视觉诱发电位提取中闪光刺激的PWM实现

视觉诱发电位提取过程中，可以通过闪光刺激获得诱发脑电信号．实验发现，闪光刺激的脉宽、频率和闪光刺激次数对于视觉诱发电位的提取具有关键作用．针对视觉诱发电位的提取特点及其相关因素，探讨了基于脉宽调制（PWM）技术的闪光刺激方法，研究了PWM的软硬件实现方法，同时利用专用集成芯片实现了精确的PWM输出，从而可以根据视觉诱发电位提取过程中的具体条件调整闪光刺激的参数，实现视觉诱发电位的有效提取．实验结果表明利用PWM的精确提取方法控制闪光刺激的发生，对于闪光视觉诱发电位的有效提取具有较好的效果．

Realization of Flash Stimulation with PWM in the Extraction of Visual Evoked Potential

Evoked EEG signal can be obtained by flash stimulation in the extraction of flash visual evoked potential(FVEP).Experiments show that the width,frequency and flash times of flash pulses will play key role for extracting FVEP.Aims at the feature of VEP extraction and its correlation factors,the flash stimulation method with pulse width modulation(PWM) technology has been discussed,and the realization methods based on hardware and software are studied,then the output of precise PWM with special integrated circuit is realized.So the parameters of flash stimulation can be adjusted based on the material conditions of FVEP extraction,then VEP can be extracted effectively.Experiments show that it is of better effectiveness for FVEP extraction by using the method based on the output of precise PWM to control the flashing stimulation.