Abstract: A predistorter, a method for predistorting, and an amplifier include a predistorter. The predistorter is particularly suitable for predistorting an input signal of an amplifier, which amplifier introduces frequency dependent distortion that increase with the frequency. The predistorter makes use of a predistortion technique involving a high pass filter such that distortion, which compensates for the distortion introduced by the amplifier, is introduced in an output signal of the predistorter for the specific frequencies for which further distortion compensation is required. An advantage is that the predistorter allows the performance of an amplifier to be improved by reducing distortion and increasing linearity. Thereby the predistorter allows low power amplifiers with relaxed distortion requirements to be used as, for example, line drivers in many telecommunications systems.

Abstract: The present invention relates to a device and a method for calculating FFT, IFFT or like transforms with the aid of a calculating unit and at least two memories. The calculating unit reads input values from the memory positions in the memories, performs a group of calculations in at least one calculation step, and writes the output values obtained with these calculations into memory positions in the memories. The invention comprises the steps of reading-in and immediately storing the input values for calculation in different groups of calculations. When all input values necessary for a current group of calculations have been read in and the calculations in a preceding group of calculations have terminated at least one first calculation step, calculations in the current group of calculations are commenced.

Abstract: To minimize power dissipation in a line driver (3) in a central office (CO) for driving a DSL connection to a network terminal (NT) with a predetermined maximum constellation size, the central office (CO) supplies the line driver (3) with a predetermined supply voltage during a training sequence, and transfers data with a predetermined power spectral density in all available channels. The network terminal (NT) measures the signal-to-noise ratio of each channel, and transfers information to the central office (CO) about channels having signal-to-noise ratios that enable transfer of data.

Abstract: The invention relates to a line driver supplied with a power supply voltage from a power supply and an amplifying method. According to the invention the following steps are performed: using whole or part of the power supply voltage to generate the output voltage if the input voltage is within the predefined range; loading at least one capacitor with at least one capacitor voltage; and using whole or part of the capacitor voltage in addition to whole or part of the power supply voltage to generate the output voltage if the input voltage is outside the predefined range.

Abstract: A method and apparatus are provided for reducing power dissipated by an amplifier circuit such as a line driver in a Digital Subscriber Line (DSL), a power amplifier in a radio environment, etc. The power supplied to the amplifier circuit changes depending upon the level of input signal to the amplifier circuit. A higher power is supplied to the amplifier circuit when the level of the input signal exceeds a threshold. Otherwise, a lower power is supplied to the amplifier circuit.