Reception of quadrature amplitude-modulated discrete multi-tone signals, employs Fourier transformation and equalization to achieve maximum signal to noise ratio

摘要

A quadrature amplitude modulated reception signal (Z(tk)) digitally converted with a first sampling frequency, is split into first and second signals (Z1(tk), Z2(tk)) with shifted sampling phases. The quadrature amplitude modulated signals (Z(t)) have excess bandwidth. The signals (Z1(tk), Z2(tk)) are each Fourier-transformed, using a second sampling frequency (f2). Respective Fourier coefficients of the transformed signals (Z1(fu), Z2(fu)) are weighted with equalization coefficients (E1(fu), E2(fu)). The Fourier-transformed and weighted signals (D1(fu), D2(fu)) are combined to an equalized reception signal (D(fu)). The equalization coefficients are first imposed and varied, until signal interference arising, is at least partly suppressed, and the resultant equalized reception signal (D(fu)) exhibits maximum signal-to-noise ratio. An independent claim is included for corresponding reception equipment.