In some embodiments, an adaptive filter employs two adaptation modes, where during one adaptation mode the adaptive filter is updated only when the received training sample is a first binary value and during the other adaptation mode the adaptive filter is updated only when the received sample is a second binary value. Each adaptation mode provides a set of filter weights, and these two sets of filter weights are averaged to provide an adapted set of filter weights. The use of two adaptation mode allows for a clock boundary in which the digital portion of the filter operates at a lower clock rate than the analog portion. In other embodiments, a filter architecture is described for providing the algebraic signs of the received data samples, important for sign-sign least means square filtering algorithms. In other embodiments, a filter architecture is described in which efficient use is made of voltage-to-current converters so as to achieve a high throughput rate during filtering. Embodiments of the present invention have application to channel equalization.