I built the circuit for simulating the all-pass filter by using optocouplers. But I don't know why its frequency response differs so much from the same but with the resistors instead of the optocouplers.

 

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Welcome to AAC!
A quick scan of your .zip file shows no problems but you should know that most members, including me, will NOT open a .zip file due to security concerns. Please post files in their native format.
Good luck!

I can't post it, because file's format is unallowed here. So I can post images:
Img.1 - two circuits(the higher one is the circuit we want to work as an all-pass filter, the bottom one is with resistors instead of optocouplers)

Img.1 - two circuits(the higher one is the circuit we want to work as an all-pass filter, the bottom one is with resistors instead of optocouplers)

Img.2 - the frequency response of the circuit with the resistors and the response which we like

Img.3 - the frequency response of the circuit with optocouplers instead of the resistors. In theory it shouldlook exactly like the Img.2
Img.4 - the characteristics of the operational amplifiers I use. I thought it might be the reason for this difference, I know it's not right but still.

If I must post something else, please tell me. I'll do it.

 

Hello,

The PC817 optocoupler will not create a linear resistor.
Better use an optocoupler with a fet as output, like the H11F1.

Bertus

 

Hello,

The PC817 optocoupler will not create a linear resistor.
Better use an optocoupler with a fet as output, like the H11F1.

Bertus

What if I don't have H11F1 in Proteus, can I interchange it with some another linear optocoupler? Or can I download a package for Proteus with it?

 

Hello,

This page of mouser shows a list of fet output optocouplers.
https://eu.mouser.com/Optoelectroni...OSFET-Output-Optocouplers/_/N-awss6?P=1yocruu

Bertus

 

Hello,

This page of mouser shows a list of fet output optocouplers.
https://eu.mouser.com/Optoelectroni...OSFET-Output-Optocouplers/_/N-awss6?P=1yocruu

Bertus

Is there a way to download it still?

 

Hello,

Perhaps someone on the EEVBLOG forum in the proteus section or the Labcenter forum might have an answer:
https://www.eevblog.com/forum/proteus/
https://support.labcenter.com/forums/

Bertus