| 摘要 |
There is provided a coherence length measurement device 10 that calculates a coherence length L c based on a spectrum v calculated by an FFT device 9 and performs, in case where the coherence length L c is shorter than an FFT gate width G w , a setting change to shorten the FFT gate width G w and a pulse width P w , and the FFT device 9 performs frequency analysis on a received signal outputted from an A/D converter 8 by a unit of an FFT gate following the setting change to calculate the spectrum v of the received signal. |
