amplifier Micro signal to control

[river78]

I have to design a circuit which amplify micro signal and compare it which a potential to find out the signal to control motor. I have used TL084 to amplify, but it has a lot of noise, so have some one help me the better circuit

 

[dengreyes]

Maybe you should use a filter after the amplifier stage to get only the frequency of signal you are interested with. Where do this signal come from anyway.

 

[sunking]

use a low noise opa

 

[dengreyes]

A better one is low noise amplifier together with a filter. by the way where do this signal come from

 

[fatwolfning]

I met the same problem before,Do you consider the arrangement of the ground?