Optical SDH/SONET
Modems designed to support single or multiple STM-1 streams. The STM-1 is the SDH ITU-T fiber optic network transmission standard. It has a bit rate of 155.52 Mbit/s. The other levels are STM-4, STM-16 and STM-64.
Single steam of SMT-1 carries 155.52 Mbps of data, and n x SMT-1 can be multiplexed to required number of channels. Alternatively, STM-4 supports 622 Mbps.
Typical features of SDH/SONET based modem:
- I/Q baseband, complex IF or real IF interface
- Input and output carrier frequencies are freely software configurable
- Transport stream is a multiplex of n x STM-1 or single STM-4
- Modulation: QPSK to 128QAM
- Roll-Off factor: software configurable 16-25%
- Bandwidth: software configurable 5 to 112MHz
- Symbol rate: software configurable 4.5-104 MSym/s
- Includes PilotSync™ technology
- FEC Reed-Solomon encoder/decoder
- Interleaver/Deinterleaver depth: I = 1/2/3/4/6/12/17
- Configuration via 8bit parallel host interface or RS 232
- Single external analogue loop for AGC 18 bits
- Input from ADC: 11-12 bits (1 or 2 (I/Q) channels)
- Output to DAC: 10-16 bits (1 or 2 (I/Q) channels)
- Decision Feed-Forward Equalizer in the receiver channel
- Modem master clock / sampling rate: single, fixed 200 or 210 MHz clock source
- Shape Filter: Root-Raised-Cosine
- Internal PRBS generator and internal BER tester
