Dumitru Stama wrote:
> I attached the updated schematics.

So you made it AC coupled and increased the input impedence.  That's better,
but there are still problems.

1 - There should be a cap to ground from the node between R1 and R2.
Otherwise any supply noise and anything that node picks up is going to end
up on the signal.  There should be at least a 100nF ceramic, and maybe a
10uF electrolytic too.  A single 1uF ceramic is probably good enough.

2 - You didn't look up the supply requirements of the TL072 like I said to,
did you?  I can't get the TI web site right now for some reason, but I'm
pretty sure 5V isn't enough.  You have also ignored what I said about supply
headroom.


******************************************************************
Embed Inc, Littleton Massachusetts, (978) 742-9014.  #1 PIC
consultant in 2004 program year.  http://www.embedinc.com/products
-- 
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist