Amplifier with filtering

摘要

Signals are processed to facilitate the mitigation and/or cancellation of undesirable components within the signal. As consistent with one or more embodiments, input/delay circuits offset the phase of an input signal, as presented to respective amplifiers. The phase offset is used, upon combination of the outputs of the respective amplifiers, to cancel the undesirable components of the signal. Such an approach may, for example, involve phase offset in a digital domain, with correction upon combination of the signals as presented in an analog domain.

主权项

1. An apparatus comprising:
a plurality of amplifiers, each amplifier having an input terminal and an output terminal; a plurality of capacitors respectively coupled to different ones of the output terminals of the plurality of amplifiers; an output circuit coupled to the capacitors and configured and arranged to combine the outputs of the amplifiers as passed via the capacitors onto a common output terminal; and an input circuit configured and arranged to
process an input signal to provide respective processed signals in which undesirable components in each processed signal are offset in phase relative to undesirable components in other ones of the processed signals,couple respective ones of the processed signals to different ones of the input terminals of the amplifiers, thereby cancelling the undesirable components of the input signal upon combination of the outputs of the amplifiers at the output circuit; and wherein the input circuit is configured and arranged to offset the phase of the undesirable components by respectively shifting successive ones of the processed signals with a constant time shift relative to the previous processed signal, rendering the phase shift proportional to frequency, thereby cancelling harmonics in the input signal upon combination of the outputs of the amplifiers at the output circuit.