Abstract: An apparatus comprises circuitry configured to generate a predicted error signal by applying to a digital signal a distortion model characterized by parameters configured to model circuit component mismatches in a digital-to-analog converter (DAC), circuitry configured to generate a pre-compensated digital signal using the digital signal and the predicted error signal, and circuitry configured to provide the pre-compensated digital signal to the DAC for conversion into an analog signal.

Abstract: An apparatus comprises circuitry configured to generate a predicted error signal by applying to a digital signal a distortion model characterized by parameters configured to model circuit component mismatches in a digital-to-analog converter (DAC), circuitry configured to generate a pre-compensated digital signal using the digital signal and the predicted error signal, and circuitry configured to provide the pre-compensated digital signal to the DAC for conversion into an analog signal.

Abstract: A digital-to-analog converter (DAC) comprises circuitry configured to generate, based on a mapping, L signals representing an N-bit digital input, wherein N and L are positive integers, and wherein N<L<2N?1, and circuitry configured to control current flow from L weighted current sources using the L respective signals, thereby generating an analog output that uniquely represents the N-bit digital input, wherein the weighted current sources have weights configured to minimize at least one error metric associated with the analog output.

Abstract: A digital-to-analog converter (DAC) comprises circuitry configured to generate, based on a mapping, L signals representing an N-bit digital input, wherein N and L are positive integers, and wherein N<L<2N?1, and circuitry configured to control current flow from L weighted current sources using the L respective signals, thereby generating an analog output that uniquely represents the N-bit digital input, wherein the weighted current sources have weights configured to minimize at least one error metric associated with the analog output.

Abstract: A receiver is configured to detect, at a communication interface, a received signal that suffers from degradations incurred over a communication channel. The receiver applies an adaptive filter to a series of received blocks of a digital representation of the received signal, thereby generating respective filtered blocks, where each received block represents 2N frequency bins, and where N is a positive integer. The receiver calculates coefficients for use by the adaptive filter on a jth received block as a function of (i) error estimates associated with an (j?D?1)th filtered block, where D is a positive integer representing a number of blocks, and where j is a positive integer greater than (D?1); and (ii) an inverse of an approximate covariance matrix associated with the (j?D?1)th received block, where the approximate covariance matrix is a diagonal matrix of size L×L, and where L is a positive integer lower than 2N.

Abstract: A receiver is configured to detect, at a communication interface, a received signal that suffers from degradations incurred over a communication channel. The receiver applies an adaptive filter to a series of received blocks of a digital representation of the received signal, thereby generating respective filtered blocks.

Abstract: An optical signal modulated with a stream of symbols comprising a sequence of training symbols is received at a receiver. First equalizer circuitry calculates and applies first coefficients to digital signals representative of the optical signal, thereby resulting in first compensated signals. Second equalizer circuitry calculates second coefficients based on a correlation between the first compensated signals and digital signals representative of the sequence of training symbols and applies the second coefficients to the first compensated signals, thereby resulting in second compensated signals. Third equalizer circuitry calculates and applies third coefficients to the second compensated signals, thereby resulting in third compensated signals. The first, second, and third coefficients compensate for impairments in the optical signal varying at respective first, second, and third rates, where the third rate is higher than the first rate and lower than the second rate.