Trellis

Trellis may refer to:

See also

Trellis (architecture)

A trellis (treillage) is an architectural structure, usually made from an open framework or lattice of interwoven or intersecting pieces of wood, bamboo or metal that is normally made to support and display climbing plants, especially shrubs. There are many types of trellis for different places and for different plants, from agricultural types, especially in viticulture, which are covered at vine training systems, to garden uses for climbers such as grapevines, clematis, ivy, and climbing roses or other support based growing plants. The rose trellis is especially common in Europe and other rose-growing areas, and many climbing rose varieties require a trellis to reach their potential as garden plants. Some plants will climb and wrap themselves round a trellis without much artificial help being needed while others need training by passing the growing shoots through the trellis and/or tying them to the framework.

Trellis can also be referred to as panels, usually made from interwoven wood pieces, attached to fences or the roof or exterior walls of a building. A pergola usually refers to trellis-work that is laid horizontally above head height to provide a partial "roof" in a garden (pergolas are also used in agricultural settings).

Trellis modulation

In telecommunication, trellis modulation (also known as trellis coded modulation, or simply TCM) is a modulation scheme that transmits information with high efficiency over band-limited channels such as telephone lines. Gottfried Ungerboeck invented trellis modulation while working for IBM in the 1970s, and first described it in a conference paper in 1976. It went largely unnoticed, however, until he published a new, detailed exposition in 1982 that achieved sudden and widespread recognition.

In the late 1980s, modems operating over plain old telephone service (POTS) typically achieved 9.6 kbit/s by employing four bits per symbol QAM modulation at 2,400 baud (symbols/second). This bit rate ceiling existed despite the best efforts of many researchers, and some engineers predicted that without a major upgrade of the public phone infrastructure, the maximum achievable rate for a POTS modem might be 14 kbit/s for two-way communication (3,429 baud × 4 bits/symbol, using QAM).