signal extract的用法和样例：
例句
- Then after amplitude limiting, to be preamplified, demodulated, bandpass filtered, the doppler frequency shift signal is extracted.
经过限幅保护，接收放大，检波和带通滤波后，将多普勒频移信号提取出来。 - Then we study the methods of image analysis and data analysis in order to extract the hybridizing intensity and retrieve the biological information.
然后从图像分析和数据分析两方面研究了影响芯片分析的因素，实现了对杂交荧光图像的信号提取和基本的生物信息分析。
