Comtech EF Data SDM-2020 - Manual (Page 176)

SDM-2020 Satellite Demodulator Revision 4
G.703 Data Interface MN/SDM2020D.IOM
11–10
11.1.5 Receive Doppler/Plesiochronous Buffer Specifications
11.1.5.1 Buffer Size
The operator can set the buffer size, ranging from 2 milliseconds to 32 milliseconds, in
2 millisecond steps. There is also a buffer bypass selection, buffer size of 0 milliseconds.
11.1.5.2 Frame Structures
The unit provides programmable plesiochronous buffer slips.
Frame structures provided according to data rate:
• 1544 kbps - None or G.704
• 2048 kbps - None or G.704
•
6312 kbps - None, G.704, G.743, or G.747
• 8448 kbps - None, G.704, G.742, or G.745
•
32064 kbps - None or G.752
• 34368 kbps - None, G.751, or G.753
•
44736 kbps - None, G.752
• 51840 kbps - None or STS-1
11.1.5.3 Buffer Clock Sources
The unit shall provide for buffer clock source selections.
Source selections:
• Internal
• Transmit terrestrial
• External Reference
• RX satellite
11.1.5.4 Buffer Clock Backup
In the event of failure of the selected buffer clock the unit automatically selects the RX
satellite clock as the backup.