MULTI-CARRIER TELECOMMUNICATION SYSTEM WITH POWER ADAPTATIONMEANS

摘要

A telecommunication transmitter (TU) for a multi-carrier transmission system of the Digital Subscriber Line ¢DSL! type and which includes a coding circuit (MMC) able to generate "symbols" derived from carriers (Cl-Cn) modulated by incoming data, and a line driver circuit (LDC) to amplify these symbols. When idle data are received, the power dissipated in the transmitter is reduced because the symbols are then merely derived from a few or even a single carrier (the "pilot tone") instead as from all the available carriers. Th e power dissipated is even more reduced because the line driver circuit comprises the parallel connection of a high voltage but low efficiency (LL) and a lower voltage but higher performant (LH) line amplifier. The higher performant, and thus less power consuming, amplifier (LH) is used when idle data are received at the input (IN). In a variant, there is only one line amplifier of which the quie scent current is controlled in function of the data traffic. In another variant, the n umber of carriers used by the coding circuit (MMC) is a function of the mean traffic o f effective data received.