24. A voice activity detector, configured to detect voice activity in an audible signal by determining a normalized difference between first and second values generated from a candidate pitch associated with voiced sounds, the voice activity detector comprising: one or more audio sensors; a candidate pitch selection module configured to select the candidate pitch from a plurality of predetermined candidate pitches, wherein the plurality of predetermined candidate pitches are generated independent from the audible signal; a windowing module configured to generate a plurality of temporal frames of the audible signal, wherein each temporal frame includes a respective temporal portion of the audible signal; and a signal analysis module configured to generate a plurality of voice activity indicator values corresponding to the plurality of temporal frames of the audible signal, each voice activity indicator value being determined by a function of a respective first and second spectrum characterization values associated with one or more multiples of the candidate pitch.
29. The voice activity detector of claim 24 , wherein the signal analysis module is further configured to: calculate the respective first spectrum characterization value associated with a first plurality of frequencies in the respective temporal frame of the audible signal, each of the first plurality of frequencies being a multiple of the candidate pitch; and calculate the respective second spectrum characterization value associated with a second plurality of frequencies in the respective temporal frame of the audible signal, wherein each of one or more of the second plurality of frequencies is associated with a corresponding one of the first plurality of frequencies.