic pen tip. The greater the force on the electromagnetic pen tip, the greater the frequency change (according to the different internal circuits, the frequency change can be in a large direction or in a small direction). When the pen tip of the electromagnetic pen is not stressed, the pressure sensitivity is 0, and its frequency is a fixed value. Therefore, as long as the frequency when the pressure sensitivity is 0 is determined as the reference frequency, different pressure sensitivity can be realized according to different changing frequencies. Effect. The electromagnetic pen circu...

AI Technical Summary

Problems solved by technology

This calibration method is very inefficient, and requires people with a certain technical foundation to realize the operation, and the error is relatively large during mass production, so it has great disadvantages

Images