ational ▁environment ▁of ▁these ▁systems ▁contains ▁a ▁mix ▁of ▁other ▁ac oust ic ▁sources ; ▁external ▁no ises ▁as ▁well ▁as ▁ac oust ic ▁cou pl ings ▁of ▁loud spe aker ▁signals ▁over wh elm ▁and ▁at ten uate ▁the ▁desired ▁speech ▁signal . ▁In ▁addition ▁to ▁these ▁external ▁sources , ▁the ▁strength ▁of ▁the ▁desired ▁signal ▁is ▁reduced ▁due ▁to ▁the ▁relatively ▁distance ▁between ▁speaker ▁and ▁micro ph ones . ▁Array ▁processing ▁techniques ▁have ▁opened ▁new ▁opportun ities ▁in ▁speech ▁processing ▁to ▁at ten uate ▁noise ▁and ▁echo ▁without ▁de grad ing ▁the ▁quality ▁of ▁and ▁affect ing ▁advers ely ▁the ▁speech ▁signal . ▁In ▁general ▁array ▁processing ▁techniques ▁can ▁be ▁used ▁in ▁speech ▁processing ▁to ▁reduce ▁the ▁computing ▁power ▁( number ▁of ▁comput ations ) ▁and ▁enh ance ▁the ▁quality ▁of ▁the ▁system ▁( the ▁performance ). ▁Represent ing ▁the ▁signal ▁as ▁a ▁sum ▁of ▁sub - b ands ▁and ▁adapt ing ▁can cellation ▁filters ▁for ▁the ▁sub - band ▁signals ▁can ▁reduce ▁the ▁demanded ▁computation ▁power ▁and ▁lead ▁to ▁a ▁higher ▁performance ▁system . ▁R ely ing ▁on ▁multiple ▁input ▁channels ▁allows ▁design ing ▁systems ▁of ▁higher ▁quality ▁comparing ▁to ▁systems ▁that ▁use ▁single ▁channel ▁and ▁solving ▁problems ▁such ▁as ▁source ▁local ization , ▁tracking ▁and ▁separation , ▁which ▁cannot ▁be ▁achieved ▁in ▁case ▁of ▁using ▁single ▁channel . ▁▁ ▁Array ▁Process ing ▁in ▁Astronom y ▁App lications ▁Astronom ical ▁environment ▁contains ▁a ▁mix ▁of ▁external ▁signals ▁and ▁no ises ▁that ▁affect ▁the ▁quality ▁of ▁the ▁desired ▁signals . ▁Most