The Use of feedback to Compensate for nonidealities () K P(s) G(s) Assume kPO is very large over the frequency range of interest In fact assume KP(j)G(0)>>1 Qiu) Y(jw kP(w) X u) 1+kPlwG(w G(jw Independent of P(s)!!
The Use of Feedback to Compensate for Nonidealities Assume KP (j ω) is very large over the frequency range of interest. In fact, assume — Independent of P(s)!!
Example of Reduced Sensitivity IThe use of operational amplifiers 2)Decreasing amplifier gain sensitivity Example (a) Suppose KP(O)=1000,G(j01)=0.099 1000 Q(O1) =10 1+(1000.099 (b)Suppose KP(@))=500, G(@))=0.099 (50% gain change) 500 Q(02)= =9.9(1% gain change) 1+(500(0.099
Example of Reduced Sensitivity 10 1 (1000)( 0 099 ) 1000 ( ) ( ) 1000 ( ) 0 099 1 1 1 = + = = = . Q j KP j , G j . ω ω ω 1)The use of operational amplifiers 2)Decreasing amplifier gain sensitivity Example: (a) Suppose (b) Suppose (50% gain change) 9 9 1 (500)( 0 099 ) 500 ( ) ( ) 500 ( ) 0 099 2 2 2 . . Q j KP j , G j . ≅ + = = = ω ω ω (1% gain change)