Patent ID: 7991069

Claim:
A method for adapting filter cut-off frequencies for the transmission of discrete multitone symbols, comprising the following steps: a) applying a transmit symbol datastream consisting of discrete multitone symbols, which is provided by a multitone transmitter device, to an interpolation device; b) interpolating the transmit symbol datastream with a symbol rate in the interpolation device to provide an interpolated symbol datastream; c) low-pass filtering of the interpolated symbol datastream in a first low-pass filtering device according to a first filter cut-off frequency, which is predetermined by a first filter cut-off determining device, to provide a filtered symbol datastream; d) converting the filtered symbol datastream into an analog datastream in a digital-analog converter; e) transmitting the analog datastream via a transmission channel; f) converting the transmitted analog datastream into a digital symbol datastream in an analog-digital converter; g) low-pass filtering the digital symbol datastream in a second low-pass filtering device in accordance with a second filter cut-off frequency, which is predetermined by a second filter cut-off frequency determining device, to provide an equalized symbol datastream; h) decimating the equalized symbol datastream in a decimation device to provide a decimated received symbol datastream having discrete multitone symbols; and i) delivering the received symbol datastream to a multitone receiver device; wherein at least one of the first and the second filter cut-off frequency of the first and the second low-pass filtering device, respectively, is changed during a cyclic prefix of a DMT symbol.