Version 4
SHEET 1 1032 700
WIRE 560 224 496 224
WIRE 592 224 560 224
WIRE 560 256 560 224
WIRE 288 272 224 272
WIRE 400 272 352 272
WIRE 496 272 496 224
WIRE 224 336 224 272
WIRE 240 336 224 336
WIRE 336 336 320 336
WIRE 400 336 400 272
WIRE 400 400 400 336
WIRE 400 400 368 400
WIRE 496 400 496 352
WIRE 496 400 400 400
WIRE 224 416 224 336
WIRE 224 416 192 416
WIRE 304 416 224 416
WIRE 400 432 368 432
WIRE 496 432 496 400
WIRE 560 432 560 400
WIRE 560 432 496 432
WIRE 400 464 400 432
WIRE 496 464 496 432
WIRE 496 576 496 544
FLAG 496 576 0
FLAG 400 432 Ref
FLAG 192 416 Err
IOPIN 192 416 Out
FLAG 592 224 Meas
IOPIN 592 224 In
FLAG 400 464 Ref
IOPIN 400 464 In
SYMBOL AmpSimp 336 352 M0
WINDOW 0 3 101 Left 2
WINDOW 39 0 -16 Invisible 2
WINDOW 40 0 8 Invisible 2
SYMATTR InstName UAmp
SYMBOL res 480 448 R0
SYMATTR InstName RLow
SYMATTR Value {RUpper}
SYMBOL res 512 368 R180
WINDOW 0 36 76 Left 2
WINDOW 3 28 120 Left 2
SYMATTR InstName RUp
SYMATTR Value {RUpper}
SYMBOL res 544 240 R0
SYMATTR InstName Rm
SYMATTR Value {RMarg}
SYMBOL cap 544 336 R0
SYMATTR InstName Cm
SYMATTR Value {CMarg}
SYMBOL res 336 320 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName Rs
SYMATTR Value {Rk}
SYMBOL cap 400 320 R90
WINDOW 0 0 32 VBottom 2
WINDOW 3 32 32 VTop 2
SYMATTR InstName Cs
SYMATTR Value {Ci}
SYMBOL cap 352 256 R90
WINDOW 0 0 32 VBottom 2
WINDOW 3 32 32 VTop 2
SYMATTR InstName Cp
SYMATTR Value {Cn}
TEXT -72 488 Left 2 !.Param RUpper=10k fc=5k\n.Param  pm=50 Gfc=-2.9 pfc=-150\n* Feedback parameters\n.Param G=10**(-Gfc/20) Boost=pm-pfc-90\n.Param K=(tan((Boost/4+45)*pi/180))**2\n.Param CMarg=1/(2*pi*fc*sqrt(k)*RMarg)\n.Param Cn=1/(2*pi*fc*G*RUpper) Ci=Cn*(K-1)\n.Param Rk=sqrt(k)/(2*pi*fc*Ci) RMarg=RUpper/(K-1)