Maintenance
M7/M7L/M7LT Modular Satellite Modem
2-22
M7/M7L/M7LT - Rev. 0.05
Turbo Product Codes or TPC is available in three versions depending on the link requirements. The
three versions are:
TPC4K which uses the same TPC chip as in legacy Datum modems
TPC16K which uses a newer 16K block size to improve performance
TPC20K board with both the TPC4k and TPC16k chips installed
Because of the larger processed block size, the TPC16K device has much higher delay or latency
than the 4K block device. The M7 can be ordered with any of these TPC options from the factory or
installed in the field by a qualified technician. Once installed, the TPC option card will provide added
functionality to the standard FEC functions already contained within the modem (Viterbi, TCM, Reed-
Solomon, and FlexLDPC).
The Turbo Product Codes option, when enabled, replaces any other FEC function. The Modulator
(Transmit) and Demodulator (Receive) functions of each option are also independent and can be
enabled and disabled as required.
The physical arrangement of the FEC slot is shown in Figure 2-15. The same size PWB is used for
the TPC4K, TPC16K, and TCP20K optional card.
Figure 2-15 - FEC Option Card Installation