On 3.12.14 03:17, Phil Allison wrote:
There must be smoething fishy with the resonator, as well. There is a very broad peak with very low gain.
I guess that the OP has been looking for something like:
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Version 4 SHEET 1 1116 680 WIRE 720 32 -144 32 WIRE 880 32 800 32 WIRE 144 128 80 128 WIRE 288 128 208 128 WIRE 592 128 288 128 WIRE 720 128 592 128 WIRE 880 128 880 32 WIRE 880 128 800 128 WIRE 944 128 880 128 WIRE 288 160 288 128 WIRE 560 208 448 208 WIRE 448 256 448 208 WIRE -144 272 -144 32 WIRE -80 272 -144 272 WIRE 80 272 80 128 WIRE 80 272 0 272 WIRE 144 272 80 272 WIRE 288 272 288 240 WIRE 288 272 208 272 WIRE 400 272 288 272 WIRE 592 288 592 128 WIRE 592 288 464 288 WIRE 944 288 592 288 WIRE 400 304 336 304 WIRE -144 352 -144 272 WIRE 80 352 80 272 WIRE 432 368 432 320 WIRE 560 368 560 208 WIRE -144 496 -144 432 WIRE 80 496 80 432 WIRE 336 496 336 304 WIRE 432 496 432 448 WIRE 560 496 560 448 FLAG -144 496 0 FLAG 80 496 0 FLAG 336 496 0 FLAG 560 496 0 FLAG 432 496 0 FLAG 944 288 Peak IOPIN 944 288 Out FLAG 944 128 Notch IOPIN 944 128 Out SYMBOL voltage -144 336 R0 SYMATTR InstName V1 SYMATTR Value 0 SYMATTR Value2 AC 1 SYMATTR SpiceLine Rser=0 SYMBOL voltage 560 352 R0 SYMATTR InstName V2 SYMATTR Value 10 SYMBOL voltage 432 464 R180 WINDOW 0 24 96 Left 2 WINDOW 3 24 16 Left 2 SYMATTR InstName V3 SYMATTR Value 10 SYMBOL res 16 256 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R1 SYMATTR Value 47k SYMBOL res 96 448 R180 WINDOW 0 36 76 Left 2 WINDOW 3 36 40 Left 2 SYMATTR InstName R2 SYMATTR Value 2.2k SYMBOL res 304 256 R180 WINDOW 0 36 76 Left 2 WINDOW 3 36 40 Left 2 SYMATTR InstName R3 SYMATTR Value 100k SYMBOL cap 208 256 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C1
SYMBOL cap 208 112 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C2
SYMBOL Opamps/LM308 432 224 R0 SYMATTR InstName U1 SYMBOL res 816 112 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R4 SYMATTR Value 10k SYMBOL res 816 16 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R5 SYMATTR Value 10k TEXT -152 576 Left 2 !.ac oct 16 1 1000
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The circuit is pretty sensitive to component tolerances. A state- variable filter would be a better choice.
There is a strong twist of phase around the notch frequency, as usual for single-resonator notches.