Sequencing scheme for reducing low frequency tone generation in an analogue output signal

摘要

A noise cancellation circuit for use with a digital signal includes a plurality of equally weighted cells (53) for providing an analogue output signal (35) in dependence upon the value of the digital signal. A switching arrangement (51) dynamically switches a number of the plurality of cells according to a sequencing scheme, which comprises a first sequence arranged to switch each of the plurality of cells (53) an equal number of times, and a second sequence arranged to define one of the plurality of cells (53) as a starting position for the first sequence. In this way low frequency tone generation within the analogue output signal is substantially eliminated.