Patent ID: 7315571

Claim:
An X-DSL transceiver configured to couple to at least one subscriber line to communicate at least one multi-tone modulated communication channel thereon; and the X-DSL transceiver comprising: a digital signal processor (DSP) configured to couple to the at least one subscriber line for multi-tone modulation and demodulation of the at least one communication channel thereon, and the DSP operative during a training phase of the at least one multi-tone modulated communication channel to determine an available range of frequencies on the at least one subscriber line and to expand or contract a tone spacing of each of a fixed number “N” of tones responsive to the determination; and the DSP including: a Fourier transform module for transforming successive tone sets of the fixed number “N” of tones of the at least one multi-tone modulated communication channel between a frequency domain and a time domain, and the Fourier transform module responsive to the determination to expand the tone spacing by decreasing a processing interval associated with the transformation of each successive tone set between the time and frequency domains and further responsive to the determination to contract the tone spacing by increasing the processing interval associated with the transformation of each successive tone set between the time and frequency domains; and at least one analog front end (AFE) coupled between the at least one subscriber line and the DSP and the at least one AFE configured to perform analog-to-digital and digital-to-analog conversion of the at least one multi-tone modulated communication channel at rates compatible with the processing interval of the Fourier transform module; whereby the range of frequencies spanned on the subscriber line between a lowest frequency one and a highest frequency one of the fixed number “N” of modulated tones of the at least one communication channel includes either a first range of frequencies associated with expanded spacing of each of the “N” tones and generally associated with a short subscriber line or a second, relatively narrower, range of frequencies associated with contracted spacing of each of the “N” tones and generally associated with a relatively long subscriber line.