Useful Fact - 1/6/09:
The PSM-500 Series of Modems split the transmit and receive FEC functions. The modulator's transmit encoder is included with the base modem firmware and it provides the capability for all currently available FEC Technologies. You do not have to purchase anything extra to get this capability. The demodulator's receive decoder is contained on a plug-in FEC card, and is based up a combination of:
- Standard firmware and Intellectual Property which we have purchased and do not charge for - Viterbi, TCM, Reed-Solomon.
- Our own firmware plus hardware chips which we have purchased and are extra cost options - TCP-4k, TCP-16k, S-Tec.
- Our own firmware plus Intellectual Property (IP) which we have purchased and license on a per use royalty basis and are extra cost options - LDPC-2k, LDPC-16k.
The LDPC-2k firmware fits within the programmable gate arrays on the standard FEC card and adding this receive capability requires only puchasing the Code Enabled Option to install and use it. The LDPC-16k requires a significantly larger FPGA and therefore requires purchasing a new standard FEC card that includes that larger part plus the IP licensing fee.
From a users perspective this means that you only have to pay for those added capabilities that cost us more.
How does this help you? Suppose you are operating a typical Star Network Topology and have a large antenna at the hub and small antennas at the remotes. Since the hub receive is aided by the large antenna you can possibly use a less powerful FEC for the receive there, like Viterbi with R-S or TPC-4k or LDPC-2k. The lower speed and cost may not impact use at the hub because the remotes are usually transmitting at a lower data rate. The Remotes can spend a little extra for the more powerful TPC-16k or LDPC-16k and potentially use a smaller antenna. You save the decoder costs for all hub station modems.