The optical signals are converted into electrical signals of same time characteristics by the technique of the in-situ spectroscopic detection.The switch-on time is obtained by calculating the time difference of the exciting and electrical signals.Results show that the proposed method can effectively measure the switch-on time of DC and HF AC plasma antennas.The switch-on time of plasma antennas driven by DC and kHz AC power supplies are about 1 ms, and that of plasma antennas driven by MHz power supplies are approximately 0.5 ms.The error of 50 Hz AC plasma antenna is very large due to the unstable discharge state.The value of switch-on time is greatly related to the exciting power and the response time of the power supplies.In a certain range, with the increase of discharge power, the switch-on time of the antenna is shortened.Besides, the error is reduced by about 1％-2％.%将发射光谱信号引入到辉光放电等离子体天线开启时间测量当中,根据等离子体光信号与激励电压信号的时间差测出辉光等离子体天线的开启时间.结果发现该方法可有效测量直流和频率较高的交流辉光等离子体天线开启时间.直流和kHz级交流等离子体天线开启时间约为在1 ms,MHz级交流等离子体天线开启时间在0.5 ms左右.而对于50 Hz低频交流等离子体天线,由于放电状态不稳定,测量误差较大.天线的开启时间与激励电源的功率和电源的响应时间有很大关系.在一定范围内,随放电功率增加,天线的开启时间缩短.同时放电功率的增加也增大了天线开启时间测量结果的可重复性,误差减小,为1％～2％.
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