Patent ID: 8705676

Claim:
A multi-tone transceiver with a plurality of components forming a transmit path and a receive path configured to couple via a subscriber line to an opposing multi-tone transceiver for frequency division multiplexed multi-tone modulated communications therewith; and the multi-tone transceiver comprising: a transform component on the receive path to transform in each successive symbol interval received communications from a time domain to a frequency domain into individual tones or sub-channels; a tone selector coupled to the transform component to select a sub-set comprising less than all of the individual tones which exhibit an elevated signal-to-noise ratio (SNR) as a clock recovery tone set (CRTS) and to dynamically drop and add tones to the CRTS in successive symbol intervals as required by changes in the SNR of the individual tones, such that a plurality of different CRTS tones are selected in successive symbol intervals during a showtime phase of operation; an error detector coupled to the tone selector to detect phase errors in each tone of the respective CRTS; an aggregator coupled to the error detector to calculate an average aggregate phase error from all tones in the respective CRTS; an oscillator coupled to transmit and receive path components to control clocking thereof and the oscillator responsive to the average aggregate phase error calculated by the aggregator to adjust a clock phase in a direction which reduces a phase error with a clock on the opposing transceiver, thereby maintaining synchronous operation with the opposing multi-tone transceiver by dynamically re-selecting CRTS tones responsive to changes in SNR in successive symbol intervals during a showtime phase of operation.