Comtech EF Data CDM-625, Инструкция по установке и эксплуатации

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CDM-625 Advanced Satellite Modem Revision 1
Front Panel Operation MN-0000036 (Ref MN/CDM625.IOM)
5.4.5.2 CONFIG: Clocks
Æ
Rx Buffer/Clock
Clk=Rx-Sat (Rx-Sat,TxTerr,Int(SCT),Ins)
Buffer-Size = 00016bytes(00002ms) Center
U
se the
▲ ▼
arrow keys to select from the choices shown in parentheses. Then, to edit the Rx
clock options, use the ◄ ► arrow keys to select the digit to edit, then use the
▲ ▼
arrow keys to
revise the digit. Press
ENTER
when done.
Rx-Sat
Sets the Receive buffer clock source to the satellite clock (The receive buffer will be
bypassed.)
Note:
This will fix the buffer size to minimum.
Tx-Terr
In this timing mode, data is clocked out of the receive buffer using the external
transmit clock.
Int(SCT)
Data is clocked out of the buffer using the same reference that drives the modem
Internal(SCT).
Ins(ert)
Sets the buffer clock to the Insert stream. Available only if Rx framing is D&I and Rx
interface is G.703.
Buffer-Size indicates the size in bytes (and size in milliseconds) of the Plesiochronous/ Doppler
Buffer. Edit each digit of the buffer size using the
▲ ▼
arrow keys, then press
ENTER
.
Note:
the minimum buffer size and step size usually the same, and are dictated by several rules:
If Framing is Insert:
If D&I Type is: Step size (bytes)
E1 @ 1920kbps 1024 or 4ms
T1-D4 24 x n or 3ms
T1-ESF 48 x n or 6ms
E1 32 x n or 4ms
If Framing is D&I++:
If n = Step size (bytes)
1,3,5 720
2,6,10,15,30 1440
9 2160
4,12,20 2880
25 3600
18 4320
7,21 5040
8,24 5760
27 6480
11 7920
13 9360
14 10080
16 11520
17 12240
19 13680
22 15840
23 16560
26 18720
28 20160
29 20880
31 22320
5–23