problem with signal

Thread Starter


Joined Mar 1, 2009
Hi i am working on a project which is based on lock in amplification. Basically the main part of the design is the phase sensitive detection where demodulation(multiplication) of two signals takes place. For my project I have to extract a very weak signal buried in large noise. In the demodulator stage, it works fine if i just multiply a simple sine wave and a square wave havin da same phase as it provides me fully rectified signal. But if I add the noise signal with the sin wave and then perform the demodulation step, the output does not turn out to be fully rectified signal. I have tried lookin at all the specs but I cant figure out whats wrong with the procedure. Can anyone please please help me out with this ?? I will really appreaciate the help :)


Joined Nov 20, 2005
You may try the same approach for the noise and the results will be the noise dc then think of what can you do with that.