Version 4
SHEET 1 2168 680
WIRE 144 -32 -176 -32
WIRE 640 -32 560 -32
WIRE 736 -32 640 -32
WIRE 1168 -32 1088 -32
WIRE 1200 -32 1168 -32
WIRE 144 80 144 -32
WIRE 144 80 32 80
WIRE 240 80 144 80
WIRE 32 112 32 80
WIRE 240 112 240 80
WIRE -176 160 -176 -32
WIRE 464 176 384 176
WIRE 560 176 560 -32
WIRE 1088 176 1088 -32
WIRE 240 208 240 192
WIRE 384 208 384 176
WIRE 384 208 240 208
WIRE 1600 208 1472 208
WIRE 1808 208 1680 208
WIRE 32 224 32 192
WIRE 112 224 32 224
WIRE 384 224 192 224
WIRE 32 240 32 224
WIRE 240 240 240 208
WIRE 384 256 384 224
WIRE 464 256 384 256
WIRE 1808 320 1808 208
WIRE 32 352 32 320
WIRE 144 352 32 352
WIRE 240 352 240 320
WIRE 240 352 144 352
WIRE -176 448 -176 240
WIRE 144 448 144 352
WIRE 144 448 -176 448
WIRE 1808 480 1808 384
WIRE 144 496 144 448
WIRE 560 496 560 256
WIRE 1088 496 1088 256
FLAG 144 496 0
FLAG 464 176 U1
FLAG 464 256 U2
FLAG 560 496 0
FLAG -176 -32 ref
FLAG 640 -32 DiffOut
FLAG 1088 496 0
FLAG 1168 -32 MixOut
FLAG 1808 480 0
FLAG 1472 208 MixOut
SYMBOL res 16 96 R0
SYMATTR InstName R1
SYMATTR Value 1001
SYMBOL res 16 224 R0
SYMATTR InstName R2
SYMATTR Value 999
SYMBOL res 224 224 R0
SYMATTR InstName R3
SYMATTR Value 1001
SYMBOL res 224 96 R0
SYMATTR InstName R4
SYMATTR Value 999
SYMBOL voltage -176 144 R0
WINDOW 123 0 0 Left 2
WINDOW 39 0 0 Left 2
SYMATTR InstName V1
SYMATTR Value SINE(0 1 50k)
SYMBOL bv 560 160 R0
SYMATTR InstName B1
SYMATTR Value V=10*(V(U1)-V(U2))
SYMBOL bv 1088 160 R0
SYMATTR InstName B2
SYMATTR Value V=V(ref)*V(DiffOut)
SYMBOL res 1696 192 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R5
SYMATTR Value 10k
SYMBOL cap 1792 320 R0
SYMATTR InstName C1
SYMATTR Value 100n
SYMBOL voltage 208 224 R90
WINDOW 3 -239 11 Left 2
WINDOW 123 0 0 Left 2
WINDOW 39 0 0 Left 2
SYMATTR InstName V2
SYMATTR Value SINE(0 10m 50)
TEXT -482 6 Left 2 !.tran 0 100m 0 100n