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I build according to the block diagram, where I am only allowed to use integrator, summing amplifier and inverting-buffer. I build accordingly with the block diagram that I got but *I am not sure what did I do wrong and why it did not come out with the expected result below I check all my calculation multiple times which I am pretty sure it is correct, so now I am not sure what's wrong with the circuit design and how do I solve this.

Original Transfer Fucntion

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Expecting Result

 Expected Result

Block Diagram enter image description here

Design Circuitry In LTSPICE enter image description here

LTSPICE Simulation Result enter image description here

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    \$\begingroup\$ Look at the way U3 is connected, that does not make sense to me. \$\endgroup\$ Nov 27, 2019 at 14:20
  • \$\begingroup\$ @Bimpelrekkie Hm how so I can't tell :/ \$\endgroup\$
    – tw.C4444
    Nov 27, 2019 at 14:21
  • \$\begingroup\$ If you don't see how that is wrong then how can you translate a block schematic into an opamp schematic? OK, Suppose U1 outputs 1 Volt, what will U3 do? \$\endgroup\$ Nov 27, 2019 at 14:23
  • \$\begingroup\$ Invert the 1 Volt to -1Volt? \$\endgroup\$
    – tw.C4444
    Nov 27, 2019 at 14:28
  • \$\begingroup\$ You're obviously just guessing, look up "inverting amplifier opamp" and see what circuits you get and compare to what you used. \$\endgroup\$ Nov 27, 2019 at 14:38

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Hmm I think your problem is that your overall feedback is positive. What you should have done is make a difference between your control and feedback signals so that the error is fed to the rest of the circuit.

Below is a quick and dirty adaptation to show you how the control and feedback should have been implemented, to get stability.

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