Comtech EF Data SDM-2020 - Manual (Page 159)

SDM-2020 Satellite Modulator Revision 7
ASI/LVDS Data Interfaces MN/SDM2020M.IOM
13-3
Table 13-1. ASI/LVDS Specifications
General Specifications
Data Framing Formats 188, 204 byte packets per ETS 300 421, and None.
Hot Pluggable Not required. Unit power is turned off before removal or insertion of the
data interface.
ASI Specifications
Data Rate 1.5 to 100 Mbit/s ASI.
Clock Rate Uncertainty Programmed data rate ± 100 ppm.
Transport Clock ASI The transport rate is 270 Mbit/s for all data rates.
Impedance 75 Ω
.
Return Loss 15 dB, frequencies, 5 to 270 MHz.
Loop Functions Loopback and Loop Thru
Connectors BNC female, 75 Ω.
Electrical Properties Per EN 80053-9.
Packet Types Burst or distributed.
Signal Types Serial data.
Voltage Level 800 mV ± 10% into 75 Ω.
ASI Data Loop 3 dB
Frequency, TX Only Wide: 2 Hz
Narrow: 0.3 Hz
Jitter Tolerance Meets ITU-T G.823 (3/93) and ITU-T G.824 (3/93)
Jitter Transfer ≤ 0.5 dB peaking up to cutoff frequency.
-20 dB per decade beyond cutoff.
Cable Length, Typical 50 meters (165 feet), RG59
70 meters (230 feet), Belden 8281
Delay Variation Of Interface
And Modulator 8 bits maximum, QPSK all data rates,
8PSK 2/3 and 5/6 all data rates. 8PSK 8/9 less than 80 Mbit/s
LVDS Specifications
Data Rate 1.5 to 100 Mbit/s, parallel LVDS
Clock Rate Uncertainty Programmed data rate + 100 ppm
Connectors 25-Pin D female per EN 80053-9.
Same connector is either TX or RX data (See Loopback / Loop Thru)
Electrical Properties per EN 80053-9
Signal Types D0 – D7, Sync, Dvalid and Clock per EN 80053-9
Data synchronization is detected by correlating the data stream for the
MPEG2 sync pattern per ETS 300 421.