Dmd1050Ts Clocking Options; Tx Clock Options; Figure 3-10. Clocking And Polarity Diagram - Comtech EF Data DMD1050TS Installation And Operation Manual

3.10 DMD1050TS Clocking Options

The DMD1050TS supports several clocking options that can be recovered from the satellite or the
terrestrial links. The clocking options allow you to decide which clock best fits the application.
Figure 3-10 shows a diagram on how the modem processes the clocks for the Tx Clock source
and the Rx Buffer Clock source. Tx and Rx Clocks can be locked independently.
SD
TT
ST
High Stability
Oscillator
EXT REF
TRANSMIT
RECEIVE
RT
BUFFER CLK POL
RD
DATA POLARITY
3.10.1

Tx Clock Options

Tx clock options can be recovered from the terrestrial or satellite interface, or generated
internally. You can select the SCTE Clock (Terrestrial), or the SCT internal clock. The modem
also allows you to recover the SCT Clock from the satellite (Serial Clock Receive (SCR)), or from
the modem internally. The modem allows you to select clock polarity. The Tx clock selections
available are:
•
SCT (Internal Oscillator)
•
SCTE (External Tx Terrestrial Clock)
•
Rx Satellite Clock
Theory of Operation
SCTE
SCT
HIGH STABILITY
INTERNAL
REF FREQ
SRC
EXTERNAL SCT CLK
SRC
SCR
NORMAL
INVERTED
SCT
BUFFER CLK
SCTE
SRC
RX SAT
INVERT NONE
INV. TERR&BASE
INV. BASEBAND
INV. TERR DATA

Figure 3-10. Clocking and Polarity Diagram

DMD1050TS Satellite Modem Board
INVERT NONE
INV. TERR&BASE
INV. BASEBAND
INV. TERR DATA
DATA POLARITY
CLOCK &
DATA
Tx CLK
CLK POL
SRC
NORMAL
INVERTED
AUTO
CLOCK & DATA
DEMODULATION
RECOVERY
3–20
Revision 1
MODULATION
MN-DMD1050TS