Which of the following statement about the optical power commissioning is wrong?
A . For 10G and 2.5G systems, the commissioning wavelength of the receiving optical power of the wavelength conversion board is "high 3 low 5", which is 3dB higher than the receiving sensitivity and 5dB lower than the overload point.
B . Adjust the VOA (adjustable optical attenuation) in front of the optical amplifier board so that the input optical power of the board = the nominal optical power of the input single wave + 10lgN, where N is the actual wave number. If it is not adjusted, adjust the VOA attenuation to the minimum.
C . Adjust the OAU gain of the optical amplifier board so that the output optical power value reaches the standard.
D . an OAU actually gain the upper threshold is smaller than the nominal gains the upper threshold, indicating that the OAU board performance degradation, recommend to replace.
Answer: D