## Practical issues with TCM

TCM is now used extensively in modern high-speed telephone and radio modems. For example, a 28.8 kbps dial-up modem (V.34 standard) can use up to 1408-QAM, with a 16-state, rate 2/3 code. |

There are some practical issues to note with TCM: Increasing the number of symbol states may incur an implementation penalty as well as the theoretical Eb/N0 penalty, requiring greater amplitude and phase accuracy in the TX/RX system. More symbol states may result in an increased peak to mean ratio for the transmit hardware to cope with. When TCM systems are operated in very poor signal conditions, they 'fall over' much more rapidly than the uncoded equivalent throughput system.

####