Patent ID: 7133443

Claim:
A modulation method for multiple-tone signalling for use in a device having a modulator and an analogue front end, the method including the steps of: processing input data through a plurality of intermediate processing stages and corresponding stages of intermediate data to generate preprocessed data; inverse Fourier transforming the preprocessed data to obtain a symbol including a number of tones; buffering the symbol in a symbol buffer; modelling a peak amplitude that the symbol would contain after subsequent processing in the analogue front end and comparing the modelled peak amplitude with a threshold; if the modelled peak amplitude in the symbol exceeds the threshold, amending predetermined intermediate data such that the input data is still represented by the amended intermediate data, carrying out subsequent intermediate processing stages on the amended intermediate data to regenerate preprocessed data, inverse Fourier transforming the regenerated preprocessed data to obtain a regenerated symbol including a number of tones, and replacing the buffered symbol with the regenerated symbol; and outputting the contents of the symbol buffer through the analogue front end.