Comtech EF Data DMD1050 - Manual (Page 57)

DMD1050 Satellite Modem Board Theory of Operation
MN-DMD1050 3–31
Revision 9
3.17.3 Overhead Rate Comparison
The SCC Overhead Ratio varies depending on the User Data Rate, the In-Band Rate, and the
Control Ratio. This gives SCC the advantage of lower overhead rates when compared to IBS,
which has a fixed overhead ratio of 16/15 or 1.067. The following table gives some examples of
SCC overhead rates for different user data and control ratios.
User Data Rate In-Band Rate Control Ratio Aggregate Data Rate Overhead Ratio
512,000 19,200 1/7 533,974 1.043
1,024,000 19,200 1/7 1,045,974 1.021
2,048,000 19,200 1/7 2,069,951 1.011
3,072,000 19,200 1/7 3,093,943 1.007
4,096,000 19,200 1/7 4,117,951 1.005
6,312,000 19,200 1/7 6,337,248 1.004
6,312,000 19,200 1/3 6,337,606 1.004
6,312,000 19,200 1/1 6,350,418 1.006