Comtech EF Data SDM-2020 - Manual (Page 108)

8-1
Chapter 8. LOW VOLTAGE
DIFFERENTIAL SIGNAL (LVDS)
8.1 G
ENERAL
The following paragraphs describe the LVDS interface. This plug-in module provides the
physical and electrical interface between an SDM-2020 modulator or demodulator and
DVB or DBS signal sources operating with LVDS electrical characteristics.
8.1.1 A
PPLICABLE
D
OCUMENTS
TM1449 Interfaces for CATV/SMATV Headends and Similar Profession
TIA/EIA-644 Telecommunications Industry Standard, Electrical Characteris
Voltage Differential Signaling (LVDS) Interface Circuits (origin
Proposal SP-3357)
8.1.2 D
ESCRIPTION
The LVDS interface has dedicated transmit and receive connectors and an auxiliary
connector. The Receive Out connector is used with the demodulator while the Transmit
In connector is used with the modulator:
• J3 Receive Out connector (25-pin D, female). This connector supports the
following data formats:
Parallel format: The interface is a DVB 8-bit parallel synchronous
interface. Data and clock exit the connector and the output clock (Clock
A and Clock B) is at the byte rate.
Serial format: MSB (Data7) is used for serial output data and the output
clock (Clock A and Clock B) is at the bit rate.