A.256

B.128

C.512

D.64

A.AU-PTR refers to the position of the J0 byte.

B.Since the value of the AU-PTR pointer is placed in the last 10 bits of the two bytes H1 and H2, its effective value is 0~1023.

C.The root cause of AU pointer adjustment is that the clocks between the upstream and downstream stations are not synchronized.

D.If the receiving end detects that the H1H2 bytes are all "1", the local end generates an AU-AIS alarm.

A.Optical line protection and ODUk SNCP protection are both single-ended switching. When a single fiber fails, the sending and receiving routes will be inconsistent

B.The switching time of optical line protection and ODUk SNCP protection is less than 50 ms. In order to avoid cable disconnection, multiple switching is triggered, and the two protections cannot coexist

C.Optical line protection is switched by the OLP board, and ODUk SNCP protection is switched by the cross-connect board

D.Optical line protection belongs to network-level protection, and ODUk SNCP belongs to service-level protection

A.LCD

B.szhw

C.1ct

D.root

A.The OSNR value of the coherent signal tested by the integral method is not as accurate as the OSNR value scanned by the sweeping board.

B.The use of PDM+QPSK/PDM+BPSK modulation can reduce the OSNR requirements of the system.

C.As the number of amplifying boards used on the line increases, noise will continue to accumulate, resulting in a decrease in OSNR.

D.The use of FEC technology can reduce the OSNR requirements of the system.