Sinusoidal Amplitude Modulation and Coherent Demodulation Technique for Chlorophyll Fluorescence Measurement
As a quick and non-intrusive probe of photosynthesis, the chlorophyll fluorescence has been widely studied. Extracting the weak fluorescence signal from the strong noise is necessary to the chlorophyll fluorescence measurement and analysis. In this paper, the time-domain and frequency-domain characteristics of the chlorophyll fluorescence signal and noise caused by the actinic light and the saturation pulse light were analyzed, and a new fluorescence measurement technique, sinusoidal amplitude modulating and coherent demodulating the fluorescence signal, was presented. Using the new technique, the measurement light was modulated by a 1KHz sinusoid, the modulated noisy fluorescence was demodulated using the coherent method with several different cut off frequencies, and signal to noise ratios and measurement errors were calculated and analyzed. The results indicated that the new measurement technique can be employed to measure accurately and efficiently the chlorophyll fluorescence in situ.
chlorophyll fluorescence sinusoidal amplitude modulation coherent demodulation signal to noise ratio measurement error
Gang Li Juan Zhang Sheng Chang
School of Mechanical Engineering and Electronic Information, China University of Geosciences, Wuhan School of Management, Hubei University of Chinese Medicine, Wuhan 430065, China
国际会议
重庆
英文
786-789
2015-12-18(万方平台首次上网日期,不代表论文的发表时间)