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Braun
Communications Consulting |
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Errata |
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Errata for Satellite Communications Payload and
System, 2nd edition |
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The
downlink budget in Chapter 14, Figure 14.5, is incorrect. With the change, part of the nearby text is
different, too. Replacement text: |
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The link budgets we present in Figure
14.15a, Figure 14.15b, and Figure 14.15c, are for an uplink to a GEO
spacecraft and a corresponding downlink.
The payload is taken to be a bent pipe so the Es/(N0+I0)
of the composite link is of main interest.
The values in the budgets are not necessarily representative. The parenthetical items are of interest
because they are used to calculate the non-parenthetical items, but they are
optionally present in the budget.
Losses are given as negative to make it more obvious how to combine
items. In most cases, interference
and intermodulation products at HPA output are well modeled as additional
noise-type terms, which is why N0 and I0 are usually
summed as they are here. The implementation-loss line-item in
discussed in the following section. Other ways of presenting budgets are variations
on what is shown in Figure 14.15a, Figure 14.15b, and Figure 14.15c. For example, for a regenerative payload the
composite link performance is of no interest.
Also, one may want to make two sets of budgets, for maximum and
minimum signal levels on the uplink. Uncertainties or variations could also
be included (Section 9.3.4). For a link that employs DVB with ACM,…. |
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Click here
for pdfs of revised Figure 14.15, a, b, and c. Click here
for Excel spreadsheet of same. |