Abstract: A device (500) and method (400) for zero-padding constellation switching with frame mapping provides reduced complexity for mapping frames having possibly a fractional number of bits and a predetermined number of symbols while eliminating the usual disadvantages of constellation switching.

Abstract: A device and method utilize a linear feedback/feedforward configuration to estimate and cancel a listener echo wherein equalizer (202) and listener echo cancellation (204 and 208) units are jointly updated, allowing determination of an error signal (204 and 208), in place of the former method of separate error signal determination for each of an equalizer and a listener echo canceller. An improved phase-correction scheme is utilized to compensate the frequency offset in the listener echo. The relationship between the listener echo and talker far echo is utilized to facilitate the listener echo cancellation.

Abstract: A device and method utilize a linear feedback/feedforward configuration to estimate and cancel a listener echo wherein equalizer (202) and listener echo cancellation (204 and 208) units are jointly updated, allowing determination of an error signal once (204 and 208), in place of the former method of separate error signal determination for each of an equalizer and a listener echo canceller. An improved phase-correction scheme is utilized to compensate the frequency offset in the listener echo. The relationship between the listener echo and talker far echo is utilized to facilitate the listener echo cancellation.

Abstract: An echo cancellation modem having a fast training echo canceller in which the echo cancellation coefficients are computed by taking correlations between a complex, periodic training signal sequence and a real component of the corresponding echo signal. The modem includes a receiver circuit for detecting a signal on a channel possibly including an echo; an echo canceller for estimating the real component of the echo signal; training circuitry for applying the complex training sequence to the channel and for taking correlations between the training sequence and the real component of the corresponding echo signal. The modem also includes a computational element for computing the period of the periodic sequence, generating the complex periodic train sequence in real time and for computing a phase roll frequency based upon the computed echo cancellation coefficients.