Improvements in, or relating to, multi-carrier transmission systems

摘要

The receiver includes a back-coupling coil which controls an oscillator device. The back coupling coil uses a back coupling signal which represents an argument value of the pilot carrier wave. The back coupling signal is obtained from an approximation of an argument for a complex number which represents the pilot carrier wave. The approximation maintains a full resolution of the complex number and the back-coupling coil controls the oscillator device so that the pilot argument tends to approach zero. The back-coupling coil compensates for channel effects. The oscillator device is a voltage controlled crystal oscillator and the multi-carrier wave transmission system is of the discrete multiple tone (MT) type or a MT-based very high bit rate digital subscriber line system.