SLM-3650 Satellite Modem
Revision 3
Operation
MN/SLM3650.IOM
3–19
BUFFER CLOCK
Programs the interface buffer output clock to one of the following modes:
RX (SATELLITE):
Sets the output buffer clock to the satellite clock.
SCT (INTERNAL):
Sets the buffer clock to operate from the modem internal clock. This is also
the fallback clock.
EXT. CLOCK:
Sets this clock source to the external clock.
TX TERRESTRIAL:
Sets the buffer output clock to recover timing from the incoming TX data
clock.
INSERT CLOCK:
Selects the recovered clock from the insert send data input received from
the terrestrial equipment.
Note:
INSERT CLOCK selection is only available when D&I overhead is enabled as the RX
Overhead type or when Modem Type is D&I.
Upon entry, the current setting of the plesiochronous buffer clock is displayed. Press [
↑
] or [
↓
]
to make the selection. Press [ENTER] to execute the change.
BUFFER SIZE
Sets the size of the buffer in either Bits or Milliseconds.
Upon entry, the current buffer length is displayed. Press [
↑
] or [
↓
] to select the desired buffer
size. The buffer size is displayed in seconds or bits. Enter the
Function Select: Utility
Interface
menu to change the buffer units to seconds or bits.
If selecting seconds, choose from 1 to 99 ms, in increments of 1 ms or 0 (Bypass).
If selecting bits, choose from 32 to 262144 bits, in increments of 16 bits. Press
[ENTER] to execute the change.
When D&I is selected for modem type, the buffer units are automatically set to ms. The user
may select as follows:
nn = 7.5, 15, or 30 ms for E1CAS format.
nn = 6, 12, 24, or 30 ms for T1IBS/T1S/T1ESFS format.
nn = 1, 2, 4, 8, 16, or 32 ms for all other D&I formats.
Note:
To have the modem calculate the plesiochronous shift, set the buffer units to ms. When
a specific buffer depth is desired, set the buffer units to bits.
BUFFER CENTER
This configuration function is used to center the buffer. Choosing YES centers the buffer.
Press [ENTER] twice to center the buffer.
RX CLOCK PHASE
Programs the RX clock phase to Normal or Inverted.
Upon entry, the current status of the RX Clock is displayed. Press [
↑
] or [
↓
] to make the
selection. Press [ENTER] to execute the change.
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