| 摘要 |
PROBLEM TO BE SOLVED: To provide a small signal detection system which enhances signal detection accuracy, and to provide an electron microscope mounting it.SOLUTION: A small signal detection system includes a statistic data acquisition section for calculating the dispersion of the amplitude and noise of a desired signal by measuring the average value and distribution of an input signal where noise is superimposed on the desired signal, and outputting the calculation data thus obtained, a nonlinear characteristic section for outputting a signal which responds to the magnitude of the voltage or current of the input signal nonlinearly, a signal detection rate evaluation section for determining whether or not the output signal from the nonlinear characteristic section is the desired signal, calculating the detection rate when it is the desired signal and outputting detection rate data, a parameter adjustment section for adjusting control parameters related to the response of the nonlinear characteristic section, based on the detection rate data obtained in signal detection rate evaluation section and calculation data obtained from the statistic data acquisition section, and a signal processing section for arithmetically processing the output signal from the nonlinear characteristic section and converting into digital data or image data. |
