Method and apparatus for suppressing tones induced by cyclic dynamic element matching (DEM) algorithms

A method for performing Dynamic Element Matching, comprising:

• inputting a plurality of digital values and, for each value, generating a plurality of N signals individual ones of which are intended to drive one of a plurality of N elements, the plurality of signals being generated so as to average the usage of individual ones of the N elements over time and to convert mismatches between the individual ones of the N elements to wide-band noise;
• and
• periodically randomizing the plurality of signals so as to suppress the generation of undesired tones in the wide-band noise, without affecting the averaging of the usage of the N elements.

Dynamic Element Matching (DEM) apparatus, comprising:

• a first DEM block having an input for receiving a plurality of digital values and an output that expresses, for each value, a plurality of N signals individual ones of which are intended to drive one of a plurality of N elements, the plurality of signals being generated in accordance with a first DEM algorithm so as to average the usage of individual ones of the N elements over time;
• and
• a second DEM block having an input coupled to said output of said first DEM block, said second DEM block operating in accordance with a second DEM algorithm to periodically rearrange the plurality of N signals so as to suppress the generation of undesired periodicities in the usage of the N elements, without affecting the averaging of the usage of the N elements.