Digital Return Path
The digital return transmitter series (DS-SG2-DRT*) converts a broadband analog RF return-path signal into digital optical signals with 10-bit resolution.
The transmitters used for digital return applications are divided into two families: DS-SG2-DRT/A and DS-SG2-DRT-2X/A.
Seven digital return transmitters per family are available to meet the needs of most digital return applications.
Table 2-2 identifies the fourteen optical digital return transmitters:
Table 2-2
Digital return transmitters
DS-SG2-DRT/A
DS-SG2-DRT/A-1310 FP DS-SG2-DRT/A-1310 DFB DS-SG2-DRT/A-1470 DFB DS-SG2-DRT/A-1490 DFB DS-SG2-DRT/A-1550 DFB DS-SG2-DRT/A-1510c (2) DFB DS-SG2-DRT/A-1530c DFB DS-SG2-DRT/A-1550c DFB DS-SG2-DRT/A-1570c DFB DS-SG2-DRT/A-1590 DFB DS-SG2-DRT/A-1610 DFB
DS-SG2-DRT-2X/A
DS-SG2-DRT-2X (1)/A-1310 FP DS-SG2-DRT-2X/A-1310 DFB DS-SG2-DRT-2X/A-1470 DFB DS-SG2-DRT-2X/A-1490 DFB DS-SG2-DRT-2X/A-1550 DFB DS-SG2-DRT-2X/A-1510c DFB DS-SG2-DRT-2X/A-1530c DFB DS-SG2-DRT-2X/A-1550c DFB DS-SG2-DRT-2X/A-1570c DFB DS-SG2-DRT-2X/A-1590 DFB DS-SG2-DRT-2X/A-1610 DFB
(1)2X in the model number denotes time division multiplexing (TDM)
(2)c in the model number denotes coarse wave division multiplexing (CWDM)
To prepare for an anticipated increase in return traffic, provisioning for CWDM is built into the transmitters. The CWDM option consists of lasers at predefined wavelengths. This option is available to support multiplexing in the optical domain, using eight-wavelength wave division multiplexing (WDM) in the DS-SG2-DRT/A-15XX DFB and DS-SG2-DRT-2X/A-15XX DFB windows.
DS-SG2-DRT/A
The DS-SG2-DRT/A digitizes a single analog 5-42 MHz return path signal to produce a 1.6 Gbps data stream. This data stream is then routed to a digital laser for transmission to a corresponding digital return receiver. The node can be configured with one or two DS-SG2-DRT/A transmitters, with dual transmitters providing redundancy. In conjunction with these transmitters, the node must also be configured with the SG2 Return Path Module/Combined (SG2-RPM/C). The return signals from all four ports are combined and fed to the optical transmitters.
SG 2000 Installation and O peration Manual
