Assumptions:

The outlink comprises a single carrier occupying a full transponder.

Symbol rate 29.270 Mbsps

Uplink contour at the hub is +6 dBK and transponder gain step is set to PFDsat=-86 dBW/m2

The single carrier operating point is -1 dB in and -0.5 dB out.

Power spectral density at the satellite is -86 -1 = -87 dBW/m2

Saturated EIRP towards the edge of beam remote sites = 51 dBW.

Operating PFD produces a downlink EIRP = 51 - 0.5 = 50.5 dBW

This conversion (-97 in and + 50.5 out) has been put into the link budget as the Transponder "gain". It applies to single carrier operation.

The input figures are all guesses and estimates. You need to overwrite the figures with your own assumptions.

Amend any white boxes and then click the calculate button to obtain results in the green boxes.

A carrier with symbol rate = 29.27 Msps would provide a data rate of 43 Mbit/s.

If you use a DVB-S2 type outlink the capacity increases due to 8PSK modulation and less FEC.

Any problems or comments please e-mail Eric Johnston Copyright (c) 23 Feb 2012 Satellite Signals Ltd All Rights Reserved |