Reed-Solomon Codec - Radyne DMD2050 Operation Manual

Theory of Operation
To View the current Timeslot Assignment:
1. If there is a question of the channels not being entered properly, the Mapping Menu may
be used to see how the channels/timeslots are configured in the modem.
2. Use <ENTER> and the Arrow Keys to make the mapping menu read (for the Tx Side):
3. Press <ENTER>. The modem has now copied the current Tx Settings to the Tx
Channel/Timeslot Display.
4. For the Rx Side:
5. Press <ENTER>. The modem has now copied the current Rx Settings to the Rx
Channel/Timeslot display ).
It is not mandatory to assign timeslots in sequential order, although the
lowest timeslot must be entered in the lowest channel. For example:
timeslots may be assigned 1 - 2, 2 - 5, etc. but not 1 - 5, 2 - 2.

3.14 Reed-Solomon Codec

Utilizing a Reed-Solomon (R-S) Outer Codec concatenated with a Convolutional Inner Codec is
an effective way to produce very low error rates even for poor signal-to-noise ratios while
requiring only a small increase in transmission bandwidth. Typically, concatenating an R-S
Codec requires an increase in transmission bandwidth of only 9 – 12% while producing a greater
than 2 dB improvement in E
encoder which adds 2t = (N – K) check bytes to produce an N byte R-S block. The R-S decoder
can then correct up to "t" erred bytes in the block.
3-20
Map
TX ACTIVE > TX EDIT
Map
RX ACTIVE > RX EDIT
Refer to Figures 3-16, 3-17, and Table 3-1.
/N . R-S is a block Codec where K data bytes are fed into the
b o
DMD2050 Universal Satellite Modem
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TM110 - Rev. 1.3