Overhead Rate Comparison - Comtech EF Data DMD-2050E Installation And Operation Manual

DMD2050E Universal Satellite Modem
3.19.3

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 example
overhead rates for different user data and control ratios.
User Data Rate
512,000
1,024,000
2,048,000
3,072,000
4,096,000
6,312,000
6,312,000
6,312,000
MN-DMD2050E Revision 2
In-Band Rate Control Ratio
19,200 1/7
19,200 1/7
19,200 1/7
19,200 1/7
19,200 1/7
19,200 1/7
19,200 1/3
19,200 1/1
Aggregate Data Rate Overhead Ratio
533,974
1,045,974
2,069,951
3,093,943
4,117,951
6,337,248
6,337,606
6,350,418
Theory of Operation
1.043
1.021
1.011
1.007
1.005
1.004
1.004
1.006
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