▁rad ians . ▁ ▁The ▁frequency ▁axes ▁are ▁in ▁a ▁[ log arith mic ▁scale ]. ▁ ▁These ▁are ▁useful ▁because ▁for ▁sin us oid al ▁inputs , ▁the ▁output ▁is ▁the ▁input ▁multip lied ▁by ▁the ▁value ▁of ▁the ▁magnitude ▁plot ▁at ▁the ▁frequency ▁and ▁shift ed ▁by ▁the ▁value ▁of ▁the ▁phase ▁plot ▁at ▁the ▁frequency . ▁ ▁Dom ains ▁ ▁Time ▁domain ▁This ▁is ▁the ▁domain ▁that ▁most ▁people ▁are ▁familiar ▁with . ▁ ▁A ▁plot ▁in ▁the ▁time ▁domain ▁shows ▁the ▁amplitude ▁of ▁the ▁signal ▁with ▁respect ▁to ▁time . ▁ ▁Fre quency ▁domain ▁A ▁plot ▁in ▁the ▁frequency ▁domain ▁shows ▁either ▁the ▁phase ▁shift ▁or ▁magnitude ▁of ▁a ▁signal ▁at ▁each ▁frequency ▁that ▁it ▁exists ▁at . ▁ ▁These ▁can ▁be ▁found ▁by ▁taking ▁the ▁Fourier ▁transform ▁of ▁a ▁time ▁signal ▁and ▁are ▁pl otted ▁similarly ▁to ▁a ▁b ode ▁plot . ▁ ▁Sign als ▁While ▁any ▁signal ▁can ▁be ▁used ▁in ▁analog ▁signal ▁processing , ▁there ▁are ▁many ▁types ▁of ▁signals ▁that ▁are ▁used ▁very ▁frequently . ▁ ▁Sin us oid s ▁Sin us oid s ▁are ▁the ▁building ▁block ▁of ▁analog ▁signal ▁processing . ▁All ▁real ▁world ▁signals ▁can ▁be ▁represented ▁as ▁an ▁infinite ▁sum ▁of ▁sin us oid al ▁functions ▁via ▁a ▁Fourier ▁series . ▁ ▁A ▁sin us oid al ▁function ▁can ▁be ▁represented ▁in ▁terms ▁of ▁an ▁exponential ▁by ▁the ▁application ▁of ▁E uler ' s ▁Formula . ▁ ▁Imp ulse ▁An ▁imp ulse ▁( Di rac ▁delta ▁function ) ▁is ▁defined ▁as