Hi, few days ago I measured the output of my circuit and it seems well. But today the waves become strange. I try to solve it but I don't know how to do. Please help me

 

Which waveforms do you consider "strange"?
Are all those waveforms from the same output?

 

hi YYY,
Please post your latest LTSpice asc file.
E

 

There seems to be a problem with ill-defined FET source voltages.
The FET gate-source voltages are insufficient to allow any useful gain. FET drain currents are only a few nA.

 

A description of what that circuit is supposed to do will be useful for any evaluation. As I examine that circuit from post#1 it is not clear to me what the circuit is supposed to be doing. So an explanation would be quite useful.
In addition, there are several portions of the circuit that appear to be susceptible to noise pickup..