Hi! This is my first post, so I'll try to keep this brief as possible.
I have a small (~uV or lower) square wave signal (f~500Hz) which is on top of a much larger DC voltage (~50mV). I need to determine the amplitude of the square wave signal to high accuracy as part of my experiment.
Currently I am using a lock-in amplifier, which works well for strong signals (~uV). However the signal becomes undetectable below around 100nV. I have a DC amplifier (adjustable 100x to 100,000x gain) to amplify to the signal before I put it into the lock-in, however because of the large DC offset (~50mV) it overloads immediately.
So the question is: What is the best way to remove the background DC voltage without affecting the amplitude of the 500Hz signal? I have a very low-ripple computer controllable voltage source available. So if I measure the offset to be 50mV I can for example set it to output -50mV. I just do not know the correct way to apply the offset to the signal
Because of the low frequency of the signal, I guess a low-pass filter is not really an option here?
Thanks in advance!
I have a small (~uV or lower) square wave signal (f~500Hz) which is on top of a much larger DC voltage (~50mV). I need to determine the amplitude of the square wave signal to high accuracy as part of my experiment.
Currently I am using a lock-in amplifier, which works well for strong signals (~uV). However the signal becomes undetectable below around 100nV. I have a DC amplifier (adjustable 100x to 100,000x gain) to amplify to the signal before I put it into the lock-in, however because of the large DC offset (~50mV) it overloads immediately.
So the question is: What is the best way to remove the background DC voltage without affecting the amplitude of the 500Hz signal? I have a very low-ripple computer controllable voltage source available. So if I measure the offset to be 50mV I can for example set it to output -50mV. I just do not know the correct way to apply the offset to the signal
Because of the low frequency of the signal, I guess a low-pass filter is not really an option here?
Thanks in advance!