NRZ测试码型的频谱成分NRZ (11000001010011111010) (NRZ) NRZ PRBS X PRBS NRZ NRZ NRZ ) SONET SDH 223 27 - 1 PRBS (127 2X - 1 PRBS ( ) NRZ K28.5± 8b10b (PRBS) (X) 2 X - 1 PRBS ) 8b10b - 1 PRBS ( 840 NRZ NRZ NRZ (T b ) ( 1) ( 0) NRZ NRZ NRZ (PSD) (a) (b) 1 PSD NRZ 50% (CID) CID 1 0 ( ( s[t] = Acos[2πf0t]) NRZ ) 2 delta Aδ(t) t 0 A 8b10b 8b10b 10 ( ) 8 CID 10 10 (BER) 64b66b BER SONET 64b66b CID SDH ( 1 0 ( n / T) A/T) ( delta *) delta delta 8 A ∑nδ(t - nT) delta T 10 delta delta delta 2 NRZ PSD ( 1) L = nTb ( ( 1a) PSD 0 1) 1a sinc2(f) 6 6 1.25Gbps 2 Tb 3 4 (1110 312.5MHz (1/L) sinc2(f) ) 1.25GHz (1/Tb) ( ( 1b) ) ( 1 1c) 1.25Gbps 2.5GHz (2/Tb) (delta ) sinc 2(f) sin( π f)/( π f) (c) sinc2(f) sinc2(f) ( sinc(f) (b) ) sinc2(f) 20 1.25Gbps ( (K28.5± 4) (1.25GHz 4 ) 2.5GHz) 125MHz……