Comtech EF Data SDM-2020 - Manual (Page 172)

SDM-2020 Satellite Demodulator Revision 4
G.703 Data Interface MN/SDM2020D.IOM
11–6
Table 11-1. G.703 Specification (Continued)
G.703 Specifications (Continued)
External Reference Clock
Input Signal Characteristics Sine wave or square wave with duty cycle of 50% ( ± 10%)
Input Amplitude 0.5 to 5.0V peak to peak
Input Impedance 75 Ω ± 5%
Input Frequency 1.544 to 20.0 MHz in steps of 8.0 kHz or at RX data rate
Connector Type BNC (female)
Auxiliary Functions Port
Signals DF (demodulator fault, open collector TTL output)
CD (carrier detect, TTL output)
Connector Type 9-pin sub-D (female)
Controlled Items:
Data Date Rate
Line Coding
Test Modes Interface Loop-Through
Interface Loopback
RX2047 Pattern
Buffer/Doppler/Plesiochronous Size
Clock Source
Frame Structure
Buffer Centering
Monitor Functions
RX Interface Faults Buffer underflow, buffer overflow, buffer clock activity, buffer clock
PLL, buffer full, data/AIS, 2047 pattern lock, FPGA program
Buffer Fill Status 1 to 99%
RX 2047 Error Rate 1E-3 to 5 E-8 (with one magnitude accuracy)
11.1.4 Receive Specifications
The following receive specifications apply when the G.703 data interface is installed in
an SDM-2020 Demodulator.
11.1.4.1 Receive Data Rate 1.544 Mbps Specifications
Refer to Table 11-2 for data rate specifications.
Table 11-2. RX Data Rate 1.544 Mbps
Parameter Specification
Data Rate 1.544 Mbps, ± 30 ppm
Line Coding B8ZS and AMI at 1.544 Mbps
Pulse Shape Rectangular per ITU-T-G.703, Figure 12/G.703.
Jitter Characteristics:
Input Jitter
Output Jitter
Complies with ITU-T-G.824 and Table 1/G824.
In accordance with ITU-T-G.824 and Figure
1/G.824.