Comtech EF Data SDM-9000 - Manual (Page 153)

SDM-9000 Satellite Modem Theory of Operation
Rev.4 5–25
The buffer clock source selection must fall within the following parameters:
G.703 Interface
TX Terrestrial No restrictions.
RX Satellite No restrictions.
External Clock Must be in the range from 1.544 to 20 MHz, in 8 kHz steps, or at the RX
terrestrial data rate.
Internal Clock No restrictions.
ECL Interface
TX Terrestrial TX and RX terrestrial clocks (data rates) must be divisible by 8 kHz, or the
TX data rate must be the same as the RX data rate.
RX Satellite No restrictions.
External Clock The external clock must be in the range from 1.544 to 20 MHz, in 8 kHz
steps, and the RX (data rate) clock must be divisible by 8 kHz.
Additionally, the external clock may be at the RX (data) clock rate.
Internal Clock Refer to “TX Terrestrial.” This clock is at the same frequency as the TX
terrestrial clock.
MIL-STD-188 Interface
TX Terrestrial TX and RX terrestrial clocks (data rates) must be divisible by 8 kHz, or the
transmit data rate must be the same as the receive data rate.
RX Satellite No restrictions.
External Clock The external clock must be in the range from 1.544 to 20 MHz, in 8 kHz
steps, and the RX (data rate) clock must be divisible by 8 kHz.
Additionally, the external clock may be at the RX (data) clock rate.
Internal Clock Refer to “TX Terrestrial.” This clock is at the same frequency as the TX
terrestrial clock.
Note: G.703 interfaces have the option of HDB3 or B3ZS line coding data to the
terrestrial interface. This selection shall be made by the user.