### TCM and the Shannon limit

The significant coding gain of TCM-based modems means that it is now possible to get very close to the Shannon limit for certain modulation types and coding levels. The implementation complexity may once have appeared daunting and almost impractical back in 1976 when the technique was first published (see Ungerboeck and Csajka (1976)) , but today TCM modems are fully integrated into a single IC and available as credit card (PCMCIA) sized plug-ins for PCs. |

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