Comtech EF Data C5 - Manual (Page 256)

Options C5/K1/K3 Integrated Satellite Terminal System
A–12 Rev. 0
The Doppler buffer receives data clocked by the overhead clock from the demodulator
and an enable line from the demultiplexer. The data is stored in RAM. Four options are
allowed to clock the data out of the buffer:
! External
! Internal
! Receive
! Transmit
Based on this selection, terrestrial data is clocked out of the buffer to the selected drivers
and on to the end user.
A.2.1.3.6 Loop Timing Operation
A loop timing option is provided. When loop timing is selected, the Doppler buffer
output clock is forced to the receive clock by the M&C. An M&C-controlled multiplexer
switches the Send Timing (ST) pin to output the receive clock. The receive clock is sent
out the ST pin to the appropriate interface drivers and on to the user. The operator is left
with the option of clocking terrestrial data into the multiplexer on the transmit side with
either the external clock source Terminal Timing (TT) or the internal clock source. The
internal clock source is the same as the ST pin.
A.2.1.3.7 Baseband Loopback Operation
A baseband loopback option is provided. When selected, the input terrestrial data and
clock from the operator are looped back to the user as the output terrestrial data and
clock.
The terrestrial data and clock output from the demultiplexer are also looped to the
terrestrial data and clock input at the multiplexer.